Sem 1 Notes PDF

+ In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Lesson 1- The human body Human body- hierarchically organized, complex, homeostatic self-regulating unit Hierarchically organized- chemical level (atoms-molecules- macromolecules; proteins, carbohydrates, nuc...

+ In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Lesson 1- The human body Human body- hierarchically organized, complex, homeostatic self-regulating unit Hierarchically organized- chemical level (atoms-molecules- macromolecules; proteins, carbohydrates, nucleic acids and lipids)-organelles-cells-tissues (epithelial, connective, muscular, nerve)-organs-organ systems-organism Complex-trillion of cells-200 different types-maintain normal structure/function-integrated function Homeostatic- requires homeostasis to be achieved for efficient life. Cells- simplest structural and functional unit of life- structure reflects function although most cells contain the basic organelles etc. Cells are the smallest unit of life- anything smaller than a cell isn’t considered living in Organs- Composed of at least 2 tissue types (epithelium, muscular, nerve, connective tissue) Body systems-integrated set of body systems- integumentary, skeletal, muscular, nervous, respiratory, cardiovascular, endocrine, lymphatic, digestive, urinary, reproductive Organ systems=DRUNC SMILER Integumentary, skeletal, muscular, cardio, resp., repro., endocrine, lymphatics, nervous, urinary Integumentary system- maintains body temperature- contains receptors on surface- protects body from foreign external substances/External covering/protection Muscular, integumentary etc. maintains temp. Integumentary o external coverings of the body o protection/cushions the body o maintains boundaries between the internal environment, and the external environment o excretes urea/salts in perspiration o contains receptors on surface e.g. thermal receptors o chemical, physical and biological barrier o protection from external substances o maintaining boundaries  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + o thermal regulation- role of sweat and controlling vasodilation/vasoconstriction of peripheral blood vessels o dessication resistance o skin, hair, nails Skeletal o provides the structural framework of the body o protects organs e.g. ribs protect lungs, skull protects brain o aids movement-muscle attach to the bones via tendons and when the muscle contract/relax, this facilitates movement of the bones and hence movement of limbs o formation of blood cells (hematopoiesis) also takes part in the bones o storage of Ca2+ o bones (long- length is greater than width- contains , short, flat, pneumatic, sesamoid, irregular), cartilage, ligaments, joints Muscular o allows for contraction/relaxation (shortening) o aids movement along with the skeletal system o if an individual is hypothermic, shivering is the vibration of muscles to produce heat o consist of excitable tissues o excitability, contractility, elasticity, extensibility of muscle tissues o skeletal, cardiac, smooth muscle cells Nervous o control system o controls responses to stimuli o sensory receptors detect the stimuli, and then send message via nerve impulses to the nervous system to request a response o Central nervous system- Brain and spinal cord- integration and control o Peripheral nervous system- cranial and spinal nerves- input and output o Homeostasis- fast mechanism used to maintain homeostasis- fast onset but short duration of action o Activates body o brain, spinal cord, nerves, sensory receptors (sensory nerves, motor neurons, interneurons) Endocrine o releases chemical molecules (HORMONES) into the blood so that it may reach all the parts of the body through the blood vessels  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + o used for homeostasis- slower than nervous system- slow onset but prolonged action o maintains body growth, development etc. o Hypothalamo pituitary axis- pituitary glands, thyroid, parathyroid, pancreas, ovaries, testes, adrenals (situated on top of kidney- releases hormone adrenaline from the adrenal medulla and cortisol from the adrenal cortex), thymus Cardiovascular o transportation of fluid, nutrients, hormones and oxygen to the different sites of the body via the blood. o heart, blood vessels- veins, arteries – STRUCTURE vs FUNCTION regarding the thickness of blood vessel walls- elastic/muscular arteries, arterioles, capillaries (continuous, fenestrated, sinusoidal), venules, medium/large sized veins o Primary role is to maintain unidirectional flow of blood throughout the body—and (important but not as important), is to transport nutrients, gases etc. to the body. Lymphatic o purpose is to return any liquid which has been leaked out back into the blood vessels 2 pressures; hydrostatic pressure of water, and osmotic pressure back into the blood vessels- hydrostatic > osmotic pressure- therefore results in fluid loss which is leaked into the lymph, and then back into the blood vessels o allows for the blood to continue its cycle around the body o also assists in cleansing the blood- removes any cell debris etc. o contains white blood cells for immunity- when the white blood cells are needed, they are released into the bloodstream to move to the required location. o location is close to blood vessels in order to release white blood cells when required o lymphatic vessels, lymph nodes, lymphoid organs- spleen, tonsils Respiratory o Acid/base balance, obtaining o2, exhaling Co2 o supplies the body with the intake of oxygen that it requires and the release of carbon dioxide o if this exchange isn’t sufficient, the CO2 will increase and based on buffer systems in blood, will eventually stop operating- concentration of hydrogen ions increase, therefore pH decreases- blood becomes more acidic- normal ranges 7.35-7.45 o internal and external respiration, protection of respiratory surfaces, facilitates smell, acid base balance  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + o lungs, nasal cavity/passages, pharynx, larynx, trachea, bronchi, alveoli, pleural cavities, diaphragm Digestive o break down of food to obtain the necessary vitamins, nutrients and liquid o reclaims water o undigested food is excreted o oral cavity, salivary glands, small/large intestines, rectum, liver, pancreas, o role of large intestine-reclaim water Urinary/excretory o release of any waste products- nitrogen based wastes from the blood o (body also excretes other substances. E.g. CO2, faeces) o maintains a balance of water and salts present in the blood o kidneys, urethra, ureters, urinary bladder Reproductive o production of offspring o ovaries, uterus, vagina- scrotum, penis, accessory glands, duct system o Female; ovaries, fallopian tubes, uterus, cervix, vagina o Male; testis-seminiferous tubules, epididymus, vas deferens/ductus deferens, urinary bladder, prostate, bulbo-urethral gland, seminal vesicles, urethra, penis Maintaining boundaries (integumentary system), movement (skeletal and muscular system), responsiveness (nervous system), growth, excretion (urinary, respiratory), metabolism, digestion (digestive system), reproduction (reproductive system) Maintaining Life-Necessary functions of life- a cell is considered the basic unit of life not only because it contains the basic genetic material for that person, but also because it carries out functions which are nearly a replica of the processes required to maintain life. Maintains boundaries- plasma membrane is a phospholipid bilayer which separates the internal environment from the external environment. Integumentary system Membrane bound organelles- important- lysosomes contain a digestive enzyme which is able to digest any foreign substances Growth- growth of cell- intake of nutrients etc will allow the cell to grow in size, and thus the organism will consequently grow as well  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Responsiveness- receptors found on the surface of the plasma membrane are able to detect any changes and facilitate a response. The nucleus is the control center and thus sends out signals to the different components of the cell activating their function. Digestion- this is facilitated by the smooth endoplasmic reticulum (responsible for digestion of drugs), lysosomes and peroxisomes. Peroxisomes are used in detoxification of free radicals which are able to interfere with the process of protein production and DNA. Peroxisomes converts the free radicals into hydrogen peroxide, and then through the use of catalase will change the hydrogen peroxide into water molecules. Lysosomes consist of the enzyme lysozyme which breaks down any matter- digestion- these organelles are abundant in phagocytes- they also contain a membrane- conceals the digestive enzymes Reproduction- mitosis occurs at a cellular level Metabolism- all the anabolic and catabolic processes that occur in the body/cell. Movement- centrioles facilitate movement- produces mitotic spindles during the process of mitosis Excretion- excretion via the plasma membrane- exocytosis Organelles- plasma membrane, nucleus, endoplasmic reticulum, golgi apparatus, centrioles, mitochondria, peroxisomes, lysosomes, ribosomes ❖ Membranous- plasma membrane, nucleus, endoplasmic reticulum, lysosomes, peroxisomes, mitochondria, Golgi apparatus ❖ Non-membranous- cytosol, ribosomes, centrioles Nucleus- ❖ the control center of the cell-provides instructions for the entire cell- contains the genetic material DNA in the form of chromosomes. To check whether a cell is active or not, check the nucleus- if the chromosomes are decondensed, then it is an active cell because the DNA is readily accessible. If the chromosomes are condensed, then the cell is not active. ❖ contains;  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + o nucleolus- dense body present in the nucleus- ribosome production- composed of ribosomal RNA and proteins. o nuclear envelope (double membrane)- separates the internal area of the nucleus from the exterior section- this membrane is also selectively permeable to allow substances to enter and exit the nucleus- substances must be carried in the nucleus via filaments- they must be recognised then carried in- Contains fluid within the bilayer, and at certain points, the membrane begins to fuse and pores begin to generate there, and allows substances to enter and exit the nucleus- substances must be carried into the nucleus through these pores o chromatin- DNA combined with protein Endoplasmic reticulum- (smooth/rough) ❖ Interconnected series of fluid filled cavities ❖ Carries substances to different parts of the body-usually found close to the nucleus ❖ Smooth- contains no ribosomes on the surface- purpose; production of calcium ions, lipid metabolism- breakdown of fats – drug detoxification, lipid and steroid synthesis--- in muscle stores ca2+ ❖ Rough- contains ribosomes on the surface of the structure- usually proteins required for the plasma membrane