General Biology PDF

aGeneral Biology compound. It is non- cellulosic. Group 1:DISTINGUISH PROKARYOTIC AND EUKARYOTIC cellulosic. 2. Cell Membrane: CELLS ACCORDING TO THEIR DISTINGUISHING FEATURES...

aGeneral Biology compound. It is non- cellulosic. Group 1:DISTINGUISH PROKARYOTIC AND EUKARYOTIC cellulosic. 2. Cell Membrane: CELLS ACCORDING TO THEIR DISTINGUISHING FEATURES 2. Cell Membrane:  It is complex made up of  The cell membrane is phospholipid bilayer. Prokaryotic Cell simple.  In eukaryotes, plasma The term “prokaryote” is derived from the Greek word  In prokaryotes, plasma membrane consists of “pro“, (meaning: before) and “karyon” (meaning: kernel). It membrane does not sterols and carbohydrates. contain carbohydrates 3. Organelles: translates to “before nuclei.“ or sterols.  Many organelles are Prokaryotic cells make up prokaryotes. Prokaryotes are 3. Organelles: present. unicellular organisms that lack membrane-bound structures,  Only few organelles are  Envelope bound the most noteworthy of which is the nucleus. Prokaryotic present. organelles present. cells tend to be small, simple cells, measuring around 0.1-5  None are bound by cell 4. Nucleus: μm in diameter. membranes.  Eukaryotes have nuclei 4. Nucleus: separated from the Prokaryotic Cell Features  Prokaryotes have no cytoplasm by a double Nucleoid: A central region of the cell that contains its DNA. true nucleus, with their membrane and containing Ribosomes: are responsible for protein synthesis. nuclear material both chromosomes and a Cell Wall:The cell wall provides structure and protection distributed diffusely nucleolus. from the outside environment. Most bacteria have a rigid cell throughout interior of  The nuclear material of wall made from carbohydrates and proteins called cell. eukaryotes is arranged peptidoglycans.  Prokaryotes contain a into multiple Cell Membrane:Every prokaryote has a cell membrane, also single circular strand of chromosomes bound to known as the plasma membrane, that separates the cell from DNA and have no the protein histone. the outside environment histones. 5. DNA: 5. DNA:  DNA is in paired Capsule:Some bacteria have a layer of carbohydrates that  DNA is in a loop. chromosomes. surrounds the cell wall called the capsule. The capsule helps  DNA floats in the  It floats in nucleus the bacterium attach to surfaces. cytoplasm and consists contained a membrane Fimbriae: Fimbriae are thin, hair-like structures that help of small ribosomes of and consists of large with cellular attachment. 70S type. ribosomes of 80S type. Pili: are rod-shaped structures involved in multiple roles, 6. Flagella: 6. Flagella: including attachment and DNA transfer.  Simple lacking  Complex with '9+2' Flagella: are thin, tail-like structures that assist in movement. microtubules. arrangement of Eukaryotic Cell  Extra cellular and 20nm microtubules. The term “Eukaryotes” is derived from the Greek word “eu“, diameter.  Intracellular and 200nm (meaning: good) and “karyon” (meaning: kernel), therefore, diameter. translating to “good or true nuclei.” Eukaryotic cells make up eukaryotes. Eukaryotes are organisms whose cells have a In conclusion, there are numerous ways in which nucleus and other organelles enclosed by a plasma prokaryotes and eukaryotes differ and resemble one membrane. another. The primary conclusion to be drawn from this report Eukaryotic cells are large (around 10-100 μm) and complex. is that eukaryotes have a nucleus, whereas prokaryotes do While most eukaryotes are multicellular organisms, there are not. some single-cell eukaryotes. Group 2: CLASSIFY THE DIFFERENT CELL TYPES (OF Eukaryotic Cell Features PLANTS\ANIMAL TISSUE) AND SPECIFY THE FUCTIONS OF Nucleus: The nucleus stores the genetic information in EACH chromatin form. Nucleolus:Found inside of the nucleus, the nucleolus is the CELL TYPE OF PLANT TISSUE part of eukaryotic cells where ribosomal RNA is produced. 1. COLLENCHYMA: Are elongated cells with irregularly thick Plasma Membrane: The plasma membrane is a phospholipid cell walls that provide support and structure. bilayer that surrounds the entire cell and encompasses the organelles within. TYPES OF COLLENCHYMA TISSUE Cytoskeleton or cell wall:The cytoskeleton or cell wall ANGULAR: Have thicker cell walls in the corners of the cell, provides structure, allows for cell movement, and plays a role giving them an angular appearance. in cell division. TANGENTIAL: Tangential collenchyma cells have cell walls Ribosomes: are responsible for protein synthesis. that are thicker only when they are parallel to the surface of Mitochondria: also known as the powerhouses of the cell, the structure where they are found. are responsible for energy production. ANNULAR: The Rarest of the types and have been observed Cytoplasm:The cytoplasm is the region of the cell between in the leaves of carrot plants.. the nuclear envelope and plasma membrane. LACUNAR: Also known as lacunate collenchym Cytosol: is a gel-like substance within the cell that contains Lacunar collenchyma, like angular collenchyma, has primary the organelles. cell wall thickenings located where adjoining cells are in Endoplasmic Reticulum: The endoplasmic reticulum is an contact. organelle dedicated to protein maturation and transportation. Vesicles and vacuoles: are membrane-bound 2. SCLERENCHYMA: Have thickened lignified walls, which sacs involved in transportation and storage. make them strong and waterproof. They are commonly classified into support types and conducting forms Difference in Cell Structures TYPES OF SCLERENCHYMA TISSUE PROKARYOTIC EUKARYOTIC FIBERS: These are long, slender cells that are typically 1. Cell Wall- Murein is the 1. Cell Wall- Cellulose is the found in bundles. They provide tensile strength to the plant. main strengthening strengthening compound. It is Fibers are commonly found in stems, roots, and leaves.  SCLEREIDS: Also known as stone cells, sclereids are variable SMOOTH MUSCLE: Found in the walls of organs, blood in shape and often shorter than fibers. vessels, and other structures. Responsible for involuntary They contribute to the hardness of seed coats, nutshells, and movements such as peristalsis in the digestive tract or certain fruits like pears. regulating blood flow. 3. PARENCHYMA : One of the simple permanent tissues that NERVE TISSUE: Also known as nervous tissue. Found in the help in creating a major portion of fundamental or ground brain, spinal cord, and nerves. tissues in plants. A simple plant tissue composed of loosely TWO MAIN TYPES OF NERVE TISSUE packed, thin walled, and isodiametric cells. They make up the 1. NEURONS: Responsible for communication within the bulk of the plant. nervous system. Send and receive signals from your brain. TYPES OF PARENCHYMA TISSUE THREE MAIN TYPES OF NEURON CHLORENCHYMA: Primarily found in the mesophyll layer of  SENSORY NEURONS: The nerve cells that are activated plant leaves. It contains chloroplasts responsible for by sensory input from the environment photosynthesis.  MOTOR NEURONS: A nerve cell forming part of a AERENCHYMA: Has small compartments are lacunae within pathway along which impulses pass from the brain or them. spinal cord to a muscle or gland. SECRETORY: Produces and releases substances for various  INTERNEURONS: Neurons that are found exclusively in functions such as defense, attraction, and protection. the central nervous system 2. NEUROGLIA: Any of the cells that hold nerve cells in place CELL TYPE OF ANIMAL TISSUE and help them work the way they should. EPITHELIAL TISSUES: Cells in this tissue form protective layers THREE MAIN TYPES OF NEUROGLIA and linings.  ASTROCYTES: A subtype of glial cells that make up the Serves as a protective barrier, secreting substances, and majority of cells in the human central nervous system absorbing substances. (CNS) TYPES OF EPITHELIAL TISSUE  SCHWANN: The glial cells that form the myelin sheath SIMPLE SQUAMOUS: Lines blood vessels and air sacs of on axons outside the brain lungs. Permits exchange of nutrients, wastes, and gases SIMPLE CUBOIDAL: Lines kidney tubules and glands. MUSCLE CELL: Also known as a myocyte, is a mature Secretes and reabsorbs water and small molecules contractile cell in the muscle of an animal. In humans and SIMPLE CULOMNAR: Lines most digestive organs. Absorbs other vertebrates there are three types: skeletal, smooth, nutrients, produces mucus and cardiac. STRATIFIED SQUAMOUS: Outer layer of skin, mouth, vagina. Protects against abrasion, drying out, infection SEX CELL: also called reproductive cells or gametes. Sperm STRATIFIED CUBOIDAL: Lines ducts of sweat glands. cells are produced in men's testicles and egg cells are Secretes water and ions produced in women's ovaries. STRATIFIED CULOMNAR: Lines epididymus, mammary Sex cells are formed through a particular kind of cell glands, larynx. Secretes mucus division called meiosis. CONNECTIVE TISSUES: Support and connect different tissues NERVE CELL: A type of cell that receives and sends messages and organs of