Science Bio Notes 1.2 PDF

The Cell: The Basic Unit of Life What is a theory ​ Scientists accumulate sufficient data → postulates are made to produce a theory ​ Explain natural processes (eg. cells and their functions) Can a theory be discarded? ​ Yes ​ Contradicting information → theory to be rejected or disc...

The Cell: The Basic Unit of Life What is a theory ​ Scientists accumulate sufficient data → postulates are made to produce a theory ​ Explain natural processes (eg. cells and their functions) Can a theory be discarded? ​ Yes ​ Contradicting information → theory to be rejected or discarded ​ New information is revealed and modification need to be made to existing theories The Cell Theory ​ Scientists began to discover the world of microorganisms ​ Discovery of microscope ​ Discoveries were brought together to formulate the cell theory Major Contributors ​ Zacharias Janssen (1590) ○​ Discovered first compound microscope by putting together 2 lenses ​ Robert Hooke (1665) ○​ Described cells by observing cork through a compound microscope ​ Anton van Leeuwenhoek (1674) ○​ Using a single lens microscope: observed the first living cells ​ “Animalcules” ○​ First to observe blood and sperm cells ​ Mathias Schleiden (1838) ○​ Botanist: studied plant cells and described what he saw ○​ Plants were made of cells with special features and structures ​ Theodor Schwann (1839) ○​ Studied animal cells and found similar observations as those of Schleiden ​ Louis Pasteur (1860s) ○​ Sterilized chicken broth ○​ Demonstrated that new cells do not spontaneously generate unless there was existing unicellular organisms Cell Theory: ​ All life forms are made from one or more cells ​ The cell is the basic unit of life ○​ All organisms need to carry out the same life functions ​ Metabolism ​ Growth ​ Reproduction ​ Response ​ Homeostasis ​ Nutrition ​ Cells only come from pre-existing cells ​ The activity of an organism depends on the total activity of its independent cells Cell Organelles Cell Organelles ​ Nucleus: 2 parts ○​ Nucleolus: condensed region in the nucleus (includes genetic information) ​ Vesicle: helps transport ​ Nucleus ○​ Largest organelle in the eukaryotic cells ○​ Control center of the cell ○​ Contains DNA scattered throughout as chromatin ​ 2 membranes surrounding the nucleus: ○​ Outer bilayer continues into the endoplasmic reticulum ○​ Inner bilayer defines the nucleus ​ Nuclear pores are found on the membrane ○​ Regulate movements of material between nucleus and cytoplasm ​ Nucleolus ○​ Condensed area of chromatin in the nucleus ○​ Synthesizes: ribosome parts ○​ These travel through the nuclear pores into the cytosol ​ Chromosomes ○​ Linear structures composed of DNA molecules ​ Cytoplasm: gel-like material ○​ Found between nucleus and cell membrane ○​ Consists: ​ Mostly of water ​ Many organelles ​ Protein-rich ​ Enzymes → biological catalysts ○​ Creates the chemical environment in which the other cells structure function ​ Ribosomes: ○​ Free ribosomes in the cytoplasm ○​ Ribosomes can also be attached to the ER making it ‘rough’ endoplasmic reticulum ○​ Function: produces proteins ○​ Ribosomes attached to the ER produces proteins move into the ER ​ Endoplasmic Reticulum ○​ System of channels made of 2 layers of membranes ○​ Smooth ER and rough ER ○​ Function: acts as a framework to support the cell ○​ Transport materials to different parts of the cell ​ Golgi Apparatus or Golgi Complex ○​ Series of flattened saucer shape sacs ○​ Located near the nucleus ○​ Function: packages useful nutrients and secretes them outside the cell for use elsewhere in the organism  ​ Lysosomes ○​ Structure: special vesicle formed from the golgi apparatus ○​ Function: transports cellular digestive enzymes safely through the cytoplasm ○​ degrades: ​ Worn out cellular components ​ Foreign molecules ​ Mitochondria ○​ Function: responsible for producing energy for the cell ○​ ‘Power plant’ of the cell ○​ They replicate themselves by dividing down the middle to create 2 daughter mitochondria ○​ Structure: ​ Contains 2 membranes with inner folds ​ Round / oval shape ​ Chloroplast ○​ Structure and function: ○​ Surrounded by 2 membranes: outer and inner membranes ○​ Internal system of membrane bound sacs called Thylakoids ​ Thylakoids are flattened to form discs ​ Contains the pigment chlorophyll (gives green color and absorbs solar energy to carry out photosynthesis) ​ Cell Wall ○​ Found in plants, fungal cells, some single celled eukaryotes ○​ Structure: consists of cellulose fibers ○​ Found outside the plasma membrane (cell membrane) ○​ Function: adds strength and rigidity to the cell → protects the cell ​ Cell membrane ○​ Structure: semi-permeable ○​ Outermost part of an animal cell ○​ Inside the cell wall of plants ○​ Function: ○​ Encloses the cell contents from surroundings ○​ Controls materials going in and out of the cell (nutrients and waste) 1.2 Genes: Answer and Questions ​ PKU: phenylketonuria ○​ Can lead to severe brain damage ○​ Can be corrected ​ Treatment: following a diet very low of natural proteins (obtained through liquid form) The Nucleus: Control Centre of the Cell ​ Nucleus: master set of instruction that determines what each cell will become, how it will function, how long it will live before being replaced ​ Chromosomes: carries instructions  ○​ Come in pairs in plants and animals ○​ One of each pair comes from each parents when an egg and sperm unite → fertilized egg ○​ Humans: 46 chromosomes (23 from mother, 23 from father) The DNA Code ​ Chromosomes: made of DNA (deoxyribonucleic acid) ​ DNA: material found in the cell nucleus that contains genetic information ​ Each chromosome contains a single molecule of DNA → divided into segments (genes) ​ Genes are located in specific places on the DNA molecule ○​ provide instructions for making proteins ○​ control cell’s activities and structure: control what and when proteins are made ​ 1953: James Watson and Francis Crick: created a model of DNA ​ Each rung of a DNA molecule: a building block molecule ○​ 4 types of building-block molecules: A (adenine), T (thymine), C (cytosine), G (guanine) ○​ Create genetic codes → different for every individual (except twins) Why is DNA Important ​ Each DNA molecule: hundreds or thousands of genes ​ Control physical features, how to digest certain foods, etc ○​ Genes in DNA determine kinds of proteins the cell can make Protein Production ​ Each protein is designed to do a specific job ○​ Eg. build parts of the body, couriers to carry materials, transfer signals ​ Enzymes speed up various chemical reactions in your body DNA Screening ​ DNA (genetic) screening: testing for the presence of genetic disorders ​ Down syndrome: type of genetic disorder ​ Amniocentesis: needle is inserted through a pregnant women’s abdominal wall → withdraw a sample of fluid from amniotic sac (surrounds the growing fetus) → cells from fetus are isolated → micrograph of chromosomes in cells (karyotype) ​ Karyotype: cannot show errors in individual genes ○​ Show if a person has too many / too few chromosomes / broken chromosomes ​ Down syndrome diagnosis: chromosome 21 (3 chromosomes) Testing for PKU ​ PKU: detected by blood sample examination ​ The presence or absence of specific proteins in blood: whether genes are functioning normally ​ Testing for PKU: baby’s blood is examined for an enzyme needed to digest certain proteins in food ○​ Without this protein → phenylalanine builds up in blood ​ Having certain genes → more likely to get cancer or heart disease Testing for Huntington’s Disease  ​ Huntington disease: genetic disorder that affects nerve cells ​ Symptoms (appear in ages 40s): loss of muscular control