Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbial Physiology > Bioenergetics in the Cytosol > Flashcards

Bioenergetics in the Cytosol Flashcards

1
Q

high free energy of hydrolysis are sometimes depicted as

A

a squiggle (~).The chemical group attached to the squiggle is readily transferred to an acceptor molecule. ATP is a good example

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

bonds that have a standard free energy of hydrolysis at pH of 7 equal to greater than -29KJ/mol

A

high energy bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

H2O + ATP  ADP Pi

A

G’= -35 KJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Glucose + Pi  Glucose-6-phosphate + H2O

A

G’ = +14 KJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ATP + Glucose  Glucose-6-phosphate + ADP

A

G’ = -21 KJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ATP has a standard free energy of hydrolysis of

A

(G’)= -35 KJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The Phosphate groups are ionized at pH 7, this produces …

A

electrostatic propulsion between phosphate groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Reactions during which phosphate is removed will be favored because the electrostatic repulsion is decreased as the result of the

A

hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ATP can phosphorylate many different compounds because

A

an electronegative group (such as hydroxyl ) can attack the electropositive phosphorus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

enzymes that catalyze phosphoryl group transfers-

A

kinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

PEP

A

phosphoenolpyruvic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

PEP is a better donor than

A

ATP. G’= -62 KJ/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The removal of the phosphate allows for

A

an enol-keto tautomerization, with the keto form being more stable than the enol form.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the reason for the high free energy of hydrolysis of Acyl Derivatives of Phosphate and Coenzyme A?

A

Acyl Derivatives of Phosphate and Coenzyme A resonate poorly.
In a normal ester, electrons shift from oxygen but phosphorus hinders resonance as does the sulfur.
Sulfur does not form double bonds easily and the positive charge in phosphorus does not allow the electrons from oxygen to shift.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Acyl derivatives of Phosphate are used to make

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Acyl derivatives of CoA are used to make ATP as well as

A

as the transfer of acyl groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Group transfer reactions are important to the biosynthesis

A

of proteins, lipids, carbohydrates and nucleic acids. The transfers occur by means of high energy donors of ATP (or other nucleotide derivative), acyl-coenzyme A and acyl-phosphates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ATP as a donor

A

ATP can donate phosphate
ATP can donate (pyrophosphate (PPi)
ATP can donate AMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A series of group transfer reactions are necessary for

A

peptide bond formation

20
Q

step A of peptide bond formation

A

The AMP from ATP is transferred to the carboxyl group of the amino acid. This is driven by the hydrolysis of pyrophosphate

21
Q

What type of bond is it that connects the amino acid to the AMP?

A

?

22
Q

Step B.

A

The AMP of the acyl-AMP is replaced by tRNA. This is reversible

23
Q

Step C.

A

The tRNA is replaced by the amino group of the amino acid docked in the ribosome. This has a large free energy change and is not reversible. The amino acid-tRNA bond is an acyl-phosphate bond

24
Q

What supplies the energy to form the peptide bond?

A

breaking of the acyl phophate bond

25
Q

The amino acid (alanine) is attached to the tRNA by the

A

3’ end of the “A” nucleotide.

26
Q

The amino acid (alanine) is attached to the 5’ end of the “A” nucleotide and

A

the 3’ end links to the tRNA.

27
Q

ATP is made in the cytosol by the

A

phosphorylation of ADP by means of high energy phosphoryl donor (these reactions are catalyzed by kinases)

28
Q

donors for substrate level phosphorylation

A

1,3 bisphosphoglycerate (1,3 BPGA) and Phosphoenolpyruvate (PEP) are found in glycolysis
Succinyl-CoA is found in the TCA cycle
Acetyl phosphate is derived from acetyl CoA used frequently in fermentation
With the exception of PEP all the high energy donor are produced by oxidation reactions.
PEP is produced by hydrolysis

29
Q

What provides the energy to add inorganic phosphate to the carbonyl group?

A

oxidation of phosphoglyceraldehyde. the electron acceptor is NAD

30
Q

Acetyl phosphate donates phosphate to ADP to produce ATP and is an important source of ATP under

A

anaerobic conditions

31
Q

acetyl phosphate is made by

A

acetate kinase

32
Q

pyruvic acid + pyruvate ferredoxin oxidoreductase (anaerobic)

A

acetyl-CoA, CO2, H2

33
Q

pyruvic acid + pyruvate dehydrogenase (aerobic)

A

acetyl-CoA, CO2, NADH

34
Q

pyruvic acid + pyruvate formate lyase (anaerobic)

A

acetyl CoA, formic acid

35
Q

Although acetyl phosphate is made from acetyl CoA, the energy was supplied by

A

the oxidative decarboxylation of pyruvate.

36
Q

Pyruvate dehydrognease, the electron acceptor is

A

NAD (NADH is produced).This happens under aerobic conditions

37
Q

The acetyl CoA that is formed under aerobic conditions does not proceed to

A

acetyl-phosphate, instead Acetyl-CoA enter the Krebs cycle

38
Q

Pyruvate dehydrogenase

A

Aerobic pathway (intermediate step between glycolysis and TCA cycle)
Pyruvate + NAD+ + CoA > Acetyl-CoA + CO2 + NADH + H+
Acetyl-CoA typically enters TCA cycle for complete oxidation

39
Q

Under anaerobic conditions, what catalyzes acetyl-coA from pyruvate?

A

pyruvate-ferredoxin oxidoreductase . H2 is produced

40
Q

Pyruvate-formate hydrogen lyase

A

Pyruvate-formate hydrogen lyase reaction
Pyruvate + CoA > acetyl-CoA + formic acid (formate)
In this reaction the electrons stay with the carboxyl group (formate

41
Q

Acetyl-Phosphate from Acetyl-CoA

A

Acetyl-CoA + Pi > Acetyl-PO4 + CoA
The reaction is (reversibly) catalyzed by phosphotransacetylase (PTA).
This reaction usually follows the acetyl-CoA formation from Pyruvate-ferredoxin oxidoreductase or pyruvate-formate hydrogen lyase

42
Q

Acetate Kinase (ACK)

A

Acetyl-Phosphate is used in a substrate level phosphorylation reaction to form ATP.
The route from Acetyl-CoA to ATP is referred to as ACK-PTA because the reations often together

43
Q

Succinyl-Coenzyme A

A

Succinyl CoA is made from the oxidative decarboxylation of alpha–keto glutarate.
The enzyme that catalyzes the reaction is alpha–keto glutarate dehydrogenase and involve a similar mechanism as pyruvate dehydrogenase.
This is because pyruvate and –keto glutarate are structurally similar (alpha–keto acids)

44
Q

Succinate Dehydrogenase

A

This is an oxidative decarboxylation. This ultimately supplies the energy for the next step which is to make ATP

45
Q

Succinate Thiokinase (ATP in the TCA cycle)

A

this is the step that makes ATP

46
Q

Pyruvate dehydrogenase

A

PEP + ADP —-> pyruvate + ATP

47
Q

Enolase (dehydration) reaction

A

2 pga —-> PEP + H20

Microbial Physiology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions