Brainscape's Knowledge GenomeTM

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


See full index

Biochem Final > Pentose Phosphate Pathway > Flashcards

Pentose Phosphate Pathway Flashcards

1
Q

The pentose phosphate pathway provides a major source of what compound?

A

NADPH

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

This pathway will also provide what sugar for the synthesis of ribonucleotides?

A

Ribose-5-phosphate

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

The oxidative portions of the pentose pathway have how many reactions that lead to the formation of ribulose-5-phosphate?

A

Three

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

The oxidative portion of the pentose pathway will produce what products (3) for each molecule of glucose-6-phosphate oxidized?

A

Ribulose-5-phosphate
CO2
two molecules of NADPH

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

This pathway is important for what 3 processes in the body?

A
  1. NADPH - dependent synthesis of fatty acids
  2. NADPH - dependent synthesis of steroid hormones
  3. Erythrocytes which require NADPH to keep glutathione reduced.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

NADPH-dependent synthesis of fatty acids is important in what parts of the body?

A

Liver, mammary glands, and adipose

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

Synthesis of steroid hormones is important for what structures in the body?

A

Testes, ovaries, adrenal cortex, and placenta.

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

Where does the oxidative stage of the pentose pathway occur in the cell?

A

Cytosol

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

Glucose 6 phosphate dehydrogenase will catalyze an irreversible oxidation of glucose 6 phosphate into ______.

A

6-phosphogluconolacetone

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

The dehydrogenation of glucose 6-phosphate needs a specific coenzyme what is it?

A

NADP+

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

What will inhibit the dehydrogenation of glucose 6-phosphate?

A

NADPH

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

What hormone up regulates the dehydrogenation of glucose-6 phosphate to 6-phosphogluconolacetone? Is this step rate limiting?

A

Insulin - yes it is rate limiting

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

What does 6-phosphogluconaolacetone hydrolyze to?

A

6 phosphogluconate

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

6 phosphogluconate is than converted to what sugar? What other compounds are released during this run?

A

ribulose 5-phosphate, CO2 and NADPH

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

In what cell types does the non-oxidative reactions of the pentose pathways take place?

A

ALL cell types synthesizing nucleotides and nucleic acids.

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

The reversible reactions permit ribulose-5-phosphate to be converted to what 3 compounds?

A
  1. Ribose 5-phosphate
  2. fructose 6-phosphate
  3. glyceraldehyde 3-phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does NADP+ differ from NAD+?

A

The presence of a phosphate group on one of the ribose subunits.

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

The high energy electrons of NADPH will be used for what function in the cell?

A

Reducing equivalence

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

What reactive oxygen species (ROS) is formed from the partial reduction of molecular oxygen?

A

Hydrogen peroxide

20
Q

The highly reactive species of free radicals can cause what type of damage to the body?

A

Damage to DNA, proteins, lipids leading to cellular damage and death.

21
Q

What is present in most cells that can chemically detoxify hydrogen peroxide?

A

Reduced Glutathione, a tripeptide-thiol

22
Q

What is Glutathione composed of?

A

Glutamate, cysteine and glycine

23
Q

Once Glutathione is oxidized to detoxify hydrogen peroxide how is it rejuvenated?

A

NADPH with the enzyme glutathione reductase.

24
Q

What does the breakdown of hydrogen peroxide by glutathione produce as end products?

A

2 water molecules and a dimerized glutathione

25
Q

What is the main function of the mitochondrial cytochrome P450 monoxygenase system and where is it found in the cell?

A

Associated with the synthesis of steroid hormones. Found on the inner mitochondrial membrane.

26
Q

More specifically, the P450 is used to hydroxylate intermediates for what biosynthetic process? Where especially does this occur in the body?

A

For the conversion of cholesterol to steroid hormones a process that make these compounds more water soluble.
- placenta, ovaries, testes, and adrenal cortex

27
Q

In the liver what is the job of the P450 system?

A

To hyroxylate intermediates in bile acid synthesis, and the synthesis of Vit D3

28
Q

What does the endoplasmic reticulum especially in the liver contain? What is it’s function?

A

Cytochrom P450 monooxygenase - to detoxify foreign compounds such as drugs, pollutants and pesticides.

29
Q

Describe Phase 1 Metabolism

A
  • Microsomal system hydroylates these compounds (drugs, pollutants…etc) using NADPH as the source of reducing equivalents.
  • The hydroxylation may inactivate the compound and make them more soluble for excretion in the urine.
30
Q

What takes place in Phase 2 Metabolism

A
  • Adding glucuronic acid or other compounds at the hydroxyl group further inactivating and/or increasing the water solubility of the compound.
31
Q

WBC can use what two types of methods to kill bacteria?

A

Oxygen dependent or non-oxygen dependent methods.

32
Q

In the oxygen dependent system what molecule is created by the activation of NADPH oxidase located in the cellular membrane of the phagocyte?

A

Superoxide

33
Q

What do we call the rapid consumption of the molecular oxygen that accompanies the creation of superoxide?

A

Respiratory burst

34
Q

What does the body do with the superoxide?

A

Either converts it to hydrogen peroxide spontaneously or through an enzyme superoxide dismutase.

35
Q

Superoxide can also spontaneously break down to what compound?

A

Hydroxy radical (OH)

36
Q

Hydrogen peroxide can also be converted into what effective bacteria killing liquid when combined with chlorine?

A

Hypochlorous acid

37
Q

What can lead to granulomatous disease?

A

Genetic deficiency of NADPH oxidase.

38
Q

What is the pathology of granulomatous disease?

A

Some bacteria are not completely destroyed and severe chronic infection develops. Granulomas are formed that sequester bacteria.

39
Q

What is an additional function of NADPH when it is combined with arginine and O2?

A

Synthesis of Nitric Oxide

40
Q

What is the most common disease producing enzyme abnormality in humans affecting 1 out of 400 individuals?

A

Glucose 6-phosphate deficiency G6PD

41
Q

G6PD is an inherited disease characterized by what pathology?

A

hemolytic anemia - which is caused by an inability to detoxify oxidizing agents.

42
Q

What chromosome is G6PD linked to?

A

X

43
Q

Why did G6PD develop?

A

It gave survival advantage to female carriers by giving resistance to falciparum malaria.

44
Q

Diminished G6PD activity impairs the ability of the cell to do what essential metabolic process?

A

To form the NADPH that is essential for the maintenance of the reduced glutathione pools. The result is a decrease in cellular detoxification of free radicals and peroxides.

45
Q

Glutathione also has an important role in proteins. Please explain.

A

Helps maintain the reduced states of sulfhydral groups in proteins including hemoglobin. Oxidation of these groups results in the denaturization of proteins.

46
Q

What can trigger symptoms in G6PD in ppl who don’t normally show clinical symptoms?

A

Oxidant drug, fava beans or infection.

47
Q

What drugs can induce hemolytic anemia?

A

Antibiotics, antimalarials, and antipyretics. AAA

Biochem Final (3 decks)

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