Biology

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kresha89
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42684
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Biology
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2010-10-18 19:07:36
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biology
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terms to know for Exam 2
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  1. What is dehydration reaction?
    Connects monomers, also known as condensation reaction. When two molecules are covalently bonded to each other through loss of water molecules.
  2. What is hydrolysis?
    • The reverse of dehydration. Disconnects polymers. Bonds between the monomers are broken by the addition of water molecules.
    • ex: the process of digestion.
  3. Dehydration and hydrolysis reactions are essentially the reverse of each other, and are facilitated by .
    enzymes
  4. What are monosaccharides?
    • * molecular formulas are some multiple ot ous.
    • *names for sugara ene in -ous.
    • *Have a carbonyl group and multiple hydroxyl groups
    • *Are a major fuel for celluar work
    • *functions as the raw material for the synthesis of other monomers, including those of amino acids and fatty acids.
  5. What is disaccharide?
    • consist of two monosaccharide joined by a glycosidic linkage, a convalent bond formed between two monosccharides by dehydration reaction.
    • ex: maltose is formed by the linkage of two molecules of glucose
    • sucrose-table sugar- glucose and fructose
  6. What are polysaccharides?
    • *Polymers of hundreds to thousands of monosaccharides joined by glycosidic linkages.
    • *An energy storage macromolecules that is hydrolyzed as needed
    • ex: for fuel storage: Glycogen ( animals only) & Starch (plants only)
    • For Structure: Cellulose ( plants only, cell wall)
    • *Strands form hydrogen bonds with other strands
    • *groups of polymers form strong strands, microfribrils that are basic building material for plants and humans
  7. Components of a fat molecule
    • *contains glycerol and fatty acids
    • *three fatty acids are joined to glycerol by ester linkage, creating a triacylglycerol
    • *fats separate themselves from water
    • *major function is energy storage
    • *c-shion vital organs and insulation
  8. What is glycerol?
    a three carbon skeleton with a hydroxyl group attached to each
  9. What are fatty acids?
    a carboxyl group attached to a long carbon skeleton, often 16 to 18 carbons long (very hydrophobic)
  10. What are saturated fats?
    • * most animal fats
    • *solid at room temperature
    • *contribute to cardiovascular disease through plaque deposits
  11. What are unsaturated fats?
    • *plant and fish fats, known oils
    • *liquid at room temperature
    • *the kinks provided by the double bonds pervent the molecules from packing tightly together
  12. What are trans-fats?
    a type of unsaturated fat that occurs at low levels in dairy and meat products
  13. What are phospholipids?
    • = a fat with two fatty acids attached to glycerol plus phospholipids group at the third positions
    • *major components of cell membrane
  14. The 4 components of an amino acid.
    • consist of four components attached to a central carbon:
    • 1.alpha carbon
    • 2. a hydrogen atom
    • 3. a variable R group ( or side chain)
    • 4.a carboxyl group
  15. A polar R group.
    there hydrophilic
  16. A non-polar R group.
    there hydrophobic
  17. What are acidic amino acids?
    are those with side chains that are generally negative in charge owing to the presence of a carboxyl group
  18. What are basic amino acids?
    have amino groups in their side chains that are generally positve in charge
  19. What is the primary structure?
    • * is the first level of protein structure
    • *is its unique sequence of amino acids
    • *is found in the blood that transport vitamin A and one thyroid hormones throughout the body
  20. What is the secondary structure?
    • * second level of protein structure
    • *hydorgen bonds at regular intervals along the polypeptide backbone
    • *coils an alpha helix
    • *folds beta pleated sheets
  21. What is the tertiary structure?
    • *thrid level of protein structure
    • *determine by interactionsbetween R groups and polypeptide backbone
    • *hydrophobic interaction contributes to the tertiary structure
    • *consist of hydrogen bonds, ionic bond and van der Waals
    • *Disulfide bridges- reinforce the shape of the protein by the covalent bond
  22. What is the Quaternanry sturcture?
    • *the fourth level of the protein structure
    • *results from the aggregation of two or more polypeptide subunits
    • ex: collagen-fibrous protein of three polypeptides that are supercoiled like a rope
    • hemoglobin-a globular protein with two copies of two kinds of polypeptides
  23. What are chaperone proteins?
    • *protein molecules that assist in the proper folding of other proteins
    • *keep the new polypeptide segregated from "bad influences" in the cytoplasmic enviroment while it folds spontaneously
  24. What is a gene?
    • *the amino acid sequence of a polypeptide is programmed by a unit of inheritance