and brain functions ○​ Symptoms worsen → death ​ Parents have it → 50% of having this gene ​ Should Individuals at Risk get Tested ​ Against: ○​ diagnosing the disease can cause people needless emotional pain (no cure to Huntington's disease) ○​ Expensive ​ In favor: ○​ Reduces uncertainty ○​ Knowing whether they do or do not have the gene: change a person’s life decisions ​ Eg. positive: people may choose to not have children ​ Results must be kept private DNA Screening in Canada ​ DNA screening: tests for PKU, Down Syndrome, Huntington’s Disease, breast cancer, cystic fibrosis, spina bifida Ethical Issues and Drug Research ​ Drug companies: carry out research for various diseases ○​ Costly and take years ○​ High financial risk ​ Develops drug (effective and safe) in lab → clinical trial on humans ​ Health Canada: approval for drug trials ​ Critics suggest clinical trial results can be biased ○​ Accused of presenting trial data more positive than they really are ​ Ethical issues: does the company own a cure? Altering Genes: Benefits and Controversies ​ Genetic code is universal ○​ Same 4 DNA building-block molecules: produce code for proteins in all organisms ○​ Genetic code in an organism can be “read” by any other organism ○​ Genetic engineering: scientists combine DNA from different species ○​ Genetically modified organisms (GMO), transgenic organisms: species whose genes are altered often P.18 1.​ DNA controls your features, whether you can digest certain foods, etc. Genes are a relatively small part of DNA that determine what kinds of proteins your cells can make, and thus how you function and look. 2.​ Genes provide instruction for making proteins (when and how they are made). So, they can control a cell’s activities and structure. 3.​ Each rung of DNA molecule is a building block strung together, Genes can vary since these building blocks (A,T,C,G) create different combinations. These form genetic codes that are unique for every individual.  4.​ There are hundreds and thousands of genes that can control various proteins. The process from gene to protein has two major steps: transcription and translation. Pg. 22 5.​ A karyotype is a micrograph used to show if a person has too many, too few, or broken chromosomes. This micrograph is used in DNA screening for Down syndrome. 6.​ Amniocentesis and blood sampling are used to screen a person’s DNA. Amniocentesis is a technique used for Down syndrome, where a needle is inserted to withdraw a sample from the amniotic sac, and a micrograph of the chromosomes is taken. Blood sampling is used to diagnose DNA, where the presence or absence of specific proteins in the blood can indicate whether a person’s genes are functioning normally. 7.​ For example, having certain genes can make a person more likely to get cancer or heart disease. Too much of protein production from the excess chromosome also causes Down syndrome. Thus, too little or too much protein production can indicate whether a person’s genes are functioning normally, and lead to developmental or physical disability if levels are not normal. 8.​ Phenylalanine causes tragic consequences if uncorrected. Chemical aspartame may cause the buildup of phenylalanine in the body. Section 1.2: DNA ​ DNA: “blueprint of life” ○​ Instructions for building and ensuring the organism functions correctly ○​ It is the chemical component of chromosomes, which are located in the nucleus of each cell ​ Gene: a segment of DNA that codes for protein → codes for trait ○​ A stretch of DNA ​ Watson Crick model: ○​ Cytosine → Guanine ○​ Adenine → Thymine ○​ Hydrogen bonds formed in between ○​ Deoxyribose sugar (bases extending from the sugar always) ○​ Phosphate group ○​ Nucleotide (PSG) → also called bases ​ Nucleotides pair in a specific way (Base-Pair Rule) ​ 5 important features of DNA: ○​ Helical ○​ Nitrogen bases are extending inside the ladder ○​ Sugar phosphate backbone ○​ Pairs (G-C, A-T) ○​ Hydrogen bonds (3 between GC, 2 between AT) ​ The rungs of the ladder can occur in any order (following base-pair rule) ​ Replication: DNA makes a copy of itself ​ Cells divide for an organism to grow or reproduce ○​ New cells need a copy of DNA for instructions  ​ DNA replicates right before the cell divides ​ DNA replication is semi-conservative ○​ Half comes from the old strand and half comes from the new ​ RNA: ribonucleic acid ○​ One strand instead of two strands ○​ Has uracil instead of thymine ○​ Has ribose instead of deoxyribose ​ Types of RNA: ○​ mRNA: brings information to the ribosome for protein synthesis (has instructions) ○​ tRNA: Brings amino acids to the ribosome (to create protein) ○​ rRNA: Found in the ribosome ​ Protein synthesis: ○​ DNA → (transcription) mRNA → (translation) protein ○​ DNA: ATGG → RNA: UACC ​ Transcription ○​ Process of producing protein from information sent from the nucleus ○​ Transcription: an RNA copy is made from DNA copy in the nucleus (mRNA) ○​ Translation: Proteins are made at the ribosome from the message on the mRNA ​ DNA screening: ○​ The process of testing individual to determine whether that have the gene or genes associated with certain genetic disorders ○​ We can observe a person’s chromosomes to determine a specific problem ○​ A karyotype is a picture of a person’s chromosomes (check to see is a person has too many or too few chromosomes) ​ Transgenic organisms: ○​ Genetic code is universal ○​ Nucleotides (ACTG) are recognized by all organisms ○​ Genetic modification: process of altering genes in a species ○​ Transgenic organism: organisms whose DNA has been altered by inserting genes from another species Mitosis ​ Occurs during cell division where the nucleus is divided ​ At the end of mitosis and cell division: 2 new daughter cells that are identical to one another and parent cell Why are new cells needed? 1.​ Growth ​ Cells grow in volume and mass ​ Inside the cell is growing in volume ​ Processes that go on in the cell become less efficient ​ Distances are too great for chemical messages to travel  ​ Organisms grows → cell differentiate to form many structure such as limbs, organs, tissues 2.​ Respond to a new need (ie. repair or environmental) ​ Cells need to regenerate new tissues in response to damage ○​ ie. growth of muscle in response to exercise or damage ​ Certain organisms regenerate an entire limb if lost ○​ ie. tail of a lizard, arm of a starfish 3.​ Maintenance of function ​ Replace cells that ○​ Do not function properly ○​ Die ​ Millions of red blood cells die everyday ​ They need to be replaced to maintain function Cell Cycle ​ Interphase ○​ The period between nuclear divisions ○​ Chromosomes are not visible ○​ The nuclear membrane is intact ​ G1: The daughter cell becomes larger ​ S phase: The nuclear material duplicates ​ G2: The cell becomes larger again ​ Mitosis: ○​ Prophase ​ Genetic material is called chromatin ​ The chromatin are double stranded and they thicken and shorten to become chromosomes ​ Each chromosome consists of 2 identical sister chromatids ​ Chromatids are attached to centromere ​ The nuclear membrane and the nucleolus disappear ​ Centrioles separate and move to opposite ends (poles of the cell) ​ Spindle fibers attach to the centromere of each chromosome ​ Plant cells do not contain centrioles ○​ Metaphase ​ The nuclear envelope breaks down ​ The centromeres of the chromosomes align on the spindle fibers ​ The tugging action of the spindle fibers pulls the chromosomes into the equator (middle) of the cell ○​ Anaphase ​ The spindle fibers begin to contract and shorten ​ The centromere divides ​ The chromatids of each chromosome are pulled to opposite ends of the cell ○​ Telophase  ​ One complete set of chromosomes is now at each pole of the cell ​ Spindle fibers begin to breakdown and disappear ​ Nuclear membranes begin to form around each set of chromosomes ​ The nucleus appears in each new nucleus ​ Single stranded chromosomes start to uncoil to form chromatin ​ Division of nucleus is complete ​ Cytokinesis ○​ Separation of cytoplasm and its contents into 2 equal parts ○​ Forms identical daughter cells ​ Animals: the cell membrane pinches in and forms a cleavage furrow ​ Plants: a cell plate forms between the 2 daughter cells, cell plate will become new cell wall P.39 1-7 1.​ Cells divide for growth, repair, and maintenance of function. With cell division, cells can grow in volume and size. Cells also need to regenerate in response to damage. Finally, cell division is used to repair parts that do not function well or cells that have died. 2.​ Prophase is the first stage of mitosis. In this stage, the nucleolus and nuclear membrane disappear. Centrioles move to the opposite ends of the cell, while the centromere moves to the middle of the cell and is attached to the centriole through spindle fibers. Telophase is the last stage of mitosis. This is when a complete set of chromosomes is already at the opposite ends of the cell. Spindle fibers disappear and a nuclear membrane forms around each set of chromosomes. A nucleus appears in each of the two nuclear membranes. Finally, the chromosomes uncoil to form chromatin. 3.​ Prophase ​ Genetic material is called chromatin ​ The chromatin are double stranded and they thicken and shorten to become chromosomes ​ Each chromosome consists of 2 identical sister chromatids  ○​ Chromatids are attached to centromere ​ The nuclear membrane and the nucleolus disappear ​ Centrioles separate and move to opposite ends (poles of the cell) ​ Spindle fibers attach to the centromere of each chromosome ​ Plant cells do not contain centrioles Metaphase ​ The nuclear envelope breaks down ​ The centromeres of the chromosomes align on the spindle fibers ​ The tugging action of the spindle fibers pulls the chromosomes into the equator (middle) of the cell Anaphase ​ The spindle fibers begin to contract and shorten ​ The centromere divides ​ The chromatids of each chromosome are pulled to opposite ends of the cell Telophase ​ One complete set of chromosomes is now at each pole of the cell ​ Spindle fibers begin to breakdown and disappear ​ Nuclear membranes begin to form around each set of chromosomes ​ The nucleus appears in each new nucleus ​ Single stranded chromosomes start to uncoil to form chromatin ​ Division of nucleus is complete 4.​ The prefix “pro” is Latin for “before”. Prophase is the first phase of mitosis. The prefix “meta” means “mid” in Latin. This phase is where chromosomes move towards the middle of the cell. The prefix “ana” in Latin means “back”. Anaphase is where the spindle fibers shorten to pull back the chromatids. The prefix “telos” means “end” in Latin. This is the final stage of mitosis, and the general shape of the two new daughter cells begin to form. 5.​ At the end of the anaphase, there will be 20 chromosomes. There will be 10 chromosomes in each new daughter cell after cytokinesis.  6.​ Plants Animals ​ The rigid cell wall makes cytokinesis ​ Rings of specialized protein around slightly different the middle of the cell starts to contract ​ Golgi body starts to produce small (like pulling drawstrings on a bag) vesicles ​ The contraction pinches the cell ​ Each of these sacs carries materials membrane until the parent cells is needed to form new cell wall divided into 2 parts ​ Vesicles line up between the 2 new ​ Each daughter cell has a complete set nuclei, forming a cell plate of chromosomes in a nucleus and its ​ Cell plate grows outwards and joins own cytosol and organelles the old cell wall ​ New cell walls are secreted on each side of the cell plate → dividing cytoplasm to two ​ New membrane forms inside the cell walls 7.​ The cell structure is a plant cell, during the prophase. The nucleolus has disappeared, but chromosomes have not separated yet. Cancer ​ Can be caused by mutagenic agents ​ Some are curable, some are treatable, some progress rapidly, some do now show for years ​ There are 3 main points where the cell “checks” its growth ○​ Special proteins receive confirmation for the cell cycle to proceed ○​ The cell cycle loses its checkpoints → cell division is no longer controlled → cancerous mass is formed ​ Cancer: group of more than 100 irregular cells forming a mass ​ Tumors: irregular cell division masses ○​ Benign (not cancerous) ○​ Malignant (cancerous) ​ Malignant tumors can spread (metastasize) to other parts of the body → form other tumors ​ Some cancers are easily curable, other are difficult to cure ○​ Depends largely on the organ of the body where cells grow abnormally & size of original tumor  ​ Cancers appears most often in middle-aged and the elderly ​ Susceptibility to cancer-causing agents varies among individuals due to genetic factors ​ No one knows for certain how normal cell becomes a cancer cell ​ Usually appear 5-40 years after exposure to cancer-causing agent ​ Long latency period: one of the reasons why it is difficult to identify the causes of cancer Tips of lowering cancer risk 1.​ Stop smoking or tobacco usage 2.​ Regular health check-ups 3.​ Eat high fiber foods daily (eg. fruits, vegetables, whole grain bread cereals) 4.​ Eat foods low in fat (lean meat, low fat dairy products) 5.​ Limit alcoholic beverages 6.​ Avoid unnecessary X-rays 7.​ Avoid too much sunlight: protective clothing and sunglasses 8.​ Awareness of health and safety rules in the workplace ​ Cloning ​ Process of producing an identical offspring from a single cell or tissue ​ Occurs naturally in nature during asexual reproduction ○​ eg. bacteria, fungi, plants, ○​ invertebrate animals: hydra, sponges Cloning a mammal: 1.​ Mammary cells are frozen 2.​ Egg is taken from sheep 3.​ The nucleus is removed from the egg cell a.​ Genetic information is removed b.​ Nutrients in egg cells allow cell division and development 4.​ Two cells are fused a.​ Full set of genetic information comes from Finn Dorset b.​ Just the genetic information that allowed cell division (no nutrients) 5.​ Egg undergoes cell divisions a.​ A mass of cells with the same genetic information 6.​ Cell mass is transferred into the uterus of a Scottish blackface sheep 7.​ Blackface sheep carries the clone a.​ Blackface sheep acts a surrogate — carries the clone until birth 8.​ Dolly is born a.​ Clone of Finn Dorset Pg. 45 1.  a.​ Anaphase b.​ Cell cycle checkpoints occur after mitosis, where the cell looks for chromosomes that have not attached themselves to spindle fibers in metaphase, or chromosomes that have not moved to the poles in anaphase. 3. Skin epidermis cells are an example of short-lived cells. The epidermis is continually renewed from stem cells. When they harden and eventually die, new cells replace them. Another example is white blood cells that defend the immune system against “invaders”. Most white blood cells only survive for a few hours to a few days, and are programmed for cell death after infection. 5. The first condition is after growth and preparation, to ensure that the cell has nutrients to support its growth and DNA is not damaged. The second condition is after DNA replication and continued growth and preparation. If the DNA has not replicated or is damaged, the cell will be repaired or destroyed. The final condition is after mitosis, to ensure that all chromosomes have attached themselves to spindle fibers in the metaphase, and chromosomes moved to the poles in anaphase. 