the body. from the body to the brain and back to the body. The messages are sent by a weak electrical current. Also called TYPES OF CONNECTIVE TISSUE neuron. LOOSE CONNECTIVE TISSUE: Includes areolar, adipose, and reticular tissues. FAT CELL: It provides elasticity and nutrients and acts as a filler  White adipocytes: Which store energy as a single large between organs and tissues. lipid droplet and have important endocrine functions DENSE CONNECTIVE TISSUE: Includes dense regular, dense  Brown adipocytes: Which store energy in multiple small irregular, and elastic tissues. lipid droplets but specifically for use as fuel to generate It offers strong support and resistance to tension, body heat such as in tendons and ligaments. Specialized tissue: Specialised Connective Tissue GENERAL FUNCTION OF CELL IN STRUCTURE Other than these, there are supportive connective tissues, They provide structure for the body, take in that help in maintaining correct posture and support internal nutrients from food, convert those nutrients into energy, and organs,e.g. cartilage and bone. carry out specialized functions. BONE: Provides structural support for the body, protects GENERAL FUNCTION OF CELL IN GROWTH vital organs, and serves as a reservoir for minerals. During cell growth, the cell ingests certain molecules CARTILAGE: Cartilage is a non-vascular type of supporting from its surroundings by selectively carrying them through its connective tissue that is found throughout the body. cell membrane Cartilage is a flexible connective tissue that differs from bone GENERAL FUNCTION OF CELL IN APOPTOSIS in several ways; it is avascular and its microarchitecture is Apoptosis is the process of programmed cell death. less organized than bone. It is used during early development to eliminate unwanted BLOOD CELLS: blood cells is based primarily on observations cells. of the presence or absence of a nucleus and cytoplasmic GENERAL FUNCTION OF CELL IN METABOLISM granules Cell metabolism is a network of biochemical MUSCLE TISSUES: The ability to contract, generating force reactions transforming metabolites to fulfill biological and causing movement or tension in the body. functions SKELETAL MUSCLE: Also known as voluntary muscle. GENERAL FUNCTION OF CELL IN REGULATION OF Attached to bones and allows for voluntary movement TEMPERATURE CARDIAC MUSCLE: Found only in the heart. Involuntary and A cell does not regulate its temperature. The heat contracts to pump blood through the circulatory system. produced by metabolism creates the temperature of a cell. GENERAL FUNCTION OF CELL IN COMMUNICATION Functions of Pseudopodia In multicellular organisms, cells constantly send and Include movement, anchoring to a substrate, capturing and receive chemical messages to coordinate the actions of other engulfing prey. organs, tissues, and cells. A pseudopod or pseudopodium is a temporary arm-like GENERAL FUNCTION OF CELL IN REPRODUCTION projection of eukaryotic cell membrane that emerged in the Cellular reproduction is a process by which cells direction of movement. duplicate their contents and then divide to yield multiple cells with similar, if not duplicate, contents. Extracellular Matrix: A large network of proteins and other molecules that surround, support, and give structure to cells Group 3: CELL MODIFICATION and tissues in the body. Cell Modification a process that occurs after cell division where the newly formed cells are. Extracellular Matrix Functions: The extracellular matrix IMPORTANCE OF CELL MODIFICATIONS also serves as a guide for cell movement within the tissue. It It allows cells to develop specialized structures and helps to make sure the cells do not migrate outside of the functions. tissue. Why does cell modification occur? Cell specialization or modification occurs after cell division, 2. Basal Modifications : Include hemidesmosomes and structurally modifying newly formed cells so they can basal folding. perform functions efficiently. Hemidesmosomes are junctional complexes that facilitate epithelial cell attachment to the basement THREE MAIN TYPES OF CELL MODIFICATION membrane in stratified and complex epithelia, including skin, 1. Apical Modifications : Inlude cilia, flagella, microvilli, cornea, gastrointestinal and respiratory tract, and amnion. pseudopods, and extracellular matrix. Hemidesmosomes: Are multiprotein complexes that facilitate the stable adhesion of basal epithelial cells to the CILIA: Triggers the discharge of stinging devices in jellyfish underlying basement membrane. and gives rise to the light-sensitive rods of the mammalian Basal Infoldings: The basal membrane can regulate the retina and the odour-detecting units of olfactory neurons. interaction with cytoplasmic organelles, the geometry of the extracellular space, and the osmotic gradient within it. FLAGELLA : Are microscopic hair-like structures involved in Basal Infoldings Function: The basal infoldings' intricate the locomotion of a cell. The word “flagellum” means “whip”. structure regulates the basal membrane's interaction with  These are present in protozoans, choanocyte cells of cytoplasmic organelles, extracellular space geometry, and the Metazoa, and in other classes. osmotic gradient within it. TYPES OF FLAGELLA  Monotrichous: A single flagellum at one end or the 3. Lateral Modifications : Include tight junctions, other. These are known as polar flagellum and can adhering junctions, and gap junctions, Desmosomes. rotate clockwise and anti-clockwise. Tight Junction: also known as occluding junctions or zonulae  Peritrichous: Several flagella are attached all over the occludentes, are multiprotein complexes that prevent solute organism. These are not polar flagella because they are and water leakage and seal between epithelial cells. found all over the organism. Adherens Junction: responsible for initiating and stabilizing  Lophotrichous: Several flagella at one end of the cell-cell adhesion, regulating the actin cytoskeleton, organism or the other. These are known as polar intracellular signaling, and transcriptional regulation. flagellum and can rotate clockwise and anti-clockwise. Gap Junction: facilitate electrical communication between  Amphitrichous: Single flagellum on both ends of the cells and small second messengers, found in all tissues and organism. These are known as polar flagellum and can cells, particularly in neurons and cardiac muscle. rotate clockwise and anti-clockwise. Desmosomes: are intercellular junctions that form strong FLAGELLA FUNCTION adhesion between cells and link intracellularly to the  Help an organism in movement. intermediate filament cytoskeleton, providing mechanical  Act as sensory organs to detect temperature and pH strength to tissues. changes.  Few eukaryotes use flagellum to increase reproduction OTHER SPECIALIZED MODIFICATIONS rates. The development of nerve, muscle, red blood, and sperm  Recent research proved that flagella are used as cells, as well as specialized cells in plants like root hairs and secretory organelle. guard cells, is crucial. MICROVILLI: Play an important role in the digestion and SPECIALIZED ANIMAL CELL absorption of intestinal contents by enlarging the absorbing Animal cells, including red blood cells, pancreatic cells, and surface approximately 25 times. pancreatic cells, are specialized in oxygen transport, protein Main function of Microvilli production, and protein export through various organelles  Are to increase the surface (like in the case of the small and enzyme-loaded storage vacuoles. intestine).  Microvilli also provides a means of anchorage (in the Group 4: Cell Cycle & their Control Points case of egg cells and white blood cells) Where are microvilli found and what is their function? Cell Cycle: a series of events that a cell passes Microvilli are found in intestinal epithelial cells to increase through from the time until it reproduces its replica. surface area to allow for more nutrient absorption. Pseudopodia: can also be observed in cancer cells, as they Binary Fussion: a type of asexual reproduction typically function as arms to enable the spread of cancer observed in prokaryotes and a few single celled eukaryotes. In this method of asexual reproduction, there is a separation of the parent cell into two new daughter cells. Eukaryotic cells have a nucleus enclosed within the nuclear 1.The G1 checkpoint, at the G1/S transition. membrane and form large and complex organisms. 2.The G2 checkpoint, at the G2/M transition. 