Exam 1 Study Guide
Exam 1 Study Guide EXSC 223
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This 27 page Study Guide was uploaded by Madison Waterman on Sunday September 18, 2016. The Study Guide belongs to EXSC 223 at University of South Carolina taught by Dr. Raymond Thompson in Fall 2016. Since its upload, it has received 337 views. For similar materials see Anatomy and Physiology I in Science at University of South Carolina.
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EXSC223 Exam 1: CH 1-4 Study Guide Exam material: 1.1-1.4, 2.6, 2.8-2.12, 3.1-3.7, 3.9-3.11, 4.2-4.3 Learning objectives for chapters 1.1 Learning objectives Define anatomy and physiology and describe their subdivisions. • Anatomy: structure of body parts and their relationship to one another o Macro § Gross: study of large structures (heart, lungs, etc.) § Surface: internal body structures as they relate to skin § Regional: all of the structures of the same region are examined § Systemic: anatomy within a system is studied o Micro § Cytology: cell level § Histology: tissue level o Developmental § Embryology • Physiology: function of living systems (think: HOW do they work?) o Physiology is subdivided based on what is being studied o Examples: § Renal physiology: kidney function and urine production § Neurophysiology: workings of the nervous system § Cardiovascular physiology: operation of the heart and blood vessels Explain the principle of complementarity. • Principle of complementarity: anatomy and physiology are interdependent • it helps explain how a structure’s function is dependent on its shape and vice versa. • Ex: red blood cells don’t have nuclei or some other organelles that take up space so that there is more room for hemoglobin and oxygen to be carried o Its shape services its function 1.2 Learning objectives Name the different levels of structural organization that make up the human body, and explain their relationships. • Atoms, molecules, organelles, cells, tissue, organs, organ systems, organism • Organization of organisms: Level Example Structure Chemical level Oxygen Atoms O2 Molecules Cellular level Nuclei, ribosomes, golgi Organelles Smooth muscle cell Cell Tissue level Smooth muscle tissue Tissue Organ level Blood vessel (made up of 3 Organ tissues: epithelial, smooth muscle, and connective) Organ system level Cardiovascular system (made Organ system up of organs: heart and blood vessels) Organism level Human (made up of many organism organ systems) List the 11 organ systems of the body, identify their components, and briefly explain the major function(s) of each system. • 11 systems (2 or more organs that work together for a specific function): o skeletal: protects and supports body organs, provides a framework for the muscles to use to cause movement o muscular: allows manipulation of the environment, locomotion, facial expression, maintains posture o digestive: takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces) o integumentary: protects the body as a whole from the external environment o reproductive: produce offspring, control sex hormones o nervous: responds to internal and external changes by activating appropriate muscles and glands o endocrine: glands secrete hormones that regulate growth, reproduction, and metabolism o cardiovascular: circulates blood continuously to carry oxygen and nutrients to all body cells: o respiratory: takes in oxygen and eliminates carbon dioxide o lymphatic: houses white blood cells, disposes of debris, attacks foreign substances o urinary: eliminates nitrogenous wastes, regulates water and electrolyte balances 1.3 Learning objectives List the functional characteristics necessary to maintain life in humans. • maintain boundaries o skin keeps dirt and bacteria out • movement o muscle o skeletal • responsive o sensory input o stimuli • digestion o food § mechanical: chewing § chemical: stomach acid o cellular § macrophages (big eaters): digest things in the body • metabolism o sum of all chemical reactions o catabolism-break down o anabolism-build • excretion o cellular level or organism level o elimination of waste § defecating § urinating § exhaling CO2 (metabolic byproduct) • growth • reproduction o procreation o cellular reproduction: mitosis List the survival needs of the body. • Nutrients (food) • Oxygen • Water • Appropriate temperature • Appropriate atmospheric pressure 1.4 Learning objectives Define homeostasis and explain its significance. • Homeostasis: a dynamic state of equilibrium which maintains a relatively constant internal environment • significant to the survival of organisms because without it they would die • If homeostasis was not maintained, something as simple as walking out into the hot sun could be life threatening Describe how negative and positive feedback maintain body homeostasis. • Negative feedback o Whole point of a negative feedback system is to reduce/eliminate the stimulus o Negative feedback systems are self-limiting o Ex: § Stimulus: go in the sun § Receptor: detect an increase in temperature **afferent pathway** § Input: message sent to control center (brain and spinal cord) **efferent pathway** § Output: gland activated § Response: sweat § END result: stimulus (heat of the sun) is reduced (body is cooled by the sweat) • Positive feedback o Instead of reducing the stimulus, it is amplified (the more, the better) o Goal: to magnify or increase the stimulus o It is self-sustaining/self-perpetuating o Only 2 examples (any other responses