6. The drugs interfere with the cancer cell’s ability to divide and make new cells during mitosis. Pg. 52 1.​ Organelles 2.​ Micrograph 3.​ DNA 4.​ Mutation 5.​ Mitosis; cytokinesis 6.​ Cell cycle 7.​ Light Microscopes Electron Microscopes ​ The image is viewed against a bright ​ An SEM sweeps a beam of electrons background. over a specimen’s surface ​ Used most often in labs to study cells ​ Electrons are emitted from the ​ specimen ​ Produces realistic 3D images ​ Images can only be viewed as photographs or on a computer monitor 11. Cells divide to grow in size and volume, respond to needs, such as replacing new tissues, and to maintain function, as some cells die or no longer meet their required functions. 13. During interphase, cells perform the activities that are designed to do, such as producing specific proteins. The cell also performs universal tasks for all cells, like taking in oxygen and glucose. Interphase is a period of growth and when DNA replicates itself in preparation for cell division. 14. Spindle fibers are attached to the centromeres of each chromosome from centrioles during mitosis. When the spindle fibers contract and shorten, the chromosomes are pulled apart to the opposite ends of the cell. Spindle fibers disappear during the telophase. 15. a)​ B b)​ A c)​ D d)​ D  e)​ C, B, A, D 16. Benefits Drawbacks ​ Human proteins manufactured by bacteria ​ Some worry about effects of causing rapid are less likely to cause allergic reactions change in species that have taken millions or diseases, compared with proteins of years to evolve obtained from other sources ​ There is too little known about the ​ Crops can be modified in this way to long-term consequences resist specific pests, to have higher nutritional value, or to better withstand drought or cold ​ GMO animals injected with a growth hormone grow faster than non-GMO animals, increasing human food supplies 17. These checkpoints ensure that cell division is going smoothly, and no errors have occurred. In case of error, these checkpoints can quickly identify the problem and stop the cell division process before this mutated cell has divided to form new error cells. Cancer is an example of malfunctions in the checkpoints that causes consequences that may be fatal. 18. Tumors refer to a clump of cells, caused by repeated and excessive cell division that ignores the stop sign in the cell cycle. When these clumps of abnormal cells develop with further mutations, cancer is formed. 19. The cell is the basic unit of life as it is the building block that creates organisms. It is the smallest unit that can perform the functions of life. 20. When body cells reproduce, there is only one parent. One cell divides to produce 2 new cells, which are called daughter cells. These identical cells perform the same functions, and group together to form tissues. 23. a)​ Interphase: 82/104=x/800 → 630 minutes Prophase: 13/104 = x/800 → 100 minutes Metaphase: 2/104=x/800 → 15 minutes Anaphase: 2/104=x/800 → 15 minutes Telophase: 5/104=x/800 → 38 minutes b)​ Interphase is the stage for growth, and also where cells perform the activities that are designed to do. This is the stage where cells serve their main functions. c)​ The cell cycle in a leaf would be longer. This is because the main function for a leaf is to perform photosynthesis and allow gas exchange. On the other hand, carrot roots are meant to be the roots of the plants, so its job is to grow larger to absorb more nutrients. Thus, a shorter cell cycle for carrot root tips means quicker growth. 2.1 Plant Cells, Tissues, and Organs ​ Cell specialization: the process by which cells develop from similar cells into cells that have specific functions within a multicellular organism ​ Cell differentiation: the point at which cells become specialized  ​ Cells are specialized based on the type of proteins they have (protein synthesis) ​ Not all genes are read and translated in every cell ​ Different genes are turned on / off: for different proteins to be made ○​ These genes are turned on and off by chemical signals Specialized cells and tissues in plants ​ Tissues: a cluster of similar cells that share the same specialized structure and function ​ Organ: a combination of several types of tissue working together to perform a specific function ​ Plants continually grow from seedlings ○​ Meristem cells: The cells that keep dividing ​ Undifferentiated ​ Develop to 3 types of tissues ​ Dermal Tissue: ○​ Forms the outermost covering of the plant’s organs ○​ Barrier between the plant and its external environment ○​ Protects delicate inner tissues from damage ○​ Controls the exchange of water and gases between the plant and its environment ○​ Eg. epidermal cell ​ Ground Tissue: ○​ Some ground tissue is made of cells that perform photosynthesis ○​ Some ground tissues provide support for the plant’s body ​ Vascular Tissue: ○​ Transports water, nutrients, and sugars throughout the plant ○​ Provide physical support for the plant’s body ○​ Xylem cells: ​ Dead tubular cells ​ Laid end to end ​ Transport water and minerals from plant roots to other parts of the plant ○​ Phloem cells: ​ Living tubular cells ​ Joined end to end ​ Transport sugar from leaves to other parts of the plant Repairing and Replacing Specialized Cells ​ Plant tissues need to be replaced: remain efficient in absorbing nutrients or producing energy ​ Growing plants push upward, downward, and out ○​ Meristematic cells are found at the tips of the roots and branches  ​ Bud: swelling of the stem that contains meristem cells ​ Terminal bud: found at the tips of branches and roots (most active with cell division) ​ Lateral bud:inactive (formant), potential to grow into branches or roots 2.1 Plant Cells, Tissues, and Organs ​ Epidermal layer: a “layer of skin” ​ Palisade mesophyll: photosynthetic ○​ Arranged vertically, so the sun can hit both sides of the cell ○​ Allow sunlight to penetrate through ​ Spongy mesophyll: ○​ Spaces between cells allow gases to accumulate ○​ Oxygen is accumulated during photosynthesis ○​ After oxygen leaves, carbon dioxide fill the spaces ​ Lower epidermal layer: still has epidermal cells ○​ Also have specialized cells (eg. stomata) ○​ Stomata: where you have opening, open / close ○​ Openings allows for air to exchange (oxygen and carbon dioxide exchange) ○​ When water moves in: swell and buckle (daytime) → open ○​ When water moves out: close (nighttime) → no accumulation of sugars and ions due to lack of photosynthesis → water leaves with them ○​ Guard cells: accumulation of sugars and ions (including water because of osmosis) ​ Area of high concentration to low concentration ​ Vascular bundle: ○​ Xylem and phloem cells → specialized for transport ○​ Xylem: transport water, dead cells, stack on each other → die → creating a column/pipe, help water move through the xylem cells ○​ Phloem: transport nutrients, sugars, hormones → stacked in a column but don't die, so nutrients can move through the cells ​ Chloroplast: consists of a outer and inner membrane ○​ Inner membrane: thylakoid membrane ○​ Arranged in stacks (grana) ○​ Sunlight strike thylakoid membrane , transfer light energy to plant Pg. 62 1.​ During the plant’s development, stem cells undergo cell differentiation, creating specialized cells in different functions. Cells will be specialized according to the set of proteins they contain, and genes are responsible for producing proteins. One set of genes is turned on in one cell type, and another set of genes is turned on in another cell type. The proteins produced will determine the function of that cell.  2.​ Dermal tissues can be found in the upper and lower epidermal layers. Ground tissue is found in the palisade and spongy mesophyll. Vascular tissue is found in the vascular bundles, xylem and phloem cells. 