3. The spindle checkpoint, at the transition from metaphase Phases of cell cycle to anaphase Inter Phase: It is the longest phase. in a typical human cell, out of the 90h, inter phase lasts for 89h. G1 Checkpoint (G1 Restriction): At the G1 checkpoint, a cell checks whether internal and external conditions are right for Prokaryotic cells are single-celled microorganisms known to division. Here are some of the factors a cell might assess: be the earliest on earth. Prokaryotes include Bacteria and Archaea. The photosynthetic prokaryotes include G2 Checkpoint: To make sure that cell division goes smoothly cyanobacteria that perform photosynthesis. (produces healthy daughter cells with complete, undamaged DNA), the cell has an additional checkpoint before M phase, G1 phase: It is the post mitotic phase and takes called the G2 checkpoint. place at the end of cell division the newly formed cells accumulate the energy prepares Metaphase Checkpoint: This occurs at metaphase. themselves for the synthesis of DNA. During Anaphase-promoting complex (APC) regulates this this synthesis of RNA and protein takes place. checkpoint. This is also called spindle checkpoint. S Phase: It is the synthesis phase during this phase Cell Cycle Regulatory duplication of DNA and centriole takes places. The The cell cycle is regulated by cycle duplication of DNA results in the duplication of 1.Cyclin chromosomes. 2.Cyclin-dependent kinase inhibitors (CDKIS) 3.Cyclin-dependent kinase (CDKs). G2 Phase: It is the pre- mitotic gap phase (invisible phase) the synthesis of RNA and protein continues in this phase. The Cyclin: Their concentration varies during the cell cycle. formation of macro molecules for spindle formation takes Cyclins are the family of proteins which regulates the cell place and the cell prepare itself to go into the mitotic phase. cycle. M phase (Mitosis) G2: G2 cells are divided into two daughter The four basic types found in human and most other cells which may enter the cycle again at G1 phase or come eukaryotes: out of the cycle to GO phase. Mitosis is the distribution of the 1.G1 cyclins. two sets of chromosomes into two separate and equal nuclei. 2.G1/S cyclins. Karyokinesis refers to the cell division of nucleus into two 3.S cyclins daughter nuclei. It has 4 sub-stages, namely prophase, 4.M cyclins. metaphase, anaphase and telophase. Cyclin-dependent kinase (CDKS): These are a family of Cytokinesis refers to the cell division of the cytoplasm protein kinases that regulates the cell cycle. They are present resulting in two daughter cells. in all known eukaryotic cells. CDKI is a protein which inhibits cyclin-dependent Mitosis is divided in to five parts: kinesis (CDK). Prophase: Mitosis begins with prophase, during which Cell cycle progression is negatively controlled by kinases- chromosomes recruit condense and begin to undergo a inhibitors (called CDIs, CKIs or CDKIs). cyclin-dependent. condensation process that will continue until metaphase. These are involved in cell cycle arrest at the G1 phase. Prometaphase: Begins with the abrupt fragmentation of the Positive Regulators: Are those which control the changes nuclear envelope into many small vesicles that will eventually necessary for cell division. be divided between the future daughter cells. They include: Metaphase: Next, chromosomes assume their most Cyclin compacted state during metaphase, when the centromeres Cyclin-dependent kinase (CDKS) of all the cell's chromosomes line up at the equator of the Negative Regulators: Are those which control the positive spindle. regulators. Anaphase: The progression of cells from metaphase into They include: anaphase is marked by the abrupt separation of sister Rb protein chromatids. P53 gene Telophase & Cytokinesis: Mitosis ends with telophase, or the Inhibitors of cdks - which are of 2 types Ink family (Inhibitors stage at which the chromosomes reach the poles. of kinase) P19,P15 CIP family (cdks inhibitory proteins). P27, P57 Three EXP. used to study the cycle regulation 1). Studies of frog oocyte P53 Protein: DNA damage leads to the activation of the gene 2). Genetic analysis of yeast- Saccharomyces cerevisiae regulatory protein p53, which stimulates the transcription of 3). Studies of protein synthesis in early sea urchin several genes. embryo. Group 5: Meiosis & Mitosis Cell Cycle Checkpoint Meiosis is the type of cell division which produces gametes These are the cell cycle control mechanisms in for sexual reproduction. Unlike mitosis, the daughter cells are eukaryotic cells. These checkpoints verify whether the genetically different from the parent cell and contain just half processes at each phase of cell cycle have been accurately the number of chromosomes (i.e. they are haploid). When completed before progression into the next phase. There are two haploid gametes join during fertilization, a diploid cell three main checkpoints that control the cell cycle in called a zygote is formed. Meiosis involves two rounds of cell eukaryotic cells. division which are referred to as meiosis I and meiosis II They Are: MEIOSIS I TYPES OF MEIOSIS DISORDERS Interphase: PATAU’S SYNDROME is a serious, rare genetic disorder the DNA replicates so there are now two identical copies of caused by having an additional copy of chromosome 13 in each chromosome (referred to as chromatids) some or all of the body's cells. It's also called trisomy 13. Prophase I: Chromatids codense arrange themselves into homologous EDWARDS' SYNDROME, also known as trisomy 18, is a rare pairs (called bivalents). Crossing over occurs. The nucleus but serious condition. Edwards' syndrome affects how long a envelope disintegrates and spindle fibers form. baby may survive. Metaphase I: Homologous chromosomes line up along the equator and DOWN’S SYNDROME is a genetic condition where people are attach to the spindle fibers by theirs centromeres. born with an extra chromosome. Most people have 23 pairs Anaphase I: of chromosomes within each cell in their body, for a total of Homologous chromosomes are separated. 46. Telophase I: XYY syndrome is a genetic condition found in males only. Chromosomes reach opposite poles of the cell. Nuclear About 1 in 1,000 boys have it. Boys with XYY syndrome — envelope reforms around the chromosomes. Cytokinesis also known as 47,XYY — might be taller than other boys. results in the formation of two daughter cells. Meiosis II: KLINEFELTER SYNDROME (sometimes called Klinefelter's, KS Prophase II: or XXY) is where boys and men are born with an extra X Chromosomes condense, chromosome nuclear envelope disintegrates and spindle fibers form. Turner syndrome is a female-only genetic disorder that affects about 1 in every 2,000 baby girls. A girl with Turner Metaphase II: syndrome only has 1 normal X sex chromosome, rather than Chromosomes attach to the spindle fiber by their the usual 2. centromeres. Anaphase II: Triple X syndrome is a genetic condition where a person is Sisters chromatids are separated. born with an extra X chromosome. This condition only Telophase II: happens in people assigned female at birth (AFAB). Chromatids reach opposite poles of the cell. Nuclear envelope reforms and cytokinesis takes places. Four Mitosis is a cell's way of making copies of itself. It happens genetically unique daughter cells are produced. when a cell needs to grow, repair itself, or replace old or damaged cells. The cell prepares for mitosis by getting ready. MEIOSIS INCREASES GENETIC VARIATION It makes sure it has everything it needs to divide into two From an evolutionary point of view, it is important that new cells. organisms produce offspring that show as much genetic variation as possible. STAGES OF MITOSIS Meiosis increases genetic variation in two ways - crossing over and independent assortment. CROSSING OVER During prophase I of meiosis, a process called crossing over occurs. This is when the homologous chromosomes move towards each other and exchange genetic material. When the pair of chromosomes have come together, we call this a INTERPHASE: mitosis begins, the cell goes through a period bivalent. called interphase. A chromatid from the maternal chromosome becomes PROPHASE: Mitosis officially begins with prophase. During twisted around the paternal chromosome and they connect this phase, the chromatin, which consists of DNA and through a structure called the chiasmata proteins, condenses into visible chromosomes. METAPHASE: During metaphase, the chromosomes line up ERRORS IN MEIOSIS along the metaphase plate, which is an imaginary plane Inherited disorders can arise when chromosomes equidistant from the two poles of the cell. behave abnormally during meiosis. ANAPHASE: characterized by the separation of sister chromatids. DISORDERS IN CHROMOSOME NUMBER TELOPHASE: the separated chromosomes reach the poles of the cell, and new nuclear envelopes begin to form around Non disjunction can occur during either meiosis I or II, them with different results. If homologous chromosomes CYTOKINESIS: the final stage of cell division, during which the fail to separate during meiosis I, the result is two cytoplasm of the cell is divided into two daughter cells. gametes that lack that chromosome and two gametes with two copies of the chromosome. DIFFERENCES BETWEEN MEIOSIS & MITOSIS MITOSIS MEIOSIS WHY MEIOSIS CAUSE THE SYNDROME?  One cell division  Produces four daughter It occurs as a random error during cell division early in fetal  Produces two daughter cells development. As a result, some of the body's cells have the cells  Produces haploud cells usual two copies of chromosome 21, and other cells have  Produces diploid cells  Daughter cells are non- three copies of the chromosome.  