    • *consist of DNA
  25. What is DNA (deoxyribonucleic acid)?
    • *enables living organisms to reproduce their complex components from one generation to the next
    • *provides directions for its own replication
    • *directs RNA synthesis and, through RNA, controls protein synthesis
    • *genetic material that organisms get from their parents
  26. What is RNA (ribonucleic acid)?
    • *enable living organisms to reproduce their complex components from one generations to the next
    • *interacts with the cell's protein-synthesizing machinery to direct production of a polypeptide, which folds into all or part of a protein
    • *conveys genetic instructions for building proteins form the nucleus tot he cytoplasm
  27. What is phosphodiester?
    • *connects polynucleotides
    • *the linkage between the 3' carbon atom and the 5' carbon if tge pentose sugar
    • *consists of a group of strong covalent bonds
  28. What are the three components of nucleic acids?
    • 1.nitorgenous base
    • 2. a five-carbon sugar (pentose sugar)
    • 3. phosphate group
  29. What are the base pairing rules?
    • *an RNA molecule is single polyncleotide chain
    • *DNA molecule have two polynucletide strands that spiral around an imginary axis to form a double helix
    • *Adenine (A) pairs with Thymine (T)
    • *Guanine (G) pairs with Cytosine (C)
  30. What are eukaryotic cells?
    • *has a plasma membrane
    • *a cytosol within the cell
    • *consist of chromosomes
    • *ribosomes-organells that make proteins
    • *chromosomes are in the nucleous
    • *has many organelles, membrane bound
    • *size is 10-100 times larger
    • *domain is eukarya
  31. What are prokaryotic cells?
    • *plasma membrane
    • *a cytosol within the cell
    • *chromosomes
    • *ribosomes
    • *has nucleoid-not membrane enclosed
    • *no organelles
    • *size is small
    • *domain is archaea & bacteria
  32. What is smooth ER (endoplasmic reticulum)?
    • *outer surface lacks ribosomes
    • *process includes synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons
    • *enzymes are improtant in the synthesis of lipids, including oils, phospholipids, and steroids
    • *detoxify drugs and poisons especially in liver cells
  33. What is rough ER?
    • *ribosomes attached to the outside
    • *packages proteins into transport vesicles
  34. What is the Fluid Mosaic Model?
    • *Hydrophilic regions of proteins and phospholipids are in maximum contact with water
    • *Hydorphobic regions are in a nonaqueous enviroment
  35. What factors affect membrane fluidity?
    • 1. Temperature: fluidity decreases as temperature decreases due to tighter packingof phospholipids
    • 2. Membrane constituents: unsturated fatty acids make membranes more fluid because the kinks prevent tight packing
    • 3. Cholesterol-restrains the movement of phospholipids ans reduces fluidity
  36. What are peripheral proteins?
    loosely bounded to the surface of the membrane, interacting with other proteins
  37. What are integral proteins?
    penetrate the hydrophobic core of the lipid bilayer, often completely spanning the membrane (a transmembrane protein)
  38. Where are membranes synthesized?
    • *membranes are asymmetrical, having distinctive inside and outside faces
    • *lipid layers may differ in specific lipid composition
    • *proteins are directional
    • *carbohydrates are only on the other surface
    • *membranes are manufactured in ER
  39. What are passive transpot?
    • 1. Diffusion-passive movement of molecules down a concentration gradient
    • 2. Facilitated diffusion-the passive movement of molecules down its concentration gradient via a transport protein
    • *Osmosis is the passive transport of water
  40. What is active transport?
    • *the active tansport of molecules against a concentration gradient
    • *requires metabolic energy
    • *is the pumping of solutes against thein gradients
    • *critical for a cell to maintain its internal concentration of small molecules
    • *performed by specific proteins embedded in the membranes
    • *ATP supplies tghe energy for most active transport
  41. What is facilitated diffusion?
    • *requires transport proteins, which
    • -have specific binding sites for the solute
    • -become saturated when translocating passengers at full capacity
    • -can be inhibited by molecules similar to normal "substrate."
  42. What is osmosis?
    • *is the diffusion of water across a selectively permeable membrane
    • *water molecules move from less concentrated (hypotonic) to more concentrated
  43. What is hypertonic?
    • *the cell will lose water to its enviroment, shrivel and probably die
    • *an increase in the salinity of a lake can kill animals there; if the lake water becomes hypertonic to the animales' cells, the cells might shrival and die
    • *taking up too much water can be just as hazardous to an animal cell as losing water
    • *water will enter the cell faster than it leaves, and the cell will swell and lyse (burst) like an overfilled water balloon
  44. What is cotransport?
    • a single ATP-powered pump that transports one solute can indirectly drive the active transport of several other solutes in a mechanism
    • ex: plants use the gradient of hydrogen ions that is generated by proton pumps to drive the active transport of amino acids, sugars, and other nutrients into the cell
  45. What is endocytosis?
    • *macromolecules and particulate matter enter the cell by forming new vesicies from the plasma membrane.