4. By taking away the terminal buds of the basil plants, the lateral buds will be activated, and the plant will start to grow laterally to form a bushier basil plant. If the terminal bud is removed, there is no longer any auxin (a hormone) to inhibit lateral growth and cells in lateral buds divide and specialize. Pg. 64 5. Chloroplasts can change their shape and location in a cell to increase the amount of light they capture. Chloroplast contains little sacs called thylakoids, which have light-trapping chlorophyll molecules. Thylakoids are arranged into a stack called a granum. 2.1 Plant Stems ​ The mass of leaves is usually greater than the mass of stem ​ Stem most be strong enough to hold the leaves in the sunlight ​ Flexible enough to bend in the wind ​ Transport water and nutrients (glucose) ​ Stem function ○​ Support ○​ Transport of materials through veins ​ If the stem is bent → cuts of transport Stem morphology ​ Primary meristem growth: green stem: usually soft, found on eg. dandelions ​ Secondary meristem growth: wood, found on trees for example, grows every year (when we cut the tree we see the rings) Vascular tissues ​ Xylem are lined up in single-file ​ Cells inside xylem will die out, cell wall remains ​ Lignin is added to strengthen the cell wall ​ Creates an empty pipe for water to flow up ​ Stomata opens: gas exchange and transpiration ​ Transpiration: water evaporates up the stomata, pull and draw water up the leaves ​ Phloem: lined up in single column like structure ​ They are living, has pores that allow for transfer of substances from one cell to another (eg. glucose) 2.1 roots ​ Roots: absorb water and minerals ​ Anchored in the ground, keep soil stable ​ Roots will grow as the plant grows ​ Types of root system: ​ Tap root system: ○​ Allow plant to dig deep, anchor a large tree, reach down for additional mineral and water ○​ Carrots: modified roots for function ​ Most often modified for storage ○​ The outside layer grows ​ Fibrous root system: smaller in width, more shallow ○​ Grass, smaller plants ​ In plants that are large, has bark: has secondary growth that leads into the roots Root anatomy ​ Roots have a central core of vascular tissue: support vascular tissue ​ Root hairs: increase surface area ○​ Increase absorption of water and minerals ○​ Tend to rot with too much water or due to types of fungus ​ Meristematic region: a lot of cell division Plant Organ Systems: ​ Shoot system: everything above ground ​ Root system: network of roots, bottom of stem found underground ​ The two systems: connected through vascular bundles Moving through the roots: ​ Getting water into the root: ​ Step 1: transport minerals into the root ○​ Makes the root hypertonic → water flows into the root, along its concentration gradient (osmosis) → creates pressure ​ Step 2: ​ Factors that cause the water to move up the stem to leaf: ​ Cohesion: ability for water molecules to stay together ○​ Attraction for water molecules ○​ Partial positive and negative charges in water molecules, attract each other ​ Eg. “dome” created at the brim of a bottle ​ Adhesion: ○​ Water sticks to the side of the xylem because of the partial charges ​ Eg. meniscus in graduated cylinder ​ Transpiration pull: when your stomata open and water evaporates from the stomata, absence of water → creates pull → pull water up the roots, xylem, into leaf ○​ Depends of cohesion and adhesion ​ Photosynthesis: ○​ 6CO2 + 6H20 → C6H12O6 + 6O2 Pg. 64 6-8 6. The 2 main functions of the stem are for physical support and transportation of water, nutrients, and sugars. The stem is made of xylem and phloem cells. Xylem cells die, leaving only the cell wall, so that water can be transported easily through the hollow pipes. Xylem vessels are grouped with phloem vessels in vascular bundles and further strengthen the stem’s ability to support the plant. Phloem tissues are vertically stacked in tubed and have porous cell walls which allow exchange of materials. 8. On a hot, dry day, the stomata would be closed to prevent further water loss. If the stomata is open, water can be easily evaporated. Pg. 76 5. The stem allows the transportation of water, nutrients, and sugars. Even if physical support is given with a tool, the damaged xylem and phloem cells means that the necessary substances to reach the leaves of the plant cannot be reached. Plants Under Attack ​ Plant tissues and organs can be attacked by viruses (400+ viruses can infect plant cells, 1000+ plant diseases) ​ Not all plant diseases are fatal / harmful ○​ Eg. Rembrandt tulips get their stripes from a virus ○​ Eg. Tobacco Mosaic virus (TMV): highly destructive → attacks leaves of tomato, potato, pepper, cucumber plants ​ Antiviral drugs fight these viruses Plant Galls ​ Galls: similar to tumors in animals ​ Galls are produced by abnormal growth of groups of cells ​ Galls are produced in response to attacks by organism (insect, fungi, bacteria, virus) ​ Attackers: use the plant’s resources to support themselves and offsprings ○​ Eg. some insects lay eggs in oak trees → larvae develop in a gall that grows in the tissue of the tree ​ Insects inject a chemical into a plant’s tissues → chemical interacts with the plant’s fluids → alters which genes are turned on / off in cells ○​ Stimulates the growth of a structure where young insects develop ​ Galls do not normally spread to other tissues ​ Gall growth is contained & seldom fatal The Reproductive Organ: The Flower ​ Flowers do not take part in the maintenance of the plant itself ​ Flowers reproduce ​ Some plants produce flowers, other reproduce by other methods ​ Different parts of the flower: “specialized leaves” ​ One of these leaves: specialized to produce pollen (manufactures sperm / eggs) ​ Most plants pollinate through the wind or animals (pick up pollen from male parts of the flower) ○​ Fertilization: Pollen is transported to the female part of another plant of the same specie ○​ Flower is pollinated: seeds are produced → embedded in fruits ​ Ethylene (hormone): stimulates the ripening of the fruit ○​ Companies use this knowledge to ship fruit internationally 3.1 Stem Cells ​ Ability to divide and differentiate into different types of cells ​ Types of stem cells (in embryo, embryonic) ​ Totipotent: versatility ○​ Totipotent cells: can become any type of cell ​ Blastocyst: cells somewhat different to outside and inner portion ○​ Not as potent as totipotent ​ Pluripotent: have the ability to divide into fewer number of cells (neural cells, cardiac, or blood cells) ​ Why are embryonic stem cells important: potential for medicine and surgery ​ To harvest embryonic stem cells: embryo has to die ○​ Issue: unethical ​ Tissue specific and adult stem cells ○​ Found in tissues that are already differentiated ​ To produce more of those types of stem cells ○​ Eg. for leukemia: we use these stem cells to cure ​ Match you with a patient ​ If there is a match, extract stem cells from the bone marrow ​ Remove all white blood cells in patient, then insert new stem cells in the patient’s bone marrow ○​ Difficult to isolate, looks similar to normal cells ​ Cord blood stem cells (in umbilical cord) The Digestive System ​ Breakdown of food into useful substances that are absorbed into the circulatory system ​ Takes an average of 24-33 hours for each meal to complete its journey ​ Composed of: ○​ tube/gut or digestive tract ○​ Liver, pancreas, gallbladder ○​ Open tube arrangement  ○​ Begins at the mouth and ends at the anus 1.​ Mouth: a.​ Teeth i.​ Incisors (for biting) ii.​ Canine (for tearing) iii.​ Molars (crushing) iv.​ Wisdom teeth (may fail to erupt) 2.