Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Unit 2 Review for Test > Flashcards

Unit 2 Review for Test Flashcards

1
Q

In the malate aspartate shuttle, glutamate is converted to ______ in the mitochondria while aspartate is converted to _____ in the cytosol.

A

Alpha-ketoglutarate

Oxaloacetate

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

What compound is used to move the reducing equivalents for NADH from cytosol to mitochondria?

A

Malate

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

Pyruvate dehydrogenase kinase catalyzes a reaction that results in which of the following results?

A

Phosphorylation and inactivation of E1 subunit of Pyruvate Dehydrogenase Complex

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

All of the following stimulate the release of insulin except:
AA
epinephrine
Glucose

A

Epinephrine (counter regulatory hormone)

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

The last cytochrome in the ETC , cytochrome oxidase, passes electrons to O2. It can do this beacuse?

A

It has a lower Km for oxygen then hemoglobin

- allows it to “pull” the Oxygen from hemoglobin/myoglobin

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

How many electrons can the last cytochrome in ETC collect for the reduction of oxygen?

A

4 electrons

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

The reduction of NAD+ is often coupled to the oxidation of an alcohol. In this reaction NAD+ obtains what from the oxidized compound?

A

Two electrons as hydride ion

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

A pyruvate carboxylase deficiency will lead to lactic academia due to what in the mitochondira?

A

Accumulation of Acetyl-CoA will inhibit the Pyruvate Dehydrogenase so Pyruvate accumulates and turns into lactic acid
-due to lack of oxaloacetate avaliable for TCA and acetyl-CoA

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

What is the description of the Km and the Vmax of phosphofructokinase-1 in the presence of AMP?

A

Km is decreased

No change in Vmax

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

Hydrogen peroxide is generated through what reaction?

A

Oxidation of a very-long chain acyl CoA

-inside perioxisomes

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

After oxidation of odd-chain fatty acids, carbon atoms of the fatty acids would be found in what?

A

Liver and kidneys

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

The driving force for the citrate synthase reaction, with its large negative Delta G, is what?

A

Hydrolysis of a high-energy thioester bond

(H20 used to cleave the thioester bond in Aceytl-CoA

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

The TCA cycle is deemed “cyclic” because of the utilization and regeneration of what?

A

Oxaloacetate

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

What is used as a substrate by Alpha-ketoglutarate dehydrogenase

A

CoAsh

makes Succinyl Co-A

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

What two compounds are used to transport reducing equivalents across the inner mitochondrial membrane?

A

Malate and Glycerol-3-P

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

A freshly prepared mitochondrial suspension is treated with antimycin A. Oxygen and malate are then added to the mixture. After 5 minutes, which components of the electron transfer chain are reduced?

A

Antimycin A blocks electron flow from Complex III to cytochrome C

Complex 1, CoQ, and complex III are reduced and the complexes after them are oxidized

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

CO2 production by the TCA cycle would be increased to the greatest extent by a genetic abnormality that resulted in what?

A

A 50% increase in the concentration of ADP in matrix

ADP is an activator of isocitrate dehydrogenase, which would speed up this reaction and increase flux

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

Cytochrome c transfers electrons between which of the following ?

A

Complex III (b-c1) to Complex IV (cytochrome c oxidase)

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

The formation of double bonds is most commonly coupled to the reduction of _____ because it can accept two electron donors. ____ is usually coupled with the oxidation of alcohols as it can accept one electron donor.

A

FAD

NAD+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Mechanical work is best described as the conversion of a high energy bond, such as that in an ATP bond, to instigate a ….?

A

conformational change in a protein

ex: energy required to change the conformation of hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The addition of Dinitrophenol (DNT) to the ETC will lead to an increase in O2 consumption, this is an example of ?

A

Uncoupler

-dissipating the proton gradient across the inner mitochondrial membrane, can not make ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Uncoupling of oxidative phosphorylation results in increased ______ consumption and heat production as electron flow and proton pumping attempt to maintain the electrochemical gradient.