are negative feedback!!!!!!) o Ex 1: Activation of platelets 1. Break/tear in blood vessel wall *pos. feedback initiated* 2. platelets secrete chemicals 3. activates more platelets which secrete more chemicals 4. platelets seal the tear o End result: homeostasis is restored because the stimulus (tear in blood vessel) is eliminated since the platelets sealed the tear ****We don’t know what shuts down positive feedback cycles**** o Ex 2: Delivering a baby 1. Contraction 2. Oxytocin released 3. Stronger contraction 4. More oxytocin released 5. Etc………cycle continues until… 6. Baby comes out Describe the relationship between homeostatic imbalance and disease. • Lack of consistency in the internal environment (homeostatic imbalance) leads to a disease state • Homeostasis is the standard set for the body to stay in a healthy condition • Examples of essential conditions that need to be maintained are o Body temperature o Blood pH o Blood glucose • When these are not maintained, the body may become diseased 2.6 Learning objectives Explain the importance of water and salts to body homeostasis. • Water o Most abundant inorganic compound o most important inorganic compound because of its properties § high heat capacity: requires a lot of energy to change its temperature (helps maintain a stable body temperature-homeostasis) § high heat of vaporization: a lot of heat has to be absorbed for water to evaporate in order to break Hydrogen bonds (when we sweat a lot of heat is removed when it evaporates) § polar solvent properties • universal solvent • polarity causes ionic compounds to dissociate • hydration layers: layers of water molecules • used to transport substances in the body because it is a good solvent § reactivity: adding water to break bonds: hydrolysis • helps conduct important reactions in the body § cushioning: protects organs o THESE PROPERTIES HELP MAINTAIN HOMEOSTASIS IN THE BODY • Salts o Ionic compounds made of cations (not H+) and anions (not OH-) § Ex/ Na SO is made up of 2Na (cations) and SO (anion) 2 4 4 o Ions=electrolytes (conduct electrical currents in solution) o Salts in body= NaCl, CaCO , 3Cl § Help with nerve impulse transmission and muscle contractions o Kidneys are responsible for maintaining proper ionic balance in body fluids Define acid and base, and explain the concept of pH. • Acid o Substance that releases hydrogen ions (H+) o Proton donor o Concentration of protons determines acidity • Base o Proton acceptors o Take up hydrogen ions (H+) o Concentration of OH- determines alkalinity • pH o a measure of Hydrogen ion concentration o more hydrogen ions = more acidic = lower pH value o pH=-log[H+] o neutral: pH = 7 o acidic: pH < 7 o basic: pH > 7 o blood pH is 7.4 o homeostasis: changes in pH in the body (especially blood pH) can interfere with cell function § pH regulated by kidneys, lungs, buffers 2.8 Learning objectives Describe the building blocks, general structure, and biological functions of carbohydrates. • Building blocks: o contain C, H, and O o monomer: monosaccharide (1 sugar) § ex: glucose o dimer: disaccharide (2 sugars) § monomers joined by dehydration synthesis (water molecule lost when bond is formed) § ex/ sucrose, lactose, maltose o polymer: polysaccharide (3+ sugars) § polymers of small sugars formed by dehydration synthesis § large § good for storage § ex/ starch (storage carb for plants) and glycogen (storage carb for animals) • General structure o single chain/ring o 3-7 carbons • Functions o Quick energy o Oxidation reduction reactions • Glucose broken down • Oxidized • Electrons transferred • Bond energy released • ATP synthesizedàenergy! o Leftover is stored as glycogen or fat o Structure (not a main function) 2.9 Learning objectives Describe the building blocks, general structure, and biological functions of lipids. • Building blocks o Contain C,H,O o Monomer: Fatty acids and glycerol (3:1 ratio) • General structure o Linear chains of hydrogen and carbon (Hydrocarbon chains) with an organic acid group (-COOH) at the end o 3 fatty acid molecules attach to one glycerol molecule by dehydration synthesis • Lipid types o Triglycerides o Phospholipids o Steroids o Lipoid substances • functions o stored energy o insulation o make up plasma membrane (phospholipids) 2.10 Learning objectives Describe the four levels of protein structure. • Protein structures o Primary: straight polypeptide chain o Secondary: spirals (a-helices) and sheets (b-sheets) o Tertiary: a-helices and b-sheets are folded up to form compact globular molecules o Quaternary: two or more polypeptide chains with its own tertiary structures to form a functional protein Describe enzyme action. • Enzyme: biological catalysts • Catalysts: 1. Lower activation energy 2. Increase reaction rate 3. Are not consumed in the reaction • Catalysts increase the rate of a reaction without being chemically changed • The investment in energy is reduced because less energy is required for the reaction to take place (activation energy is lowered) 2.11 Learning objectives Compare and contrast DNA and RNA. Deoxyribonucleic acid vs Ribonucleic acid DNA RNA Sugar: deoxyribose Sugar: ribose Structure: Double-stranded coiled into a Structure: Single-strand, straight or folded double helix Major cellular site: nucleus Major cellular site: cytoplasm Major function: is the genetic material, Major function: carries out the genetic directs protein synthesis, replicates itself instructions for protein synthesis before cell division Bases: adenine, guanine, cytosine, thymine Bases: adenine, guanine, cytosine, uracil 2.12 Learning objectives Explain the role of ATP in cell metabolism. • ATP: adenosine triphosphate o Energy stored in the bonds of ATP o Primary energy transferring molecule o Breaking a phosphate bond releases a lot of energy • Since ATP is the primary energy source in cells, it is responsible for fueling cell metabolism (sum of all reactions in a cell) • ATP is produced during cellular respiration in the mitochondria 3.1 Learning objectives Define cell. • The basic structural and functional unit of living organisms • Cell theory: o Cells are the basic structural and functional units of living organisms o Activity of an organism depends on individual and combined activities of its cells o Shapes/forms of cells determine their functions o Cells can only arise from other cells Name and describe the composition of extracellular materials. • Extracellular materials: substances contributing to body mass found outside of the cells o Body fluids § Interstitial fluid § Blood plasma § Cerebrospinal fluid o Cellular secretions § Substances that aid in digestion • Intestinal and gastric fluids § Lubricants • Saliva • Mucus • Serous fluids o Extracellular matrix § “cell glue”, holds body cells together § jellylike substance composed of proteins and polysaccharides List the three major regions of a generalized cell and their functions. • Eukaryotes (3 major parts): 1. Nucleus a. Brain of cell b. Location of transcription 2. Cytoplasm a. Cytosol + all the organelles in it b. Fluid material that holds all the organelles 3. Plasma membrane a. Outer boundary of the cell b. Separates intracellular space from extracellular space c. Transports molecules in and out of the cell 3.2 Learning objectives Describe the chemical composition of the plasma membrane and relate it to membrane functions. • Membrane lipids o Phospholipids § Hydrophilic head (polar) § Hydrophobic tail (nonpolar) o Glycolipids § Lipids with attached sugar groups § Found on the outer membrane surface § 5% of membrane lipids o cholesterol § 20% of membrane § polar region: hydroxyl group § non-polar region: fused ring system § stabilizes the membrane § buffers the fluidity • Membrane proteins o Integral § Transmembrane (spans whole membrane) § Hydrophobic and hydrophilic regions § Can have channels for transport of materials o Peripheral § Not embedded § Attach loosely on exterior Compare the structure and function of tight junctions, desmosomes, and gap junctions. • Tight junctions o Impermeable junction that encircles the cell o Prevent molecules from passing through the extracellular space between adjacent cells o Ex: blood-brain barrier separates the brain from the body o Interlocking junctional proteins: claudins and occludins • Desmosomes o Anchoring junctions scattered along the sides of cells o Form an internal tension-reducing network of fibers o Parts of a desmosome: § Plaque § Linker proteins § Intermediate filaments § Plaque anchors linker proteins to the intermediate filaments o Linker proteins fit together like a zipper in the extracellular space o Ex: many are prevalent in the heart and skin because they are under constant mechanical stress • Gap junctions o A nexus that allows chemical substances to pass between cells o Communication between cells o Cells connected by channels/pores called connexons o Selectivity of substances varies o Ex/ Cardiomyocytes: synchronize electrical activity and contraction • Membrane junctions allow cells to o Hold onto each other to form sheets o Make water tight seals o Communicate 3.3 Learning objectives Relate plasma membrane structure to passive transport processes. • Passive transport o Simple diffusion o Facilitated diffusion o Osmosis • Diffusion o Movement from high to low concentration o Passive process (does not require energy) o Ex: dropping a tablet in a beaker of water and the contents spread throughout the beaker until there is a uniform substance o Rate of diffusion affected by: § Gradient: big contrast in gradient=faster diffusion rate § Temperature: high temperature=faster diffusion rate § Particle size: smaller particles=faster diffusion rate • Hydrophobic membrane prevents diffusion except if o Lipid soluble o Small size o Assisted by carrier molecule • Simple diffusion: lipid soluble (fatty acids, steroids), small, uncharged molecules • Facilitated diffusion: still a passive process because the substances move with their concentration gradients but they need help crossing the membrane because they are large, charged, or lipid insoluble o Channel proteins: ex/ depolarization (transport Na+ and K+) o Carrier proteins: lipid insoluble solutes (glucose, amino acids) o Substances move through according to concentration gradient o Carriers can become saturated • Osmosis o Diffusion of water across a semi-permeable membrane o Water moves through aquaporins o Occurs when concentration of water is different on opposite sides of the membrane o Increased concentration of a solute will decrease the concentration of water (due to displacement) o Osmolarity: total concentration of solute particles in solution o When 2 solutions differ in osmolarity, water will move along a concentration gradient to reach equilibrium o When hydrostatic pressure of water=osmotic pressure, there is no more net movement by osmosis • Osmosis vs diffusion o Diffusion is movement of solute from high to low concentration o Osmosis is the movement of water from low to high solute concentration