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MicroBiology > Introduction to metabolism > Flashcards

Introduction to metabolism Flashcards

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Biology 101 flashcards
1
Q

what is metabolism?

A

the total of all chemical reactions in the cell

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2
Q

describe Catabolism (6)

A
  • bio degradation
  • the breakdown of a larger molecule into smaller one(s)
  • Breaks covalent bonds and releases energy, so they are exergonic
  • Enzyme catalyzed
  • Most are also oxidations (provides reducing power)
  • Generates precursors for anabolism
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3
Q

describe anabolism (5)

A
  • Biosynthesis
  • The synthesis of a larger molecule from a smaller one or smaller ones
  • Creates many new covalent bonds and requires energy input so they are endergonic (never endothermic)
  • Enzyme catalyzed
  • Mostly reductions
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4
Q

what is chemical work?

A

synthesis of complex molecules

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5
Q

what is transport work?

A

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

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6
Q

what is mechanical work?

A

cell motility and movement of structures within cells

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7
Q

describe Free Energy and Reactions (3)

A
  1. ) G = H - TS
  2. ) Expresses the change in energy that can occur in chemical reactions and other processes
  3. ) Used to indicate if a reaction will proceed spontaneously
    - if G is negative, reaction is spontaneous
    - if G is positive, reaction is not spontaneous
    * *slide 7**
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8
Q

slide 8

A

KNOW

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9
Q

what is an exergonic reaction?

A

chemical reactions with a negative Go′value that release free energy (if heat released it also exothermic)

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10
Q

what is an endergonic reaction?

A

chemical rReactions with a positive Go′ value require an energy input (it is never endothermic in biological systems)

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11
Q

slide 11-16

A

LOTS OF SHIT

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12
Q

what is a redox reaction?

what does it result in?

A
  • Transfer of electrons from a donor to an acceptor

- results in energy release, which can be conserved and used to form ATP

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13
Q

what is oxidation?

A

the loss of an electron or electrons from an atom, or the loss of an electron, electrons or whole hydrogen atom (2 electrons and 1 proton) from a molecule

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14
Q

is oxidation exergonic or or endergonic?

explain

A

Removing electrons or a hydrogen atom removes energy so oxidations are exergonic

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15
Q

what is reduction?

A

the gain of an electron or electrons by an atom, or the gain of an electron, electrons or whole hydrogen atom (2 electrons and 1 proton) by a molecule

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16
Q

is reduction exergonic or endergonic?

explain

A

Adding electrons or a whole hydrogen atom (bonds) adds energy so reductions are endergonic

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17
Q

what is reduction potential(Eo′)?

A

tendency of a compound to donate electrons (to be oxidized) or to gain electrons (to be reduced)
(slide 23)

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18
Q

slides 24-26

A

take a look

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19
Q

SLIDE 27

A

look at (hard to make a flashcard for)

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20
Q

describe electron carriers (where they are located in bacteria and archaea and eukaryotic cells; also give examples)

A
  • Located in cell membranes of chemoorganotrophs in bacteria and archaeal cells
  • Located in internal mitochondrial membranes in eukaryotic cells
  • Examples of electron carriers include NAD, NADP, and others
21
Q

what does NAD stand for?

A

nicotinamide adenine dinucleotide

22
Q

what does NADP stand for

A

nicotinamide adenine dinucleotide phosphate

23
Q

slide 30

A

LOOK AT

24
Q

what does FAD stand for?

A

flavin adenine dinucleotide

25
Q

what does FMN stand for?

A

flavin mononucleotide

*riboflavin phosphate

26
Q

what does coenzyme Q (CoQ) stand for

A

a quinone

also called ubiquinone

27
Q

what do cytochromes do?

A

use iron to transfer electrons

iron is part of a heme group

28
Q

what do Nonheme iron-sulfur proteins

A

use iron to transport electrons
(iron is not part of a heme group)
e.g., ferrodoxin
(slide 32)

29
Q

what are enzymes? what do they allow?

A
  • Organic molecules that act as catalysts and increase the rate of a chemical reaction
  • Allow reactions to occur at physiological conditions so they proceed in a timely manner
30
Q

Some enzymes are composed solely of one or more _______________-
Some enzymes are composed of one or more __________ and ________ components

A

polypeptides; polypeptides and nonprotein

31
Q

what is the protein component of an enzyme?

A

Apoenzyme

32
Q

what is a cofactor? describe

A

nonprotein component of an enzyme
prosthetic group – firmly attached
coenzyme – loosely attached, can act as carriers/shuttles

33
Q

Holoenzyme = _________ + __________

+ ___________

A

apoenzyme + cofactor

+ coenzyme

34
Q

what is activation energy?

A
  • energy required to form transition-state complex

- Enzyme speeds up reaction by lowering Ea

35
Q

how do enzymes lower Ea? (3)

A
  • By increasing concentrations of substrates at active site of enzyme
  • By orienting substrates properly with respect to each other in order to form the transition-state complex
  • Induced fit model for enzyme-substrate interaction
36
Q

enzyme activity is significantly impacted by what three things?

A

substrate concentration
pH
temperature

37
Q

what is a competitive inhibiter?

A

directly competes with binding of substrate to active site

38
Q

what is non-competitive inhibiter?

A

binds enzyme at site other than active site

changes enzyme’s shape so that it becomes less active

39
Q

slide 42

A

meh :)

40
Q

Regulation of Metabolism is Important for _____________________________________ and for Maintenance of ____________________

A

conservation of energy and materials; metabolic balance despite changes in environment

41
Q

what are the three major mechanisms for metabolic regulation?

A

-metabolic channeling
-regulation of the synthesis of a particular enzyme (transcriptional and translational)
-regulation of enzyme activity
direct activation or inhibition of the activity of a critical enzyme

42
Q

describe metabolic channeling (2)

A
  1. ) Differential localization of enzymes and metabolites
  2. ) Compartmentation
    - differential distribution of enzymes and metabolites -among separate cell structures or organelles
    - can generate marked variations in metabolite concentrations
43
Q

for regulation of enzyme activity what are the Two important reversible control measures?

A

allosteric regulation

covalent modification

44
Q

give 2 facts about allosteric regulation

A

Most regulatory enzymes

Activity altered by small molecule

45
Q

describe allosteric effector (4)

A
  • binds non-covalently at regulatory site
  • changes shape of enzyme and alters activity of catalytic site
  • positive effector increases enzyme activity
  • negative effector inhibits the enzyme
46
Q

give 2 facts about covalent modification

A
  • Reversible on and off switch

- Addition or removal of a chemical group (phosphate, methyl, adenyl)

47
Q

what are 2 advantages of covalent modification?

A
  • respond to more stimuli in varied/sophisticated ways

- regulation of enzymes that catalyze covalent modification adds second level of control

48
Q

describe feedback inhibition

A

-Also called end-product inhibition
-Inhibition of one or more critical enzymes in a pathway regulates entire pathway
(catalyzes the slowest or rate-limiting reaction in the pathway)
-Each end product regulates its own branch of the pathway
-Each end product regulates the initial pacemaker enzyme
(slide 50)

MicroBiology (17 decks)

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