Daughter cells are identical genetically identical  Produces sex cells  Produces body cells  Crossing-over occurs   No crossing-over  Homologous The major disadvantage is that all of the organisms occurs chromosomes do not in a population or all of the plants in an area will have the  Homologous pair up exact same DNA. chromosomes do not pair up DISADVANTAGES OF MEIOSIS An organism cannot reproduce all by itself, but must Group 6: Explain the significance or application of find another organism to reproduce. This takes more time mitosis/meiosis and energy than simply being able to created a clone through mitosis MITOSIS: is a part of the cell cycle in which chromosomes in a cell nucleus are separated into two identical sets of chromosomes, each in its own nucleus. GROUP 7: Identify disorders and diseases that result from MEIOSIS: A type of cell division that results in four daughter the malfunction of the cell during the cell cycle cells each with the half the number of chromosomes of the parent cell. Cells are the basic building blocks of all living things. The WHY THEY OCCUR? human body is composed of trillions of cells.  Survival  Mitosis is a cell division. ALZHEIMER'S DISEASE  This cell division can be for growth, maturity, or to Alzheimer's disease is a brain disorder that gets worse over repair/ replace damaged cells. time. It's characterized by changes in the brain that lead to  Meiosis is basically required for reproduction to take deposits of certain proteins. place. Cancer  Meiosis produces gametes, which are required for Cancer is a large group of diseases that can start in almost sexual reproduction. any organ or tissue of the body when abnormal cells grow IMPORTANCE OF MITOSIS uncontrollably, go beyond their usual boundaries to invade  Mitosis helps in maintaining an equal number of adjoining parts of the body and/or spread to other organs. chromosomes in each separatedseperated daughter cell The latter process is called metastasizing and is a major after division. cause of death from cancer. A neoplasm and malignant  This process is responsible for the growth and tumour are other common names for cancer. development of multicellular organisms.  Mitosis repairs all the damaged tissues, and in recovery Parkinson of damaged organs. Parkinson's disease is a brain disorder that leads to SIGNIFICANCE OF MITOSIS shaking, stiffness, and difficulty with walking, balance, and  Mitosis is important for sexual reproduction indirectly. coordination. Older woman and her caregiver  It allows the sexually reproducing organism to grow and Parkinson's symptoms usually begin gradually and get develop from a single cell into a sexually mature worse over time. As the disease progresses, people may individual. have difficulty walking and talking.  This allows organisms to continue to reproduce through Ciliopathies the generations. Ciliopathies comprise a group of disorders associated with  Repair of worn out parts (healing of wounds) takes place genetic mutations encoding defective proteins, which result by mitosis. in abnormal formation or function of cilia. ASEXUAL REPRODUCTION is the process by which a single organism produces genetically identical offspring. DOWN SYNDROME BINARY FISSION single- celled organisms reproduces simply DOWN SYNDROME IS TYPICALLY CAUSED BY A CELL DIVISION by splitting into two new cells. ERROR KNOWN AS "NONDISJUNCTION." NONDISJUNCTION BUDDING: Bud on parent organism (e.g. yeast) develops into CAUSES AN EMBRYO TO HAVE THREE COPIES OF a view organism through repeated cell division CHROMOSOME 21 RATHER THAN THE USUAL TWO SIGNIFICANCE OF MEIOSIS Patau Syndrome  One of the benefits of sexual reproduction is the Patau's syndrome is a severe genetic condition caused by an diversity it produces within a population. That variety is extra copy of chromosome 13 in some or all of the body's a direct product of meiosis. cells. Trisomy 13 is another name for it. Each cell has 23 pairs  Every sex cell made from meiosis has a unique of chromosomes, which contain the genes you inherited from combination of chromosomes. That means that no two your parents. sperm or egg cells are genetically identical.  Every fertilization event produces new combination of Turner Syndrome traits. Turner syndrome is a hereditary condition that primarily  This is why siblings share DNA with parents and each affects females. Turner syndrome is caused by a totally or other, but are not identical to one another. partly absent X chromosome.  Recombination at meiosis plays an important role in the Turner syndrome symptoms include small height, a lack of repair of genetic defects. breast development, andirregularmenstruation. Hormone  The conventional view that is generates by treatment may be used to treat Turner syndrome. recombination and sexual reproduction the genetic diversity on which natural selection. Clift lip Syndrome  It is essential, at least in animals, for the reprogramming A cleft lip is a hole or split in the top lip that arises when an of gametes which give rise to the fertilized eggs. unborn baby's developing facial tissues do not seal fully. Cleft lip and palate can be unilateral or bilateral. A baby with DISADVANTAGES OF MITOSIS a cleft lip may also have a cleft in the roof of his or her mouth (cleft palate). GROUP 8: THE STRUCTURAL COMPONENTS OF THE CELL Glycoproteins are proteins which contain MEMBRANE oligosaccharide chains covalently attached to amino acid side-chains. WHAT IS CELL MEMBRANE ? Cell Membrane (plasma membrane) is a physical and chemical barrier which separates the inside and outside of Transport protein the cell providing fixed environment inside the cell. may either be channel proteins or carrier proteins *channel proteins -serve as tubes or channels that allow Structural Components of the Fluid Mosaic Model passage of molecules across the membrane (do not require The accepted structural model of the cell membrane. It energy) describes how the cell membrane is made of different *carrier proteins-they change shape as they receive certain components, free moving in the membrane. substances to allow the movement of specific molecules  fluid because the molecules can move freely past one across the membrane (may or may not require energy) another  mosaic because of the diversity of proteins embedded Adhesion protein in it fasten adjacent cells together in animal tissues  it is composed of diverse protein molecules suspended in a fluid phospholipid bilayer Recognition Protein  lipid content-responsible for its fluidity which prevents  function as unique identity tags for each cell or species. it from solidifying as external temperatures drop  Help in recognition when the body is being invaded by  presence of cholesterol molecules maintain membrane pathogens so that the necessary immune response may fluidity particularly by preventing the membrane from be triggered becoming too fluid at higher temperatures and too solid at lower temperatures and too solid at lower Receptor Protein temperatures bind to specific extracellular substances such as hormones or toxins, or to molecules on another cell's plasma The main component of the membrane is phospholipids. membrane However, there are also others, which include four total  have certain shapes that allow only specific molecules components: to bind to them  Phospholipids  binding to these proteins triggers the change in the  Proteins cell's shape which brings a cellular response that is  Carbohydrates related to metabolism, movement, division, or even cell  Cholesterol death  different receptor proteins occur an different cells, but  Phospholipids all are critical for homeostasis The fundamental building block of cell membrane is the phospholipid which is an amphipathic molecule Carbohydrates consisting of both hydrophobic and, hydrophilic regions. Found on the outside surface of the cells and are bound either in protein forming glycoproteins or to lipids forming The hydrophilic or "water loving" (polar) region is glycolipids. It may consist of 2-60 monosaccharide units and the globular head containing phosphate group: the can either be straight or branched. hydrophobic or "water-fearing" (nonpolar) regions are their Carbohydrate Chains fatty acid tails. attached to either the phospholipids or the proteins Phospholipids are amphipathic, meaning they have glycolipids- phospholipids with attached carbohydrates both hydrophobic parts, which do not readily mix with water, chains and hydrophilic parts, which mix with water. glycoproteins- proteins with carbohydrate chains Are amphipathic fats that form the majority of the carbohydrate chains occur only on the outside surface of the membrane. lipid bilayer or the peripheral proteins that occur on one surface or the other There are four main types of phospholipids that make up most of the cell membrane in animal cells: Cholesterol  Phosphatidylcholine It not only contributes to making the membrane  Phosphatidylethanolamine thicker and more impenetrable, but surprisingly also softer.  