​ Tongue a.​ Covered with Papillae (pimple like structures) b.​ Taste buds are found here c.​ Allow you to differentiate between sweet, sour, bitter, salty d.​ Composed of muscle e.​ Mixes chewed food with saliva into a mass called bolus 3.​ Roof of mouth: a.​ Hard palate (anterior) b.​ Soft palate (posterior) i.​ Ends at the uvula ii.​ Prevents food from entering the pharynx 4.​ Salivary Glands a.​ The glands use ducts found in mouth cavity to secrete saliva b.​ Parotid glands: i.​ largest salivary glands ii.​ Lie at side of face immediately below and in front of ears iii.​ Ducts: cheeks c.​ Sublingual Glands: i.​ Smallest gland ii.​ Lie beneath the tongue iii.​ Ducts: under tongue d.​ Submandibular glands i.​ Lie beneath the lower jaw ii.​ Ducts: floor of mouth 5.​ Esophagus a.​ Chewed food: bolus b.​ The bolus moved from the mouth into the esophagus c.​ When you swallow the trachea moves up behind the epiglottis (a flap of tissue) to close off the opening 6.​ Lower esophageal sphincter (L.E.S) a.​ Found at the entrance of esophagus into the stomach b.​ Muscle that encircles tubes and acts as valves c.​ When it contracts → tube closed d.​ When it relaxes → tube open e.​ Swallowing causes the sphincter to relax f.​ Prevents acidic contents of stomach from entering the esophagus 7.​ Stomach  a.​ Thick walled (muscles that help churning motion happen) b.​ Muscular c.​ J-shaped organ d.​ Lies on the left side beneath the diaphragm e.​ Thick layer of mucus to protect the lining f.​ Muscular wall of stomach churns or mixes food with gastric juices creating a thick liquid called chyme g.​ Stomach empties every 2-6 hours h.​ Chyme leaves stomach and enters small intestine by way of the pyloric sphincter (contracts and relaxes to control flow of food) 8.​ Small intestine a.​ Avg. 6 meters in length b.​ Walls of small intestine contain: i.​ Folds ii.​ Villi - finger like projections iii.​ Villi have microvilli (brush-like border) c.​ All increase surface area for maximum absorption d.​ Blood vessels are found in folds of the intestine and microvilli → nutrients absorption e.​ Duodenum → jejunum → ileum i.​ Toward the end, the number of microvilli decrease ii.​ Majority of absorption happens in the duodenum and beginning of the small intestine f.​ Duodenum: important site for further chemical breakdown i.​ Bile duct (from gallbladder) and pancreatic duct open into the duodenum ii.​ Pancreatic duct sends chemicals to neutralize acidic environment of the chyme g.​ Jejunum: i.​ Breaks down remaining protein and carbohydrates ii.​ Decrease in digestion h.​ Ileum i.​ Contains fewer villi ii.​ Absorbs remaining nutrients iii.​ Pushes undigested material into large intestine (cecum: first part of the large intestine) 9.​ Large Intestine (Colon) a.​ Valve separates small and large intestine b.​ Larger in diameter than small intestine c.​ Includes i.​ Cecum: ii.​ Smaller projection called appendix that has no role in digestion but may play a role in immunity (not part of the immune system!) d.​ Water and dissolved minerals absorbed from undigested food e.​ Bacteria found here break down undigested food and produce certain nutrients such as Vitamin K  f.​ Feces refers to the remains from this process and passes through the rectum, anal canal, and out the anus 10.​ Anal sphincters are found here to control the timing of elimination Hw. p.107 1.​ The small intestine is covered with millions of interior folds, which are villi and microvilli, with enzymes embedded for quicker absorption. These structures maximize the surface area over which nutrients and water can be absorbed into the bloodstream. 2.​ The digestive enzymes from the pancreas cannot be released. Therefore, it will be more difficult to break down food. P.92 1.​ In photo A, skeletal muscles are lined up in the same direction, making it look striped. It is designed to change shape easily and act by shortening and lengthening to help with body movement. In photo B, the skin epithelial cells form thin sheets and act as semi-permeable barriers. They have strong connections between membranes to form a strong barrier. In nervous cells, the structure allows it to relay signals with finger-like projections. In photo D, blood tissue performs a variety of functions to transport and protect. The structure allows it to move easily to clot or transport nutrients. 2.​ a) → photo D b) → photo C c) → photo B d) → photo A 4. If a chick embryo did not specialize, the chick cannot grow to an organism as it cannot perform the different functions for an organism to survive. 5. Stem cells perform functions similar to that of a meristem cell, they produce more cells so the animal could grow larger. They are unspecialized and can produce various other specialized cells. 8. Although embryonic cells are versatile, they remain an ethical issue as these stem cells are taken from eggs fertilized in the vitro. Adult stem cells can be transformed into pluripotent stem cells, avoiding this potential ethical issue, since donations are done under the agreement of the donor. Digestion Digestion begins in the mouth and stomach ​ Enzyme amylase (end “lase”: an enzyme, amylase: breaks down amylose) ○​ Secreted with saliva ○​ Mixed with food as it is chewed ○​ It is a carbohydrase ○​ Begins to break up starch In the stomach ​ Gastric juices consists of: ○​ The enzyme pepsin ​ Pepsin breaks down protein ​ Activated by the low pH in the stomach  ​ Why don't you want the enzymes to be activated in the stomach walls: it will break down the proteins in the stomach walls (the stomach is a muscle!!) ​ Pepsin only works when it is exposed to an environment with a pH of 2 (after hydrochloric acid is secreted) ○​ HCL ​ Gives the stomach a very low pH (between 1-3) ​ Optimal pH for pepsin to work ​ Gastric pits: ○​ There are cells that secrete mucus, hydrochloric acid, inactivated form of pepsin ○​ Secreted into stomach interior ○​ Pepsinogen converted to pepsin by HCl exposure and existing pepsin ○​ Mucus is secreted by the stomach to protect the walls from being eroded or digested by HCl and pepsin ​ Chyme is the mixture of gastric juices and partially digested food (thick liquid) ​ Few substances are absorbed across the lining of the stomach: Coffee, aspirin, alcohol ​ When food enters the stomach nerves found in the stomach sense this and signals for churning to take place Small Intestine ​ Chyme enters the duodenum ​ Site of major digestion and absorption Secretions of the small intestine ​ Pancreatic juices are secreted from the pancreas to ○​ Neutralize the acidic chyme (becomes weakly basic) ○​ Deactivates pepsin ○​ Consists of many enzymes that help break down fat, protein, and carbohydrates ​ Enzymes embedded in the small intestine lining also help with digestion (blood vessels run in the villi for nutrients to be absorbed and transported) Bile ​ Liver produces bile (one of its functions) → goes through the hepatic duct → to the gallbladder (storage) → bile duct → small intestine ​ Produced by the liver and stored in the gallbladder ​ Break down fats so enzymes can do the job ​ Breaks down fat ​ Enters the duodenum via the bile duct Absorption in the small intestine ​ Nutrients are absorbed across the lining Structure and Function of the Human Heart The Heart Function: ​ to pump blood throughout the body Structure: ​ Cone shaped  ​ Muscular organ (size of a fist) ​ Located between the lungs, behind the sternum and tilted so the apex is pointing to the left ​ Major part of the heart is cardiac tissue (myocardium) ​ Right side and left side: separated by septum ​ The chambers: ○​ 4 chambers ​ 2 atria: upper, thin walled ​ 2 ventricles: lower thick walled (stronger & larger than the atria) ○​ On the right side: right atrium & right ventricle ○​ On the left side: left atrium & left ventricle ​ Each atrium pumps blood into its respective ventricle ​ Each ventricle pumps blood into arteries ○​ Right ventricle pumps blood through Pulmonary artery (to the lungs) ○​ Left ventricle pumps blood through the body Valves ​ The heart has valves to direct the flow of blood ​ Prevents backward flow or mixing of blood ​ Atrioventricular valves: ○​ Lie between atria and the ventricles (right AV and left AV) ○​ Prevent backflow into the atria when ventricles contract ​ Semilunar valves ○​ Between the ventricles and the arteries ○​ Prevents backflow of blood into the ventricles The Path of Blood in the Heart ​ Blood always: ○​ Returns to the hearts via veins ○​ Leaves the heart via arteries 1.