A

Oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

This uncoupling protein is found in brown fat and specialized for nonshivering thermogenesis?

A

Thermogenin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The lower Km for oxygen allows _______ ______ to “pull” oxygen from myoglobin and hemoglobin, additionally it is bound to copper ions that allows for the collection of ____ electrons required for the reduction of oxygen.

A

cytochrome oxidase

4 (electrons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

In the case of an exothermic reaction, what would Delta G0 be ?

A

Negative (spontaneous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Delta S is the change in _____ or an increase in disorder, this value is often negligible.

A

Entropy (increase in disorder)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Delta H is the change in ____, or heat content.

A

Enthalpy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  1. What is Delta G?
A

Change in gibbs free energy (can be influenced by concentration of substrates and products, temp, pH, and pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is Delta G0?

A

Energy change starting at concentration of 1M of each product and substrate (different than Delta G0’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is Delta G0’ ?

A

The value for Delta G0 (1M of substrate and product) under standard conditions (25C and pH=7.0)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does this mean in words:

Delta G = Delta H - T(Delta S)

A

Change in Gibbs free energy =

Change in enthalpy minus the absolute temperature multiplied by the change in entropy (increase in disorder)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

The release of insulin from the pancreatic B-cells is mediated by what process related to calcium?

A

Increase in intracellular calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Insulin stimulates fatty acid synthesis in the liver. These fatty acids are transported to the adipose tissue as ?

A

VLDL particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Insulin stimulates all of the following pathways except:

  1. AA catabolism
  2. Fatty acid synthesis
  3. Glycogen synthesis
  4. Glycolysis
A
  1. AA catabolism
  • Cortisol is responsible for mobilization of AA from muscle
  • Insulin is an anabolic hormone not catabolic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which GLUT transporter is an insulin insensitive GLUT transporter found primarily on the liver?

  1. GLUT 1
  2. GLUT 2
  3. GLUT 3
  4. GLUT 4
A

GLUT 2
-also in kidney, pancreatic B-cell
intestinal mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Where are GLUT 1 transporters found?

A

-Blood-brain barrier
-Blood-retinal barrier
-Blood (barriers)
Human Erythrocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Where are GLUT 3 transporters found?

A

Brain (neurons)- high affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Where are GLUT 4 transporters found?

A

Adipose
Skeletal
Heart muscle
(insulin sensitive- # will increase in presence of insulin)- high affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Where are GLUT 5 transporters found? What makes it different from all the other GLUT transporters?

A

Intestinal epithelium
Spermatozoa

-ACTUALLY a fructose transporter

40
Q

What are the main strongly Negative Delta G reactions in TCA?

A
  1. Acetyl CoA to citrate
  2. Isocitrate to A-KetoGlut
  3. A-KetoGLut to Succinyl CoA
41
Q

Malate generated by the TCA cycle can be used as a substrate for what process?

A

Gluconeogenesis

42
Q

Succinyl CoA generated by the TCA cycle can be used as substrate for what process?

A

Heme Synthesis

43
Q

Citrate generated by the TCA cycle can be used as a substrate for what process?

A

Fatty Acid Synthesis

44
Q

What two things can Alpha Keto-Glutarate generated by the TCA cycle be used for as a substrate?

A

AA synthesis

Neurotransmitters (Glutamate)- (GABA)

45
Q

What 2 BCCA will contribute to the anapleurotic production of Propionyl CoA?

A

Valine

Isoleucine

46
Q

What two things will produce Oxaloacetate in Anapleurotic reactions?

A

Asparate

Pyruvate (by Pyruvate Carboxylase that is activated by Acetyl-CoA)

47
Q

What are the two most regulated enzymes in TCA ?

A

Isocitrate Dehydrogenase

Alpha-Keto Glutarate Dehydrogenase

48
Q

At physiological pH (7.4) carboxylic acids (COOH containing acids) are :

A

approx 100% dissociated

-pKa of most carboxylic acids is between 2 and 5 so at 7.4pH these acids are nearly fully dissociated

49
Q

Hemoglobin bound to heme is termed a ______.