is synthesized here – or if they are going to be excreted out from the cell Rough endoplasmic reticulum- consists of ribosomes on the surface- ribosomes produce proteins which are then taken by the endoplasmic reticulum to form a 3D structure. This is then transported to the Golgi apparatus via transport vesicles where the proteins accumulate in the sacs. These then swell and dispatch form the Golgi apparatus and travel to the plasma membrane- at the plasma membrane, that region may rupture and the proteins may be excreted from the cell, or be used by the membrane. Ribosomes- ❖ Made of proteins and ribosomal RNA ❖ Do not have a membrane, but have a large and small ribosomal subunit. ❖ Site for protein synthesis- translation ❖ Found on endoplasmic reticulum (rough) and in cytoplasm in a state of free float Prokaryotes- larger ribosomal subunit- 50S/small- 30S total=70S Eukaryotes- larger ribosomal subunit – 60S/small- 40S total= 80S  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Golgi apparatus ❖ Organizes transport out of the cell ❖ Modifies and transports proteins ❖ The ends of the Golgi apparatus swell and detach to form secretory vesicles- travel to membrane and secrete the substance Mitochondria ❖ Double membrane; o External membrane o Folded internal membrane which increases the surface area – cristae- contains enzymes which catalyse the reactions ❖ Oxygen used to break down food- energy is released ❖ Contains a specific DNA for its particular structure= mitochondrial DNA- therefore mitochondria has its own way of replication. Lysosomes- contains lysozymes which breaks down foreign matter- digestive Phagocytes contains lysosomes- immunity- engulfs bacteria and other foreign substances Phagocyte approaches bacteria- and surrounds and engulfs the bacteria. Once engulfed, the lysosome will then release lysozyme which destroys both the bacteria and the phagocyte. Out of the 5 types of white blood cells, 3 of them contain the properties of phagocytes. Peroxisomes- contains powerful oxidase enzymes- use molecular oxygen to detoxify harmful substances ❖ Able to disarm dangerous free radicals= highly reactive chemicals with an unpaired electron which can affect the structure of nucleic acids, and proteins- they are by-products of metabolism, but if they accumulate, may affect the cell ❖ Convert free radicals to hydrogen peroxide ❖ Catalase then converts the hydrogen peroxide into water and oxygen ❖ Abundant in liver/kidney  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ Replicate by themselves by splitting in two- sometimes they bud off the endoplasmic Cytoplasm- material between plasma membrane and nucleus- includes organelles, inclusions and cell fluid (cytosol) Cytosol- cell fluid- water with dissolved substances Cytoplasmic organelles- miniaturized organs which are found in the cell- carry out different functions Membranous- nucleus, mitochondria, endoplasmic reticulum, peroxisomes, lysosomes, endoplasmic reticulum, golgi apparatus Ribosomes- some are found floating in the cytosol and others are attached to the endoplasmic reticulum- those found in the cytosol- are sites for protein synthesis Those around endoplasmic reticulum excretes substances out of cells reticulum Non-membranous- cytoskeleton, centrioles, ribosomes Inclusions- chemical substances e.g. lipid droplets Plasma membrane- ❖ selectively permeable phospholipid bilayer which contains embedded proteins ❖ Separates the intracellular fluid from the extracellular fluid but still allows substances to enter and exit the cell through the use of the embedded proteins ❖ Fragile and transparent barrier ❖ Cholesterol is also found in the lipid bilayer- 20%--> balance of fluidity and rigidity of the membrane ❖ Phospholipids- hydrophilic head which is exposed to the intracellular and extracellular environments and intracellular environments. ❖ Orientation of the phospholipids means that if there is a tearing, it is quite easy for the cell to rearrange its structure ❖ Proteins- some of them are receptors, others control the substances entering and exiting the cell Centrioles- ❖ Lie close to the nucleus- rod shaped and lie at right angles ❖ Made of a pinwheel of microtubules ❖ Role (movement);  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + o Production of microtubules (also produce some cell extensions e.g. cilia and flagellum) o And during mitosis, they form mitotic spindle Cytoskeleton Microtubules- support the cell and give it it’s structure Microfiaments- muscle contraction and movement inside the cell Intermediary filaments- resist mechanical forces in the cytoskeleton Homeostasis- the state of maintaining/obtaining relatively stable internal environments within a normal range despite the fluctuating external environment. It is a state of dynamic equilibrium. Internal environment is defined by a range of regulated variables-e.g. temp, heart rate, glucose, insulin, amino acids, carbohydrates etc. Narrow range= normal range- all results are compared to the normal range – there is a certain point within the normal range which is optimum= set point HOMEOSTATIC CONTROL MECHANISM Stimulus- produces a change in the variable Receptor- detects change- communicates via afferent pathways to control centre Control centre- makes decisions- and reacts via efferent pathways- to effector Components can play more than one role Enable regulation within a narrow range Homeostasis ❖ maintaining relatively normal/stable internal conditions for efficient body processes despite the fluctuations of the external environment- it is a state of dynamic equilibrium ❖ homeostasis is the mechanism of maintaining relatively normal/stable internal environments- the process begins when there is an imbalance with the normal ranges of the body which the control center detects and analyses once the signal has been sent from the receptor via the afferent pathways. In order to obtain relatively stable conditions once again, the control center sends the required action via the efferent pathways to the effector which does the action and supplies a positive/negative feedback which either enhances or depresses the original variable. ❖ dynamic state of equilibrium  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ nervous and endocrine systems play an integral role in homeostasis- communication- through information carriers Examples of negative feedback loops- e.g. temperature control, pancreas secreting insulin to lower blood glucose levels. e.g. of homeostasis- breastfeeding the baby suckles on the mothers nipple= stimulus this stimulates a signal via the afferent pathway to the mothers brain- hypothalamo-pituitary axis (control center)- which stimulates the release of oxytocin out of the posterior pituitary- oxytocin is then sent via the efferent pathway to the breast and stimulates the contraction of the muscles which secretes the milk. This is an example of a positive feedback loop- because as the baby continues to suckle, the milk is continually excreted until the stimulus is removed Uterine contractions- COMPONENTS OF HOMEOSTASIS o RECEPTOR- sensor which monitors/responds to changes in the environment-stimuli ▪ Sends information to the control center via afferent pathways o CONTROL CENTER- determines the normal ranges and determines the appropriate actions o EFFECTOR- response from the control center travels along the efferent pathways to the effector with the appropriate response o FEEDBACK- response of the stimuli then results with the feedback ▪ NEGATIVE- Shutting it down/depressing the original stimulus ▪ POSITIVE- affirming/enhancing the original stimulus homeostasis- is the mechanism to ensure that the systems in the body remain within a narrow  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + range for optimal performance- normal range Adequate blood levels of vital nutrients must be continuously present, and heart activity and blood pressure must be constantly monitored and adjusted so that the blood is propelled with adequate force to reach all body tissues. Additionally, wastes must not be allowed to accumulate, and body temperature must be precisely controlled. Nervous and Endocrine systems are important for homeostasis- signals travel via nerve impulses or as blood borne hormones- endocrine system is usually associated with the effect of the imbalance Nervous- fast onset but short duration Endocrine- slow onset but long duration Feedback control-specific type Control mechanisms which involve the endocrine system-series of glands which produce chemical messenger which goes to a target and responds to the way that it acts Ability to measure response Negative feedback-most common Set point-middle of normal range- ideal value within the range Body temp-more than one process Once initial stimulus is removed, positive feedback stops Central regulatory system- nervous/endocrine systems Lesson 2-Terminology Anatomical position; standing upright, hands by side, feet at shoulder length, and facing forward. Ventral body cavity- abdominopelvic region, thoracic, diaphragm Dorsal cavity- cranial to caudal region- including the spine- cranial/spinal cavity Root, prefix, suffix Electrical pattern of the brain Eponyms- putting a name (nymph) upon (epi) Aneurysm- loses elasticity- ruptures Anatomy- cutting down tissues  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Anatomical position- body erect Frontal/coronal (crown)- cutting/separating body anterior/posterior Transverse/horizontal-upper/lower body Saggital- left and right halves Midsaggital- cut body in exactlty two halves Parasaggital- next to/around the midsaggital plane Superior/cranial- towards Inferior/caudal Front body-ventral/anterior Back-dorsal/posterior Dorsum-hand-back of hand Palmar-palm of hand dorsum of foot Plantar aspect of foot Deep-towards the core of the body Superficial-towards the surface of body Elbow is distal to shoulder Elbow is proximal to hand Endo- endoplasmic reticulum Lesson-Intro to cell structure and function Importance of compartmentalization- it is necessary so that every organelle specializes in a specific area and is more efficient in its required job. However, due to this, more energy must be invested in the cell to maintain it- in the form of ATP. Cells all contain the basic genetic material, however some parts are activated and others are not. This means that not all the cells are the same, although they all contain the same genes.