​ Right atrium receives deoxygenated blood from superior and inferior vena cava ​ Large veins that collect blood from upper and lower body 2.​ Right atrium contracts and empties the blood into the right ventricle 3.​ RV pumps blood into pulmonary artery (to lungs) 4.​ Pulmonary vein: returns oxygenated blood from lungs to left atrium 5.​ Powerful contraction of the LV sends blood through aorta → begin circulation ​ Both atria contract simultaneously ​ Both ventricles contract simultaneously ‘Lub-Dub’ ​ Created by slamming hut of heart valves ​ ‘Lub’: ventricles begin to contract → atrioventricular valves close ​ ‘Dub’: ventricles begin to relax → blood gathered in aorta and pulmonary artery → semilunar valves slam shut Open Circulatory System ​ Major vessel that pumps blood into other parts of the body ​ Cells are bathed in blood ​ Muscle movement: pushes blood back to pump Closed Circulatory System ​ Mammals: closed circulatory system ​ Blood stays in blood vessels Different Number of Chamber ​ Fish: 2 chambered heart (1 atrium & 1 ventricle) ​ Frogs: 3 chambered heart (2 atria & 1 ventricle) ○​ There is mixing of oxygenated and deoxygenated blood ○​ Oxygen diffuses across the moist skin of a frog → fulfills oxygen demand Cardiovascular Disease Atherosclerosis ​ Hardening of arteries ​ Silent killer: begins many years before symptoms are detected ​ Smooth epithelial lining of the arteries can be damaged by ○​ Chronic high blood pressure ○​ Smoking ○​ High fat diet ○​ Microorganisms ​ Fatty deposits called plaque form at sites of endothelial damage ​ Growing plaque: ○​ Narrow the artery ○​ Blood platelets stick to a plaque and initiates formation of a blood clot (thrombus) ○​ This further blocks the artery and decrease blood flow to the heart ​ Symptoms: ○​ Chest pain ○​ Shortness of breath during mild exertion ​ Atherosclerosis leads to: ○​ Total blockage of the coronary artery → heart attack ​ Embolism: ○​ Pieces of thrombus breaks loose (embolus) ○​ Travels and becomes lodged in a vessel of small diameter → blocks flow ○​ Can occur in artery in the brain → stroke ​ Cells fed by that artery dies ​ Results in memory loss, speech impairment, paralysis -​ Depends on location of blocked artery  ○​ Can occur in heart → interfere in movement of blood → heart attack ​ Treatment: ○​ Exercise and healthy diet ○​ Aspirin: prevents platelets from sticking together ○​ Digitalin: strengthens heart contractions ○​ Angioplasty: surgery to force open clogged artery ​ Balloon inflates in blood vessel: creates space to “unclog” ​ Stent is placed ○​ Coronary bypass: using a healthy blood vessel from another part of the body ​ Creates new pathway around blockage in a blood vessel near the heart ​ Eg. single bypass, double bypass, triple bypass P.106 5. 6.​ The first path the blood takes is from the heart’s right atrium to its right ventricle, which pumps blood through the pulmonary artery to the lungs. The blood eliminates carbon dioxide and picks up oxygen. The oxygenated blood goes back to the heart’s left atrium, then the left ventricle. The blood will be pumped to the aorta, and the rest of the body. The left ventricle is more muscular than the right, since it has the job of pumping blood into the aorta, which is a huge artery, and the blood needs to be sent to the rest of the body. p.107 4. a) C b) B c) D d) A P.122 13, 15, 19, 24 13. The aorta has the highest blood pressure, because they are directly connected to the heart ventricles. The high blood pressure ensures that the blood is flowing through the arterioles. The veins in the circulatory system have the lowest blood pressure, since they have thinner walls than arteries. A lot of pressure is also lost by traveling through the arteries. 15. a)​ 2 b)​ Aorta c)​ The lungs d)​ oxygenated 19. White blood cells 24.  a)​ The excretory system is shown in the diagram. b)​ The renal arteries send in large amounts of blood to kidneys for filtering. The large blood vessels are branched into smaller vessels that reach the nephrons. Large vessels mean more efficient filtration of blood. 3.3 Maintaining Healthy Systems Advances in Medical Technologies ​ Biophotonics: all procedures and devices that use various light technologies to work with living systems, including humans ○​ Minimally invasive surgeries that result in fewer complications and less discomfort ○​ Endoscopy: used to conduct surgeries ○​ Surgical lasers: allow pinpoint accuracy for operating delicate tissues Prenatal Care and Ultrasound ​ Medical imaging technologies: helps prenatal care ○​ Ultrasound: used in first months of pregnancy Preventive Health Care ​ Individuals can take steps to guard their own health ○​ Eg. exercise, healthy diet ​ Public health strategies: coordinated effort to track, research, reduce the incidence of a specific health problems in population ○​ Vaccinations: giving a vaccine by mouth or injection to provide active immunity against a disease Fighting Infectious Disease ​ Pathogens: disease-causing agents → cause infectious diseases ○​ Virus, bacteria, fungi ​ The immune system attacks and destroys the pathogen that has entered ​ First response to invasion: ○​ send a flow of fluid containing white blood cells (phagocytes) ○​ Dissolve substances from the blood to the site of infection → inflammation and swelling ​ Phagocytes: fight infection ​ Antigen: any material that the body considers foreign & stimulates response ​ Antigens: proteins on the surface of pathogens Developing Antibodies ​ White blood cells and other disease-fighting molecules are manufactured in the bone marrow ​ Antibodies: identify and attaches to specific antigen ○​ Prevents the invader from infecting the rest of the body ○​ Signal other parts of the immune system of the intruder Stopping the Spread of Disease ​ No vaccinations → contain the spread of disease ○​ Eg. SARS, AIDS, West Nile virus SARS ​ SARS: severe acute respiratory syndrome ​ Causes fluid to fill a patient's lungs → lack of oxygen  ​ Transferred through the air → disease spread → public health crisis AIDS ​ AIDS: acquired immunodeficiency syndrome (AIDS) ​ Caused by the human immunodeficiency virus (HIV): attack immune system ​ Pathogens enter the body → immune system is unable to defend the body West Nile Virus ​ Those who were infected had no symptoms or became seriously ill ​ Public Health Agency of Canada coordinates strategies to reduce people’s exposure to the virus ○​ Identifying the presence of disease in various animals & where it is present ○​ Use pesticide to reduce mosquito population and provide educational programs Cancer Prevention ​ One of the best ways to avoid cancer is to avoid substances leading to cell mutation for cancer ○​ No smoking, avoid excessive sun exposure ○​ Asbestos insulation: carcinogenic Screening for Cancer ​ Cancer screening: tests to detect cancer cells at an early stage of the disease ○​ Increases a person’s chances of survival ​ 65-95% of individuals survive ​ PAP smear: remove small sample of a cervix → examined for abnormalities P.115 1.