A

Holoprotein

50
Q

The heme porphyrin ring is required for oxygen binding and it is termed a ?

A

Prosthetic group

51
Q

What does a lyase do ?

A

catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation
-often forms new double bond or ring structures

52
Q

What type of inhibitor best is described by increasing the Km but does not change the Vmax?

A

A competitive inhibitor

53
Q

What inhibitor will decrease the Vmax but have no effect on the Km?

A

Non-competitive inhibitor

does not interfere with substrate binding

54
Q

Does covalent modification (such as phosphorylation) impact Km or Vmax (kinetics)?

A

No

-changes enzyme activity by making it active or inactive

55
Q

What inhibitor will increase Km AND decrease Vmax?

A

Allosteric inhibitor

competitive inhibitor will only increase Km and not effect Vmax

56
Q

The activity of an enzyme is increased when the enzyme is phosphorylated on an exposed tyrosine residue. Phosphorylation of the AA is classified by what ?

A

Covalent modification

57
Q

What is Protein ubiquitination?

A

Ubiquitin covalently bonds to proteins to target them for degradation by Proteasome (proteolysis- breaking peptide bonds)

58
Q

What is an example of a serine threonine kinase receptor?

A

TGF-beta receptor

-Smad proteins are phosphorylated and activated downstream

59
Q

In pyrimidine synthesis, uracil can feedback and inhibit what enzyme ?

A

Carbamoyl phosphate synthase II

60
Q

A nucleoside contains a ?

A

nucleobase and a sugar

61
Q

A nucleotide contains a ?

A

Nucleobase, sugar, phosphate (all 3)

62
Q

What are the two first required substrates for the synthesis of purines?

A

PRPP (5-phosphoribosylpyrophosphate)

Glutamine

63
Q

In the salvage of purines, Hypoxantine-guanine phosphoribosyl transferase is responsible for converting?

A

Guanine to Guanosine Monophosphate (GMP)

Hypoxanthine to Inosine Monophosphate (IMP)

PRPP is required for the Pi

64
Q

Hypoxanthine is converted to xanthine by what ?

A

xanthine oxidase

65
Q

What is Lesch Nyhan disease caused by ?

A

X-linked mutation inherited

  • deficiency of enzyme HGPRT (rare)
  • impaired kidney function, acute gouty arthritis, self-harm, neurological impairment
66
Q

How is Lesch Nyhan syndrome treated?

A

Drug allopurinol (purine analog) used to control excessive amounts of uric acid (no effect on neurologic or behavior problems)

67
Q

What does Xanthine oxidase do ?

A

catalyze:
oxidation of hypoxanthine to xanthine
then
oxidation of xanthine to uric acid (toxic)

68
Q

Histone acetylation has what impact on the super structure of DNA?

A

Decreases the association of DNA and histones (decreases positive charge on lysine within histones. DNA is negatively charged)

69
Q

DNA joining complexes utilize which class of histones?

A

H1

H2A, H2B, H3 and H4 are all used as nucleosome cores for histones

70
Q

Which polymerase is responsible for removing RNA primers during DNA replication?

A

RNaseH (eukaryotes)

or Polymerase 1 (prokaryotes)

71
Q

Histones have an abundance of what 2 AA?

A

Lysine (positive)

Arginine (positive)

72
Q
  1. What enzyme will remove supercoil twists into circular DNA?
  2. What will seperate the DNA strand?
A

Topoisomerases

Helicase

73
Q

Which DNA polymerase is the primary and which is the one that reads the fragments?

A

DNA poly III = primary

DNA poly 1 = reads okazaki fragments

74
Q

DNA Polymerase will only read DNA in what direction?

synthesize nucleotides in what direction?

A

Reads: 3’ to 5’

Synthesizes: 5’ to 3’ (because Polymerase can only act on 3’-OH to add free nucleotides)

75
Q

DNA damage resulting in large bulky distortions of the DNA helix are repaired by what mechanism?