when separated by a semipermeable membrane Effects of varying solute concentration • Tonicity: ability of a solution to change the shape of a cell by altering its internal solvent (water) volume • Isotonic: solutions with same solute concentration as the cytosol o Cell stays the same o Water diffuses in and out of the cell at equal rates • Hypertonic: solution with greater solute concentration than cytosol o Water diffuses out of the cell (to dilute the higher solute concentration that is outside the cell) o Cell shrivels • Hypotonic: solution with a lower solute concentration than the cytosol o Water diffuses into the cell (to dilute the higher solute concentration that exists inside the cell) o Cell swells and lyses (breaks) Compare and contrast simple diffusion facilitated diffusion, and osmosis relative to substances transported, direction, and mechanism. ***ALL ARE PASSIVE PROCESSES NO ENERGY IS REQUIRED*** Simple diffusion Facilitated diffusion osmosis Substances Fat-soluble solutes Large or charged water transported molecules Direction High to low High to low Water moves from concentration concentration high to low concentration mechanism Through the Ion channel, carrier aquaporins membrane because protein they are lipid soluble molecules 3.4 Learning objectives Differentiate between primary and secondary active transport. • Active processes: metabolic energy required from the cell • Energy is necessary for pumping substances up (against) a concentration gradient o Primary: directly uses energy o Secondary: indirectly uses energy • PRIMARY active transport example: Sodium-Potassium Pump (SPP) (fig. 3.10) o 3 Na+ attach to the SPP § causes phosphorylation by ATP o phosphorylation causes protein to change shape o shape change causes Na+ to be released outside of the cell o 2 K+ ions attach o K+ binding triggers the release of the phosphate group that was added in step 1 o Loss of the phosphate restores original shape of the pump protein • SECONDARY active transport example o Na+-glucose symport transporter loading glucose from the extracellular fluid o As Na+ diffuses back across membrane through a membrane cotransport protein, it drives glucose against its concentration gradient into the cell • Secondary active transport takes advantage of the gradient created by the primary active transport Compare and contrast endocytosis and exocytosis in terms of function and direction. • Vesicular transport o transportation of large particles and macromolecules across the cellular membrane inside membranous fluid sacs o types: § endocytosis: moves substances from outside the cell into the cell in a vesicle § transcytosis: moves substances through the cell and out the other side through a vesicle § exocytosis: moves a substance out of a cell through a vesicle Compare and contrast pinocytosis, phagocytosis, and receptor-mediated endocytosis. • All are types of endocytosis o Plasma membrane pinches off into a small pit coated with protein(clathrin) o Ingests substance o Protein coated vesicle detaches and goes into the cell o Protein coat detaches and is recycled to the plasma membrane o Uncoated vesicle fuses with an endosome (sorting vesicle) § Helps direct substance to where it needs to go o Transport vesicle (membrane components) goes to the plasma membrane for recycling o Fused vesicle may: § Fuse with a lysosome for the digestion of its contents § Deliver its contents to the plasma membrane on the opposite side of the cell (transcytosis) • Phagocytosis: cell eating o Engulf material into the cell o Pseudopods: cytoplasmic extensions that wrap around the particle o Form phagosome (type of vesicle) o Ex/ common function of macrophages • Pinocytosis: cell drinking o Cell gulps drops of extracellular fluid containing solutes o No receptors are used so the process is non-specific o Most vesicles are protein coated o Routine activity of most cells for extracellular fluid sampling • Receptor mediated endocytosis o Extracellular substances bind: § Specific receptor proteins § The cell ingests § Concentrates substance in protein coated vesicles § Selective endocytosis o Ligands (molecules that bind to receptors) may be: § Released inside the cell § OR combined with a lysosome to digest its contents o Receptors are recycled to the plasma membrane in vesicles 3.5 Learning objectives Define membrane potential and explain how resting membrane potential is established and maintained. • Membrane potential= voltage across the membrane o Voltage=electrical potential energy resulting from separation of oppositely charged particles • Resting membrane potential: -50 to -100 millivolts (mV) o Polarized o Inside cell=negative o Determined by K+ concentration o Active transport of K+ and Na+ maintains gradient (sodium-potassium pump) 3.6 Learning objectives Describe the role of the glycocalyx when cells interact with their environment. • Glycocalyx used in both: o Cell adhesion molecules (CAMs) o Plasma membrane receptors • CAMs o Thousands on every cell o Play key roles in embryonic development, wound repair, immunity o Jobs: § It is the “Velcro” cells use to anchor themselves to molecules in the extracellular space and each other § “arms” that migrating cells use to pull themselves past one another § SOS signals to white blood cells to go to an infected/injured area § Mechanical sensors to respond to changes in tension and fluidity at the cell surface § Transmit intracellular signals that direct cell migration, proliferation, and specialization