Bio For Exam 1

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Bio For Exam 1
2013-02-04 08:05:10
bio 107

Study Questions
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  1. identify the eight unifying themes we will encounter in biology and give an example of these ideas.
    hiearchy or organization, organisms interact with each other and their environment, life requires energy transfer and transformation, structure corrrelates with function (wing structure for flight), cells are the basic unit of life, DNA provides instructions and continuity for life, feedback regulates biological systems, evolution is a core theme.
  2. why is water polar? why is this significant?
    oxygen is more electronegative than hydrogen, causing a partial - charge on O and + on H. results in ability to form hydrogen bonds and emergent properties.
  3. what are the four emergent properties of water? how is hydrogen bonding involved in each of these?
    cohesion (H bonds hold molecules together), temp moderation (high specific heat/resists change in temp), expansion upon freezing (molecules form a crystaline lattice due to H bonding), versatility as a solvent (high dielectric constant-ability to keep opposite charges apart).
  4. distinguish between the following terms relative to water: cohesion, adhesion, and surface tension.
    cohesion-H bonds hold water molecules together, ashesion- molecules stick to other surfaces, surface tension- stuff can float ontop
  5. water has a high specific heat and a high heat of vaporization. explain how water's high specific heat contributes to its ability to moderate temperatures.
    water resists change, it takes more energy to change the temp. it absorbs or releases a lot of heat for each degree of change. (air is hot: heat used to break H bonds, cool: released when forming bonds)
  6. explain why water expands upon freezing
    as liquid molecules are close together, as solid a crystalline lattice is formed due to H bonding, expanding the structure and volume of water
  7. why is water a good solvent? how are solutes dissolved in water?
    high dielectric constant (keep opposite charges apart), water forms hydration shell around ions
  8. distinguish between hydrophilic and hydrophobis substances.
    philic- ionic/polar, usually dissolves in water. phobic- nonionic/nonpolar, cant be dissolved in H2O.
  9. why is carbon such a versatile element?
    four valence electrons (can form 4 covalent bonds)
  10. describe hydrocarbons
    only C and H. store energy. very diverse
  11. what is an isomer? distinguish between structural, geometric and enantiomer isomers.
    same chem formula (# of molecules). structural: differ in covalent arrangement. geometric: cis/trans-differ in spatial arrangement. enantiomer: mirrored/cant be superimposed.
  12. name and describe the reactions by which macromolecules are synthesized and broken down.
    synthesis- dehydration, breakdown-hydrolysis. both need enzymes
  13. seven functional groups that are important in biology.
    hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl
  14. what elements are found in carbohydrates? what are the polymers and monomers of carbohydrates called?
    C, H, O. monosaccharides (hydroxyl, carbonyl), disaccharides, polysaccharides
  15. distinguish between an aldose and a ketose
    aldose (aldehyde sugar)- end of carbon chain. ketoses (ketone sugars) - middle of carbon chain. C=O.
  16. what is a glycosyidic linkage and how is it formed? what are maltose, sucrose and lactose made of?
  17. describe the structure and function of the following polysaccharides: starch, glycogen and cellulose.
    starch:energy storage for plants. helical glucose polymer (can be branched)glycogen:energy storage for animals, branched helical polymer of glucose. collulose- plant cell walls, straight polymer of glucose(can H bond).
  18. describe the structure and function of the following three lipids: fats phospholipids and steroids. why are these lipids not really polymers?
    fats:storage, structure. phospholipids: glycerol, 2 fatty acids, phosphate grouop. steroids:4 fused carbon rings (cholesterol and hormones).
  19. how is a fat synthesized and what type of linkage is formed?
    synthesized by dehydrations between glycerol and fatty acids to form triacylglycerol. ester linkages. (bond between hydroxyl and carboxyl)
  20. distinguish between saturated and unsaturated fats. explain why they are solid and liquid at room temp, respectively.
    Saturated (no = and solid). unsaturated (= and liquid). double bond in unsaturated causes molecules to be further apart and create a liquid where a molecule with no double bonds can pack closely together.
  21. what are the monomers and polymers of proteins? what elements are found in proteins?
    monomer-amino acid. polymer-polypeptide. consist of C, H, O, N, S.
  22. what are the possible functions of proteins? why are the possible functions so diverse?
    anzymatic, defensive, storage, transport, hormonal, receptor, consractile and motor, and structural. proteins can have many different functions because of the many different shapes they can have.
  23. describe the key features of an amino acid. which groups of amino acids are hydrophobic and which are hydrophilic?
    alpha carbon with amino, carboxyl, H, and R group attached. HHN-CHR-C=OOH
  24. Name and describe the four levels of proteinstructure.
    Primary- amino acid chain (length and composition determine shape and function). Secondary- interactions between backbone groups (H bonds) alpha helix (keratin) and beta pleated sheet (silk). tertiary- interactions between R groups. Quarternary-interactions between 2+ polypeptides(collagen). 
