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CHEE 229 Cell Bio > Chapter 10 > Flashcards

Chapter 10 Flashcards

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Biology 101 flashcards
1
Q

What work processes in a cell require energy?

A
  • Chemical work (complex mol)
  • Mechanical work (motility/movement)
  • Transport work (uptake, elim., maintenance)
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2
Q

Delta(E’º) and delta(G’º) for FAD/FADH2 with 1/2 O2/H2O?

A

(see Half-Reaction Table), LEO says GER

Delta(E’º) = E’º(reduced/acceptor) - E’º(oxidized/donor)
Delta(E’º) = 0.82-(-0.18) V
Delta(E’º) = 1 V

Delta(G’º) = -nF(Delta(E’º))
Delta(G’º) = -2(96.63 kJ/mol V)(1 V)
Delta(G’º) = -193.26 kJ/mol

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3
Q

Redox chemical reaction for FAD/FADH2 with 1/2 O2/H2O

A

FADH2 → FAD+ + 2H+ +2e-
1/2 O2 + 2H+ + 2e- →H2O
Resulting equation: FADH2+ 1/2 O2 <—> FAD+ + H2O

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4
Q

“Activation E”?

A
  • E required to form TS complex
  • Enzyme lowers Ea, increases rxn rate
  • Enz. increases [S] @ activation site
  • Enz. orients S properly to form TS complex
  • Keq unchanged
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5
Q

How do enzymes function?

A
  • Speeds up rxn rate @ which it proceeds towards eq’m
  • Enz. increases [S] at activ. site + orients S properly
  • Lock & key: only specific S will fit in Enz. to catalyze rxn
  • Induced fit: S binds and Enz. changes to accommodate shape
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6
Q

“Michaelis constant”?

A

Mich. const. (Km) = [S] @ half maximum velocity (represents affinity of enz. for its substrate)

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7
Q

“Maximum velocity [of rxn]”?

A

Velocity of rxn when enzymes become saturated w/ S

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8
Q

How does enz. activity change w/:

a) [S]
b) pH
c) temp

A

a) Does not change w/ [S]
b) Increased activity @ optimal pH
c) Increased activity @ optimal temp

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9
Q

How is “covalent modification” used for metabolic regulation?

A

Add./remov. of chemical group (phosphate, methyl, adenyl) will increase/decrease activity of spec. enz. Reversible, can act as on/off switch.

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10
Q

Two processes that make up metabolism?

A

Catab: Breakdown of complex compound to provide ATP, source of reducing power, small precursor metabolites

Anab: Biosynthesis rxns to generate precursor metabs, carbs/polysaccs/AAs/nucleotides/lipids

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11
Q

Define “exergonic” and “endergonic” rxns

A

Ex (release of free G):

Keq > 1
delta(G’º) < 0

End (absorption of free G):

Keq < 1
delta(G’º) > 0

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12
Q

T/F: ATP breakdown is an exergonic reaction.

A

TRUE: ATP breakdown is exergonic but the reaction it undergoes is endergonic. Energy from breakdown is absorbed by products (more favorable)

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13
Q

T/F: Other energy molecules besides ATP are GTP, CTP and ADP

A

FALSE: ADP is formed w/ ATP breakdown and lacks E. UTP (uridine 5’-triphosphate) is the last example involved in peptidoglycan/polysaccharide synthesis.

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14
Q

T/F: ATP has high transfer potential.

A

TRUE

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15
Q

Define st. reduc. potential (Eº)

A

Measure of tendency for donor half to lose e-. More -ve = more tendency to spont. donate e-, whereas more +ve = greater affinity for e-

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16
Q

Electron Transport Chains (ETCs) are a set of sequential _______________ rxns that protect cell from random non-productive _______________ of other molecules: each carrier is __________ and then re-__________.

A

Electron Transport Chains (ETCs) are a set of sequential REDOX rxns that protect cell from random non-productive REDUCTION of other molecules: each carrier is REDUCED and then re-OXIDIZED.