List several roles of membrane receptors and that of G protein-linked receptors. • Roles of plasma membrane receptors o Integral proteins and glycoproteins serve as binding sites o Contact signaling § Cells touch and recognize one another § Important for notmal development and immunity o Chemical signaling § Ligands: chemicals that bind to plasma membrane receptors • Most neurotransmitters • Hormones • Paracrines § Different cells respond differently to the same ligand • Ex: Acetylcholine stimulates skeletal muscle cells but it inhibits heart muscle § Steps • Ligand binds to receptor • Receptor’s structure changes • Cell proteins are altered § G-protein linked receptors: exert effect indirectly through a G-protein • Signals one or more intracellular chemical signals (second messengers) • Carries out message inside the cell 3.7 Learning objectives Discuss the structure and function of mitochondria. • Mitochondria o Structure § has own DNA, RNA, and ribosomes § double membrane • outer: smooth and featureless • inner: folds (cristae) § matrix= gel-like substance o Function § power plants of cell § provide most of the cell’s ATP § the higher the cell’s energy requirement, the more mitochondria are present • ex: the kidney and liver have a lot of mitochondria § generates ATP by aerobic cellular respiration Discuss the structure and function of ribosomes, the endoplasmic reticulum, and the Golgi apparatus, including functional interrelationships among these organelles. • Ribosomes o Structure § Small § Made of proteins and rRNA § Made of 2 globular subunits o Function § Site of protein synthesis § Free ribosomes: float freely in cytosol • Make soluble proteins § Membrane bound ribosomes: attached to ER (rough ER) • Synthesize proteins for incorporation in cell membrane or lysosomes or export from the cell § Can switch between free and membrane bound • Endoplasmic Reticulum (ER) o Structure § Extensive system of interconnected tubes and parallel membranes enclosing fluid filled cavities (cisterns) § Continuous with outer nuclear membrane o Rough ER § Studded with ribosomes § Function: Ribosomes here manufacture all proteins secreted from cell § Integral proteins and phospholipids for cell membrane manufactured here o Smooth ER § Continuous with rough ER § No ribosomes attached to it § Enzymes integrated in its membrane catalyze reactions involved with these tasks: • Metabolize lipids • Synthesize cholesterol and phospholipids • Synthesize steroid based hormones • Absorb, synthesize, and transport fats • Detoxify drugs • Break down stored glycogen § Skeletal and cardiac muscle cells have elaborate smooth ER (sarcoplasmic reticulum) • Golgi apparatus o Structure § Stacked and flattened membranous sacs o Function § “traffic director” for cell proteins § modify, concentrate, and package proteins and lipids made at the rough ER • transport vesicle from rough ER fuses with the cis face (receiving side) if tge Golgi § proteins are modified • sugar groups added • sugar groups removed • sometimes phosphates are added § proteins tagged for delivery for specific location in 3 types of vesicles and leave from the trans face (shipping side) • 1: secretory vesicles: export from plasma membrane (exocytosis) • 2: vesicles with lipids and transmembrane proteins go to plasma membrane or a membranous organelle • 3: vesicle with digestive enzymes are packaged into lysosomes and stay in the cell • Endomembrane system o Work together to produce, degrade, store, and export biological molecules and degrade potentially harmful substances o Made of the following organelles: ER, Golgi apparatus, secretory vesicles, lysosomes, and nuclear membrane Compare the functions of lysosomes and peroxisomes. • Peroxisomes o Sacs with enzymes in it: oxidases and catalases o Oxidases § Use oxygen to detoxify harmful substances (ex: alcohol, formaldehyde) § Neutralize free radicals (convert to hydrogen peroxide) § But hydrogen peroxide is also dangerous § So catalase converts it to water § Free radicals and hydrogen peroxide are normal byproducts of cellular metabolism o Numerous in liver and kidney (important organs for detoxification) • Lysosomes o Start as endosomes with inactive enzymes inside o Spherical membranous organelles with activated digestive enzymes o Large and abundant in phagocytes o Work best in acidic conditions o Membrane has H+ (proton) pumps to maintain acidic pH o Place where digestion can happen safely in the cell Name and describe the structure and function of cytoskeletal elements. • Provides supporting cell structure • Provides machinery to generate cell movement • 3 types of structural rods o actin subunit: microfilament o fibrous subunit: intermediate filament o microtubule • microfilaments o strands made of spherical protein units o called actins o attached to cytoplasm side of the plasma membrane o supports cell surface and resists compression o microvilli: cell membrane projections composed of microfilaments § increase surface areas § increase absorption • intermediate filaments o tough, insoluble protein fibers constructed like woven ropes o high tensile strength o internal stabilizer can resist pulling forces o does not bind ATP o made of keratin and vimentin • microtubules o hollow tubes of spherical protein sub units called tubulins o extend from the centrosome o composed of tubulin o dynamic o determines the cell’s shape and organelle distribution o associates with motor proteins • centrioles o small barrel shaped organelles located