Exam 1 Human Biology Study Guide
Exam 1 Human Biology Study Guide BSC
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This 11 page Study Guide was uploaded by Aliona Maquet on Wednesday March 23, 2016. The Study Guide belongs to BSC at Florida International University taught by Paul Sharp in Fall 2016. Since its upload, it has received 4 views.
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Date Created: 03/23/16
Exam 1 Human Biology Study Guide Chapter 1 Homeostasis- “staying the same”, a stable internal environment Allows you to respond to changes in your internal environment by modifying some aspects of your behavior Humans can only function properly if their homeostasis stays within narrow changes of temperature and chemistry. Examples of homeostasis maintenance: Your body shivering when cold, your body aims at keeping you warm and generate internal heat through chemical reactions. Radiation: the transfer of heat from a warm body to the surrounding atmosphere Most common type of feedback system is the negative feedback. Negative feedback: operates to reduce or eliminate the changes detected by the stimulus receptor. For example: Prevents you from drinking so much water that your blood chemistry becomes dangerously unbalanced Positive feedback: Serves to amplify the original stimulus Chapter 4 Cell structure and function Cytology: Study of cells studied by cytologists Cell theory: All living things are composed of cells All cells arise from preexisting cells through cell division Cell contain hereditary material, which they pass to daughter cells during cell division The chemical composition of all cells is quite similar The metabolic processes associated with life occur within cells. *Cells can vary remarkably in shape and size but all share the same characteristics (You need approximately a trillion to make up a typical mammal as most cells are microscopic Prokaryotic cells: A type of cell with no internal membrane-bound compartments, usually only ribosomes as organelles (bacteria) Eukaryotic cells (YOU/Human and plants cells): A cell that contains a distinct membrane bound nucleus Differentiation in cells: Particular genes are activated (turned on or turned off) Why do cells have to little? Surface area to volume ratio 6/1. The smallest the cells is, the larger the surface area to volume ratio will be, which is best. Plasma membrane- Structure that separate the cell from the extracellular fluid Membrane in composed of two layers of phospholipids interspersed with proteins, fats, and sugars Hydrophilic layer- water loving heads Hydrophobic layer- water-fearing, non polar, lipids tails Some of the proteins and lipids associated with the cell membrane have sugars attached to their external surface and are called glycoproteins (A protein plus a carbohydrate) and glycolipids (A lipid plus at least one carbohydrate group) Glycocalyx: The layer of glycoproteins and glycolipids (unique and defines the cell as belonging to a specific organism) Blood type and tissue type are defined by the specific structure of the glycolyx Cholesterol: necessary component of the cell membrane, helps to maintain this viscosity by interfering with the movement of the fatty acid tails of the phospholipids. The phospholipid bilayer defines the cell and protects it from the aqueous environment. The membrane is a selectively semipermeable barrier that allows nutrients to enter the cell and waste and secretory products to exit it. Types of transportation in the membrane WITHOUT requiring energy Filtration- movement of solutes in response to fluid pressure Diffusion- movement of a substance towards an area of lower concentration (ex: spraying perfume) Facilitated diffusion- Use of plasma membrane carrier to move a substance into or out of a cell from higher to lower concentration (ex: glucose) Lipid- soluble molecules and gases can diffuse freely through the phospholipid bilayer Phospholipid bilayer blocks the diffusion of aqueous, or water soluble, solutes such as glucose. Thus, it requires: - Integral protein: A protein that spans the plasma membrane - Peripheral protein: A protein that sits on the inside or the outside of the cell membrane. Both serve as channels and receptors for dissolved substances to enter and exit the cell. Most abundant compound in the body is water. o To maintain homeostasis, cells must allow water to move between the intracellular fluid and the extracellular fluid Osmosis: Diffusion of