Phosphatidylserine It regulates the membranes fluidity in changing  Sphingomyelin temperatures.  It's essential for the structure, elasticity and the various  Proteins functions of cell membranes. Another integral part of the cell membrane. Proteins are  Acts like a buffer and extends the temperature range in large molecules formed from long chains of amino acids. which membranes can stay fluid in both directions. Peripheral Proteins Glycocalyx Associated within the surface of the cell membrane  in animal cells, the carbohydrate chains attached to and found either on the cytoplasmic or extracellular side. proteins give the cell a "sugar coat" called glycocalyx Integral Proteins  imparts protection and other functions such as cell-to- It integrated into the membrane proteins that cell adhesion, reception of signaling molecules, and cell- penetrate the lipid bilayer. to-cell recognition Transmembrane protein  classified as channel, carrier, adhesion, recognition, Role of Fatty acids or receptor proteins  It determine how fluid is the membrane. Saturated GLYCOPROTEINS fatty acids have no double bond so they are relatively  straight while unsaturated fatty acids contain one or Phospholipid Bilayer more double bond often resulting in a bend or kink.. is a dynamic and flexible structure that forms the fundamental barrier of the cell membrane. Role of Cholesterol  Its presence makes it possible for the cell membrane to FUNCTION OF PHOSPHOLIPID BILAYER maintain its fluidity across a wide range of The phospholipid bilayer is a barrier and filter that regulates temperatures. It helps to minimize the effects of transport, maintains structure, facilitates communication, temperature on fluidity. and provides fluidity for cell division and membrane fusion The Importance of Membrane Fluidity Membrane Proteins  it imparts flexibility to the membrane which is important for cells that particularly move such as an Integral Membrane Proteins - Integral membrane proteins amoeba performing cytoplasmic streaming span the entire lipid bilayer and are embedded within it. They  allows the synthesized membrane proteins and are often classified based on their structure and function: phospholipids to be easily incorporated into the  Transmembrane Proteins: These extend across the membrane bilayer and can have domains both inside and outside  provides a perfect compromise between a rigid the cell. They often function as channels or transporters. structure which makes mobility absent and a completely - Channel Proteins: Form pores that allow specific ions or fluid where mechanical support would be lacking. molecules to pass through by diffusion.  allows interactions to take place within the membrane. - Carrier Proteins: Bind to specific molecules and undergo conformational changes to transport substances across the The Fluid Mosaic Model membrane.  It was first proposed by S. J. Singer and G. Nicholson in  Glycoproteins: Integral proteins with carbohydrate 1972 to describe the structure of the plasma groups attached to them. They play roles in cell-cell membrane. recognition and communication.  It describes the cell membrane as several molecules (phospholipid, cholesterol and proteins) that are Peripheral Membrane Proteins - Peripheral membrane constantly moving. proteins are attached to the membrane's surface, either to  This movement helps the cell membrane maintains its the lipid bilayer or to integral proteins. role as a barrier between the inside and outside of the  Cytoskeletal Proteins: Peripheral proteins that interact cell environment. with the cell's cytoskeleton (e.g., spectrin). They help maintain the cell’s shape and mechanical support. GROUP 9: Structure and Function of the Cell Membrane  Enzymes: Some peripheral proteins function as enzymes that catalyze specific reactions near the membrane. The Cell Membrane, also called as Plasma Membrane, is a  Signal Transduction Proteins: Involved in transmitting thin, biological membrane present in all eukaryotic and signals from the extracellular environment to the cell's prokaryotic cells that forms a boundary between the cell and interior. They often interact with receptor proteins to its environment and regulating the flow of materials in and relay messages. out of cell. Swiss botanist Carl Naegeli and C Carmer discovered Functions of Membrane Proteins the cell membrane in 1855, despite microscopes' limitations.  Transport: Facilitating the movement of substances across the cell membrane through channels, carriers, or  The cells maintain an appropriate amount of all pumps. molecules within them to function effectively.  Enzymatic Activity: Catalyzing biochemical reactions  So, this plasma membrane acts as a semi permeable either on the cytoplasmic or extracellular side of the membrane allowing the entry and exits of certain membrane. materials.  Signal Transduction: Acting as receptors for signaling  It is like a guard at a gated community who inspects molecules, triggering intracellular responses. those who enter and leave, to make sure that only  Cell-Cell Recognition: Using glycoproteins and people and things needed in the community are there. glycolipids to identify and communicate with other cells.  Intercellular Joining: Linking cells together through IMPORTANCE OF THE CELL MEMBRANE IN MAINTAINING junctions like tight junctions, desmosomes, or gap CELLULAR INTEGRITY AND FUNCTION junctions.Attachment to the The cell membrane is crucial as it provides a barrier  Cytoskeleton and Extracellular Matrix: Providing that regulates what enters and exits the cell, maintaining structural support and helping to maintain the cell's internal stability. shape. Carbohydrates on the Membrane Fluid Mosaic Model: was first proposed by S.J. Singer and Garth L. Nicolson in 1972 to explain the structure of the Carbohydrates, specifically in the form of glycoproteins and plasma membrane. glycolipids, are located on the extracellular surface of the cell The fluid mosaic model describes the structure of membrane. the plasma membrane as a mosaic of components —  Glycoproteins: Carbohydrate chains are covalently including phospholipids, cholesterol, proteins, and attached to proteins. carbohydrates—that gives the membrane a fluid character.  Glycolipids: Carbohydrate chains are covalently attached to lipids in the membrane The cell membrane's fluidity and interactions with its components, including lipid bilayer, phospholipids, and Functions of the Carbohydrates on the Membrane proteins, create a dynamic mosaic that facilitates transport, Carbohydrates on the cell membrane, primarily in the form signaling, and cell movement. of glycoproteins and glycolipids, serve several important functions:  Cell-Cell Recognition and Communication - Osmosis: A specific type of facilitated diffusion where water - Glycoproteins and Glycolipids: The carbohydrate chains moves through aquaporins (water channels) in response to attached to these molecules act as identification tags that are differences in solute concentration. recognized by other cells.  Active Transport - Cell Adhesion: Carbohydrates help cells adhere to each - Primary Active Transport: Direct use of energy (usually ATP) other and to the extracellular matrix, which is essential for to move substances against their concentration gradient via forming tissues and maintaining cellular organization. pumps.  Protection and Lubrication - Secondary Active Transport: Indirect use of energy. It relies - Glycocalyx: The carbohydrate-rich coating on the on the electrochemical gradient created by primary active extracellular surface of the membrane forms the glycocalyx. transport to move other substances against their gradient. Vesicular Transport - Antigen Recognition: Carbohydrates on cell surfaces can - Endocytosis: The cell membrane engulfs extracellular serve as antigens, which are recognized by immune cells material to form a vesicle that is brought into the cell.  Signal Reception - Exocytosis: Vesicles containing substances fuse with the cell - Receptor Binding: Carbohydrates can be involved in membrane, releasing their contents to the extracellular receptor-mediated signaling. environment. - Nutrient Uptake: Carbohydrates can assist in the binding Receptor-Mediated Transport and uptake of nutrients or other molecules from the - Receptor-Mediated Endocytosis: Specific molecules bind to extracellular environment, facilitating cellular nutrition and receptors on the cell membrane, triggering vesicle formation interaction with surrounding tissues. and internalization of the bound substance.  