A

Nucleotide excision repair (very important function)

76
Q

DNA damage of small areas are repaired by what?

A

Base excision repair

77
Q

When is Homologous repair used typically in DNA repair?

A

Nucleotide sequences are exchanged between two similar or identical molecules of DNA
-harmful breaks on BOTH strands of DNA (double-strand breaks)

78
Q

What is added to the 3’ end of many eukaryotic tRNA’s after transcription and is required for the ability of the tRNA to carry AA?

A

Trinucleotide CCA

79
Q

What is the eukaryotic equivalent of the prokaryotic Prinbow box?

A

Goldstein-Hogness (TATA) box

80
Q

What are the three different blotting techniques and what is each one used to evaluate?

A

Northern blot-RNA
Southern blot-DNA
Western blot -Protein

81
Q

In Electrophoresis, DNA segregate based on molecular weight and charge, what does that mean for the small fragments?

A

Small fragments travel furthest toward the far end positive electrode
(DNA is negatively charged)

82
Q

Synthesis of tyrosine requires which what vitamins or cofactors?

A

(BH4) Tetrahydrobiopterin

-required for ring hydroxylation reactions

83
Q

What does Phenylalanine hydroxylase do ?

A

Converts Phenylalanine to Tyrosine

  • addition of OH group(hydroxyl)
  • requires BH4 cofactor
84
Q

What happens if a deficiency of Phenylalanine hydroxylase ?

A

Inherited disease variable severity

-most severe=phenylketonuris(PKU)- sever mental retardation, microencephaly

85
Q

Classical PKU is an ______ recessive disorder, with defiiency of what enzyme (needs rr) that causes ?

A

autosomal

Phenylalanine hydroxylase

Accumulation of Phenylalanine in blood and brain (can’t be converted to Tyrosine- precursor for neurotransmitters)

86
Q

PKU can present due to what two causes ?

A 
BH4 (tetrahydrobiopterin) deficiency 
or 
Phenylalanine hydroxylase (classic PKU-more severe)
87
Q

Metabolism of glycine requires what vitamin or cofactor?

A

Tetrahydrofolate (THF)

88
Q

All transamination reactions require what vitamin or cofactor?

A

Pyridoxal Phosphate (PLP)

89
Q

Ketogenic AA are metabolized to which of the following compounds:

  1. Oxaloacetate
  2. Acetyl-CoA
  3. Pyruvate
  4. Fumarate
A

Acetyl-CoA

-if AA is fully metabolized to AcetylCoA it does not provide excess carbons to generate glucose through gluconeogenesis

90
Q

What are Glucogenic AA metabolized to ?

A

Glucose

Ketogenic will make Acetyl-coA

91
Q

Who has higher Km and Vmax, Glucokinase(liver) or Hexokinase?
What is Glucokinase associated with?

A

Glucokinase has Km about 100 times higher and a higher Vmax than Hexokinase
- Glucokinase with GLUT2 transporters and regulation of Insulin release - can handle large amounts of Glucose in blood without over or under-reacting

92
Q

Where does NADH regulate Glycolysis and how?

A

NADH will allosterically inhibit Pyruvate Dehydrogenase complex in the Mitochondria
(reduces conversion of Pyruvate to AcetylCoA)

93
Q

Where does Fructose-2,6 BisP regluate Glycolysis ?

A

It activates and increased the activity of Phosphofructokinase 1 enzyme
-will increase conversion of Fructose 6-P to Fructose 1,6 BisP

94
Q

Where does Fructose 1,6 BisP regulate Glycolysis ?

A

ONLY IN LIVER - increased activity of Pyruvate Kinase

- increased conversion of PEP to Pyruvate

95
Q

How does AMP influence Glycogen and Glycolysis ?

A

Muscles contract- ATP to ADP
Adenylate Kinase -ADP to AMP

AMP will directly stimulate glycogenolysis to provide fuel - allosterically activates Glycogen phosphorylase b into phosphorylase a (active)
AMP stimulates glycolysis by activating phosphofructokinase-1

Biochemistry (20 decks)

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