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Human body consists of eukaryotic cells-structure and function, and prokaryotic- e.g. bacteria in gut- they are considered as a characteristic of cell- prokaryotic is more primitive than eukaryotic but don’t have a nucleus Both are membrane defined units Eukaryote- gives rise to all human cells Prokaryote- do not have a membrane bound nucleus and they don’t have membrane bound organelles- bacteria in gut (archaea is an example of bacteria)- required for normal metabolic rate- can also cause illnesses Cells contain a membrane which separates the intracellular fluid from the extracellular fluid- but they still allow communication between the two regions- plasma membrane Contain the basic genetic information for function and reproduction Functions as a mechanism to facilitate the necessary functions of life- o Maintains boundaries o Exchange of mechanisms o Produce energy- respiration o Synthesis of biological macromolecules o Excrete waste o Grow/divide Cell-basic structural/functional unit of life 3 components of a cell; ❖ Plasma membrane- phospholipid bilayer which is selectively permeable and contains embedded proteins- fluid mosaic model ❖ Cytoplasm- consists of cytosol (cell fluid), organelles, and inclusions ❖ Nucleus- control center of the cell- consists of nuclear membrane, nucleolus, and chromatin Compartmentalized leads to specialization however, it requires more energy Compartmentalization is required in order to ensure that the different organelles are specialized to one specific function. Plasma membrane- selectively permeable membrane which separates the internal and external areas of the cell- lipid bilayer- fluid mosaic model  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Cytoplasm- material between plasma membrane and nucleus- includes organelles, inclusions and cell fluid (cytosol) ❖ Cytosol- cell fluid- water with dissolved substances e.g. nutrients, ions etc. ❖ Cytoplasmic organelles- miniaturized organs which are found in the cell- carry out different functions ❖ Membranous- nucleus, mitochondria, endoplasmic reticulum, peroxisomes, lysosomes, endoplasmic reticulum, Golgi apparatus ❖ Non-membranous- cytoskeleton, centrioles, ribosomes ❖ Inclusions- chemical substances e.g. lipid droplets, glycogen o Ribosomes- some are found floating in the cytosol and others are attached to the endoplasmic reticulum- those found in the cytosol- are sites for protein synthesis o Those around endoplasmic reticulum excretes substances out of cell Membrane Specialization- Extensions o Microvilli- found in the epithelial layer of the small intestine- finger like projections which increase the surface area and thus ensures for more efficient absorption of substances- aids absorption by increasing surface area o Cilia- found in digestive tract- aids movement of substances down to the stomach- used in junction with muscles which push the food down Moves substances on the surface PRODUCTION- CENTRIOLES OF THE CELL MULTIPLY AND LINE UP BENEATH THE PLASMA MEMBRANE- MICROTUBULES BEGIN TO SPROUT FORM THE CENTRIOLES WHICH FORMS PROJECTIONS o Flagella-sperm- allows the cell to move- LONG CILIA EXTENSIONS o Stereocilia- long microvilli- which aid absorption of water e.g. epididymis Junctions o Tight (blue tack)- connects the cells together to ensure that no substances are able to flow/travel within the extracellular space in between the two cells- adjacent plasma membranes begin to fuse and prevents substances to pass in between the cells e.g. in the small intestine, tight junctions exist in order to ensure that the digestive enzymes to not escape from within the intestine.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Tight junctions are present in skin, and in the gut in order to ensure that there is no interaction between species in the apical region, and that of the basolateral areas. Tight junctions are not found in cardiac muscles- because tight junctions don’t allow movement, but instead keep the cells together, and this is not required in the heart, which needs to continually contract. Also, there needs to be movement of substances around the cells. o Adherence- keeps the cells together e.g. keeps the cardiac muscle cells together during contraction/relaxation o Desmosomes- ensures that the cells remain in place/together when mechanical stress is exerted on the cells-e.g. cardiac muscle cells- strong adhesion between cells DESMOSOMES ARE CONNECTED TO INTERMEDIATE FILAMENTS o Gap- allows for communication between cells- they are pores which allow the cytosol to communicate- gaps are called connexons- common within the heart and embryonic cells o Hemi desmosomes- connect the epithelial cells to the basement membrane Stem cells- Embryonic stem cells- found from particular structures from preimplantation embryo- Inner cell mass-give rise to all tissues for the embryo=embryonic stem cells- located on only one side. Blastocyst enters into the endometrium on the side of the inner cell mass. Developmental potential-totipotent, pluripotent, multipotent, unipotent- give rise to how many cell types e.g. morula= pluripotent- due to the determination of the cells based on their position relative to the external environment. Stem cells are found in the lower layers of the skin-epidermis layer- stem cells are still able to replicate and specialize- constantly dividing and specializing When skin cells are shed, they are being replaced with specialized stem cells Cell contains 2 types of fluids- interstitial and intracellular; ❖ Intracellular contains minimal amounts of nutrients and ions ❖ Interstitial is abundant with nutrients etc.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + The cell is selectively permeable to allow substances to enter and exit the cell. This is done in two ways; ❖ Passive (no energy required) o Diffusion; ▪ across the concentration gradient- from high salt concentration to low salt concentration ▪ Molecules possess their own kinetic energy (speed is based on size and temperature) and so they collide with each other which changes their direction and allows them to move ❖ Active (requires input of ATP) Lesson-Macromolecules Water- universal solvent- able to form hydrogen bonds between other molecules Macromolecules-carbohydrates, proteins, lipids, nucleic acids (lipids aren’t really macromolecules since they are not polymers but are made up of a lot of fatty acids) Human body consists of complex chemicals reactions which are dominated by molecules that allow growth and reproduction-they also require energy Composition of cells- water, macromolecules, ions, miscellaneous substances etc. Cell contains- 70% water, 30% other chemicals Human body contains; 60-80%water, macromolecules (e.g. RNA, DNA, proteins, lipids etc.), ions, smaller molecules, and other organic matter Macromolecules, energy, water the universal solvent (main component of cell) ❖ Water-chemical reactions & solvent ❖ Cells-chemicals dissolved in water ❖ Required for metabolism- and cell functioning, energy, reproduction etc. ❖ Most chemical reactions occur in a solvent ❖ Water is required for hydration/dehydration reactions.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ Tightly regulated-found in particular compartments ❖ Production of macromolecules- o Building blocks found in cytosol o Food-building blocks come from nutrients from food-used to build macromolecules WATER ❖ Maintains body temp-homeostasis- sweating- able to absorb a lot of heat-heat capacity/vaporization Water contains a high heat capacity ❖ Transportation of substances in the blood ❖ Moisture for epithelial surfaces ❖ Carries away wastes- urine/blood ❖ Allows for an adequate blood volume- Pressure-good circulation ❖ Participates in chemical reactions- condensation reactions, hydrolysis ❖ Most chemical reactions occur in solutions. ❖ UNIVERSAL SOLVENT BECAUSE IT IS ABLE TO FORM HYDROGEN BONDS Water provides the watery environment required for chemical reactions. Chemical property-polar molecule- atomic structure- oxygen larger than hydrogen- electrons around oxygen more than hydrogen- dipole- interact with other polar molecules-electronegativity of oxygen is greater than hydrogen-bonds with other polar molecules- forms hydrogen bonding with each other and with other molecules Hydrogen bonds-intramolecular-fairly weak- but because there are so many, they are significant Attraction of water to each other- produces surface tension- water molecule is attached to 4 other water molecules- forming 4 hydrogen bonds per every water molecule Non organelles-no membrane around them- E.g. ribosomes (contain two ribosomal subunits) Macromolecules- large molecules made up of discrete building blocks contain O, C, H and sometimes N Important for organelle structure and characteristics of the organelle shape  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Macromolecules=polymers- a large chain of many monomers-joined by covalent bonds-enzymes used to catalyse these reactions Condensation reaction= dehydration synthesis Turnover within cells? Ribosomes-protein synthesis HAVE SOME EXAMPLES Intermediate filament-structure- found in cytoskeleton Lipids/fats- aren’t really macromolecules because they don’t form polymers- no monomers but know the different examples; triglycerides, phospholipids, steroids, cholesterol Sugar/phosphate/base-nucleotides Carbohydrates- contains C, H, O sugars-glucose- 1-2% of cell mass- polymer made up of monosaccharides Monosaccharide- simple sugar- hexose/pentose- (number of carbon atoms present in structure)- most common is glucose Disaccharide- 2 simple sugars joined together via dehydration synthesis (condensation reaction); maltose, sucrose, lactose (lactose=galactose+glucose) o They are too big and thus cannot pass through the cell membrane and are required to be digested via hydration in order to form monosaccharides Polysaccharide- long chain of simple sugars- usually used for storage- e.g. glycogen- storage of glucose in skeletal muscles, and live The large carbohydrates must be synthesized to their monomers to travel through the cell membrane- they are too large. Galactose-milk Energy stored as glycogen is a small amount- able to maintain glucose levels  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + LIPIDS- hydrophobic, insoluble ❖ Solid/fluids- based on saturation and the bonds ❖ Saturated-no hydrogen bond in tail-solid-GOOD FOR CELLS- cell membrane (balance between fluidity and being a solid) ❖ Unsaturated- Bends-double bond between carbons-liquid ❖ Balance of both present in cell ❖ Energy storage ❖ Glycerol back bone, and 3 fatty acid tails ❖ Triglycerides stored as Fat- stored in adipose tissues/adipocytes (inclusion- component of the cytoplasm)- found under skin/around thighs, hips ❖ Adipose tissue able to change size based on triglycerides present ❖ Fats-cushioning, insulation, protection ❖ Phospholipids-found in membrane- contains hydrophilic head, and 2 hydrophobic tails ❖ Examples; phospholipid (cell membrane), triglycerides, steroids (hormones, vitamins, cholesterol), eicosanoids PROTEINS ❖ 10-30% of cell mass ❖ structure-present in membrane (facilitates transport into and out of the cell), cytoskeleton ❖ functional- transport (hemoglobin), motor, enzymes, defense, storage, receptors, gene regulation ❖ Activity of cell-more proteins ❖ Motor proteins-cause contractions-muscle cells ❖ Structure- underpins function ❖ Fold into specific shape-determines function ❖ Anything that interferes with structure affects