Cell Communication and Signaling Role of Cholesterol - Signal Reception: Membrane proteins (receptors) detect Cholesterol is essential for the structure, elasticity and the and bind to signaling molecules (ligands), initiating a cascade various functions of cell membranes. of intracellular events that can affect cellular processes,  Membrane Fluidity Regulation including substance movement. - Fluidity Buffer: Cholesterol maintains membrane fluidity by Substances that Pass Freely Through the Cell Membrane: preventing the phospholipid tails from packing too closely  Small Nonpolar Molecules: together. - Oxygen (O₂): Essential for cellular respiration and easily Membrane Stability diffuses across the lipid bilayer. - Stabilization: Cholesterol helps to stabilize the membrane, - Carbon Dioxide (CO₂): Produced as a waste product of making it less permeable to very small water-soluble cellular metabolism and diffuses out of cells. molecules.  Small Polar Molecules:  Formation of Lipid Rafts - Water (H₂O): Though polar, it can diffuse through the - Lipid Rafts: Cholesterol is involved in the formation of lipid membrane relatively easily due to its small size and the rafts, which are microdomains within the membrane presence of aquaporins, which are specific channels that enriched with cholesterol and sphingolipids. facilitate water movement.  Modulation of Protein Function - Protein Interactions: By altering membrane fluidity and the Communication and Signaling organization of lipid rafts, cholesterol can influence the Receptor proteins are specialized membrane-bound or distribution and function of membrane proteins, impacting intracellular proteins that play a crucial role in cellular processes like signal transduction and cellular communication by detecting and responding to external communication. signals. Here's a breakdown of their structure and function: Structure of Receptor Proteins Selective Permeability 1. Extracellular Domain: The cell membrane controls substance movement through - This part of the receptor extends outside the cell and binds various mechanisms that regulate the flow of ions, to signaling molecules (ligands) such as hormones, molecules, and particles into and out of the cell. Here’s how neurotransmitters, or growth factors. It is specific to the the membrane achieves this: ligand it recognizes.  Selective Permeability 2. Transmembrane Domain: - Lipid Bilayer: The hydrophobic (water-repelling) interior of - This region spans the lipid bilayer of the cell membrane and the phospholipid bilayer acts as a barrier to most water- connects the extracellular domain to the intracellular soluble substances domain. It facilitates the transmission of the signal across the  Transport Proteins membrane. - Channel Proteins: These form pores or channels in the 3. Intracellular Domain: membrane that allow specific ions or molecules to pass - Located inside the cell, this part of the receptor interacts through.. with intracellular signaling proteins or enzymes. It transmits - Carrier Proteins: These bind to specific molecules and the signal from the extracellular domain to the cell’s interior, undergo conformational changes to shuttle them across the initiating a cellular response. membrane. - Pumps: Specialized carrier proteins that use energy (usually Types of Receptor Proteins from ATP) to move substances against their concentration 1. G-Protein Coupled Receptors (GPCRs): gradient. - These receptors activate G-proteins, which then influence  Passive Transport various intracellular signaling pathways. - Simple Diffusion: Movement of molecules from an area of 2. Receptor Tyrosine Kinases (RTKs): higher concentration to an area of lower concentration - Upon ligand binding, these receptors undergo through the lipid bilayer without the use of energy. autophosphorylation on tyrosine residues, which activates - Facilitated Diffusion: Movement of molecules through a downstream signaling pathways involved in cell growth, membrane via transport proteins, following their differentiation, and metabolism. concentration gradient, without using energy. 3. Ion Channel Receptors: - Ligand binding causes these receptors to open or close ion - Immune Function: The cell membrane plays a role in channels, allowing specific ions to flow across the membrane. immune responses by presenting antigens through This type of receptor is crucial for rapid signaling, such as in glycoproteins and glycolipids, helping the immune system synaptic transmission. recognize and respond to pathogens. 4. Nuclear Receptors: - These receptors are located inside the cell (in the cytoplasm Cell Recognition and Interaction or nucleus) and bind to ligands like steroid hormones. They 1. Role of Carbohydrates in Cell Recognition: act as transcription factors to regulate gene expression  Glycoproteins and Glycolipids: directly. - Cell Surface Markers: Carbohydrates on glycoproteins and glycolipids on the cell membrane act as specific markers or Role in Cellular Communication "tags" for cell recognition. 1. Signal Reception: 2. Importance for Tissue Formation and Immune Responses: - Ligand Binding: Receptor proteins bind to specific ligands  Tissue Formation: with high affinity. This binding often induces a - Cell Adhesion: Carbohydrates on cell surfaces mediate cell- conformational change in the receptor. cell adhesion, which is essential for tissue formation and 2. Signal Transduction: maintenance. - Activation of Intracellular Pathways: The conformational - Development and Morphogenesis: During development, change activates intracellular signaling pathways. specific carbohydrate molecules guide the interactions - Second Messengers: The receptor-ligand interaction can between cells, influencing how tissues and organs form and generate second messengers (e.g., cAMP, IP₃) that amplify organize. the signal within the cell.  Immune Responses: 3. Cellular Response: - Immune Recognition: The immune system uses - Gene Expression: Receptor activation can lead to changes in carbohydrate markers to distinguish between self and non- gene expression by influencing transcription factors. self cells. - Metabolic Changes: Signaling pathways can alter cellular - Pathogen Detection: Carbohydrate structures on cell metabolism by activating or inhibiting specific enzymes. membranes can be recognized by pattern recognition - Cell Growth and Division: Growth factor receptors can receptors on immune cells, allowing the immune system to regulate the cell cycle and promote proliferation. detect and respond to infections. - Cell Movement and Adhesion: Receptors can modulate cytoskeletal arrangements and affect cell movement and Carbohydrates. They are crucial for tissue formation adhesion. by facilitating cell adhesion and organization, and they are 4. Signal Termination: essential for immune responses by enabling the immune - Desensitization: Receptors can be internalized or modified system to distinguish between self and non-self cells. to reduce their sensitivity to continuous stimulation. Transport Mechanisms - Degradation or Inactivation: Receptors or second 1. Types of Transport Across the Membrane: messengers may be broken down by cellular enzymes, halting A. Passive Transport: the signaling process.  Diffusion: - Description: Movement of molecules from an area of higher Signaling molecules play a crucial role in coordinating concentration to an area of lower concentration without the physiological processes, regulating cellular functions, and use of energy. maintaining homeostasis. Hormones, such as insulin, Facilitated Diffusion: adrenaline, and thyroid hormones, regulate glucose uptake, - Description: Movement of molecules across the cell heart rate, and energy levels. membrane through specific transport proteins, down their concentration gradient, without using energy. Protection and Support B. Active Transport: 1. Structural Support: Primary Active Transport:  Phospholipid Bilayer: - Description: Movement of molecules against their - Barrier Function: The phospholipid bilayer provides a concentration gradient using energy directly from ATP. fundamental barrier, protecting the internal components of Secondary Active Transport: the cell from the external environment. - Description: Movement of molecules against their Membrane Proteins: concentration gradient using energy indirectly, derived from - Structural Anchoring: Integral membrane proteins and the electrochemical gradient created by primary active cytoskeletal proteins (such as spectrin) anchor to the cell transport. membrane, providing additional structural support and Transport mechanisms across the cell membrane are maintaining the cell's shape. essential for regulating the internal environment of the cell.  Cytoskeleton Interaction: - Support and Shape: The cell membrane interacts with the GROUP 10: Transport mechanism in cell cytoskeleton (microfilaments, intermediate filaments, and microtubules) to maintain and stabilize cell shape. what is TRASNPORT MECHANISM? 