water across a semipermeable membrane, such as the cell membrane. Water moves in a direction that tends to equalize solute concentration on each side of the membrane. *Water cannot cross the phospholipid bilayer, so it must travel through proteins Hypotonic solution- Expands because salt concentration is lower outside the cell so the water all goes in the cell where the salt is (hemolysis) Water goes in Hypertonic solution- Shrivels because salt concentration is higher outside the cell so the water exits (crenation) Water goes out Cells: Salt concentration in our cell is of 0.9% ***Water always follows the greatest concentration of salt (Seawater has 3.5% of salt) Isotonic- A solution with the same concentration as the cell cytoplasm Active transport (Solute pumping): Use of a plasma membrane carrier to move a substance into or out of the cell from lower to higher concentration. Requires ATP (Adenosine triphosphate Sodium-potassium pumps require ATP- Transfers two potassium ions into the cell (K+) for every three sodium ions (NA+) it removes. Stockpiling potassium inside the cell. Important for removing acid from the body - The source of energy to power the sodium-potassium pump is the breakdown of ATP - The ATP is broken down into ADP and phosphate and the sodium ions are thrown inside the cell - Transmembrane protein Metabolism: All chemical reactions that occur in the cell Enzyme- A protein that is capable of speeding up a specific chemical reaction by lowering the required activation energy Active site- Surface of the enzyme where substrate binds and reaction occurs Substrate- A reactant in a reaction controlled by an enzyme Organelles Cytosol- Fluid portion of the cytoplasm Cytoskeleton- Lies directly under the plasma membrane & maintains cell shape, anchor organelles, and used in cell mobility Is composed of three types of filaments: Microtubules- Long hollow protein cylinders, present in the cytoplasm, cilia, and flagella o Used as tracks for organelle movement Intermediate filaments- Protein fibers that provide support and strength Microfilaments- Actin proteins fibers that move organelles and the cell (motors that pushes those organelles in the microtubules tracks) Flagella- Long, whip-like structures that propel cells forward (Sperm is the only human cell moved by flagellum) Cilia- Shorter extensions that look like hairs or eyelashes referred to as “Power stroke” to move mucus across the surface of the cell and dirt out the human lungs. Rough Endoplasmic Reticulum- Stubbed with ribosomes on side of membrane that faces cytoplasm (why its rough) Protein are synthesized by ribosomes & enter ER interior Where initial processing and modification of protein begins Smooth endoplasmic reticulum- Responsible for the synthesis of fatty acids and steroid hormones and phospholipids. End product for both Rough and smooth is a vesicle filled with product ready for the next step in processing. Golgi Apparatus- Modifies lipids and proteins from the ER; sorts, packages, distributes, and secrete molecules synthesized by the cell using saccules Saccules- A small circular vesicle used to transport substances within a cell Lysosomes- Chemical packages produced by the Golgi complex that contain hydrolytic enzymes (break down anything, very powerful), can fuse with endocytic vesicle Hydrolytic enzymes- Proteins that help decompose compounds by splitting bonds with water molecules Endomembrane system- A series of membrane organelles that function in the processing of materials for the cell and includes: - Nuclear envelope - Endoplasmic reticulum - Golgi apparatus - Lysosomes - Vesicles Ribosomes- Carries out protein synthesis using mRNA template - Consists of aggregated protein and rRNA - 20 different amino acids - amino acids are the building blocks of protein - 7 amino acids or more to make a protein - The order of the amino acids makes the shape of the protein Mitochondria- Organelle with 2 membranes that carries out cellular respiration; converts chemical energy of glucose to chemical energy of ATP - Cristae- Folded extensions of the inner membrane ATP production occurs at the cristae - Matrix- Gel-like fluid of inner space surrounded by cristae Contains enzymes for breaking down glucose products - Intermembrane space- Space between inner and outer membrane - Cellular respiration- Metabolic reactions that uses energy primarily from carbohydrates (glucose) to produce ATP molecules Process in our body when we eat: Glucose + oxygen leads to production of carbon dioxide + water +energy - The mitochondria break down glucose to produce ATP in four steps 3 pathways involved: 1. Glycolysis 2. Citric acid cycle 3. Electron transport chain ADP- Adenosine diphosphate Glycolysis- Anaerobic breakdown of glucose that occurs in the cytoplasm of the cell (not in the mitochondria and does not require oxygen) Splits glucose C6 into 2 pyruvates C3; yielding 2 molecules of ATP and converts 2 molecules of NAD+ to NADH Taking a glucose, splitting it and getting 2 pyruvates, which will then go inside the mitochondria to produce more energy and break down that pyruvate further. Nicotinamide adenine dinucleotide (NAD+): a coenzyme that carries hydrogen and 2 electrons Conversion of ADP to ATP NAD is converted to NADH NAD+ Cannot do much with it (empty) NADH- Conversion of NAD to NADH which will be useful (It can now carry one hydrogen and 2 electrons) Citric Acid Cycle (Kreb cycle)- Aerobic (needs oxygen) process that occurs in the matrix of the mitochondria; pyruvate enters matrix and completes the breakdown of glucose - Produces 2 ATP per glucose molecule - Electron and hydrogen are picked up by NAD+ as NADH - Each pyruvate goes through the cycle; carbon is always taken out by enzyme to produce carbon dioxide for a result of more ATP Last step is the Electron Transport Chain- Passage of electrons alongside a mitochondrial membrane-bound carrier molecules from a higher energy to lower energy level 1. Hydrogen consist of a proton and an electron 2. Electrons enters the transport chain when NADH transfers its hydrogen into an hydrogen ion or (proton) as it lost its electrons that was then sent inside the electron transport chain 3. The electrons are then carried through the electron transport chain while the protons are shoveled to the outside of the membrane 4. Some of the electrons carriers accept a proton from the inside as it accepts electrons 5. Proton is then transported through the membrane as the electrons passes allowing for an increase in the proton gradient across the membrane and enhances the proton motive force 6. The last protein carrier transfers a pair of electron to oxygen at the end of the electron transport chain and water is formed 7. ATP synthase then utilizes the energy of protons to synthesize ATP by allowing the protons to comes back in the cell to couple it with ADP and Pi to produce ATP - Proton (hydrogen) gradient will yield 32 ATP - For it to be successful, you have to have oxygen to coach those molecules to pass from a higher energy to lower energy level. - Purpose of the process- Setting up a concentration gradient (putting hydrogen on the outside). Stockpiling hydrogen out the membrane. The hydrogen comes back in through the protein channels (ATP synthase) where it spins and is able to convert ADP into ATP. Last process called chemiosmosis. Fermentation- Anaerobic process that enable NADH to pass off hits hydrogen and electrons to pyruvate. When this happens the pyruvate is converted into lactate which can be converted into lactic acid fermentation - Converts pyruvate into lactate and yields 2 ATP per glucose - Yeast fermentation produces alcohol and carbon dioxide - NEED MORE INFORMATION COMPLETELY UNCLEAR AND MISUNDERSTOOD Endocytosis- A portion of the plasma membrane invaginates to envelop a substance or fluid from outside the cell to bring it inside the cell a) Phagocytes: Endocytosis of a solid particle b) Pinocytosis: Fluid uptake by endocytosis (cell drinking) c) Receptor-mediated endocytosis: Form of endocytosis that utilizes a membrane protein receptor to concentrate specific molecule of interest (outside the cell attracted by receptor on the protein receptors) It will be transported through the cell by the use of a vesicle For the receptor-mediated endocytosis the vesicle will be a coated vesicle Exocytosis- When a vesicle within the cell fuse with the plasma membrane during secretion, the release of the proteins inside the vesicle are then thrown outside the cell. Cytoplasm- Contents of a cell between the nucleus and plasma membrane - Consist of cytosol and organelles Cytosol- Fluid portion of the cytoplasm Organelle- Small membranous structure with a specific structure and function - Allows for compartmentalization of the cell Centriole- Short cylinders of microtubules - Divides and organizes spindle fibers during mitosis and meiosis in order to produce the centrosome Centrosome- A pair of