the function  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ AMINO ACIDS- are the monomers for production of proteins- 20 common amino acids- contain a amino group and a carboxylic acid group ❖ Amino acids are joined by Peptide bond- C-N- condensation reactions ❖ Features-depends on which amino acids are joined-side chain ❖ Protein structure- primary, secondary, tertiary, quaternary Pg33 hemoglobin NUCLEIC ACIDS Made of nucleotides- base/sugar/phosphate RNA-intermediate molecule between DNA and protein- DNA hold the code for protein synthesis a nitrogen-containing base, (2) a pen- tose (5-carbon) sugar, and (3) a phosphate group ❖ Base = 4 possible bases Adenine (A) Guanine (G) Cytosine (C) Thymine (T) (only in DNA) Uracil (U) (only in RNA) Function of nucleotides- carry chemical energy in ATP, form coenzymes, signaling molecules Function-2 helix joined by hydrogen bonds- DNA STEM CELLS- LEAST DIFFERENTIATED CELL TYPE INTRODUCTION TO TISSUES: STRUCTURE AND FUNCTION  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Cell- functional unit of life Tissues- cells which have the similar function Histology- study of the tissues of the body- microanatomy- anatomy on a microscopic level 4 Basic Tissue Types- epithelial, connective, muscular, nerve; ❖ Epithelial tissue=epithelium -lining of tracts, lining of skin for separation of the internal environment and the external environment. o e.g. skin is lined with epithelial tissues o Glandular epithelium= coverings of the body which contains glands and secretes substances- exocrine- secreted directly to the environment, or endocrine- secretes chemical substances (hormones) into the blood to be circulated around the body. o Forms boundaries between the internal and external surfaces e.g. skin o Protection, secretion, absorption etc. o Fit together to form sheets o Membrane contains one surface which is exposed to the exterior part of the body o Lower surfaces of epithelium rest on the basement membrane/basal laminar o No blood supply of their own= avascular, but depend on diffusions from capillaries Facilitated by the hemidesmosomes o Naming- ▪ Simple- single layer- associated with absorption, secretion, filtration – no protection- CONTROLS PERMEABILITY ▪ Stratified- multiple layers (this is usually the case where the tissue will be exposed to large amounts of mechanical stress) ▪ Squamous- flattened structures Simple squamous- lining of the alveoli- efficient transfer of energy from blood vessels to alveoli and vice versa. Or the walls of capillaries where there is exchange of gaseous to the cells capillaries and the lining of the alveoli Stratified squamous- outer skin layer or esophagus/oral cavity ▪ Cuboidal- cube like shape- tall as it is wide  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Simple cuboidal- common in glands, kidney tubules and surface of ovaries ▪ Columnar- long, elongated- nucleus is elongated Simple columnar- line the gastro intestinal tract- usually contains goblet cells- produce mucous Pseudostratified columnar- some have different shapes and so they give the false impression that it is stratified- the positioning of the nucleus in the cells gives the impression that it is stratified while it isn’t- absorption/secretion- all the cells are actually touching the basal laminar, but not all of them reach the surface which gives the impression that it is stratified. Transitional epithelium- stratified squamous epithelium- linings of organs part of the urinary system- because they are subject to stretching- originally, the cell on the surface are rounded, but when filled with urine, they flatten and become squamous- in a histological slide, you will probably only see rounded ‘umbrella’ cells because no liquid will be present in the section. Glandular epithelium- secretion- endocrine/exocrine ❖ muscle- skeletal, cardiac, smooth- excitable cells/tissues o Skeletal- ▪ when they contract, they pull the bones that they are attached to and thus facilitate movement ▪ striated, elongated nuclei in between strips of cells-multinucleate ▪ peripheral nuclei ▪ striated o Cardiac muscles- ▪ Surround the heart- smooth rhythmic movements to allow the heart to pump rhythmically.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ▪ Striated, uni-nucleate (usually 1 or 2), short, branching but fit tightly at junctions called intercalated discs which contain gap junctions which allow ions to pass through and desmosomes- keeps the cells together ▪ Involuntary control ▪ Intercalated discs have gap/adheren/desmosomes ▪ Cross sectional image- nucleus found in the center of the cell. o Smooth- ▪ No striations, single nucleus, spindle shaped ▪ Fusiform cells ▪ Found in the walls of hollow organs ▪ Contraction and dilation of organs - movement ❖ connective- supporting tissue which underlie epithelial e.g. blood, bone, cartilage, dense irregular connective tissue o most abundant tissue type o provides structure, form and strength to the body ❖ nerve-based on central and peripheral nervous systems o excitable tissues-produce an electrical signal Histopathology- abnormalities of the tissues/cells Understand staining properties- organelles are stained in different ways- Tissue- fixed, dehydrated, embedded in wax, sectioned with microtome, rehydrated then stained- ❖ Hematoxylin- cationic dye-reacts with negative charged structures- ribosomes/ everything which has RNA/DNA e.g. rough endoplasmic reticulum, ribosomes, nucleus, nucleolus BASOPHILIA Nucleus=DNA-deoxyribonucleic acid- phospho back bone- negatively charged Rough endoplasmic reticulum- ribonucleic- ribosomes RER- basophilic- due to presence of ribosomes (rRNA)  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ Eosin- anionic dye- reacts with positive charged structures- amino groups on proteins- collagen, cilia, mitochondria (ATP), HAEMOGLOBIN IS BASIC SO IT LIKES EOSIN ACIDOPHILIA/EOSINOPHILIA Cytoplasm- contains protein- therefore acidophilic Mitochondria- Adenosine triphosphate- lipid bilayer- proteins present on the membrane Cell component Nucleus Blue-DNA contains a phosphate groups which makes it overall negatively charged. Thus it is basophilic and will be stained with haematoxylin and appear as blue. The activity of the cell will control the strength of the blue colour- e.g. active cell will have decondensed chromosomes, thus will be a weaker blue than an inactive cell. Rough endoplasmic reticulum/ Blue- Rough endoplasmic reticulum contains Ribosomes Ribosomes on the surface. These ribosomes stain blue since it has an abundant supply of rRNA which is negatively charged and thus is basophilic. PROTEINS Any protein substances will????????????????????????????????????????????????????? Cytoplasm Eosinophilic- due to the presence of proteins Mitochondria Due to the proteins present Lipids Does not stain with H&E- lipids are dissolved during the preparation of the slide through the use of alcohol, and thus it will not stain Mucin Does not stain with H&E- mucin is neutral and thus will not stain Red blood cell Composed of 66% of hemoglobin which is basic. Therefore, eosinophilic Melanin- brown- some brown substances that are seen could be artifacts or melanin (pigment which gives skin its dark colour)  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + PALE STAINING- MUCOUS- (mucous= carbohydrate- neutral) - or lipid- lipid dissolve when placed in alcohol- therefore are removed and there is nothing to stain How to stain lipid in a cell- e.g. myelin sheath- sudan black- because it isn’t placed in the alcohol during preparation of the slide. Silver stains- neuron elastin Periodic acid Schiff- stain used for carbohydrates- mucin=mucous is viewed as a bright pink. Sudan black/osmium tetroxide-lipophilic- lipids- (when a tissue is placed in alcohol for process of staining, the lipids are removed- but for live tissues, this staining technique is used to detect the presence of lipids) Van Gieson stains elastic fibers purple/black Trichromes- used to differentiate between different tissues- epithelial cells=pink and collagen=green/blue Giemsa or Wright- for blood- differentiate acidophilic form basophilic basic tissues; ❖ Skin-epithelial ❖ Skeletal muscle- muscle tissue ❖ Nervous tissues-nerve ❖ Bone, cartilage, blood, loose connective tissues- connective tissue Wall of the gastrointestinal tract- Only skin for desiccation is keratinizing (dead skin- don’t have a nucleus but instead they contain keratin) – water proofs skin so you don’t lose fluid in the skin  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Stratified- multiple layers Squamous- flattened cells Exocrine glands- ducts Endocrine glands- no ducts- release directly onto the blood vessel Skeletal muscle- connective tissue surrounding each section NUCLEUS- IF THE CHROMOSOMES ARE CONDENSED, SO IN THE TRADITIONAL X STRUCTURE, THEN THE CELL IS NOT ACTIVE, SINCE THE DNA IS NOT EASILY ACCESSIBLE- THUS THE NUCLEUS WILL STAIN DARKLY. IF THE CELL IS ACTIVE, THE NUCLEUS WILL NOT STAIN DARKLY. Basic epithelial types; Lining epithelial- lines internal and external surfaces Simple- one layer Stratified- multiple layers Simple squamous- alveoli for efficient gaseous exchange Simple cuboidal Simple columnar Stratified squamous Stratified cuboidal Stratified columnar Transitional pseudostratified Wear and tear- stratified Esophagus-wear and tear- layers are continually utilized Tongue Exocrine- glands with ducts Endocrine-no glands Glandular tissues-epithelial- exocrine gland- epithelial layer grows down to form duct area- then the secretory part which produces a substance and releases it to the surface  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Apical surface specialization- cilia- beat in arithmetic (rhythmic) direction Pseudostratified- falsely implying that it is stratified------ e.g. PSEUDOSTRATIFIED CILIATED EPITHELIUM- looks as if it is stratified, but it isn’t. it contains cilia on the surface and is an epithelial cell Microvilli- fingerlike extensions- aids absorption by increasing surface area Goblet cell- secretory epithelium- because it contains mucin, when stained with H&E, it will not show, because of the neutral pH. CONNECTIVE TISSUE- binds and supports other tissues- bones, blood, cartilage, loose connective tissue, adipose, lymphoid Connective tissue proper- loose/dense Mesenchymal connective tissue- Blasts-immature cell Cyte-mature cell White adipose- little cytoplasm Muscle tissue Intercalated discs- cardiac muscles Connective tissue- smooth muscles Nerve tissues- neuron=functional unit- one axon and a lot of dendrites- respond to stimuli --------------------------------------------- Stratified, squamous, keratinized – base of foot-plantar, palmnar- lysosomes- rupture and degrade everything in the cell except for keratin What lies beneath epithelium? – basal laminar/basement membrane  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Most common fibrous tissue= collagen Lymphocytes- fibroblasts- product matrix of connective tissue