in the centrosome near the nucleus o pinwheel arrangement of 9 triplets of microtubules o organize mitotic spindles during mitosis o form the bases of cilia and flagella 3.9 Learning objectives Outline the structure and function of the nuclear envelope, nucleolus, and chromatin. • Nucleus o Larger than any cytoplasmic organelle o Usually spherical or oval o 3 regions § nuclear envelope (membrane) § nucleoli § chromatin • nuclear envelope o structure § double membrane separated by a fluid-filled space (like mitochondria) § outer nuclear membrane: continuous with the rough ER, studded with ribosomes § inner nuclear membrane: lined by nuclear lamina • lamina=network of lamins (rod shaped proteins that form intermediate filaments) that maintains the shape of the nucleus § nuclear pores cover nuclear envelope • nuclear pore complex lines each pore o function § selectively permeable § regulates what enters and exits the nucleus • nucleoplasm o Structure: § jellylike fluid in nucleus o Function: § holds nuclear elements like the cytoplasm does § contains dissolved salts, nutrients, other solutes • nucleoli o structure: § not membrane bound § typically 1-2 nucleoli per nucleus § large in growing cells o function: § ribosomal subunits assembled here • chromatin o composed of: § 30% DNA § 60% histone proteins • cluster of 8 of them form a nucleosome that the DNA wraps around • package and regulate DNA § 10% RNA chains 3.10 Learning objectives List the phases of the cell cycle and describe the key events of each phase. Cell cycle • 2 phases: interphase and mitotic phase • cells spend most of their time in interphase • interphase subphases o G1: growth § Checkpoint: make sure everything is in its proper place to advance in the cell cycle o S: DNA replication and growth o G2: growth and final prep for division § Enzymes and regulatory proteins for the mitotic phase are produced § Checkpoint: make sure cell is ready for division o G0: cell stops in the cell cycle, never enters S phase § Sometimes called “post-mitotic” or “amitotic” § Most cells are always in G0 • Mitotic Phase o Mitosis: a subphase of the mitotic phase § MITOSIS IS THE DIVISION OF THE NUCLEUS NOT THE CELL o Cytokinesis=cell division § Can begin before mitosis is finished o Early vs late prophase § Early prophase: spindles have not yet moved to opposite sides of the cell § Early prophase: there is still a nucleus • Late prophase: the nuclear envelope dissolves § Chromosomes condense in early prophase § Late prophase • Nuclear envelope degenerates • Spindles are on opposite sides of the cell • Microtubules start pushing chromosomes to the center o Metaphase § Very brief § All chromosomes lined up at the center (metaphase plate, equator) § Chromosomes are still attached at the centromere o Anaphase § Sister chromatids are pulled apart § Microtubule structures attach to kinetochore proteins o Telophase § Nuclear envelope reforms § Contractile ring at the cleavage furrow forms § Cells start to separateàdivide all contents equally • Cell cycle regulated by cyclin and cdk o Both are proteins o Work together to produce MPF (mitotic producing factors) o Cdk will always be present regardless if cell will go through mitosis or not o Cyclins vary: sometimes they are prevalent, sometimes not o Regulate progression of the cell by regulating the amount of cyclin present § Cyclin=cytosolic protein § Produced in standard protein synthesis § Eliminated by ubiquitin proteasome pathway Describe the process of DNA replication. • DNA replication in S phase o Helicase unwinds the DNA and separates the 2 strands o DNA polymerase: enzymes that work together to read the template and bring in complementary nucleotides for the existing strand (template) § There is a DNA polymerase on both strands (leading and lagging strands) • Leading: DNA polymerase works continuously • Lagging: DNA polymerase makes complementary pieces in fragments (Okizaki fragments) o Ligase comes and connects the Okizaki fragments 3.11 Learning objectives Define gene and genetic code and explain the function of genes. • Gene: segment of a DNA molecule that carries instructions for creating one polypeptide chain • Genetic code: rules by which the base sequence of a gene is translated into an amino acid sequence • Function of genes: carry the code to create polypeptides Name the two phases of protein synthesis and describe the roles of DNA, mRNA, tRNA, and rRNA in each phase. • Two phases: transcription and translation o Transcription: DNA’s information is encoded in mRNA § DNA: provides the template to be copied in order to transfer the information for the assembly of amino acids § mRNA: • messenger RNA • carries the coded information from the nucleus to the cytoplasm where protein synthesis will occur o Translation: information carried by mRNA is decoded and used to assemble polypeptides § rRNA: • ribosomal RNA • with the help of proteins, forms ribosomes (sites of protein synthesis) § tRNA: • transfer RNA • carries amino acids to the ribosomes where they decode the mRNA’s message for the amino acid sequence in the polypeptide to be built Contrast triplets, codons, and anticodons. • Triplet: sequence of three nucleotide bases on DNA • Codon: 3 nucleotides on RNA that codes for 1 amino acid • Anticodon: located on tRNA, complementary 3 base sequence to the codon on RNA 4.2 Learning objectives List several structural and functional characteristics of epithelial tissue. • Functions o Protection o Absorption o Filtration o Excretion