# BIO 370 C3 E1

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 Author: shockwave ID: 135572 Filename: BIO 370 C3 E1 Updated: 2012-02-16 00:50:58 Tags: BIO 370 C3 E1 Folders: Description: CELL BIO 370 C3 E1 GSU 2012 Show Answers:

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1. FIRST LAW OF Thermodynamics.
Energy cannot be created or destroyed, Energy can be converted from one form to another
2. The universe is divided into system and surroundings.
DEFINE BOTH
System is a subset of the universe.

Surroundings are everything in the universe not part of the system
3. Systems can be closed or open.
DEFINE BOTH
• Closed: systems exchange energy with surroundings
• Open: systems exchange matter and energy with the surroundings

In energy transformations heat may be generated, work may be done.
4. T OR F?

First law does not predict + or - DE in a system
TRUE
5. TheSecond Law of Thermodynamics IS.....
In any energy transformation, entropy of the universe increases.

Entropy is a measure of disorder
6. T OR F ?
Living systems maintain a state of order by working against disorder, Keep entropy low.
TRUE
7. WHEN WATER FREZES, WHAT HAPPENS ENTROPY?
LOWERS
8. Combination of the first and second laws can be expressed mathematically...WHAT'S THE FORMULA?
• -DH = DG + TDS
• DS....entropy
• DG....free energy (available to do work)
• -DG is a measure of spontaneity of a reaction.
• DG < 0, spontaneous reaction......Exergonic
• DG > 0, reaction requires energy input .....Endergonic
9. DG < 0, spontaneous reaction

Exergonic OR Endergonic
Exergonic
10. DG > 0, reaction requires energy input
Exergonic OR Endergonic?
Endergonic
11. Cells are_______ thermodynamic systems
• Open
• (systems exchange matter and energy with the surroundings)
12. Cellular metabolism exists in a "steady state"...WHAT DOES THAT MEAN?
Concentrations of reactants to products remain constant, but not at equilibrium

New substrates enter; products removed.

Maintenance of steady state requires a constant input of energy
13. T OR F ?
Maintenance of steady state requires a constant input of energy
TRUE.

Maintaining equilibrium does not
14. IN A "STEADY STATE" WHAT IS THE CONCENTRATION OF ATP?
HIGH OR LOW?
• HIGH.
15. ENZYMES CAN FUNCTION OUTSIDE OF CELLS, WHO DISCOVERED IT AND WHEN?
Hans and Eduard Buchner, 1897
16. WHO AND WHEN DISCOVERED ENZYMES ARE ALMOST ALWAYS PROTEINS?
James Sumner, 1926
17. Enzymes may be conjugated with protein & nonprotein
components...name them
• Cofactors inorganic enzyme conjugates. EX:metals
• carry out activities amino acids are not suited for.

Coenzymes: organic enzyme conjugates.
18. ENZYMES Cannot affect thermodynamics of a
reaction, only_______.
RATES
19. Reactants that reach the peak of activation energy barrier are in the _____ _______.
transition state
20. Potential energy is....DEFINE
21. DEFINE KENETIC ENERGY
• The kinetic energy of an object is the energy which it possesses due to its motion.
• It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
22. Catalysts like enzymes________ activation energy
• LOWER
• With a catalyst large proportions of substrates can reach the transition state
23. Charged R groups on the enzyme effect substrates...NAME 3 WAYS
• ATTACK
• BEND
24. Cofactors of the enzyme increase the reactivity of the substrate by DOING WHAT ?
removing or donating protons
25. Inducing Strain in the Substrate..WHAT TYPE OF BONDS ARE STRAINED?
COLVALENT
26. Various changes in atomic and electronic structure occur in both enzyme and substrate
during reaction...NAME TWO WAYS TO VIEW THIS.
• time-resolved crystalography
• picosecond X-ray
27. DEFINE KINETICS
study of rates of enzymatic reactions under various experimental conditions
28. DEFINE THE TURNOVER NUMBER IN ENZYME KINETICS
The turnover number is number of substrate molecules converted to product/min/enzyme molecule at Vmax
29. DEFINE maximal velocity, Vmax
At saturation every enzyme molecule is working at maximal capacity