case 3- describe major characteristics and functions of the 4 basic tissues. Size shape function. formaldehyde- artifact transitional- change shape- bladder red blood cells- erythrocytes- no nucleus white blood cells-neutrophil- takes both hematoxylin and eosin long cells- block capillaries ---------------------------------------------------------------------------------------------------- Scientist and Scholar Oxidated phosph… chain= respiratory chain- mitochondria- know equation Zenobiotic- ingested substances= both toxic, and not Smooth endoplasmic reticulum- detoxification of chemicals, calcium storage etc. Structure=bilayer of phospholipids= polar and non- polar (hydrophilic and hydrophobic)- interface between aqueous environment- hydrophilic section is exposed to the watery aqueous environment Membrane=cannot be a true solid/liquid-based on presence of cholesterol- effective but not completely limiting barrier- rigidity of cell increase and substances will not be able to enter or exit the environment  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Small amounts of cholesterol increases fluidity??? Cytoplasm- all the fluids and solids in the cytosol and the arranged structures Centrioles- acts as an engine to allow components of cell to move- e.g. mitosis/meiosis- ability to move chromosomes etc. Microtubule formation- skeleton for membrane/microtubule extensions Importance of lysosome membrane- if this is compromised, then the lysozyme will spread to the remaining areas of the cell, and so it will eventually destroy the cell- the intracellular and extracellular are composed of different substances Inner/outer leaf/layer membrane- plasma Integral/peripheral proteins??? - structure, function Proteins-enable transport 2 main components of plasma membrane=proteins and lipids; Main purpose of the phospholipids= separation Proteins-transport etc. Purpose of cholesterol in the plasma membrane??? Fluid mosaic model- balance between fluidity and solidity Search rRNA, mRNA, tRNA, RNA, DNA Differential gene expressions- based on proteins= transcription factors mRNA moves from inside the nucleus to the remaining parts of the cell  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Stem cell therapage Smooth ER- relevant to Ca2+ release 8-16 cell stage- cells stop being totipotent??? Pluripotent=multipotent Pluripotent cells exist in the human body, totipotent does not exist- totipotent only exists at the 2,4,8 stage- of the fertilized egg. Activation of the cells; every cell contains the same genes, but some are not activated Detoxification; smooth ER, and peroxisomes PRINCIPLE OF COMPLEMENTARITY- Biochemical activities of cell depends on specific subcellular structures Bladder- transitional - must facilitate expansion and contraction Gastro- columnar- does not allow any acid to escape from the stomach- requires a longer distance for acid to travel too to escape from that region. NUCLEUS; DNA exists in the nucleus in two forms; Euchromatin-dispersed- unable to be viewed Heterochromatin- small, darkly staining, irregular particles, scattered around the nucleus, common in cells that are less active. Cell Cycle and Mitosis Cell reproduction is based on a mother cell splitting in two to form 2 genetically identical offspring.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + 4 phases of the cell cycle; ❖ G1- cell growth, preparation for chromosome replication G1+S+G2= interphase M=mitosis ❖ S- synthesis of DNA, duplication of centrosome/chromosomes ❖ G2- preparation for cell division- checking that the duplication of chromosomes has occurred successfully ❖ M- cell division= mitosis Mitosis- production of 2 genetically identical diploid daughter cells from one diploid parent cell (meiosis- reductive cell division where 4 haploid genetically different daughter cells are produced from one diploid parent cell) G0 is an inactive stage where the cell cycle does not occur- the cell dismantles all the necessary organelles required for cell division- thus it is hard for it to leave G0 and enter mitosis straight away. Cells that always exist in G0= Mature red blood cells don’t leave G0 (don’t divide at all) Active cells/cells that are constantly being renewed, are constantly dividing🡪 therefore don’t enter G0- e.g. Mitosis= cell division-production of 2 genetically identical daughter cells to each other and to the parent cell Meiosis- production of 4 haploid cells are produced (half the number of chromosomes) - gametes/sex cells- germline cells produce the gametes which have only half the number of chromosomes Sex cells are haploid because they contain half the number of chromosomes required for a full cell= so when the egg and sperm fuse, they add the two chromosomes together to get the full amount. The process of reproduction/production of 2 daughter cells requires for replication of organelles. Mitochondria contain its own DNA and thus it’s replication is different to that of the other organelles. During the S phase of the cell cycle- the chromosomes are copied so that there are two Similarities and differences of mitosis and meiosis Cell cycle=replication of a cell- process of cell division  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + One parent cell which replicates into 2 genetically identical daughter cells- function, number of chromosomes and DNA structure should all be the same Chromosomes double during the cell cycle--- G1-preparation of chromosome replication and during S phase, the chromosomes duplicate. Organelles change in number and each cell takes approximately 50% of the organelles from each cell- this is important to ensure that both cells which are produced, have the same role 3 reasons why a cell would divide- growth, repair, replacement maintenance-replacing- e.g. skin cells, cells in gastro intestinal tract, blood cells etc. repair- skin tear growth- phases of growth spurts distinct phases- 4 phases of cell cycle-cyclic and continuous process-DNA/chromosome perspective S- duplication of centrosomes and synthesis of DNA- synthesis phase (DNA replication)- doubling the amount of DNA present in cell- by doubling the chromosomes so that there are 2 chromatids – duplication of centrosomes (centrosomes consist of 2 centrioles) G2- preparation for division- Gap-did nothing for a while M- Mitosis- splitting of cell from 1cell to 2 identical cells G1-Gap- breather- cell growth and preparation of chromosome duplication. G1/S/G2= interphase Gaps- separate out DNA synthesis and mitosis and allows the cell to check whether the previous process was completed successfully. G1-Straight after mitosis= the cell checks if it has all the organelles- repair or produce these organelles G2- straight after it has replicated the DNA- make sure everything is ok regarding the number of chromosomes and the order etc. Because the DNA is exposed to the external environment, there is a possibility of collisions, therefore G2 checks that nothing is wrong. G1/G2- checks that the previous stage was completed successfully and that the cell is prepared for the next stage.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Most active- interphase- won’t be able to see the chromosomes When the chromosomes are condensed, it is an inactive cell- Therefore when you can see distinct features of the chromosomes, it won’t be an active cell. (condensed chromosomes consist of proteins histones etc. therefore the DNA is tightly wound and is relatively inaccessible) When the chromosomes are relaxed/de-condensed, it is an active cell, to allow for effective interactions and communication with the DNA. Chromosomes condense only for mitosis/meiosis- Chromosomes are only in the traditional X structure for mitosis to occur- otherwise, it would be in the relaxed spaghetti form in order to ensure efficient communication for gene expression- chromosomes begin to condense in prophase, but are completely condensed during metaphase. Stage in G1 called G0=quiescent stage- don’t differentiate (terminally differentiation which lose the ability to proliferate-will not replicate- which means that it doesn’t need anything that is required for cell replication)- is when the cell decides to duplicate or not- during G1 stage, the cell prepares for Chromosome replication- during this stage, the cell may decide that it does not need to replicate Once the cell has replicated the DNA, it will either continue with its division towards mitosis, or it will eventually stop working. 24 hrs approximately- for most eukaryotic cells bacteria- 20mins why do bacteria duplicate quicker than eukaryotic cells? Bacteria are prokaryotes- this means that they don’t have a membrane defined nucleus- therefore it is relatively easy for them to duplicate. They also divide via binary fission Cell doesn’t require the organelles for replication if they aren’t going to replicate- e.g. centrioles. It is difficult for cells who live in G0 to leave and continue during replication because it needs to make all the necessary machinery for replication again. Nerve cells spend their life in G0- e.g. if brain issues Cardiac muscle cells- once they are made, or during early development they don’t replicate themselves  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Skin cells, stomach cells, red blood cells never enter G0 stage- continually replicating and they have a short life span What type of cell may temporarily move in or out of G0? - all other cells If cells come out of it, it must produce all the machinery again- and sometimes it will take a long time Some cells stay permanently in G1 and don’t look any different than those in G0 Cells in G1- contains all the organelles required for cell division and so are quick responder’s G0- cells dismantled all the replication machinery – cannot respond quickly MITOSIS- photocopying/replicating a cell- genetically identical copy- (growth, repair, replacement) same function, same sequence in DNA, number of chromosomes etc. MEIOSIS- reductive cell division-gametes only- 4 cells produced= haploid- 23 chromosomes each- when the egg and the sperm fuse, they form the 46 chromosomes that every cell contains- 23 paternally and 23 maternally Chromosomes are relaxed and thus cannot be seen in the nucleus after cell division- DNA is accessible- to give instructions for gene expression etc. When chromosomes become condensed, you can see the X shaped chromosomes- only at mitosis and meiosis Nuclear envelope- protect DNA from other components of the cell-but to replicate the cell, the nuclear membrane and the nucleolus disintegrate and so the chromosomes are exposed to the cytoplasm, which may cause issues because they are not protected, however, that is why there is a G1 stage where the cell checks that nothing has gone wrong during the process. At the interphase stage, the DNA duplicates- S phase (synthesis of DNA), but during Prophase, the chromatins condense to form chromosomes. MITOSIS Interphase- G1, S, G2 stages= cell growth occurs, the chromosomes