​ Ultrasound, endoscope, CT scanner. Endoscopy is used in surgery, ultrasound has low sound waves that don't penetrate into the tissue. 2.​ Bone marrow tissue produces white blood cells and other disease fighting molecules, like antibodies, that help with the body’s immune system. The skin is an organ that physically prevents pathogens from entering. 3.​ These procedures can be done through forms of medical imaging. An endoscope can be used in the procedure. These growths in the colon can be concerning because it might suggest the development of cancer in the colon. 4.​ a) This may be because of the increased number of fast food restaurants, which lead to an unhealthy diet and more obesity. b) This is alarming because an increase from 3% to 9% is large. This is a large increase in obesity in a short amount of time. 5.​ Vaccination introduces a small number of antigens of a certain disease, which triggers the immune response. This lessens the effects of the disease in the future, and the immunity cells have developed “memory” of the antigen, and can attack the pathogen more effectively. 6.​ Cancer screening allows cancer to be detected early, which increases a person’s chances of survival. Depending on the type of cancer, early detection and treatment allows 65-95% of individuals to survive 7.​ A public health strategy is vaccination. Vaccination across the population can reduce the incidence of common diseases and the spread of it across the population. The Mammalian Respiratory System ​ Human respiratory system consists of: ○​ Upper respiratory tract ○​ Lower respiratory tract The Upper Respiratory Tract ​ The nose ○​ Air enters through the nostrils ○​ These lead into hollow spaces called nasal passages or the nasal cavity ○​ Hairs at the opening of the nostrils: stop foreign particles from entering ○​ Nasal passages are lined with: ​ Mucuos: moisten air and trap particles ​ Cells may have cilia ​ Under the mucous membrane: vessels that warm the air ​ The Pharynx ○​ Common passageway for both food and air ​ Glottis ○​ The opening of the trachea ○​ Epiglottis: flap like structure that blocks glottis opening when swallowing occurs ​ Larynx ○​ After passing the pharynx → air passes into the larynx ○​ Also known as voice box ​ Made of cartilage contained 2 vocal cords ​ Air breathed out: vocal cords vibrate → make sound ​ Trachea: ○​ Larynx connects to trachea ○​ A tube about 12 cm long, 2.5 cm wide ○​ Always kept open by horse-shoe rings of cartilage The Lower Respiratory Tract ​ Bronchi (singular: bronchus) ○​ The trachea continue downward into the chest ○​ Divides into 2 bronchi ○​ Bronchi branch into network of smaller tubes called bronchioles ○​ Starts with cartilage rings → ends without cartilage rings ​ The bronchioles ○​ Lack the supporting rings of cartilage present in the trachea ○​ Lead into a group of alveoli ​ Alveoli: ○​ Sites of gas exchanges ○​ Looks like cluster of grapes ○​ Walls are one cell thick ○​ Moist and surrounded by pulmonary capillaries (how oxygen diffuses) ​ Oxygen diffuses into the body and capillaries that surround the alveoli ​ CO2 diffuse out, O2 diffuse in (higher → lower concentration)  ○​ Lungs contain 300 million alveoli (a lot of surface area) ​ Total SA: 70-90 m2 ​ Lungs ○​ Connective tissues that surround these delicate structures ○​ Tissues that connect to the ribcage ○​ Bronchioles and alveoli are held together by connective tissues ○​ Tissues contain nerves and pulmonary capillaries ○​ Surrounded by double-membrane: pleural membrane ○​ Pleural membrane: seals off the thoracic cavity from the rest of the body ​ Diaphragm ○​ Manipulate volume in chest cavity (air move in / push out) ​ A very thin film of fluid is sealed between the 2 layers of the pleura ○​ Holds them together when the lungs move ​ Seal between pleural membrane breaks → lungs are not connected to walls of chest cavity → lungs collapse ○​ Determined through x-ray P. 106 7. In anemia, there is a lack of red blood cells. Red blood cells have the primary responsibility of carrying oxygen around the body. When there is a lack of red blood cells, less oxygen can be carried throughout the body. Oxygen is essential for cellular activities, processing food to energy, brain functions, etc. P.107 5. As there is less oxygen available in the city of Wenzhuan, people living in these high altitudes may have adapted by having faster breathing rates and respiratory processes to obtain more oxygen. A faster breathing rate also increases blood circulation in the body and heart rate to reach the demands of the tissues. 6. Alveoli are tiny sacs and sites of gas exchange. In the alveoli, the air is only one thousandth of a millimeter away from the bloodstream. The thin layer of epithelial tissues keeps most inhaled bacteria and viruses away from the bloodstream, while gases cross into the capillaries. O2 diffuses into the capillaries and CO2 diffuses out. 7. During hyperventilation, the breathing rate increases rapidly. This breathing rate increase creates an imbalance between inhaling oxygen and exhaling carbon dioxide. Carbon dioxide levels are lowered as it is breathed out, which leads to the narrowing of blood vessels that supply oxygen to the brain. The lack of oxygen in the brain leads to loss of consciousness. The Mechanics of Breathing ​ Intercostal muscles: muscles associated with breathing and can be found between the ribs ​ Diaphragm ○​ Muscle layers that separates the thoracic cavity and the abdominal cavity ○​ Assist in ventilation of lungs ○​ Relaxed position: a dome ○​ Contract: flattens ​ Inhalation  ○​ The diaphragm contracts downwards ○​ Intercostal muscles of the chest contract → ribs to move up and out, away from the body ○​ Chest cavity increase → pull air in (high concentration to low concentration) ○​ Oxygen: 21% ○​ CO2: 0.04% ○​ N2 and trace gases: 79% ​ Exhalation ○​ Intercostal muscles relax (rib cage goes down) ○​ Lungs recoil nacl to original position ○​ Diaphragm relaxes back to a dome shape ○​ Decrease of volume → increase pressure → sends air out ○​ Oxygen: 16% ​ The body does not have time to take up all the oxygen breathed in ○​ CO2: 3-5% ○​ N2 and trace gases: 79% ​ These gases are not diffuses into the body ​ Do not pass alveoli walls Respiratory Disorders ​ Bronchitis ○​ Viral infections spreads from nasal cavities to ears, larynx, and to bronchi ○​ Secondary infection ○​ Starts as flu, fever, etc ○​ Acute bronchitis arises from a secondary bacterial infection that results in ​ Inflammation of the airways ​ Heavy mucus discharge ​ Coughing ​ Pneumonia ○​ More serious than bronchitis (stills secondary infection) ○​ Most forms are caused by a bacterium or a virus that has infected the lungs ○​ Pneumonia localizes in a specific lobe ○​ The lobe will be inoperative as they fill with mucus and pus ​ Smoking Chemical What does it affect Long term effect on the body ​ Nicotine ​ CNS ​ Increases heart beat ​ Heart ​ Causes heart disease ​ Circulation ​ Raises blood pressure ​ Digestion ​ Stomach ulcers/cancer ​ Body’s defense ​ Lung disease ​ Tar ​ Mouth ​ Cancer ​ Throat, airways, and (mouth/lips/throat)  lungs ​ Smoker’s cough ​ Block up cilia ​ Emphysema ○​ Small sacs of alveoli rupture ○​ Becomes rigid ○​ Loses ability to bring gases in and out ​ Bronchitis ​ Pneumonia ​ Carbon monoxide ​ Oxygen in the blood ​ Affects Hb affinity for oxygen ​ Arteriosclerosis ​ Heart attack / stroke ​ Irritants and toxic ​ Respiratory tract ​ Bronchitis substances ​ Poor health ​ Reduced energy