centrioles that functions as microtubule organizing center - Active during cell division Nucleus- Membranous organelle that house chromosomal DNA Nuclear envelope- Double membrane with nuclear pores that encloses the nucleus Chromatin- Diffuse thread containing DNA protein Nucleolus- Region that produces the subunits of ribosomes (the center part of the nucleus/the core) Nucleoplasm- Semi fluid medium inside the nucleus Nuclear pores- Pores of the nuclear envelope that allow ribosomal subunits to exit nucleus, and proteins to enter nucleus Chapter 20 Mitosis **23,000 human body genes with more than 99% of human genes matching each other Mitosis- Type of cell division in which daughter cells receive the exact same chromosomal and genetic makeup of the parent cell; occurs during growth and repair as many as every 7 days. Cell cycle- Repeating sequence of cellular events that consists of: - Interphase - Mitosis - Cytokinesist(splitting of the cytoplasm to get two daughter cells) Interphase- 1 step where the cell is in the “resting phase”. 1. Growth (G1 stage): Cell return to normal size; resumes its function in body Double its organelles (ribosomes and mitochondria) 2. Synthetic (S) Stage: A copy is made of all the DNA in the cell (DNA replication)- 2 chromatids per chromosome 3. Growth (G2) Stage: Increase in growth and final preparation for cell division. You can have two sorts of chromosomes, one with one chromatid and one with two chromatids (sister chromatids). Thee center ondthose chromosome is called thestentromere. Prophase- 2 stage of the cell cycle and 1 stage of mitosis Nuclear envelope is disintegrating; chromosome gets very condensed and is visible in the cell as chromosomes Centrioles separate and migrate to opposite ends of the cell Spindle apparatus forms Longest phase of mitosis Metaphase- 2 ndstage of mitosis Middle phase of mitosis Chromosomes line up on the central axis of the cell Lirdd up with the help of microtubule Anaphase- 3 stage of mitosis Chromosomes from the middle have their sister chromatids separate and pulled apart Double genetic material separates into the exact amount of DNA nethed for each daughter cell Telophase- 4 stage of mitosis Final phase of mitosis Construction of nucleus starts forming DNA de-condenses into chromatin The center of the cell pinches to form a cleavage furrow The furrow deepens, separating the cell into two separate cells Each contains a nucleus containing the same amount of DNA as the parent cell Cytokinesis- Last stage of cell cycle Division of the cytoplasm following mitosis and meiosis DNA- Genetic material of all organisms - Composed of 2 complementary strands of nucleotides - Has “sugar-phosphate backbone”; sugar is deoxyribose (main support of the ladder) - DNA is located in nucleus and can never leave - Nitrogenous bases make “rungs” of ladder Cytosine Guanine Adenine Thymine Chromosome- Vehicle by which hereditary information is passed to the next generation - Chromatin condensed into a compact structure Chromatid- One of the 2 identical copies of DNA making up a duplicated chromosome Centromere- Point of attachment for mitotic spindle; where sister chromatids attack Mitotic spindle- Microtubule structure that brings about chromosomal movement DNA Replication- Synthesis of a new DNA double helix prior to mitosis and meiosis - Occurs during synthetic (S) phase of interphase 1. Parental DNA molecule contains old strands by hydrogen-bonded by complementary base pairing 2. Region of replication. Parental DNA is unwound and unzipped. New nucleotides are pairing with those old strands 3. Replication is complete. Each double helix is composed of an old (parental) strand and a new (daughter) strand. DNA polymerase separate the DNA strand 23 pair of chromosome is the sex chromosome that defines whether one is male or female - A female will have two identical sister chromatid (same genes) and will be called homologous autosome pair. - A male will get one X and a little Y Meiosis Reductional division- Occurs during meiosis I - Goes from diploid to haploid Diploid- Having the total number of chromosomes of the body cells, twice that of the gametes Haploid- Having half the number of chromosomes of normal body cells, as in eggs and sperm Meiosis I- Second kind of cell division, which only happens in sex cells - Passing on your genes requires you to form haploid gametes Prophase I- Meiosis includes steps very similar to those of mitosis Main difference