duplicate, and the cell prepares to undergo mitosis  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Prophase- the nuclear membrane and the nucleolus disintegrate and the chromosomes become more condensed and more visible. centrosomes begin to move to opposite poles of the cell and begin to form microtubules. Kinetochores begin to form Prometaphase- Microtubules attach to the centromeres of the chromosomes, nuclear envelope begins to dissolve Metaphase- the chromosomes align themselves along the metaphase plate (middle) Anaphase- the kinetochores microtubules begin to pull and split the centromeres and attract the chromosomes to opposite ends- during anaphase, the cell becomes elongated Telophase- nuclear membrane and nucleolus begin to form, chromosomes decondense Cytokinesis is the splitting of the cytoplasm which includes all organelles- this usually occurs during telophase- formation of a cleavage furrow. The cell cycle ensures that both daughter cells contain the same number of chromosomes but it is important that both cells still contain the necessary organelles- organelles must also duplicate and they must be split roughly evenly in order to ensure that both cells contain the necessary organelles for their required function. Centrosomes are composed to 2 centrioles- they form the mitotic spindles which attach to the centromeres of the chromosomes and separates them. Microtubules/mitotic spindles- made of tubulin- attach to protein attachment sites called kinetochore on the chromosome Mitotic spindles= Protein tubulin- attach to center of chromosomes and enable them to move. Sister chromatids- when they split during anaphase Cytokinesis – occurs during telophase- formation of a cleavage furrow and then separation into 2 separate cells When the nucleolus and the nuclear membrane dissolve, the DNA is exposed to the internal environment of the cell including organelles during mitosis- so they have to check that it wasn’t damaged during G1. Prometaphase- nuclear envelope dissolving  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Centrosomes- organization center- Tubulin able to attach to proteins on the chromosomes called kinetichores Replication of organelles- during G1 stage- usually occurs at random times- mitochondria is able to replicate on its own because it contains its own DNA, other organelles will also have to replicate as well, and then during cytokinesis when there is a cleavage furrow which is formed, the organelles will split approximately 50/50. Be able to identify STAGES OF CELL CYCLE from diagram DNA REPLICATION AND CHROMOSOMES: Before mitosis- cell has 23 pairs of chromosomes- 46 chromosomes in total with only one chromatid After S phase- the cell has 23 pairs of duplicated chromosomes- therefore 46 chromosomes in total with 2 chromatids each. Chromosomes🡪is made up of chromatin🡪 which is made up of DNA and protein (histones-8 histones-H1, H2A, H2B, H3, H4 and non-histones)🡪 interaction depends if they are condensed or relaxed- Chromosomes- made up of chromatin=solenoid+non-histone proteins, 🡪 solenoid= nucleosome + histone 1 proteins🡪 nucleosome= DNA + H2A/B/3/4 During S-phase- DNA synthesis Humans have 2 genomes- one from mother/father Chromosomes- single The double X is when it has been duplicated and is only visible during mitosis- because it has become more condensed starting from prophase and being the most condensed during metaphase. Centromere, p, q arms The 2 arms of the single chromosome are duplicated individually DESCRIBE HOW MANY CHROMOSOMES Count based on the number of centromeres to find out the number of chromosomes G1- 46 S phase- 46 Anaphase- 92- but 1 chromatid each  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + DNA- nucleotides bond via hydrogen bonds Must break the hydrogen bonds- by putting energy ATP Replication origin- bonds broken through the use of initiator proteins- contain high A, T – only 2 hydrogen bonds compared to C-G which have 3 hydrogen bonds- begin through the use of initiator proteins which opens different regions of the DNA strand to allow DNA replication to occur. Replication origin is a region within the double helix which contains multiple A-T bonds. These bonds will require ATP to be broken, however, they contain only 2 hydrogen bonds which is easier to break with less energy required compared to C-G which contains 3 hydrogen bonds. ❖ C-G bond within the DNA strand has 3 hydrogen bonds, while the A-T bond has only 2, thus breaking this bond, will require less energy. Replicate DNA at different sites= these sites are the replication origins- opened by initiator proteins- DNA replication is BIDIRECTIONAL DNA synthesis occurs at the replication origin- the double helix is separated by initiator proteins. And the DNA replication is considered bidirectional because it starts at the replication origin and spreads in both directions. DNA replication in both/2 directions- like 2 zippers Different proteins used during the DNA replication process; ❖ DNA helicase- this protein splits the DNA double helix into two strands and forms a replication fork- the direction that the DNA helicase travels in is the same as that of the leading strand. ❖ DNA gyrase- places nicks within the DNA strand to reduce the tension ❖ Single stranded binding proteins- binds to the 2 strands that have been separated from the DNA helicase in order to ensure that they don’t form bonds or interact in any way- keeps them separate ❖ RNA Primase- the DNA polymerase is not able to start the production of nucleic acids, so the RNA primase produces a small section called a primer- this is eventually removed- this is for both the leading and lagging strands- ❖ DNA polymerase- adds the complementary nucleotides to the growing strand o DNA polymerase 3- places the DNA nucleotides next to the RNA primer o DNA polymerase 1- replaces the RNA primer with DNA nucleotides  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ DNA ligase- seals up any breaks in between the primer and the new strand of nucleotides. DNA Helicase- unwinds the double helix of the DNA and requires ATP, because it needs to DNA gyrase- stops any untangling DNA polymerase- cannot initiate the strand—therefore RNA primase begins the replication process through the use of a primer and then DNA polymerase 3 continues on with DNA replication DNA has a polarity- 5’/3’ 5’= 5th carbon 3’= BASE P P P 5 4 1 3 2 Only add nucleotides to the 3’ end DNA replication requires no ATP Gaining energy from ATP- ATP has a similar structure to DNA- by breaking the phosphate bonds this produces enough energy to fuel the reactions- breaking the phosphodiester bonds- and forms energy that can fuel DNA replication. During DNA replication- self generating energy by the bonds Can’t do it on the 5’ end because the phosphates have already been removed 3.2 billion- nucleotides in the human genome DNA synthesis- 4-6 genome- exact replication Requires ATP to go back and fix the mistake ----- slide 14- DNA exonuclease moves from 3’ to 5’ backspace properties to correct any mistakes  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Add nucleotides to the 3’ end Not bidirectional on both strands Time required= lagging strand will take more time for DNA replication GO THROUGH slide 18 Phosphodiester DNA polymerase exists as a dimer- exists as 2 identical subunits Trombone model- loop DNA polymerase places the nucleotides from a 5’ to a 3’ direction. The original strand of DNA will form a guide for the nucleotides to be placed- complementary- A-T/C-G However, DNA polymerase is not able to place the first couple of nucleotides- so the RNA primase will place a primer which consists of 10-12. DNA polymerase will then complete the structure. DNA polymerase still makes mistakes- 1 in 10 000 but there are 3.2 billion nucleotides, so these mistakes have a large impact. However, this is greatly reduced through the use of 3’-5’ exonuclease (proofreading) activity- which re-reads the nucleotides placed- if there are any mistakes, it will remove the nucleotides until this mistake in order to replace the wrong nucleotide. Re-reads approximately 10-15 base pairs. The enzyme exonuclease travels from 3’ to 5’- in the opposite direction to DNA polymerase During DNA replication there is a leading and lagging strand. The leading strand follows the replication fork and once it starts by the RNA Primase, it will continue. The lagging strand however, flows in the opposite direction (due to the position of the 3’ and 5’). Thus, it is impossible for it to form a continuing strand due to the difference of direction. Thus, synthesis of nucleotides are produced in short fragments called OKAZAKI FRAGMENTS- which are then connected by DNA ligase DNA REPLICATION;  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Semi conservative- both DNA strands being produced contain a strand from the original DNA which ensures that strands produced are identical, as well as a new strand being produced- the original DNA strand is used as a template Bi-directional- DNA replication starts from the replicating origin and flows outwards in both directions Requires Priming- this is due to the fact that the DNA polymerase is unable to start the first few nucleotides, so a RNA primase forms a primer in order start the strand. Semi discontinuous- okazaki fragments of the lagging strand Accurate- use of 3’ to 5’ exonuclease enzyme Complex DNA gyrase- creates nicks within the DNA double helix strand, in order to reduce the tension in between-which could eventually lead to fragmentation CHROMOSOMES Chromosome from dad isn’t same as that form mum- have slight variations- but they are corresponding chromosomes – same number but different alleles of the genes Centromere- binds the arms together- mitosis- mitotic spindle attachment- to the kinetochores on the centromeres Telomeres- ends of the chromosomes- shorten after each division- loses some of the repeats- when it reaches a certain number, it is targeted to stop DNA replication- depending on the number of errors during cell replication- responsible for stability Errors during cell replication is 3 per 3.2 billion nucleotides so when it is at a critical point, it stops replicating because of this region. Telomeres- like the ends of our shoelaces 8 histones- in an octamer---  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + kinetochore- proteins around centromere- these change or more proteins are present around it to bind to microtubules P arm- chromosomes are orientated with p arm on top Q arm Telomere- contributes to the overall stability of the chromosome and reduces in size after cell division. DNA strand is wrapped around proteins called histones, this is then coiled, and forms a fibre GARY- CELL DEVOLPMENT Proliferation, determination, terminal differentiation, apoptosis Cell increasing number- embryogenesis and growth, maturity, specialization Differentiation=specialization These processes are all regulated- in order to ensure optimum efficiency Proliferation= regulated process where cell contents duplicate followed by division into two cells (mitosis)- - if this isn’t regulated process- this leads to mutations/cancer- dysregulation of processes lead to mutations Cell cycle- controls the process of proliferation Underpinning requirements- nutrients, etc. Primary regulators for multicellular organisms= messengers- e.g. hormones, neurotransmitters= chemical messengers Primary regulators for single-celled organisms- environmental factors and nutrients etc. Chemicals- produced in tissues- help coordinate cell division Differentiation –cells gain or lose structural and functional characteristics- requires appropriate environment and chemical messengers to regulate this Despite the fact that all cells contain the basic genetic material for them to become any cell in the body, this is either activated or deactivated which will affect what is being produced.