2. Protection Against Harmful Substances: The act or means by which molecules, ions, or substrates are  Selective Permeability: transferred across a biological membrane, such as plasma - Regulated Entry: The cell membrane's selective (cell) membrane. permeability ensures that essential nutrients and ions enter the cell while restricting the entry of potentially harmful Two types of transport mechanism substances  Passive transport  Barrier to Toxins: Passive transport is a type of membrane transport that does - Protection: The membrane acts as a barrier to toxins, not require energy to move substances across cell pathogens, and large molecules that could damage the cell. membranes. Defense Mechanisms: Two common types of Passive transport FACILITATED DIFUSSION hypertonic solution, the net movement of water will be out molecules diffuse across the plasma membrane with of the body and into the solution. assistance from membrane proteins, such as channels and carriers. Hypotonic solution has a lower solute concentration compared to the SIMPLE DIFFUSION intracellular solute concentration. When a red blood cell is movement of a substance from a region of high placed in a hypotonic solution, there will be a net movement concentration to a region of low concentration. Neither a of free water into the cell transport protein nor ATP is required. Similarities Between Simple Diffusion and Facilitated 1. The concentration of solute in the solution can be equal to Diffusion the concentration of solute in cells. In this situation the cell is  Both simple and facilitated diffusion occur down the in an isotonic solution (iso = equal or the same as normal concentration gradient from a high concentration to a 2. The concentration of solute in the solution can be greater low concentration of molecules. than the concentration of solute in the cells. This cell is  Both types do not require energy for the transportation described as being in a hypertonic solution (hyper = greater of molecules. than normal).  The net movement of molecules on either side of the 3. The concentration of solute in the solution can be less than cell membrane is zero at the equilibrated state. the concentration of solute in the cells. This cell is in a hypotonic solution (hypo = less than normal Difference Between Simple Diffusion and Facilitated  Active transport Diffusion an energy-driven process where membrane proteins Category Simple diffusion Facilitated transport molecules across cells, mainly classified as primary diffusion or secondary, based on how energy is coupled to fuel these mechanisms. Occurrence Simple diffusin Facilitated occurs through diffusion occurs two types of active transport the phospholipid through  Primary active transport, also called direct active bilayer. transmembrane transport, directly uses chemical energy to transport all proteins. species of solutes across a membrane against their Transported Simple diffusion Facilitated concentration gradient. Molecules transports small, diffusion  Secondary active transpor, the transport of a solute in non-polar transports large the direction of its increasing electrochemical potential particles. or polar Facilitator Simple diffusion particles. coupled to the facilitated diffusion of a second solute Molecules occurs directly Facilitated (usually an ion) in the direction of its decreasing through the cell diffusion occurs electrochemical potential. membrane. through specific Primary active transport facilitator One of the most important pumps in animal cells is the molecules called sodium-potassium pump, which moves Na+ out of cells, and transmembrane K+ into them. Because the transport process uses ATP as an integral proteins. energy source, it is considered an example of primary active transport. OSMOSIS 4 types of Primary active transport Osmosis is a specific type of diffusion; it is the passage of In secondary active transport, otherwise called coupled water from a region of high water concentration through a transport or cotransport, energy is utilized to transport semi-permeable membrane to a region of low water particles over a membrane; however, unlike primary active concentration. transport, there is no immediate coupling of ATP; rather it depends upon the electrochemical potential difference made Semi-permeable membranes - are very thin layers of by pumping particles in/out of the cell. material which allow some things to pass through them, but prevent other things from passing through. Similarities Between Primary and Secondary Active Transport Osmotic pressure  Both primary active transport and secondary active the amount of force applied to a solution that prevents transport are two active transport methods. solvent from moving across a semipermeable membrane  Both methods are involved in the pumping of molecules against the concentration gradient, from a low to further demonstrate osmosis and osmotic pressure , we concentration to a high concentration. can immerse red blood cells into sugar solutions of various  Transmembrane proteins are involved in facilitating concentrations. There are three possible relationships that both primary and secondary active transport. cells can encounter when placed into a sugar solution.  Transmembrane proteins are specific to the molecules transported across the membrane. Isotonic solution  The main purpose of both transportation methods is to is any external solution that has the same solute speed up the movement of molecules across the cell concentration and water concentration compared to body  membrane. fluids, In an isotonic solution, no net movement of water will take place. Category Primary Secondaru Hypertonic solution any external solution that has a high solute concentration definition Primary active Secondary active and low water concentration compared to body fluids. In a transport is the transport is the transport of transport of two  molecules against different  The vesicle delivers its component to an organelle or a concentration molecules across stores them in a cytoplasmic region. gradient by the a transport  Occurs in three ways: phagocytosis, pinocytosis, and use of energy membrane using receptor-mediated endocytosis. from ATP. energy in other forms than ATP. coupled A single molecule Two types of TYPES FUNCTION MECHANISM transport is transported in molecules are It functions as a The cell ingulfs Phagocytosis primary active transported at repair for the the particle then transport. once in secondary human body. packs it with a active transport. membrane- enclosed sac called vacuoles. GROUP 11: Differences between Exocytosis and Endocytosis The vacuole fuses Endocytosis & Exocytosis with a lysosome, The processes by which cells move materials into or out of in which the the cell that are too large to directly pass through the lipid hydrolytic bilayer of the cell membrane. enzymes digest the contents of the Exocytosis vacuole. the process by which cells move materials from within the cell into the extracellular fluid. Exocytosis occurs when a Pinocytosis It functions for It functions for vesicle fuses with the plasma membrane, allowing its ingestion. ingestion. contents to be released outside the cell. Receptor- It functions for It uses receptor  An intracellular vesicle fuses with the plasma membrane Mediated regulated protein to as secretion occurs Endocytosis processes of recognize  Hormones, neurotransmitters, and digestive enzymes molecules that are compatible are secreted from cells transported into molecules which  Exocytosis can be constitutive and regulated the cell. they bring into the cell. Constitutive Secretion It is involved in Transports proteins like receptors that function in the plasma the uptake, membrane. transfer, and exchange of Regulated Secretion substances triggered when a cell recieves a signal from outside between cells. for example, the blood sugar rises, the pancreatic cells are signaled to release the hormone insulin Phagocytosis Types of Exocytosis  Common in unicellular organisms TYPES FUNCTION MECHANISM  Occurs in humans because of white blood cells that are Constutive It transports This process called amoeboids. molecules outside transports  These cells engulf worn out red blood cells, viruses, the cells through molecules outside bacteria, cancerous body cells, or other large particles. vesicles. the cell then the  Digestion occurs once an endocytic vesicle fuses with vesicle fuses with lysosome. the plasma  The cell engulfs the particle by wrapping around membrane. extensions called pseudopodia then packs it within a Regulated It transports It transports membrane-enclosed sac called vacuoles. molecules outside molecules outside The Steps of Phagocytosis the cell because of the cell because of 1. A particle or substance binds to receptors on the cell’s triggered signals. triggered signals. surface, stimulating the release of pseudopodia (extensions of the plasma membrane filled with cytoplasm). 2. Pseudopodia surround the object until their membranes fuse, forming a phagocytic vesicle. The Steps of Exocytosis 3. The phagocytic vesicle pinches off from the cell 1. A vesicle is formed, typically within the endoplasmic membrane, entering the cell. reticulum and the Golgi apparatus or early endosomes. 