  25. What are the monomers and polymers of nucleicacids?  What elements are found in nucleic acids?
    monomer-nucleotide. polymer- DNA/RNA. elements: C, H, N, O, P.
  26. What components make up a nucleotide?
    nitrogenous base, sugar, phosphate group.
  27. What is a phosphodiester linkage?  What does it join?
    bonds 3' hydroxyl of one nucleotide with 5' phosphate of another nucleotide.
  28. Describe the structure of the DNA double helix.  What is complementarity and how does it contribute to the function of DNA?
    double helix. antiparallel strangs. bases pair by H bonding...AT CG
  29. Distinguish between light microscopy and electronmicroscopy.  What is the differencebetween SEM and TEM?
    light(LM)- light passed through sample. electron (EM)- electrons focused on sample. scanning (SEM)- to see cell surface. transmission (TEM)- to see inside cell.
  30. Explain how scientists use cell fractionation to purify organelles.
    separates each part of cell. homogenization. centrifugation (formes pellet and supernatant)
  31. Describe the features that distinguish prokaryotic and eukaryotic cells
    prokaryotic-no nucleus, no membrane bound organelles, DNA in nucleoid region, has cell wall. eukaryotic-nucleus, membrane bound organelles, DNA in nucleus, not always a cell wall. both have plasma membrane, cytosol, chromosomes, ribosomes.
  32. Which features are unique to animal cells and whichare unique to plant cells?
    animal-lysosomes, centrosomes, flagella. plant-chloroplasts, central vacuole, cellwall, plasmodesmata.
  33. What are the functions of the nucleus?  Describe the following: nuclear envelope,nuclear lamina and nuclear pore complex.
    holds DNA bound to protein. includes nucleoli (ribosome assembly). surrounded by nuclear envelope(double membrane, lined with muclear lamina, preforated by nuclear pore complexes).
  34. what is the function of the ribosome?  What is a ribosome made of?
    protein synthesis. made of RNA and protein. form large and small subunits. can be free or membrane bound.
  35. name the members for the endomembrane system.  What are the major functions of this system?  What does the term “traffic”refer to?
    contains: nuclear envelope, ER, Golgi, lysosomes, vacuoles, plasema membrane. functions: protein synthesis/transport, lipid metabolism/transport, detox of poisons/drugs. traffic: movement of proteins and molecules through system via vesicles.
  36. vesicles
    small sacs of membrane for transport
  37. Where is the endoplasmic reticulum (ER) located?  Distinguish between the structure and functionsof smooth and rough ER.
    located near nucleus("perinuclear"). smooth-lacks ribosomes, lipid synthesis, drug detox, Ca storage. rough-bound by ribosomes, protein synthesis/folding/glycosylation, veicular transport "gatekeeper role", also involved in membrane synthesis.
  38. stands protein disulfide isomerase, a protein that helps other proteins fold correctly in the lumen of the ER.  What is GFP and why did the Lippincott-Schwartz lab fuse PDI to GFP?
    GFP is green fluorescent protein used to follow the ER during fruit fly nuclear division.
  39. Watch the Drosophila ER movie again by clicking on the hyperlink in the power point slides or use the web address below.  What are two important take home messages from this movie?
  40. Describe the location and structural features of the Golgi. What are the functions of the Golgi?
    located near the nucleus ("juxtanuclear"). groups of flattened stackes (cisternae). two faces- cis/trans. vesicles bud off Golgi to transfer materials. functions: protein modification/storage/sorting, carbohydrate synthesis.
  41. What is FRAP and what does it allow scientists to do?  Explain what happened in the FRAP Golgi movie in your own words.  What are the important take home messages?
    FRAP=fluorescent recovery after photobleaching. membrane proteins are fused with GFP and movement is followed. laser bleaches fusion proteins in an area allowing us to watch proteins move into area.
  42. Describe the structure of the lysosome.   Explain the two major roles of the lysosomein phagocytosis and autophagy and give examples of each.
    membranous sac of hydrolytic enzymes; acidic compartment. functions: phagocytosis (engulfment of organisms/food into a vacuole which then fuses with lysosome and is digested), autophagy (digestion of old organelles/recycles macromolecules).
  43. Name and distinguish between the three types of vacuoles discussed in class
    membrane bound storage vesicles. types: food, contractile (mediates movement in a cell), central (plants).
  44. What is a temperature sensitive protein?  Why did the Lippincott-Schwartz lab use one for the endomembrane movie?  Explain whathappened in the move in your own words. What are the important take home messages?
    temperature sensative protein (VSVG) can move out of the ER at 32 degrees C. allows us to follow a protein from the ER through the endomembrane system.