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Structure depends on function- differentiation ensures that the cells become specialized in order to carry out their required function effectively. Terminal Differentiation- one of the capacities lost by the cell is division- when these cells are destroyed, they cannot be recreated, once they decide on a certain function, this will not change, and it won’t be able to replicate further = e.g. nerve cells – If these cells are destroyed, they won’t be able to reproduce/replicate because of the terminal differentiation Ability to become specialized, however, will not be able to replicate any more. Early stages can be reversible, but later on they may not. Apoptosis (programmed cell death)- death of cells- in a regulated and controlled fashion Stem cells sit on dermis= have the capacity for proliferation- enough cells to meet need, but not too many- lag phase could result if they exist at different times e.g. of car on highway trying to maintain speed- brakes and accelerator Proliferation and apoptosis must occur in order to ensure that cells do not produce rapidly with no need- or else there will too many skin cells- and also that not too many cells are dying and not enough being produced to take their place Thickened and thin areas of skin due to proliferation and apoptosis Population number of cells exist due to apoptosis and proliferation Information sources that provide info to the cell to tell the cell whether it will continue divide, die etc. Cells are embedded in tissues in an extracellular matrix which is composed of chemicals- source of info is signals from chemicals in the extracellular matrix. Growth factors, hormones- control the developmental fate. Cell memory- when they obtain a signal to differentiate, they know what they have to divide into- during embryogenesis Key role of plasma membrane. Restriction point in G1- specialize, divide, or don’t divide In G2- are we ready to divide and is that process appropriate- distribution of chromosomes  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Cleavage development- b/c slide 15- multiple cells- produce enough biological structures to form the embryo During the Morula- first signs of differentiation- pluripotent- because the outer cells are exposed to a different environment when compared to the internal environment. Blastocysts- inner cell mass and trophoblasts (outer)- give rise to the fetal part of the placenta Developmental fate of cell has become determines- determination Cells in the 2 day 4cell embryo are totipotent. Connective tissues and blood vessels abide under the skin which provides the cells with the appropriate nutrients- diffusion- difference between the nutrients for the trophoblasts and inner cell mass**** Cell becomes determined then differentiates Determination and embryogenesis- determination refers to the fact that cells already know what they will become, it is already preset, before they differentiate- they look similar to stem cells because their structure has not yet changed to reflect their function. Embryogenesis- is the regulated process of proliferation, determination, differentiation and apoptosis. Embryonic Development; The zygote is formed when the sperm fertilizes the egg in the oviduct. Day 2- 4 cell stage- formed from 2 mitosis processes occurring- the overall cell size doesn’t change, but the number of cells inside increases. Day 3- forms the morula which is the final stage of totipotent cells- and consists of a ball of identical cells. DAY 3/4 IS THE FIRST SIGN OF CELL DIFFERENTIATION Morula= small ball of identical cells called blastomeres Provides enough cells to begin forming the different tissues etc. Rapid cell divisions Size of morula  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Day 4- early blastocysts- morula hollows out and filled with fluid- the surrounding membrane, the zona pellucida begins to degenerate- shows two layers forming which are both totipotent. Day 6- developed blastocyst which is able to embed itself into the wall of the uterus. Day 0-3; cleavage stage- gives rise to the morula= spherical ball of identical cells Day 3-4; first signs of differentiation occurring Membrane specialization exists near the oviduct to allow for the ovulated egg to travel to the oviduct- cilia Cells are able to understand what cell they will become because their role/function has been pre- determined. Thus, the cells on day 4, will be able to convert into the inner cell mass or the trophoblasts because it has been preset. Determination occurs before the cell has differentiated. Embryonic determination??? Slide 17 cell development. Consider diagram on 22- epiblasts, hypoblasts etc. Syncytiotrphoblast- expands within the lining of the uterus until it dissolves the wall of the blood vessels so that the blood becomes in direct contact with the cell Tri-laminar discs- primary germ layers-ectoderm, mesoderm, endoderm The ectoderm, mesoderm and endoderm are the 3 primary germ layers- they give rise to the 4 basic tissue types; connective, epithelial, nerve and muscular. The three primary germ layers are all responsible for epithelium and connective tissue- ❖ Endoderm- epithelium cells of the skin- epidermis- cranial bones/branchial cartilage ❖ Mesoderm- lining of blood vessels- cartilage, bone, other connective tissues ❖ Ectoderm – lining of digestive tract- connective tissue components of some glands, e.g. thyroid, parathyroid Ectoderm Mesoderm Endoderm  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Refers to the outer most Middle layer of the human Internal layer of the human layers of the body body body Nerve tissues, epidermis of Responsible for the formation skin (hair, nails, sweat glands), of muscle tissue- skeletal, cornea of eye etc. cardiac and smooth THE TIMING OF REPRODUCTION IN THE LIFE COURSE---- exam- actual content!!! Pregnancy- parents will be worried about different factors of pregnancy. Some issues include; ❖ Family planning ❖ Concerns of parents individually and together Lately, women have been having kids at a much later age. Some reasons may include- financial hardships, women wanting to work, maturity etc. Also, environmental factors and geographical factors may affect this discrepancy. Men finish their reproduction life much later than women, however there has been issues regarding men’s ability to reproduce due to sperm. Male reproductive age is much later than women. As women age, their probability of having a child rapidly decreases (also based on how long they have been trying to conceive)- main reason is due to oocyte depletion Failing sperm count- due to pollution of estrogens- from chemicals and foods. Family related issues- if the difference in age of pregnancy is 2years or less, there is an increased risk of poor performance in cognitive skills, increase in risk of low birth rate, smaller for gestational age. Child care- responsibility has been differed from the patients to relatives. Teenage pregnancy- financial care, maturity, education.  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Men have a gradual decline of fertility- based on age 95% confidence- scientists believe that the true value is in-between the two dotted lines- slide 14 having a child with a disability- most families have their next child sooner in order to ‘replace’ that existing child instead of enlarging this gap in order to take care of the child. Fertility levels collapse- child care constraints- women work- P= probability by chance alone Slide 21- is >1- increased chance, if 1 layer By shape ❖ Squamous ❖ Cuboidal- central ROUND nucleus- tall as they are wide ❖ Columnar- taller than they are wider Specialization ❖ Goblet ❖ Ciliated ❖ Keratinizing- water resistant- epidermis Pseudostratified- falsely stratified- looks like it is stratified but all the cells rest on the basement membrane/basal laminar but don’t always reach the lumen of the surface Transitional- stratified-only in urinary/renal systems- able to stretch- when bladder is full- tight junctions don’t allow urine to pass through the adjacent cells- contain specialized umbrella cells. Simple squamous- single layer of flat cells- alveoli- lining of blood vessels, lining of body cavities etc. – only able to see flat nucleus because cytoplasm is minimal- Vein- thin wall with large lumen Simple cuboidal- tall as they are wide- e.g. kidney tubules, ducts, bronchioles Renal medulla- Simple columnar- absorption, secretion, structural- nucleus placed towards the bottom of the cell Stratified squamous epithelium- surface cells are flat AND ALIVE- NUCLEI PRESENT- therefore IF NUCLEI ARE PRESENT THEN THE CELL IS NON KERATINISING Stratified squamous keratinizing- Desiccation tolerant- layer of dead cells  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Stratum cornium- dense keratinized tissue-dead- no nuclei- packed with protein called keratin- Production- lysosomes gets rid of everything except for keratin Characteristics- ❖ Avascular- no blood vessels- nutrients/oxygen obtained from underlying connective tissue ❖ Polarized- top(apical)/bottom(basolateral)/lateral sections All epithelia rest on a basement membrane ❖ Little intercellular material/matrix- because they make the lining ❖ Basal lamina/basement membrane- anchors epithelia to connective tissue via desmosomes ❖ Limited lifespan- die and shed and renewed by mitosis Epithelia- apical/basolateral domains- Apical- free surface-specializations exist on the apical domain Basolateral- adjacent epithelial cells/underlying connective tissue Hemi desmosomes- at the bottom*** Apical surface - Cilia- beat rhythmically in one direction- cilium=singular- found in fallopian tube- movement of the ovum along towards the uterus - Microvilli- finger like extensions- surface extensions- microvillus= singular- contains actin in the core to keep it patent for support- not motile. Increases surface area for absorbtion- Collectively they form a brush border. - Stereocilia- long microvilli- not motile, absorb some fluid in the lumen to