17
Q

T/F: The ETC is found in the plasma membrane of euk. cells.

A

FALSE: ETC is found in internal mitochondrial membrane in euk, but plasma memb. in prok

18
Q

T/F: NAD is produced during glycolysis, TCA (Kreb’s), and beta-oxidation

A

FALSE: NADH is produced during these processes, not NAD

19
Q

List two characteristics of NADP.

A
  • 60% cell’s needs produced in pentose phosphate pathway (“P”)
  • Used in anabolic rxns as e- source
20
Q

List two flavoprotein e- carriers

A

FAD:
- can accept 2e-/2H+
- ETC

FMN:
- riboflavin phosphate like FAD w/out adenine nucleotide
- can accept/donate 1 or 2e-
- can mediate betw. 1e-/2e- acceptors/donors

21
Q

T/F: Coenzyme Q (CoQ)/ubiquinone can accept 2e- and 2H+ on its own, but only 1e- when bound to respiratory complexes.

A

TRUE

22
Q

What characteristic is shared between FMN and CoQ?

A

They can mediate between 1e- and 2e- acceptors/donors.

23
Q

__________ is the non-protein group of cytochromes. They use __________ to transfer electrons.

A

HEME is the non-protein group of cytochromes. They use IRON to transfer electrons.

24
Q

“_________” are changes in metabolite levels.

A

Flux

25
Q

__________ are changes in metabolite levels.

A

FLUX are changes in metabolite levels.

26
Q

What are the 6 classes of enzymes?

A

THILLO:

Transferase
Hydrolase
Isomerase
Lyase
Ligase
Oxidoreductase

27
Q

T/F: At very low temperatures, an enzyme’s activity is initially low because the protein is denatured.

A

FALSE: At high levels the enzyme is denatured and activity immediately drops.

28
Q

“Cofactor”?

A

Non-prot. component of enzyme, prosthetic group: act as carriers/shuttles for substrates betw. enzyme complexes.

29
Q

Diff. betw. competitive and noncompetitive inhibitor?

A

Comp.:
- Direct competed w/ binding of substrate to active site

Noncomp:
- Binds to enzyme in place other than active site (which changes shape of site)

30
Q

T/F: The sulfa drug is a noncompetitive enz. inhibitor for rxns involving PABA to folate.

A

FALSE: It is competitive and structurally similar to PABA>

31
Q

T/F: The sulfa drug is a noncompetitive enz. inhibitor for rxns involving PABA to folate.

A

FALSE: It is competitive and structurally similar to PABA.

32
Q

Differentiate betw. rxn rate graph of comp. and noncomp. enz inhibitor.

A

Comp:
- rxn rate is more linear than if there were no inhibitors at all, but Vmax eventually reached cuz true substrate will win comp

Noncomp:
- Plateau is reached/Vmax is lower cuz more sites will be skewed due to noncomp inhibitors

33
Q

List the three major mechanisms of metabolic regulation

A
  1. Metabolic channelling/compartmentation (ex. shutting down pathways to conserveE)
  2. Control amnt of enz synth via transcription/translation
  3. Stimulation or inhibition of crit. enz activity via posttranslational regulation (reversible/irreversible)
34
Q

List the three major mechanisms of metabolic regulation

A
  1. Metabolic channelling/compartmentation (ex. shutting down pathways to conserveE)
  2. Control amnt of enz synth via transcription/translation
  3. Stimulation or inhibition of crit. enz activity via posttranslational regulation (reversible/irreversible)
35
Q

“Allosteric enzymes”?

A
  • Two sites: catalytic + regulatory
  • Allosteric effector binds to reg site + changes shape of catalytic site
36
Q

Define feedback/end prod. inhibition

A
  • End prod of process used to inhibit enz activity (feedback loop)
  • Pacemaker enz catalyzes slowest/rate-lim rxn
  • Ex. threonine and lysine used as feedback inhibitors in synth of essential AAs

CHEE 229 Cell Bio (8 decks)

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