Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry I/II > Lecture 23: Fat-Soluble Vitamins > Flashcards

Lecture 23: Fat-Soluble Vitamins Flashcards

1
Q

Which two fat soluble vitamins are synthesized endogenously?

A

Vit D/K

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

Which two fat soluble vitamins are metabolized?

A

D/A

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

Provitamin A is a part of ___ family while Vit A is a part of ___ family

A

Carotenoids; Retinoids

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

B-carotene can convert to ___, which can convert to ___ , which can produce ____

A

retinal <—-> retinol
retinoic acid
11-cis retinal

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

What form of Vit A treats psoriasis and promyelocytic leukemia?

A

Trans retinoic acid

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

Which form of Vit A treats severe acne?

A

13-cis retinoic acid

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

What Vit A can you get from animal tissue vs. plants?

A

animal: retinyl esters; retinol
plants: b-carotene

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

Retinyl esters are broken down into ___ and ___ in the intestinal lumen

A

Fatty acids and retinol

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

In the intestine cells, retinol is re-esterified and incorporated into _____, which can be transported to liver/adipse

A

chylomicrons

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

How is Vit A stored? Where is it stored?

A

Retinyl Esters
-liver
-adipose

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

The liver can store 8-6 mths of Vit A with the help of a retinol binding protein known as _____

A

Transthyretin

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

Rhodopsin is typically bound to inactive 11 cis-retinol and opsin. When light strike, __ breaks down and actives ___ and ___

A

rhodopsin ; trans-retinal and cGMP

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

Conformational change in opsin generated nerve ___

A

impulse

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

All trans retinal can be use to make more _____

A

11-cis retinal

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

In target tissues, retinol is oxidized to ______

A

retinoic acid

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

What complex can active/inhibit genes?

A

Retinoic acid-receptor complex

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

What form of Vit A functions in gene regulation?

A

All-trans retinoic acid

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

If epithelial cells have a good supply of retinal, it is converted to retinoic acid and no ___ is made

A

Keratin

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

____ _____ suppresses synthesis of keratin by binding to nuclear receptor

A

Retinoic Acid

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

Why do epidermal epithelial cells usually undergo terminal keritinization?

A

Not vascularized, no retinal, therefore: no retinoic synthesis

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

______ cells secrete mucus to keep moist. They do not usually keratinize.

A

Internal Epithelial Cells

22
Q

How does Vit A decrease cancer risk?

A

Acts as an anti-oxidant substance

23
Q

Hypervitaminosis of Vit A?
Hypovitaminosis of Vit A?

A

Hypervitaminosis: Teratogen

Hypovitaminosis: Severe xeropthalmia

24
Q

Mild hypovitaminosis of Vit A

A

-night blindness
-anemia
-follicular hyperkeratosis

25
Q

What 4 populations require additional Vit A?

A

1) premature infants
2) people w/ fat malabsorption/deficiency/pancreatic insufficiency
3) hepatobil tree disease
4) intestinal mucosa dysfunction

26
Q

How can ergocalciferol (Vit D2) can be obtained?

A

Dairy

27
Q

How can cholecalciferol (Vit D3) be generated?

A

UV light converted 7-dehydrocholesterol to Vit D3

28
Q

For Vit D3 to be converted to its active form two processes must occur, one in the ___ and the other in the ___.

A

Liver; kidney

29
Q

CYP2R1 in the liver creates ____

CYP27B1 produces ____, active form of Vit D, which inhibits further Vit D3 production

A

25-OH-cholecalciferol

1,25-diOH-cholecalciferol

30
Q

Ergosterol + UV = ?

A

Ergocalciferol

31
Q

How does Vitamin D/PTH inhibit calcium excretion from kidney?

A

Stimulates calcium reabsorption

32
Q

Under what two conditions do you require more Vit D?

A

1) Fat malabsorption disorder
2) Use of corticosteroids/anticonvulsants

33
Q

Hyper vs. Hypovitaminosis of Vit D?

A

Hypervitaminosis: growth retardation, calcify soft tissues, permanent kidney damage
Hypovitaminosis: rickets; osteomalacia

34
Q

What happens when serum calcium levels are low?

A

Increase PTH, calcitrol, more calcium is reabsorbed from bone, more renal absorption of calcium, more calcium absorbed from intestine

35
Q

Three functions of 1,25-dihydroxycholecalciferol (calcitrol)?

A

1) Induces synthesis of calbindin
2) Works with PTH to ensure bone reabsorption
3) Works with PTH to inhibit calcium excretion from kidney

36
Q

In the intestine, Vit D induces synthesis of ___, which absorbs dietary calcium

A

calbindin

37
Q

What fat-soluble vitamin has no toxicity associated with excess of it?

A

Vit K

38
Q

Under what two conditions would a patient require more Vit K than usual?

A

1) Broad spectrum abx’s
2) Counteract OD of coumadin

39
Q

Why do newborns often get prophylactic dose of Vit K?

A

They have sterile GI and low liver stores of Vit K. Also, breast milk is low in Vit K

40
Q

Hypovitaminosis of Vit K?

A

Hemorrhage

41
Q

What can pre-dispose a patient to hypovitaminosis of Vit K?

A

1) Total parentral nutrition
2) Liver Dysfunction
3) Maladaption Syndrome

42
Q

Role of Vit K?

A

Co-factor in gamma-carboxylation of glutamine residues in:
-Coag factors
-Bone proteins

43
Q

Phylloquinone = Vit

A

K

44
Q

While various forms of vit E are absorbed, which is the only one to be retained?

A

alpha-tocopherol

45
Q

Main function of Vit E?

A

Anti-oxidant

46
Q

Increase fragility of RBC membrane is associated with hypovitaminosis of what fat-soluble vitamin

A

Vit E

47
Q

Epithelial cells will not make ___ as long as they are supplied with retinal to make retinoic acid

A

keratin

48
Q

Three functions of Vit A?

A

Vision
Gene regulation
Anti-oxidant

49
Q

______ is a component of the visual pigment rhodopsin

A

11 cis-retinal

50
Q

Cholecalciferol is converted to the
active form by two hydroxylations - the first is in the ____ while the second is in the ____

A

Liver; kidney (yields active form of vit D: 1,25 diOH cholecalciferol)

Biochemistry I/II (23 decks)

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