concentrate the spomatozoa- Lateral surface- contains functional complexes- join adjacent cells together/ anchorage of cell, communication within cell - Tight (occluding)- seals the basolateral compartment from the apical compartment - Adhering- hold cells together - Desmosomes- strong sdhesion between cells- has filaments (intermediate filaments) attached to it - Gap-intercalated discs, and found in smooth muscles to allow for contraction as a unit- allow for rapid communication  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + - Only for LATERAL/BASAL SURFACE-hemidesmosomes anchor cells to basal laminar/basement membrane- hemi=filaments on only one side- nutrients pass via these junctions or from the lumen into the cell Intercalated discs- stepped appearance- contains 3 types of junctions - Desmosomes- - Adherent junctions - Gap junctions- Basement membrane- junction between epithelium and connective tissue- hemidesmosomes would anchor the cells to the basement membrane Exocrine glands= epithelial derivative Lining epithelia; Connective Tissue-proper Tissue which supports, connects (connects organs, blood vessels etc. – keeps them in place) and protects the body (shock absorber- ground substance=gel- hydrated--- adipose tissues around kidneys) Laminar propria= underlying connective tissue Epithelium + laminar propria= mucosa Embryonic=mesenchyme- gives rise to all connective tissue CT proper- support- not really metabolic except for adipose tissue. E.g. loose, areolar, adipose, reticular (forms the framework in lymphoid tissue), dense regular/irregular CT Specialized- cartilage, bone, blood, lymphoid Fibroblasts- associated with collagen fibers- key substance for production of ground substance and fibers- produces matrix Ground substance + fibers=matrix Ground substance- gel like- made up of proteins Elastic fibers thinner than collagen fibers Some cells are; ❖ FIXED (permanent)  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ TRANSCIENT (migrating) Everything starts form mesenchyme cells- multipotential- gives rise to all cells in body Embryonic cells Umbilical cord contains mesenchyme cells -Blast- immature/active form of a cell -Cyte- mature/quiescent cell fibroblasts- active tissue therefore will always be called fibroblasts TYPES OF CONNECTIVE TISSUE; ❖ Fibroblasts- gives rise to matrix= ground substance + fibers Thinner, darker, elongated nuclei Collagen fibers= strength ❖ Macrophages- phagocytes-clear up debris, bacteria, foreign substances, anything that is dead/dying Present antigen to lymphocytes Contain multiple lysosomes- because they are involved in digestion Cant be differentiated from fibroblasts with a light microscopes Originated from the monocytes of blood and form a part of the mononuclear phagocytic system- will digest anything that is foreign ❖ T or B lymphocytes- or plasma cells- activated by B lymphocytes ❖ Adipocytes Store triglycerides- poorly vascularized????? ❖ White blood cells- eosinophils/neutrophils Irregular connective tissue- way it is arranged  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Blood cells- granulocytes; ❖ Move from blood into the tissue ❖ Eosinophils, neutrophils, lymphocytes Lymphocytes- Plasma cells- more de condensed nucleus—pale areas called ‘negative Golgi image’- produce protein=antibody Synthesis of immunoglobulins therefore cytoplasm is basophilic due to presence of RER CT- general Matrix- produced by fibroblasts or chondrocytes or osteoblasts etc. Matrix=ground substance and fibers (collagen, reticulin, elastin) Ground substance= viscous solution/soft gel which is aqueous- shock absorbing- barely visible/stains faintly Main constituents- tissue fluid (extracellular fluid) Glycosaminoglycans (GAGs)- large polymers of repeating disaccharides-responsible for hydrating and making the Groudn substance more fluid Glycosaminoglycans added to a protein=proteoglycans Adhesive glycoproteins- protein with a monosaccharide attached Tissue fluid- produced as a result of hydrostatic pressure of blood as it passes through capillaries- as it moves out into tissue - Medium through which diffusion occurs nutrients/O2/CO2/hormones etc. can pass out- or through receptors - Reabsorbed into capillaries- returned for circulation- drained out into lymphatic vessels - If something goes wrong- doesn’t come back=oedema=swelling- accumulation of tissue fluid due to inadequate absorption/excessive movement into tissue Glycoproteins- fibronectin- binds cells Laminin- binds cells to basal lamina FIBERS Collagen- most common- tough white fibers (no staining), vary in diameter. Give CT its strength  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Papillary dermis/ reticular dermis- thin vs thick collagen fibers- irregular- goes in different directions TENDON- COLLAGEN FIBERS RUNNING IN ONE DIRECTION- JOINS MUSCLE TO BONE- RESPONSIBLE FOR MOVEMENT- STRONG TENSILE STRENGTH TYPES OF COLLAGEN - Type 1- thick fibers - Type 2- found in cartilage- collagen fibrils embedded in cartilage ground substance - Type 3- reticular fibers - Type 4- major component of basal lamina Reticulin- supports central vein- framework for support- type 3 with associated glycoproteins Elastic fibers- able to recoil Types of CT Embryonic/mesenchyme- referred to as mucous CT- jelly like matrix Connective tissue proper Specialized- cartilage, bone, blood Loose/dense CT- depends on how much space there is between the different components Loose areolar connective tissue- Dense regular connective tissue- dense- packed together Dense irregular connective tissue New born babies- generate a lot of brown fat- insulation becasue babies can’t regulate their own temp properly Classification of microorganisms True nucleus- eukaryotes- contain a membrane bound nucleus Prokaryotes- no nucleus present- state before you have a nucleus- they are primitive eukaryotes  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + The three domain system- classifies ORGANISMS into BACTERIA, ARACHAEA, EUKARYA ❖ Bacteria- mitochondrion, cyanobacteria, gram negative, gram positive etc. ❖ Archaea- Archaea-old-look like bacteria- no nucleus-good functions in harsh conditions- e.g. extreme halophiles- loves salts, methanogens etc. ❖ Eukarya- animals, fungi, plants, amoeba etc. Bacteria and archaea are prokaryotes Common features of all cells; ❖ Contain a lipid bilayer membrane ❖ Require the use of ATP for energy ❖ Contain genes/DNA ❖ Constant genetic code ❖ Proteins control cell structure and function ❖ Dogma- DNA transcribing into RNA, RNA forms proteins etc. Property Bacteria Archaea Eucarya Predominantly multi-cellular No No Yes Cell contains a nucleus & other No (prokaryotes) No (prokaryotes) Yes membrane bound organelles Cell walls contain muramic acid Most No No (acid for the cell wall) Membrane lipids ester-linked Yes No (ether-linked) Yes DNA Usually 1 circular Usually 1 circular Paired chromosomes a chromosome (nucleoid) chromosome with histones Genome size (bp) 0.03 - 10 million 0.3 - 5.8 million 0.6 million - 670 billion mRNA introns No Some Yes Polycistronic mRNA Yes Yes No  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + Location of ribosomes Dispersed in cytoplasm Dispersed in Attached to endoplasm cytoplasm reticulum and can also free float within cytopl Size of ribosomes 70S (50/30) 70S 80S (cytoplasmic) (60/4 Rifampin-sensitive RNA polymerase Yes No No Methanogenesis No Yes No Extremely thermophylic (growth at No Some No 110°C) Prokaryotic DNA= nucleoid- able to simultaneously convert DNA to RNA to proteins- in the cytosol of the cell- simultaneously- TRANSCRIPTION AND TRANSLATION OCCUR SIMULTANEOUSLY Ribosomes- RNA being read to form proteins- prokaryotic DNA doesn’t contain introns- therefore no modification is needed before translation occurs Prokaryotes- DNA is not enclosed within a nuclear membrane- they lack membrane bound organelles. Some prokaryotes contain pilus which is an additional part of the cell which allows them to attach to substances. Virulent - pathogenic Flagellum-MOVEMENT- allows bacteria to be mobile- some bacteria contain flagellum, some don’t E.g. bacteria and archaea are prokaryotes Algae, fungi, protozoa, animals and plants are eukaryotes Eukaryotic cells- contain a membrane bound nucleus, and membrane bound organelles. Transcription which is the conversion of a gene into an mRNA signal occurs in the nucleus and then moves to the cytoplasm for translation to occur. Translation is the conversion of the mRNA to proteins/AA sequence- occurs in the cytosol- ribosomes are used in this process- if the fate of the protein is for the cell itself- then the protein is synthesised in the cytoplasm- however, if the protein is going to be used in the plasma membrane or is supposed to be exported outside of the cell, the ribosomes will migrate to the ER and deposit there and the protein which is synthesised will be produced inside the ER. Archaea- extreme bacteria-  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + ❖ Psychrophilic- love low temperatures ❖ Thermophiles- live in high temps ❖ Methanogens- live in anaerobic environments (no oxygen)- and produce methane ❖ Halophiles- live in extreme salt conditions/environments Exploit particular bacteria for use in biotechnology- (Acid for cell wall=muramic acid Bacteria/archae have small genome size when compared to eukarya Dna- made uup of coding/non coding regions- coding= exons (coded), introns (sequences that arent coded) 90% non coding, 10% coding- The 10% is made up of introns/exons) PCR- tach polymerase- extract what they can do and use them Mycoplasma- tiny bacteria- no cell wall Bacteria doesn’t have a large genome size, so they only contain the necessary structures- therefore they don’t contain introns- and because transcription and translation occurs simultaneously, splicing does not occur in prokaryotes. Polycistronic- messenger rna formed by multiple--- gene forms many messenger rnas Monocistonic- Each gene makes only one messenger RNA KNOW THE SIZE OF RIBOSOMES; Eukaryotes- 60S/40S. Prokaryotes- 50S/30S E.G. BACTERIA- 70S- SVEBERG- WHEN PARTICLES ARE PLACED IN TESTTUBE AND PLACED IN centrifuge- the sediments fly to side, and then measure this- in Svedberg Different ribosome subunits can be targeted to prevent translation to occur Rna polymerase- transfers DNA to rna- sensitive to particular antibiotics- rifampin- doesn’t affect eukaryotic cells 6 subgroups of microbes- FAB PAV bacteria, archaea, fungi, protozoa, algae, viruses  + In our lowly state, the Lord has remembered us. Alleluia for His mercy endures forever + fungi= mono and/or multicellular- yeast= fungus made of one cell Taxonomy- relationships- based on how close they are to one another- now based on DNA Molecular taxonomy- more precise than older Naming based on genus and species. GENUS SPECIES Humans= homo sapiens House fly- Musca domestica Corn- Zea mays Microbe- Escherichia Coli Microbial classification; Morphology- shape, group arrangement Biochemical- ability to chang