Brainscape's Knowledge GenomeTM

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


See full index

NUTR 302 > Vitamin C > Flashcards

Vitamin C Flashcards

1
Q

How many hydrogen is AA able to donate

A

2OH

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

What are the two steps to get to DHAA

A
  • Ascorbyl radical (loss H +e-)
  • DHAA (loss H +e-)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the precursor to AA

A

D-glucose

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

Bays, birds, fish and humans lack which enzyme to make AA

A

Gulonolactone oxidase

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

2 transporters of AA

A

SCVT1 - low affinity high capacity, whole body homeostats
SCVT2 - high affinity, low capacity, metabolically active and specialized tissue

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

What is the bioavailable difference of AA and DHAA

A

AA - 80-90% bioavailable up to 100mg dose
DHAA - 10% bioavailable

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

How does DHAA get transported around the body

A

facilitative transport
GLUT - 1,3,4

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

What is the total body pool size of AA

A

1500mg

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

Half life of AA

A

20 days

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

Where would you find SVCT1

A

Dietary absorption, renal reabsorption
intestine, kidney transporter, reproductive organs, skin, lung, liver, pancreases

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

Where would you find SVCT2

A

Brain, adrenal glands, leukocytes, platelets

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

if AA is oxidized to DHAA how does it get back

A

Reduced back by GSH and NADPH (NADPH to recycle GSSG back to GSH)

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

What forms of AA are excreted into the urine.

A

Dehydroaxcocorbate, diketogluconate, oxalic acid and excess ascorbate

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

What % of Vit C is excreted as oxalic acid

A

25%

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

Plasma levels above ___ exceeds renal threshold and vit c will not be reabsorbed

A

1.4mg/dL

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

What body pool total leads to metabolites in urine and which leads to ascorbate acid in the urine

A

<1500 mg leads to only breakdown metabolites
>1500mg leads to proportionally more ascorbate

17
Q

What are the enzymatic and the non-enzymatic functions of Vit C

A

Enzymatic: monooxygenases, dioxygenase
Non-enzymatic: antioxidant, iron absorption, tetrahydrobiopterin recycling

18
Q

What is required in the conversion of dopamine to norepinephrine (monooxygenase)

A

Vit C and Copper

19
Q

hydroxylation of proline and lysin stimulates?

A

proper folding to structural stability

20
Q

Collagen hydroxylation requires

A

proline or lysin,
Fe3 to Fe2
AA
GSH
NADPH

21
Q

What is the role of tocopherol

A

Lipid membrane
protects against lipid membrane stress
Has a benzene ring of double bonds which allows it to accept free radicals

22
Q

Can Vit C become a radical?

A

Yes, but it is less harmful than other forms

23
Q

At what increase rate does Vit C enhance Fe absorption

A

10-fold

24
Q

Why do people with Vit C deficiency have low energy?

A

Iron absorption
Epinephrin production

25
Q

RDA for Vit C

A

Females: 75mg — 85(P) — 120 (L)
Males: 90mg

26
Q

UL for Vit C

A

2000mg

27
Q

What provides stability to or destruction of vit C

A

Stability: acidic

Destroyed: heat, light, oxidation, alkaline

28
Q

What are some symptoms to AA deficiency

A

Anemia - fatigue (NE, Iron)\
Atherosclerotic-type plaques (recycle BH4, NO)

Collagen syn =
Dermal hemorrhages, bone fragility, wound healing, infection, bleeding gums, loose teeth

29
Q

What are the 4 H’s of scurvy

A

Hemorrhagic
Hyperkeratosis of hair follicles
Hypochondriasis (psy)
Hematological (iron)

30
Q

How much mg prevents scurvy?

A

10mg

31
Q

If the body can tolerate 1g of AA why does AA toxicity happen?

A

repeated doses

32
Q

Why would AA toxicity lead to kidney stones?

A

must AA is broken down into oxalic acid with calcium in the kidneys leads to kidney stones

NUTR 302 (20 decks)

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