The velocity at saturation is called maximal velocity, Vmax
30. Enzyme Inhibitors...NAME THEM
• Irreversible...... bind tightly to enzyme
• Reversible.......bind loosely to enzyme
• 2 TYPES:
• Competitive inhibitors: compete with enzyme for active sites.
• Noncompetitive inhibitors: bind sites other than active site and inactivate enzyme
31. IF YOU HAVE AN ISSUE WITH REVERSIBLE, COMPETIVE INHIBITORS, HOW WOULD YOU OVERCOME IT?
can be overcome with high substrate/inhibitor ratios.
32. Of the following elements, which is likely to form the least polar covalent bonds with hydrogen:
A.nitrogen
B. carbon
C. phosphorus
D. oxygen
B. carbon
(this multiple choice question has been scrambled)
33. Of the following chemical bonds, which is the strongest in water?
A. HOH2C–CH2OH
B. Na–Cl
C. CH3COO–H
D. HO–H
A. HOH2C–CH2OH
(this multiple choice question has been scrambled)
34. The major cellular macromolecules include:
A. proteins, nucleic acids, carbohydrates, and lipids.
B. proteins, nucleic acids, carbohydrates, and antibodies.
C. proteins, lipids, amino acids, and carbohydrates.
D. proteins, amino acids, lipids, and nucleic acids.
A.proteins, nucleic acids, carbohydrates, and lipids.
(this multiple choice question has been scrambled)
35. Which of the following has been used as evidence that primitive life forms lacked both DNA and enzymes?

A. RNA can both code genetic information and act as a
catalyst.
B. DNA and enzymes are only present in the most advanced cells.
D. All of the above.
A. RNA can both code genetic information and act as a catalyst.
36. Of the following functional groups, which would make a carbon-based compound the least polar?
A. phosphate
B. methyl
C. carboxyl
D. amino
B. methyl
(this multiple choice question has been scrambled)
37. Cytoplasm has a pH of about 7. What is the concentration, in moles/liter, of the hydrogen ion?
1 x 10-7
38. Which of the following pairs of functional groups might form weak bonds with one another?
A. carboxyl and amino
B. methyl and phosphate
C. phosphate and carboxyl
D. carbonyl and methyl
A. carboxyl and amino
(this multiple choice question has been scrambled)
39. Proteins and macromolecular structures take on their higher order structures

A. with the help of molecular chaperones.
B. with the help of precursor sequences that are removed from the final structure.
C. by self-assembly.
D. all of the above.
C. by self-assembly.
(this multiple choice question has been scrambled)
40. Which amino acids would most likely reside in the membrane-anchoring domain of a membrane-embedded protein?

A. leucine, threonine, and lysine
B. lysine, arginine, and histidine
C. phenylalanine, valine, and aspartate
D. isoleucine, valine, and phenylalanine
D. isoleucine, valine, and phenylalanine
(this multiple choice question has been scrambled)
41. ATP is from which general category of biomolecules?

A. polysaccharides
B. proteins
C. nucleotides
D. amino acids
C. nucleotides
(this multiple choice question has been scrambled)
42. LEAST LIKELY TO OCCUR IN A CELL?
A
43. DEFINE ENTROPY
• THE GAIN/LOSS OF DISORDER
• (DS)
44. DEFINE ENTHALPY
• ENERGY GAIN OR NEEDED
• (DH)
45. When sea water is evaporated leaving behind salt crystals, the entropy of the water is ________.
A. increased
B. decreased
C. unchanged
A. INCREASED
(this multiple choice question has been scrambled)
46. When a fertilized egg cell develops into an embryo, the entropy of the living system is ________.
A. decreased
B. increased
C. unchanged
A. decreased
(this multiple choice question has been scrambled)
47. Reactions that have positive standard free energy changes (ΔG'°>0) can be made to occur in cells by:

A. coupling them with exergonic reactions via a common intermediate.
B. manipulating the concentrations of products and reactants such that ΔG'<0.
C. coupling them to the hydrolysis of ATP.
D. all of the above.
D. all of the above.
48. Cellular metabolism is an example of:
A. equilibrium metabolism.
C. a series of reactions that defy the second law of
D. a series of reactions occurring under standard conditions.
thermodynamics.
(this multiple choice question has been scrambled)
49. Any system that is not at equilibrium:

A. requires an enzyme to reach equilibrium.
B. is rushing toward equilibrium at a very rapid rate.
C. is thermodynamically unstable, although it may be kinetically stable.
D. is kinetically unstable, although it may be thermodynamically stable.
C. is thermodynamically unstable, although it may be kinetically stable.
(this multiple choice question has been scrambled)
50. Protein catalysts:

A. increase the rates of chemical reactions in cells while remaining unchanged.
B. can change the standard free energy of a cellular
C. are sometimes referred to as ribozymes.
reaction.
D. all of the above.
A. increase the rates of chemical reactions in cells while remaining unchanged.
(this multiple choice question has been scrambled)
51. Which of the following statements is not true of enzymes?

A. Enzymes only function when they are in intact
B. Enzymes are proteins that bind to specific substrates and increase the velocity of reactions involving those substrates.
C. Enzymes function by overcoming the activation energy barrier of a reaction.
D. Enzymes can only make thermodynamically favorable reactions proceed; they cannot make unfavorable reactions occur.
cells.
A. Enzymes only function when they are in intact cells.
(this multiple choice question has been scrambled)
52. As opposed to an uncatalyzed reaction, in an enzymatically catalyzed reaction...what happens?
the activation energy of the reaction is lowered, and a larger proportion of substrate molecules has sufficient energy to overcome it.
53. A certain inhibitor of an enzymatic reaction was determined to act as a competitive inhibitor. Which one of following statements about the inhibitor is most probably true?