  45. Describe all the structural features of mitochondria and chloroplasts discussed in class. What are the functions of mitochondria and chloroplast?
    mitochondria: double membrane, inner is folded for surface area (enzymes), intermembrance space (between membranes), mitochondrial matrix (inside inner membrane). functions: cell respiration, ATP production, number correlates with cell activity. chloroplasts: double membrance feat thylakoids, granum, stroma. functions: glucose production-important for photosynthesis.
  46. Why type of cell might have a lot of mitochondria and why?
  47. What are the functions of a peroxisome?
    break down fatty acids, detoxify harmful compounds.
  48. Distinguish between the following cytoskeletal fibers:microtubules, microfilaments and intermediate filaments.  Be sure to include their subunits, structure and major functions.
    microtubules (MT): hollow tubes, maintenance of cell shape, cell motility, chromosome movements in cell division, organelle movements, subunit-tubulin dimers. microfilaments (MF): two intertwined strands of actin, maintenance of cell shape, changes in cell shape, muscle contraction, cytoplasmic contraction, cell motility, cell division, subunit-actin. intermediate filaments: fibrous proteins supercoilded into thicker cables, maintenance of cell shape, anchorage of nucleus and certain other organelles, formation of nuclear lamina, subunit-keratin protein.
  49. Describe the structure and function of a cell wall. Distinguish between the primary cell wall, secondary cell wall, and middle lamella.
    extracellular plant structure outside plasma membrane. functions: protects cells, maintains cell shape. primary, secondary, and middle lamella (includes pectin to glue cells together).
  50. Name and explain the roles of the two major glycoproteins described in lecture that are found in the extracellular matrix.  What are the functions of the extracellular matrix?
    functions: support, adhesion, movement, regulation. collagen and proteoglycans.
  51. What are the four major types of intercellular junctions described in class?  Describe each one briefly.
    Tight junctions-prevent leakage, desmosomes-attaches cells to one another, gap junctions (animal)- provide channels between cells, plasmodesmata (plant)- provide channels between cells.
  52. What are the functions of cell membranes?  What are cell membranes comprised of?
    functions: serve as a partition, control passage of materials, receive and transmit info, provide a surface for organizing materials. phospholipid bilayers, cholesterol, proteins, carbs.
  53. What are the key features of the Fluid Mosaic Model?
    membrane is a mosaic of membrane and its infused proteins.
  54. What are lipid rafts and what are there functions?  How are they are a variation of the FluidMosaic Model?
    microdomains rich in certain phospolipids and membrane proteins. allow membrane subcapartmentalization (may be inportant for cell signaling or traffi)
  55. Explain how each of the following effects membrane fluidity:temperature, unsaturated hydrocarbons, and cholesterol.
    temp- can increase/decrease fluidity, unsaturated hydrocarbons increase fluidity, cholesterol- high temp decreases fluidity vice versa.
  56. What are the two major types of membrane proteins?  What functions are membrane proteins known to possess?
    integral/transmembrane (embedded) and peripheral (loosely attached).
  57. Which molecules can cross the cells membrane easily and which do not cross easily?
    easy- hydrophobic, small uncharges and nonpolar. hard- large charged polar and hydrophilic.
  58. Define the following: diffusion, passive transport and osmosis.  What is wrong with the phrase “learning by osmosis”?  Explain what would happen in this analogy.
    diffusion-high to low concentration, rendom movement to equilibrium. passive transport- diffusion across a membrane (no added energy). osmosis- diffusion of water across selectively permeable membrane.
  59. Define tonicity. Distinguish between hypotonic, isotonic and hypertonic solutions.  What happens to an animal cell and a plant cell in each of these situations?
    tonicity-ability of a solution to cause a cell to lose or gain water. hypotonic-explode/lyse(turgid/normal in plant), isotonic-balanced (flaccid in plant), hypertonic-shrivel (plasmolyzed)
  60. What are facilitated diffusion and active transport?  How do channel proteins and carrier proteins differ?  Briefly explain examples of each.
    facilitated diffusion- down concentration gradient with proteins but no energy. active transport- moves up concentration gradient, uses proteins and energy. channel- corridor to pass through (ions), carrier-pacman (glucose, potassium-sodium pump).
  61. Briefly describe the steps in the sodium-potassium pump cycle.  What do the sodium-potassium pump and the proton pump establish for a cell?
    salt attaches to protein, atp->adp and releases salt. potassium then attaches but its gradient is opposite so it doesnt use atp.
  62. What is cotransport? Explain how the sucrose-H+ transporter works.
    active transport assisted by a concentration gradient. H+ cycled through to increase gradient and help push sucrose through
  63. How do exocytosis and endocytosis occur in a cell?  Distinguish between the following: phagocytosis, pinocytosis, and receptor mediated endocytosis
    exocytosis (secretion of materials) endocytosis (engulfing materials). phagocytosis- engulfs entirely, pinocytosis- gulps droplets into cell (not specific to type), receptor mediated endocytosis- bulk quantities of specific items (items bind ti outside membrane)