Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Week 10 - Unit 2 > Flashcards

Week 10 - Unit 2 Flashcards

1
Q

PPP stands for ?

A

Pentose MonoPhosphate Pathway- alternative oxidative pathway for glucose-6P

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

What are the two primary roles of PPP?

A
  1. Generation of 5-C sugars for nucleotide synthesis
  2. Generation of NADPH
    (essential in red blood cell which does not have mitochondria to fully oxidize glucose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The generation of ______ within the red blood cell is critical for the maintenance of glutathione in the reduced state.

A

NADPH

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

_______ is required to maintain hemoglobin in the reduced form to bind oxygen.

A

Glutathoine

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

Deficiencies in the ____ greatly impact red blood cell stability.

A

PPP

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

Fructose can come from what 3 sources?

A
  1. Dietary fructose (honey)
  2. Dietary Sucrose (Glucose + fructose)
  3. Converted from Glucose to Fructose in Polyol pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Fructose, like glucose, comes into the cell and is immediately phosphorylated by ?

A

Fructokinase

  • Makes Fructose 1-P
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fructose ——-> Fructose -1P——–>(cleaved by what enzyme into two products?)

A

Aldolase B

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

Fructose—–>Fructose-1-P——>cleaved by Aldolase B ———–> (what are the two products?)

A
  1. Dihydroxyacetone - P

2. Glyceraldehyde

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

Aldolase B is active in what organ? how is it different from Aldolase A?

A

Aldolase B is in liver- used in both fructose and glucose pathway
Aldolase A- in muscle- only in glucose pathway

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

What does Aldolase B cleave in the Fructose pathway?

in the glucose pathway?

A

Fructose-1P

Fructose 1,6 Bisphosphate (glycolysis)

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

After Fructose 1-P is cleaved into Dihydroxyacetone-P and Glyceraldehyde, what must occur next for Glyceraldehyde before it can be used to make Pyruvate?

A

Glyceraldehyde is already 3-P version in glycolysis , but not in fructose pathway, so it must be phosphorylated by ATP into Glyceraldehyde 3-P

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

What is the enzyme that phosphorylates Glyceraldehyde in the fructose pathway to make its 3-P version?

A

Triose Kinase (takes P from ATP to make it ADP)

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

What is the rate limiting step for Fructose pathway ?

A

the Aldolase B enzyme (cleavage of Fructose 1-P)

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

Aldolase B has a much higher affinity for _______ in the Glycolysis pathway from glucose than _______ in fructose pathway.

A

Fructose 1,6 Bisphosphate

Fructose 1-P (will be much slower reaction)

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

After ingesting high amounts of fructose , normal individuals will accumulate ______ in the liver while is slowly cleaved by Aldolase B.

A

Fructose 1-P

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

Hereditary Fructose Intolerance is what type of genetic disorder?

A

Autosomal Recessive disorder

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

What are individuals missing in Hereditary Fructose Intolerance disorder?

A

Aldolase B

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

What happens to people with Hereditary Fructose Intolerance when they ingest fructose?

A

Accumulation of Fructose 1-P in liver (no aldolase B to cleave it)

  • impacts ability to regulate blood glucose
  • can lead to HYPOGLYCEMIA
  • Can cause major clinical problems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Essential Fructosuria?

A

Individuals lack Fructokinase enzyme - can not convert fructose to fructose-1-P inside cells
-few clinical consequences

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

What happens when someone with Fructosuria ingests fructose?

A

It is not phosphorylated and metabolized but is rather just excreted in urine (sugar is not present in urine normally), few clinical problems

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

What enzyme will act on Galactose once it enters the cell?

A

Galactokinase (adds a Phosphate group to make Galactose 1-P)

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

Galactose 1-P interacts with UDP Glucose and is charged to UDP Galactose by what enzyme in a circular cycle?

A

Galactose 1-phosphate uridylyltransferase

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

What does Galactose 1-phosphate Uridylyltransferase do ?

A

It will charge Galactose 1-P to UDP Galactose while converting UDP glucose to Glucose 1-Phosphate for use in Glucose pathway and can be metabolized or maintain blood glucose levels

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

What does Epimerase do in the Galactose pathway?

A

It will convert UDP Galactose to UDP Glucose by modifying the carbon structure
-circular cycle to replenish and provide UDP Glucose to be transformed into Glucose 1-P

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

What is Nonclassical Galactosemia?

A

Galactokinase is not present

  • can not be phosphorylated so it cant be trapped in cell
  • few clinical problems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is Classical Galactosemia?

A

Missing - Galactose 1-P Uridylyltransferase enzyme

- major clinical problem- Galactose 1-P will accumulate in cell as it is trapped but can not be broken down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What happens when Fructose 1-P builds up in liver in Hereditary Fructose Intolerance?