    • *reverse of exocytosis
    • *Three types:
    • 1. phagocytosis-celluar eating
    • 2. pinocytosis-celluar drinking
    • 3. receptor-mediated endocytosis
  46. What is phagocytosis?
    the cell engulfs a particle by extending pseudopodia and packaging it in a large vacuole, then digesting it when the vacuole fuses with a lysosome
  47. What is pinocytosis?
    • *a cell creates a vesicle around a droplet of extracellular fluid
    • *a non-specific process
  48. What is receptor-mediated endocytosis (RME)?
    • *very specific in what substances are being transported
    • *triggered by receptor-ligand interaction (which triggers the formation of a vesicle
    • *enables a cell to "store up" componds
  49. What is exocytosis?
    a transport vesicle budded from the Golgi apparatus is move by the cytoskeleton to the plasma membrane
  50. What are anabolic pathways?
    • *in contrast, consume energy to build complicated molecules from simpler ones; they are sometimes called biosynthetic pathways
    • ex: the synthesis of a protein from amino acids
    • * used to drive uphill reactions
  51. What are catabolic pathways?
    • *breakdown pathways
    • *energy is released form the downhill reactions
  52. What are endergonic reactions?
    • *is one that absorbs free energy from its surroundings
    • *stores free energy in molecules
  53. What are exergonic reactions?
    • *proceeds with a net release of free energy
    • *since chemical mixture loses free energy, change in G is negative
    • *occur spontaneously
  54. What is free energy?
    • *is the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell
    • *can be calculated by change in G=change in H-Tchange inS
  55. What is the first law of thermodynamic?
    • *the energy of the universe is constant
    • *energy can be transferred and tansfromed but it cannot be created or destroyed
    • *also known as the principle of conservation of energy
    • ex: energy in the food will be conerted to the kinetic energy of the cheetah's movement
  56. What is the second law of thermodynamic?
    • *every energy transfer or transformation increases the entropy of the universe
    • *there is an unstoppable trend toward randomization of the universie verse as a whole
    • ex: disorder is added to the cheetah's surroundings in the form of heat and the small molecules that are the by-products of metabolism
  57. The break down of glucose to CO2 and water=-687kcal/mol.
    • C6H12O6+6O2>6CO2+6H2O
    • *converts sugar and oxygen to carbon dioxide and water
  58. The reverse break down of glucose =+686kcal/mol
    • 6CO2 +6H2O>C6H12O6+6O2
    • *must be strongly endergonic
  59. What are the parts of an ATP molecule?
    • *base (adenine)
    • *three phosphates
    • *a sugar (ribose)
  60. How does enzymes lower EA but not change in G?
    • *An enzyme catalyzes a reaction by lowering the EA barrier, enabling the reactant molecules to absorb enough energy to reach the transition state even at moderate temperatures.
    • *cannot change change in G for a reaction; it cannot make an endergonic reaction exergonic
  61. What are factors that affect enzyme activity?
    • 1. Substrate concentration
    • 2. Temperature
    • 3.pH
    • 4.Cofactors
    • 5. Inhibitors
  62. What is substrate concentration?
    • *increase in substrate concenteration=increase in rate
    • *there is a limit to how fast a reaction can occur
    • *a high substrate concentrations, the active sites on all enzymes are engaged, called enzyme saturation
  63. How temperature effect enzymes?
    • *increase in temperature=increase in rate
    • *at some point heat denatures protein
    • *each enzyme has as optimal temperature
  64. How pH effect enzyme?
    • *influences shapt of therefore reaction rate
    • *each enzyme has an optimal pH
    • *this falls between pH6-8 for most enzymes
    • *exceptions include digestive enzymes in the stomach
  65. How does cofactors effect enzyme?
    • *no-protein helper for enzyme activity
    • *includes inorganic molecules
    • *organic cofactors, coenzymes, include vitamins or molecules derived from vitamins
  66. How does inhibitor effect enzymes?
    • *covalent interactions or ionic with enzymes
    • *competitive inhibitor binds to the same site as the substrate, and blocks substrate binding
    • *noncompetitive inhibitor binds somewhere other than the active site, ans block substrate binding via altering shape of enzyme
  67. What is feedback inhibition?
    is a metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway

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