o Secretion o Sensory reception • Characteristics of epithelia o Polarity: all epithelia have an apical surface (upper, free surface exposed to body exterior or cavity of internal organ) and a basal surface (lower, attached) § Apical-basal polarity o Specialized contacts § Fit close together and form continuous sheets § Tight junctions and desmosomes bind adjacent cells together § Tight junctions keep proteins in the apical region from going to the basal region o Supported by connective tissue § Epithelial sheets supported by connective tissue o Avascular but innervated § Avascular: no blood vessels § Innervated: supplied by nerve fibers § Cells nourished by substance diffusing from blood vessels o Regeneration § High regenerative capacity Name, classify, and describe the various types of epithelia, and indicate their chief function(s) and location(s). • Types o Simple squamous § Single layer, flat cells § Allows diffusion and filtration § Ex: blood vessels o Simple cuboidal § Single layer, cube-like cells § Secretion and absorption § Ex: kidney tubules o Simple columnar § Single layer of tall cells § Absorption, secretion of mucus § Ex: digestive tract o Pseudostratified columnar § Single layer, differing heights, nuclei seen at different levels § Secrete things, especially mucus § Ex: trachea o Stratified squamous § Several layers, basal cells are cuboidal, surface are squamous § Protects underlying tissues from abrasion § Ex: esophagus, mouth, vagina, skin (keratinized version) o Transitional epithelium § Resembles stratified squamous and stratified cuboidal § Basal cells are cuboidal or columnar, surface cells are dome shaped/squamous-like § Stretches readily § Ex: ureter, bladder, urethra Define gland. • Gland: one or more cells that make and secrete a particular product (secretion) Differentiate between exocrine and endocrine glands, and between multicellular and unicellular glands. • Exocrine: externally secreting o Secrete products onto the skin or into body cavities o Ex: salivary glands • Endocrine: internally secreting • Unicellular: o One celled glands o Ex: mucous cells and goblet cells • Multicellular: o Structurally more complex o Two basic parts: duct and secretory unit Describe how multicellular exocrine glands are classified structurally and functionally. • Structurally o Duct structures § Simple: unbranched duct § Compound: branched duct o Secretory units § Tubular: secretory cells form tubes § Alveolar: secretory cells form small flask-like sacs § Tubuloaveolar (acinar): have both tubular and alveolar secretory units • Functionally o Merocrine glands § Secrete products by exocytosis o Holocrine glands § Accumulate products until they rupture 4.3 Learning objectives Indicate common characteristics of connective tissues and list and describe its structural elements. Common properties o Common origin: Mesenchyme § Stem-like cell that arises during embryonic division o Extracellular matrix § Majority is non-cellular § Proteins, water, etc. o Degrees of vascularity (lacks uniformity) § Some have a large blood supply, others not so much Structural elements • 3 main components o Ground substances (extracellular matrix) o Fibers (extracellular matrix) o Cells (produce extracellular matrix) • The amount of each structural element varies, some connective tissue has a lot of ground substances and fibers and few cells and others have lots of cells and few fibers and ground substances • Ground substance: proteoglycan structure o Unstructured material filling the space between cells o Cell adhesion proteins § Connects tissue cells to matrix elements § Ex: laminin, fibronectin § Connect fibers to integral proteins § Directly connects extracellular matrix to the cells o Proteoglycans § Have a protein core that glycoaminoglycans (GAGs) attach § Intertwine and trap water § Regulate ground substance viscosity o Interstitial fluid § Water § Bathes cells § Fluid that comes and goes • Fibers o Collagen fibers § Most abundant protein in the body § Fibrous collagen proteins § Secreted into extracellular space and spontaneously assemble into cross- linked fibers § High tensile strength § Rigid, limited flexibility o Elastic fibers (elastin) § Elastin protein (with some collagen) § Stretches and recoils § Found where elasticity is needed • Skin • Lungs • Blood vessels o Reticular fibers § Short, fine proteins § Delicate networks § Fine collagenous fibers § Abundant in lymph nodes § Support soft tissue around organs • Cells o Development of connective tissue from mesenchyme § First tissue formed from mesoderm layer • Composed of mesenchymal cells, fluid and ground substances § Differentiates into all other connective tissue § Some mesenchymal cells remain (undifferentiated) o MESENCHYME § Cellular descendants: • Fibroblast-fibrocyte o Class of connective tissues: connective tissue proper o Subclasses § Loose connective tissue • Areolar • Adipose • Reticular § Dense connective tissue • Regular • Irregular • Elastic • Chondroblast-chondrocyte o Class of connective tissue: cartilage o Subclasses § Hyaline cartilage § Fibrocartilage § Elastic cartilage • Osteoblast-osteocyte o Class of connective tissue: osseous (bone) o Subclasses: § Compact bone § Spongy bone • Hematopoietic stem cells o Class of connective tissue: blood cells o Subclasses § Blood Describe the types of connective tissue found in the body and indicate their characteristic functions. Loose areolar • Description: gel-like matrix with all 3 fiber types; cells: