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Microbio 3220 > Exam 2 - Lecture 9 > Flashcards

Exam 2 - Lecture 9 Flashcards

1
Q

what three kinds of work must cells do?

A
  • chemical work
  • transport work
  • mechanical work
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2
Q

what is chemical work?

A

the synthesis of complex molecules

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3
Q

what is transport work?

A

the take up of nutrients, elimination of wastes, and maintenance of ion balances

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4
Q

what is mechanical work?

A

cell motility and movement of structures within the cell

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5
Q

metabolism is a _______ of all the chemical reactions in a cell

A

total

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6
Q

which of the following generates precursors for biosynthesis, catabolism or anabolism?

A

catabolism

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7
Q

which of the following requires energy, catabolism or anabolism?

A

anabolism

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8
Q

match the following:

a. catabolism
b. anabolism

  1. synthesis of large, complex molecules
  2. breakdown of large molecules into smaller, simpler ones
A

a2. catabolism: breakdown of large molecules into smaller, simpler ones

b1. anabolism: synthesis of large, complex molecules

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9
Q

what is thermodynamics?

A

a science the analyzes the energy changes in a collection of matter called a system (example: a cell)

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10
Q

what are the laws of thermodynamics?

A
  • energy can neither be created nor destroyed
  • entropy (the universe wants to constantly increase in entropy)
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11
Q

what is entropy?

A

the amount of disorder/chaos in a system

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12
Q

what is the free energy equation?

A

deltaG = deltaH - TdeltaS

(G = H - TS)

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13
Q

what is the free energy equation used for?

A

it is used to indicate if a reaction will proceed spontaneously

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14
Q

true or false: a positive deltaG mean a rxn is spontaneous.

A

false; a negative deltaG means a rxn is spontaneous

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15
Q

is a negative deltaG indicate an exergonic or endergonic reaction?

A

exergonic = negative deltaG

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16
Q

when is a reaction at equilibrium?

A

when the rate of the forward reaction matches that of the reverse reaction

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17
Q

what is the Keq equation?

A

[C][D]/[A][B]

  • concentration of products over reactants
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18
Q

deltaG = -RT*log(Keq)

A

just know this i guess

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19
Q

what is the energy currency of the cell?

A

adenosine 5’-triphosphate; ATP

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20
Q

what is done to make endergonic reactions more favorable?

A

they are coupled with the breakdown of high energy ATP (an exergonic reaction)

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21
Q

what is the deltaG of ATP hydrolysis?

A

-7.3 kcal/mol

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22
Q

many metabolic processes involve oxidation-reduction reactions, which is the transfer of ___________

A

electrons

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23
Q

when electrons move from a donor to an acceptor, this can result in energy _________ which can then be used to form ATP

A

release

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24
Q

the more electrons a molecule has to donate, the more _________ _____ it is

A

energy rich

25
Q

an electron donor and acceptor pair are called what?

A

conjugate redox pair

26
Q

what is the equilibrium constant for a redox reaction called?

A

the standard reduction potential (Eo; “E-naught”)

27
Q

what is Eo a measure of?

A

the tendency of a donor agent to lose its electrons

28
Q

a more negative Eo, the better electron ________ it is. the more positive, the better _________ it is

A

donor; acceptor

29
Q

does NADH have a positive or negative Eo? what about O2?

A
  • NADH: negative
  • O2: positive
  • when electrons move from NADH to O2, energy is made available
30
Q

the first electron carrier in the ETC has the most ___________ Eo (hint: it’s NADH)

A

negative

31
Q

the first electron carrier in the ETC is _________ when electrons are moved onto the next carrier

A

oxidized (OIL RIG)

32
Q

where does the electron transport chain take place in bacterial and archaeal cells? how about eukaryotic cells?

A
  • plasma membranes
  • mitochondrial (or chloroplast) membranes
33
Q

what does NAD(P) stand for?

A

nicotinamide adenosine dinucleotide (phosphate)

34
Q

an important consequence of the ETC is the formation of a __________ __________

A

proton gradient

35
Q

during oxidation of NADH, protons are transported _____ ___ the cell. they ________ the cell through ATP synthase and generate ATP

A

out of; re-enter

36
Q

reactions can be linked together to form ______________ __________

A

biological pathways

37
Q

what are three biological pathway orientations?

A
  • linear
  • cyclic
  • branched
38
Q

what are enzymes?

A

molecules that speed up reactions

39
Q

enzymes can be made from ________ or _____ (___________)

A

protein or RNA (ribozymes)

40
Q

what are protein catalysts?

A

highly specific substrates that increase the rate of a rxn without being permanently altered

41
Q

what are substrates? products?

A
  • substrates: reacting molecules
  • products: substances formed by the reaction
42
Q

what is an apoenzyme?

A

the protein component of an enzyme

43
Q

what is a cofactor?

A

non-protein component of an enzyme

44
Q

what are two types of cofactors?

A
  • prosthetic group: firmly attached
  • coenzyme: loosely attached; can act as carriers/shuttles
45
Q

what is a holoenzyme?

A

apoenzyme + cofactor

46
Q

what are the six general classes of enzymes?

A
  • oxidoreductases
  • transferases
  • hydrolases (breakdown using water)
  • lyases (breakdown w/o water)
  • isomerases
  • ligases
47
Q

what does the transition state complex resemble in a reaction?

A

it resembles both the substrates and the products

48
Q

what is the activation energy of a reaction?

A

the energy required to form the transition state complex

49
Q

how do enzymes speed up reactions?

A

by lowering the activation energy (Ea)

50
Q

what are three environmental factors that significantly impact enzyme activity?

A
  • substrate concentration
  • pH
  • temperature
51
Q

what are the effects of substrate concentration on enzyme activity?

A
  • the rate of a rxn increases as the substrate conc. increases
  • it stops increasing when all enzyme molecules are saturated with substrate
52
Q

how do pH and tempertaure affect enzyme activity?

A

the enzyme can be denatured if the pH or temp goes outside its specific range that it can tolerate

53
Q

what are the three important mechanisms of metabolism for conservation of energy?

A
  • metabolic channeling
  • regulation of the synthesis of a particular enzyme (transcription or translation)
  • direct stimulation or inhibition of the activity of the activity of a critical enzyme (post-translational)
54
Q

what is compartmentation?

A

differential distribution of enzymes and metabolites among other cell structures and organelles

55
Q

what the the two types of reversible post-translation regulation of enzyme activity?

A
  • allosteric regulation
  • covalent modifications
56
Q

what is an allosteric effector?

A

a small molecule that non-covalently binds to the regulatory site, changing the shape of the enzyme and altering its catalytic activity

  • positive effector: increases enzymatic activity
  • negative effector: inhibits
57
Q

what is covalent modification of an enzyme?

A
  • addition or removal of a chemical group (example: phosphate, methyl, adenylyl)
  • reversible on and off switch
58
Q

what is feedback inhibition (end-product inhibition)?

A

when the product builds up and inhibits the pathway

59
Q

what is a pacemaker enzyme?

A

an enzyme that catalyzes the slowest step/rate-limiting reaction in a pathway

Microbio 3220 (24 decks)

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