4. The phagocytic vesicle fuses with lysosomes, which recycle 2. The vesicle travels to the cell membrane. or destroy the vesicle’s contents. 3. The vesicle fuses to the plasma membrane, during which the two bilayers merge. Pinocytosis 4. The vesicle’s contents are released into the extracellular  Occurs when vesicles form around a liquid or around space. small particles. 5. The vesicle either fuses with or separates from the cell  Blood cells, cells that line kidney tubules, intestinal membrane. walls, and plant root cells use pinocytis to ingest the substances. Endocytosis  Cells do not shrink in size because the loss of plasma the process by which cells take in substances from outside of membrane is balanced by the occurence of exocytosis. the cell by engulfing them in a vesicle. Cells take substances The Steps of Pinocytosis by forming vesicles that bud inward around the material. 1. Molecules bind to receptors located along the surface of Enzymes control various reactions like photosynthesis, the cellular membrane. respiration, digestion, and protein synthesis, and are used in 2. The plasma membrane folds in, forming a pinocytic vesicle everyday life. that contains the molecules and the extracellular fluid. 3. The pinocytic vesicle detaches from the cell membrane Enzymes sidekicks- because enzymes are not alone inside the cell. 1. Confactorst typically metal ions(ex. Iron) 4. The vesicle fuses with early endosomes where the 2. Coenzymes organic molecules (ex. Vitamis) contents found within are sorted. Classes of enzyme Receptor-Mediated Endocytosis 1. Oxidoreductases: these enzymes carry out oxidation and  Uses a receptor protein to recognize compatible reduction. Ared+Box Aox+Ared molecules to bring into the cell. 2. Transferases: they transfer groups between  Vitamins, peptide hormones, or lipoproteins can bind to twosubstrates. specific receptors found in special locations called For example. Hexokinase Glucose + ATP Glucose-GPhosphate coated pits because there is a layer of protein on the + ADP cytoplasmic side of the pit. 3. Hydrolases: They hydrolyze substrate by addition of water.  The vesicle is uncoated and may fuse with a lysosome 4. Lyases: they breakdown the substrate without addition of when formed. When empty, the used vesicle fuses with water. the plasma membrane and the receptors return to their 6. Ligases: they join two molecule using energy released fro former location. D Alanine L Alanine  selective and much more efficient For example: Acethyl COA Synthetase Acetate + COA +ATP  Involved in uptake and also transfer and exchange of Acethyl COA + AMP 2Pi substances between cells. The Steps of Receptor-Mediated GROUP 13: Oxidation/Reduction Reaction 1. Ligand binds to a specific cell surface receptor 2. Invagination of cell membrane, clustering of the ligand– What is Oxidation/Reduction Reactions? receptor complexes An oxidation-reduction reaction is any chemical 3. Formation of clathrin-coated pit reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Redox GROUP 12: DESCRIBE THE COMPONENTS OF ENZYME reactions are common and vital to some of the basic functions of life, including photosynthesis, respiration, What is enzymes? combustion, and corrosion or rusting. Enzymes are really important protein that speeds up the rate of reaction such as photosynthesis, respiration and What is Oxidation? protein synthesis. Oxidation is a chemical process. It is defined as a Enzymes can work in different ways, some enzymes help process that occurs when atoms or groups of atoms lose breakdown large molecules into smaller ones, others build up electrons. Another way to define oxidation is when a large molecules from smaller ones and some enzymes help chemical species gains oxygen or loses hydrogen. change one molecule into another. What is Reduction? How do enzymes work? Reduction, on the other hand, is the gain of Enzymes work in conjunction with substrates. electrons by a chemical species. This gain of electrons leads The Enzyme and Substrates are always moving and to a decrease in the oxidation state of the species. Reduction occasionally they collide at the right speed and orientation so is the process where an atom or molecule gains one or more the substrate fits into the enzyme at the active site. electrons, becoming more negatively charged. Substrate is used to describe a molecule that an enzymes acts upon. Classical Idea of Oxidation and Reduction reactions Enzymes work in conjunction with substrates. Oxidation reactions involve: The Enzyme and Substrates are always moving and 1. Addition of oxygen: occasionally they collide at the right speed and orientation so C + O2 → CO2 (oxidation of carbon) the substrate fits into the enzyme at the active site. 2. Addition of electronegative element: Substrate is used to describe a molecule that an enzymes Fe + S → FeS (oxidation of Iron) acts upon. Collision Theory dictates that collision must occur 3. Removal of hydrogen: with sufficient energy and in specific orientation for reaction H2S + Br2 → 2 HBr + S (oxidation of sulphide) to occur. 4. Removal of electropositive elements: 2 KI + H2O2 → I2 + 2 KOH (oxidation of iodide) Examples of Enzymes: 1. Protease > Proteins > Amino Acids Oxidizing agent is a substance which brings about 2. Carbohydrase > Carbohydrates > Glucose oxidation. In the above examples O2, S, Cl2, Br2, and H2O2 3. Lipase > Fats > Fatty Acids / Glycerols are oxidizing agents. Reduction reactions involve: Hydrogen peroxide, often formed during reactions, can be 1. Addition of hydrogen: harmful if left untreated. N2 + 3 H2 → 2NH3 ( reduction of nitrogen) Enzymes, which are fast catalysts, break down hydrogen 2. Addition of electropositive element: peroxide into harmless water and oxygen SnCl2 + 2HgCl2 → SnCl4 + Hg2Cl2 ( reduction of mercuric Enzymes work in specific conditions, such as the stomach, chloride) where a more acidic pH is necessary. 3. Removal of oxygen The enzyme and substrates form a lock and key mechanism, ZnO + C → Zn + CO (reduction of zinc oxide) releasing a product that can be reused. 4. Removal of electronegative element 2FeCl3 + H2 → 2FeCl2 + 2HCl (reduction of ferric chloride)  Temperature A substance, which undergoes oxidation, acts as a reducing Raising temperature generally speeds up a reaction, and agent while a substance, which undergoes reduction, acts as lowering temperature slows down a reaction an oxidising agent. A slight increase in the temperature can speed up the reaction rate as the reactants acquire more kinetic Oxidation and Reduction in terms of Electron Transfer energy This is the most commonly used definition of oxidation and Substrate reduction and most widely applicable. A substance to which another substance is applied we call it In this case, Oxidation is the loss of electrons and Reduction as a substrate. is the gain of electrons. Increasing substrate concentration also increases the rate of A very clever mnemonic to remember this concept is oil rig. reaction to a certain point OIL RIG Oxidation is loss Reduction is gain Oxidation and Reduction reactions are always interlinked. Because electrons are neither created nor destroyed in a chemical reaction, oxidation and reduction always occur in pairs, it is impossible to have one without the other Since oxidation and reduction cannot occur individually, they as a whole are called ‘Redox Reactions’ Where do we find Oxidation/Reduction Reactions in everyday life? Here's are some examples of Oxidation/Reduction Reactions 1. Combustion Combustion, often referred to as burning, is a chemical process involving a rapid reaction between a substance, called the fuel, and an oxidant, typically oxygen, releasing energy in the form of heat and light. Corrosion Corrosion is a natural process that involves the deterioration of materials, primarily metals, due to chemical or electrochemical reactions with their environmentPhotosynthesis Photosynthesis is a fundamental process in biology that allows plants, algae, and some bacteria to convert light energy into chemical energy, which is stored in organic compounds. 2. Battery A battery is a device that converts chemical energy directly into electrical energy. 3. Digestion Digestion is the process by which food is broken down into smaller, simpler molecules that the body can absorb and use for energy, growth, and repair. 6.Respiration The lungs and respiratory system allow us to breathe. GROUP 14: Determine how factors such as pH, Temperature, and Substrate Affect Enzyme Activity Catalyst - a substance that speeds up a chemical reaction without being changed. Enzyme - a biological catalyst (usually a protein) Substrate - the reactant molecule that an enzyme works on. Active site - the part of the enzyme where the substrate binds. Enzymes work best within specific temperature and pH ranges, and sub- optimal conditions can cause an enzyme to lose its ability to bind to a substrate. Enzyme activity can be affected by a variety of factors, such as temperature, pH, and substrate pH Each enzyme h