A

Decrease in free phosphate
Decrease in ATP availability (increase in AMP)
-will greatly effect gluconeogenesis and Glycogenolysis so blood glucose can be poorly regulated (hypoglycemia)

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

Lack of ATP levels caused by build up of Fructose 1-P in Hereditary Fructose Intolerance will inhibit what pathway?

A

Gluconeogenesis (energy requiring- synthesized from precursors)

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

Lack of free phosphate caused by build up of Fructose 1-P in Hereditary Fructose Intolerance will inhibit what pathway ?

A

Glycogenolysis (need phosphate to activate)

-negatively impacts blood glucose regulation (hypoglycemia)

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

What is the genotype of the parents of a child with Hereditary Fructose Intolerance when the parents do not present with it?

A

the child must have rr (autosomal recessive disease)

Parents must be Rr (heterozygous)

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

In PPP Glucose-6P is put through an oxidative pathway to make?

A

Ribulose 5-phosphate

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

What can Ribulose 5-phosphate do ?

A
  1. undergo non-oxidative pathway to convert back to intermediates for use in glycolysis
  2. be converted to Ribose -5-P for use in Nucleotide synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the critical byproduct of converting Glucose-6P to Ribulose 5-P in the oxidative pathway?

A

NADP+ is converted to NADPH (essential to other reactions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is NADPH essential to?

A

Fatty acid synthesis
Glutathione reduction
Other reactions such as detoxification

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

In the Oxidative pathway portion of PPP, Glucose 6-P is ________ to Pentose Phosphates- 5 carbon sugar (Ribulose 5-P)

A

Decarboxylated - primary role of 5-C sugars is for Nucleotides

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

In the non-oxidative portion of PPP, the Pentose Phosphates can be converted back into what 2 examples of intermediates for use in glycolysis depending on needs of cell (pathway reverses)?

A

Fructose 6-P

Glyceraldehyde 3-P

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

Ratio of NADPH to NADP+ in cell is ______ than NADH to NAD+ in cell

A

Greater - more NADPH will be floating around than NADH because the NADH is oxidized rapidly in the ETC (more availability of NADPH in cell)

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

All tissues require _____ for reductive detoxification.

A

NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

NADPH is generated by ?

A

PPP and Malic enzyme pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

PPP is critical in Red blood cells because it is only pathway that can create ______ that is necessary for ______ glutathione.

A

NADPH

reducing (necessary to bind Oxygen in reduced state)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

In oxidative phase of PPP, Glucose 6-P is catabolized to Ribulose 5-P, and the oxidation of 1 mole of glucose generates ____ NADPH

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What enzyme will be the first in PPP pathway acting on Glucose 6-P? (making NADPH)

A

Glucose 6-Phosphate Dehydrogenase (critical enzyme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the intermediate created when Glucose 6-P is acted on by the Glucose 6-P dehydrogenase ?

A

6-Phosphogluconolactone

45
Q

In the oxidative phase of PPP, there is an oxidation of the _____ and reduction of _______ in the first step.

A

Aldehyde (H-C=O) is oxidized into C=O

46
Q

The intermediate 6-phosphogluconolactone undergoes rapid _______ in the Oxidative portion of PPP.

A

hydrolysis

47
Q

What is 6-Phosphogluconolactae converted to after rapid hydrolysis in PPP oxidative pathway?

A

6-Phosphogluconate

48
Q

What happens to 6-Phosphogluconate in PPP oxidative pathway (intermediate)?

A

Accepted by 6-Phosphogluconate dehydrogenase

  • undergoes a decarboxylation reaction
  • NADP+ is reduced to NADPH
  • CO2 is released
49
Q

What is the end product after 6-phosphogluconate is acted on by the dehydrogenase and is decarboxylated and reduced NADP+ to make NADPH (the second one in series)?

A

Ribulose-5 Phosphate (irreversible pathway product)

50
Q

What part of PPP pathway is reversible and irreversible?

A

oxidative part is irreversible

non-oxidative is reversible

51
Q

What enzymes does the non-oxidative phase of PPP involve?

A

4 types

Epimerase
Isomerase
Transketolase
Transaldolase

All reversible and direction depends on cell needs

52
Q

What enzyme converts Ribulose 5-P to Ribose 5-P?

A

Isomerase

53
Q

What enzyme converts Ribulose 5-P to Xylulose 5-P?

A

Epimerase
(changes the H structure on Carbon 3)
-reversible

54
Q

What does the Transketolase enzyme do in the non-oxidative pathway of PPP?

A

Transfer of 2-C group from 5 carbon sugar to a different 5 Carbon sugar to make:
Glyceraldehyde 3-P

55
Q

What is a coenyzme required for Transketolase reactions?