A. The inhibitor acts at a site other than the substrate binding
site.
B. The inhibitor increases KM but has no effect on
Vmax.
C. The inhibitor decreases KM but has no effect on Vmax.
D. The inhibitor lowers the maximum velocity of the
enzyme.
B. The inhibitor increases KM but has no effect on Vmax.
54. During glycolysis, a net of how many ATPs are produced for each glucose that enters the pathway?
A. 4
B. ≥35
C. 1
D. 2
D. 2
(this multiple choice question has been scrambled)
55. For most of the reactions of glycolysis, the ΔG under cellular conditions is close to 0. Why does the pathway continue in the direction of glucose catabolism?
There are three essentially irreversible (ΔG<<0) reactions that act as the “driving force” for the pathway.
56. All of the following techniques were used to study the mechanism of lysozyme action except:
A. x-ray diffraction.
B. site directed mutagenesis.
C. equilibrium thermodynamics.
D. the use of synthetic, chemically altered substrates.
C. equilibrium thermodynamics.
(this multiple choice question has been scrambled)
57. JUST UNDERSTAND THIS:
58. JUST UNDERSTAND THIS:
59. Noncompetitive inhibitor ______ Vmax without affecting Km
REDUCES
60. Competitive inhibitor ________ Km without affecting Vmax
INCREASE
61. HOW DO Ab WORK?
• targets:
• bacterial metabolism, no harm to host
• Enzymes involved in synthesis of the bacterial cell wall
• genetic information transfers
62. Bacteria become resistant to antibiotics by acquiring genes from other bacteria...HOW?
Transformation,transduction, conjugation
63. T OR F ?
Pathways usually confined to specific cellular location but Enzymes of a given pathway may be physically linked to one another
TRUE
64. Catabolic pathways _______ ______complex substrates into simple end products..PROVIDE MATERIALS AND ENERGY
break down
65. Anabolic pathways ________complex end products from simple substrates, it ________energy.
• synthesize
• requires
• Use ATP and NADPH from catabolic pathways
66. THE 3 STAGES OF METABOLISM.
NAME STRUCTURES IN EACH.
67. In redox pairs, the substrate that gains electrons is the _____
agent
oxidizing
68. The substrate that donates electrons is the _______ agent
reducing
69. With organic substrates redox involves atoms bound to ____.
CARBON
70. THERE ARE 2 STAGES IN THE CATABOLISM OF GLUCOSE..NAME THEM
• GLYCOLYSIS FIRST IN CYTOPLASM
• MAKES PYRUVATE ACID THEN TCA CYCLE
71. CARBON IN THE MOST REDUCED STATE IS ATTACHED TO WHAT? WHAT ABOUT MOST OXIDIZED STATE?
• MOST REDUCED: 4 HYDROGENS, SINGLE BONDS.
• MOST OXIDIZED: 2 OXYGEN
• (DOUBLE BONDED TO EACH)
72. The oxidation state of a carbon atom...NAME THE GROUPS FROM MOST REDUCED TO MOST OXIDIZED.
73. WHEN YOU REDUCE ATOMS, WHAT DO YOU GET?
• ENERGY
• THINK Fats and carbohydrates are oxidized in cells to release energy to do work.
• Chemical energy is transferred to form ATP
74. _________is the carbohydrate central to the
energy-producing pathways of cells
Glucose
75. T OR F ?
THE MORE A SUBSTANCE IS REDUCED THE MORE ENERGY CAN BE RELEASED.
TRUE
76. Kinase enzymes...FUNCTION
transfer phosphate groups
77. Substrate level phosphorylation occurs when ?
ATP is formed by a kinase enzyme
78. NAD+ IS AN OXIDIZING AGENT IN GLYCOLYSIS?
TRUE
79. DEFINE PHOSPHORYLATION
WHEN A PHOSOPHORUS GROUP IS ADDED TO A MOLECULE. IN GLYCOLYSIS, AN ENZYME ACT TO MOVE IT AROUND, KNOWN AS SUBSTRATE-PHOSPHORYLATION
80. hexokinase is an enzyme that does what ?
• phosphorylates a six-carbon sugar, a hexose, to a hexose phosphate.
• PHOSPATE FROM ATP.
• 1ST STEP OF GLYCOLYSIS.
• THIS IS SUBSTRATE PHOSPHORYLATION
81. JUST KNOW THIS:
82. DEFINE Allosteric Feedback Inhibition
Flow of metabolites through metabolic pathway stops when end products inhibit the first enzyme in the pathway

Avoids wasting resources in the cell

Allosteric site binding causes conformational change and inhibits enzyme activity

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