being the formation of tetrads in prophase I Chromosomes have duplicate, homologous chromosomes pair during synapsis and crossing over occurs. Only happens in prophase in meiosis Crossing over- Increases genetic diversity, exchange of corresponding chromatid segments between homologues Genetic recombination- Allows homologues to exchange chromosomal material Chiasmata- Site of crossing over event Independent assortment- deals with the random orientation of homologous chromosomes at the metaphase rate A pole may receive either paternal or maternal homologue for each chromosome pair Occurs during meiosis I Metaphase I- Homologous pairs align independently at the equator Tetrads are pairs of homologous chromosomes that remain close to one another until they are pulled apart in anaphase I Spindle attaches to the centromere Anaphase I- Homologous chromosomes separate and move toward the pole Telophase I- Daughter cells have one chromosome from each homologous pair Forms two cells that enclose doubled copies of half the chromosomes of the original diploid cell Meiosis II- Sister chromatid separate, becoming daughter chromosomes Prophase II- Cells have one chromosome from each homologous pair Metaphase II- Chromosomes align at the equator Anaphase II- Sister chromatids separate and become daughter chromosomes Telophase II- Spindly disappears, nuclei form, and cytokinesis takes place Results in four haploid cells Daughter cells- Meiosis results in four haploid daughter cells Spermatogenesis- Process in which spermatozoa are produced from male primordia germ cells by way of mitosis and meiosis. - Primary spermatocyte divides meiotically (Meiosis I) into two secondary spermatocytes; each secondary spermatocyte divides into two spermatids by Meiosis II - Then develops into sperm cells Oogenesis- Production of an eff in females via meiosis Polar body- In oogenesis, a nonfunctional product, 2 or 3 occur in meiosis secondary oocyte becomes an egg At the end of meiosis, I and II, the fertilization becomes a zygote with 46 chromosomes ***Female will never finish meiosis II is fertilization doesn’t take place Genetics Genes- Unit of hereditary made up of DNA sequence, located on a chromosome Alleles- Alternate form of a gene; occur at same locus on homologous chromosomes - In diploid organisms typically 2 alleles are inherited (one from each parent) Locus- Particular site where a gene is found on a chromosome - Homologous chromosomes have corresponding loci for a specific gene Genotype- Alleles of an individual for a particular trait, often designated by letters Ex: Aa or BB Phenotype- Physical characteristics of a genotype (visible) Dominant allele- Allele that exerts its phenotype effect in the heterozygote - It masks the expression of the recessive allele Recessive allele- Allele that exerts its phenotype effect only in the homozygote Homozygous dominant- Possessing two identical dominant alleles for a particular trait Homozygous recessive- Possessing two identical recessive alleles for a particular trait Heterozygous- Possessing unlike alleles for a particular trait Punnett square- Used to calculate expected results of simple genetic crosses One-trait cross- Method for determining the inheritance pattern of a trait between male and female parents Principle of segregation- 2 alleles of a gene segregate during gamete formation and are rejoined at random during fertilization Incomplete dominance- Occurs when the heterozygote is intermediate between the 2 homozygote Codominance- Occurs when alleles are equally expressed in the heterozygote Multiple-allele inheritance- Inheritance pattern in which there are more than 2 alleles for a particular trait- blood type: A, B, O, AB Antigen- Protein that is on the red blood cell Polygenic inheritance- Inheritance pattern in which more than 1 gene affects a train ex: Skin color (blacks/white/brown), height, etc. Autosomes- Any chromosome other than the sex chromosomes Sex chromosomes- Chromosomes that determine the sex of an individual - Females have 2X chromosomes - Male have both X and Y chromosome Sex-linked- Refers to allele that occurs on the sex chromosome, but may control a trait that has nothing to do the sex characteristic of an individual X-linked- Refers to an allele located on the X chromosome Pedigree- A graphical representation of matings of offspring over multiple generations for a particular genetic trait
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