fibroblasts, macrophages, mast cells, some white blood cells • Function: wraps and cushions organs • Location: under epithelia of body, forms lamina propria, surrounds organs Adipose • Description: not much matrix, closely packed adipocytes, fat droplet takes up most of the cell so the nucleus is pushed to the side • Function: stores energy, insulates, protects organs • Location: subcutaneous tissue, around kidneys and eyeballs, abdomen, breasts Loose (reticular) • Description: loose network of reticular fibers in gel-like ground substance, reticular cells lie on the network • Function: fibers form a soft internal skeleton that supports other cell types • Location: lymph nodes, bone marrow, spleen Dense regular • Description: parallel collagen fibers, few elastic fibers, fibroblasts • Function: attaches muscles to bones or to muscles, attaches bones to bones, withstands tensile stress • Location: tendons, ligaments, aponeuroses Dense irregular • Description: irregularly arranged collagen fibers, some elastic fibers, fibroblasts • Function: structural strength, withstand tension • Location: dermis, submucosa of digestive tract Elastic • Description: dense regular connective tissue, lots of elastic fibers • Function: allows tissue to recoil after stretching • Location: walls of large arteries, bronchial tubes, ligaments in the vertebral column Cartilage • Properties are intermediate qualities to bone and dense connective tissue and include o Avascular o Lacks nerve fibers o Ground substance § Rich in glycoaminoglycans: chondroitin sulfate, hyaluronic acid, collagen, and elastic fibers § Up to 80% water o Can withstand tension and compression forces • Primary cell type: chondroblast which secretes matrix • Types: hyaline, elastic, fibrocartilage Hyaline • Description: firm matrix, collagen fibers, chondroblasts produce the matrix and mature into chondrocytes and lie in lacunae, no blood supply to cells • Function: supports and reinforces, resists compressive stress • Location: covers the ends of long bones in joint cavities, ribs, nose, trachea, larynx Elastic • Description: similar to hyaline but more elastic fibers in matrix • Function: maintains shape of a structure while allowing great flexibility • Location: external ear (pinna), epiglottis Fibrocartilage • Description: matrix similar to hyaline but less firm, lots of collagen fibers, much denser than other cartilage • Function: absorb compressive shock • Location: intervertebral discs, discs of knee joint Bone, osseous • Description: hard, calcified matrix with many collagen fibers, very well vascularized, osteocytes lie in lacunae • Function: supports and protects, stores calcium, marrow inside is site of blood cell formation • Location: bones Blood • Description: red and white blood cells in a fluid matrix (plasma) • Function: transport respiratory gases, nutrients, wastes, etc • Location: in blood vessels • Classification as a connective tissue o Develops from mesenchyme o Surrounded by a fluid matrix (plasma) o Has fibers (blood fibers)-visible during clotting Notes from additional reading selections Cellular Extensions (p.89-91) • Cilia and flagella o Cilia: whiplike, motile cellular extensions § Typically occur in large numbers § Moves substances in one direction across cell surfaces § Propels other substances § Cilia production • Centrioles multiply and line up beneath plasma membrane • Microtubules sprout from each centriole • Ciliary projections formed o Flagella: projections similar to cilia but longer § Sperm: only flagellated cell in human body § Propels the cell itself • Microvilli o Minute, fingerlike extensions of the plasma membrane o Increase plasma membrane surface area o Mostly found on the surfaces of absorptive cells § Ex: intestinal and kidney cells A closer look: Illuminating the Body (p. 14-15) • X ray: directs X rays (electromagnetic waves of very short wavelength) to the body • Computed tomography (CT): refined version of X ray, produces a cross-sectional picture of the body region scanned • Xenon CT: CT brain scan enhanced with inhaled radioactive xenon to trace blood flow • Dynamic spatial reconstruction (DSR): uses fast CT scanners to produce 3D images of body organs • Digital subtraction angiography (DSA): provides view of small arteries • Positron emission tomography (PET): observes metabolic processes by scanning for glucose use • Sonography (ultrasound): body probed with pulses of sound waves that cause echoes that are reflected to create outlines of body organs • Magnetic resonance imaging (MRI): produces high contrast images of soft tissue areas • Magnetic resonance spectroscopy (MRS): maps the distribution of elements other than hydrogen to reveal more about how disease changes body chemistry • Functional MRI: tracks blood flow into the brain A closer look: Cancer (p. 140-141) • Neoplasm: abnormal mass of proliferating cells produced when cells fail to follow normal cell division o Benign: essentially harmless o Malignant: harmful • Metastasis: traveling of cancer cells to another part of the body (a secondary site) • Oncogenes: cancer-causing genes • Proto-oncogenes: benign forms of oncogenes in normal cells • Tumor suppressor genes: inhibit cell growth and division • Almost half of all Americans develop cancer • Biopsy: surgically removing a tissue to examine it microscopically for malignant cells • Stage: level of probability of cure (stage 1: best probability for cure…stage 4: worst)
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