A

Thiamine Pyrophosphate (TPP)

56
Q

What is an example of a Transketolase reaction?

A

Ribose 5-P to Glyceraldehyde 3-P

57
Q

Describe the mechanism of the Transketolase enzyme in non-oxidative TPP pathway?

A

Cleaves the Carbon Carbon bond next to aldeyhyde and bonds to TPP where it can be transfered (2 Carbon moiety)

58
Q

Where is the 2 Carbon moiety that is bound to TPP due to Transketolase transferred to ?

A

onto Ribose 5-P to then Generate 7 -Carbon sugar and release 3-Carbon sugar Glyceraldehyde 3-P

59
Q

Transaldolase reactions involve the transfer of 3 Carbon chain from one sugar to another between ?

A

2 hydroxyl carbons adjacent to keto group

60
Q

What is an example of a Transaldolase reaction?

A

Cleaving 3-C moiety from a 7 Carbon molecule and adding it to Glyceraldehyde 3-P to make Fructose 6-P for use in glycolysis to make pyruvate

61
Q

For every 1 glucose 6-P molecule that enters the PPP oxidative pathway, how many NADPH, how man CO2 are made

A

2 NADPH

1 CO2

62
Q

What are the two enzymes that can act on Ribulose 5-Phosphate that will determine its path in PPP

A

Epimerase

Isomerase

63
Q

What will Epimerase do to Ribulose 5-P?

A

convert it to:
Xylulose 5-P that can make Glyceraldehyde 3-P that can either be used directly in Glycolysis or shunted into making Fructose 6-P

64
Q

What will Isomerase do to Ribulose 5-P

A

convert it to Ribose 5-P

65
Q

What are the paths that Ribose 5-P can take?

A
  1. Nucleotide synthesis

2. Acted on my Transketolase then Transaldolase

66
Q

What does Ribose 5-phosphate get converted to when Transketolase first acts on it?

A

Sedoheptulose 7-P

67
Q

What does Xylulose 5-P get converted to when Transketolase first acts on it ?

A

GLyceraldehyde 3-P

68
Q

Ribose 5-P or ______ can interact with Xylulose 5-P using Transketolase enzyme to make Glyceraldehyde 3-P

A

Erythrose 4-Phosphate

69
Q

What is the second step of the non-oxidative pathway involved for its enzyme? product?

A

Glyceraldehyde 3-P and Sedoheptulose 7-P interact using Transaldolase enzyme to add the 3 Carbon to Frutctose to make Fructose 6-P for using in GLycolysis

70
Q

What is the secondary interaction that Erythrose 4-Phosphate can interact with if it does not interact with Transalodolase?

A

Transketolase acts on it and Xylulose 5-P

  • Erythrose 4-P is converted to Fructose 6-P
  • Xylulose is converted to Glyceraldehyde 3-P to use directly in glycolysis
71
Q

Where is PPP regulated?

A

Oxidative phase

72
Q

What is the regulatory enzyme (one that is regulated/inhibited) in PPP?

A

Glucose 6-dehydrogenase

-inhibited by high levels of NADPH (its own byproduct)

73
Q

True or false:
NADPH is typically high in the cell to inhibit enzyme Glucose 6-P dehydrogenase from converting Glucose 6-P to 6-phosphogluconolactone

A

True

74
Q

If the oxidative pathway in PPP is inhibited , can the non-oxidative pathway work?

A

Yes- allows cell to divert substrate in different pathways depending on needs
-can convert intermediates still

75
Q

When a cell needs Ribose 5-P only what is likely to occur?

A

Only non-oxidative reactions

76
Q

If the cells needs NADPH only, what will the pathways do?

A

Oxidative reactions make the NADPH

-Non-oxidative reactions will convert ribulose 5P to glucose 6-P to produce more NADPH

77
Q

If the cells needs NADPH and Ribose 5-P , what will the pathways do

A

Oxidative pathways produce NADPH and ribulose 5-P

-the isomerase converts ribulose 5-P to ribose 5-P

78
Q

If the cell needs Ribose 5-P only, what does the High levels of NADPH do ?

A

inhibts glucose 6-P dehydrogenase from making more NADPH

- Transketolase and Transaldolase are free to convert fructose 6-P and glyceraldehyde 3-P to ribose 5-P

79
Q

What if the cell needs NADPH and Pyruvate, what do the PPP pathways do?

A

Both oxidative and non-oxidative reactions are used.

  • Oxidative will make NADPH and Ribulose 5-P
  • non-oxidative will convert ribulose 5-P to fructose 6-P and glyceraldehyde 3-P
  • Glycolysis will convert the above intermediates to pyruvate
80
Q

What detoxification pathways require NADPH?

A
  1. Reduction of oxidized glutathione

2. Cytochrome P450 monooxygenases

81
Q

What reductive synthesis pathways need NADPH?

A 
Fatty acid synthesis
Fatty acid chain elongation 
Cholesterol synthesis 
Neurotransmitter synthesis 
Deoxynucleotide synthesis 
Superoxide synthesis
82
Q

What type of transporter does RBC use to uptake GLucose?

A

Glut 1 transporter

83
Q

What is the Cori Cycle?

active between muscle and liver and the RBC and liver

A

Glucose from the liver is taken up by the RBC and then the RBC creates 2 Lactate from 1 glucose which is taken up by liver and converted back to glucose in Gluconeogenesis

84
Q

What are the two options that Glucose can go once inside the RBC?

A
  1. Phosphorylated to Glucose 6-P

2. Can either be converted to lactate in glycolysis or oxidized by the Pentose phosphate pathway to make NADPH

85
Q

NADPH is required for ______ of glutathione in RBC.

A

reduction

86
Q

Glutathione is a _______ compound that facilitates detoxification of free oxygen species that can damage cells/proteins. (Glutathione protects RBC)

A

tripeptide

87
Q

What are the three AA that Glutathione is comprised of from top to bottom ?

A

Glycine
Cysteine (Sulfur R chain)
Glutamate

88
Q

What is the free radical that is used as an example that Glutathione will detoxify?

A

Hydrogen peroxide

H2O2

89
Q

____ molecules of Glutathione react with the enzyme ______ ______ to convert Hydrogen Peroxide to water (reduce it).

A

Two

Glutathione peroxidase

90
Q

Who is reduced and who is oxidized in the reaction of Glutathione with Hydrogen peroxide in RBC?

A

H2O2 is reduced to water

Glutathione is oxidized to Glutathione disulfide (2 molecules linked by sulfide bond)

91
Q

How does the product of Glutathione disulfide created when you detoxify free radicals (hydrogen peroxide) get recycled back to be used again?

A
  1. NADPH will donate its H to reduce GSSG back to two molecules of Glutathione
92
Q

What enzyme does the NADPH use to reduce GSSG back to 2 molecules of Glutathione in RBC?

A

Glutathione reductase

93
Q

What happens in RBC when there is a deficiency of Glucose 6-P dehydrogenase enzyme?

A

PPP pathway can not function to make NADPH (needed for glutathione recycling back from GSSG)

94
Q

What is an effect in the RBC if NADPH is not being produced in PPP?

A

Free radicals and Hydrogen Peroxides can not be reduced and can damage cell

95
Q

What happens to the RBC if free radicals and peroxides are allowed to roam free due to a deficency of the Glucose 6-P dehydrogenase that then causes NADPH to not be produced?

A

Hemolysis of RBC

Inability of Hemegloblin to bind oxygen (due to change to F3 state of iron)

96
Q

What state does the Hb iron molecule need to be in to bind oxygen ?

A

Fe+2

97
Q

What state does the iron in Hemeglobin change to if free radicals are not controlled

A

it is oxidized to a met-hemoglobin molecule and changed to a Fe+3 that can not bind oxygen

98
Q

What is a Heinz body?

A

denatured hemoglobin in RBC (called met-Hb)that is caused by free radicals and peroxides

99
Q

______ with only one copy of the defective allele for Glucose 6-P dehydrogenase can present with problems in RBC related to food and certain drugs with poor NADPH production.

A

Females

100
Q

What type of disorder is Glucose-6-P dehydrogenase deficiency ?

A

X linked

Females can present with clinical symptoms if exposed to radical inducing compounds

101
Q

Jaundice comes from the degregation of _______ from the RBC with excessive accumluation

A

Heme

102
Q

In step one of RBC degradation, the Heme and Globin are separated and what happens to each?

A
  1. Globin is the AA and is degraded back to AA pathway

2. Heme is converted to Bilirubin

103
Q

The conversion of Heme to Bilirubin occurs usually in the blood within a _______

A

macrophage

104
Q

Bilirubin is______ soluble, so it must be bound to _______ to circulate in the blood

A

Not

Albumin

105
Q

If the Bilirubin (insoluble version) or the soluble version Bilirubin Diglucuronide accumulates in the blood, it can cause ________

A

jaundice

106
Q

Under normal conditions , bilirubin-albumin will go to liver where it is combined with ________ to generate a more soluble compound that can be excreted in feces and urine.

A

UDP-Glucuronate

107
Q

What is Bilirubin called when it has been conjugated with UDP-glucuronate to be more soluble?

A

Bilirubin diglucuronide

108
Q

What type of regulator is NADPH for Glucose 6-P Dehydrogenase ?

A

Allosteric effector (negative- too much NADPH will inhibit the enzyme)

Biochemistry (20 decks)

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