Brainscape's Knowledge GenomeTM

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


See full index

IHN BIOCHEMISTRY FINAL > FINAL: vitamin D > Flashcards

FINAL: vitamin D Flashcards

1
Q

vit D is __ soluble

A

vit D is fat soluble

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

how is vit D carried in blood

A

by vit D binding protein

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

vit D is not really a __ but a __

A

vit D is not really a vitamin but a steroid

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

D3 =

A

animal sources
supplements
cholecalciferol

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

D2 =

A

prescription
ergocalciferol
plant form

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

__ and __ are biologically inactive

A

D2 and D3 are biologically inactive

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

D2 and D3 transformation steps

A
  1. liver: D3+D2 –> 25(OH)D
  2. kidney: 25(OH)D –> 1,25(OH2)D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

vit D from diet/UVB is turned to __ by __ in __

A

vit D from diet/UVB is turned to 25(OH)D by CYP2R1 in liver

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

25(OH)D has 3 fates

A
  1. local conversion to 24, 25 (OH)2D
  2. kidney conversion to 1,25(OH)2D, then local to 1,24,25 (OH)2D
  3. extra-renal conversion to 1,25(OH)2D then to targets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

local conversion is upregulated by

A

1,25(OH)2D
Caclium
FGF23
PO43-

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

kidney conversion enzyme

A

CYP27B1

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

kidney conversion from 25OHD to 1,25(OH2)D regulation

A

upregulated by PTH
downregulated by Calcium, FGF23, PO43-

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

after extra-renal conversion 1,25(OH)2D is bound to __

A

after extra-renal conversion 1,25(OH)2D is bound to DBP and albumin

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

DBP and albumin bound 1,25(OH)2D target tissues

A

gut
kidney
bone
immune cells
muscle
pancreas

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

vit D deficiency in kids

A

rickets
demineralized bones bow as child’s weight increases

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

vit D deficiency in adults

A

osteomalacia

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

__ can prevent rickets and osteomalacia

A

400 IU vit D supp daily can prevent rickets and osteomalacia

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

vit D as a trxn factor

A
  1. 1,25 (OH)2 vit D3 binds, VDR acts as trxn factor
  2. heterodimer with RXR (retinoic X receptor)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

VDR mediates most __ actions

A

VDR mediates most 1,25 (OH)2D actions

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

where is VDR found

A

many tissues, including cancer cells

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

using __, VDR turns 25OHD3 to __ which enables cell __

A

using 1 alpha hydroxylase, VDR turns 25OHD3 to 1,25(OH)2D3 which enables cell proliferation and differentiation

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

25(OH)D is bound by (2)

A

albumin
vit D binding protein (DBP)

23
Q

free 25(OH)D is aka

A

bioavailable

24
Q

__ may help understand why total 25(OH)D levels show variability for disease outcomes btwn individuals

A

free 25(OH)D may help understand why total 25(OH)D levels show variability for disease outcomes btwn individuals

25
Q

RDA for vit D increases with

A

age
pregnancy/lactation

26
Q

vit D increases (4)

A

Ca2+ absorption
osteoclast activity
immune function
renal 1,25(OH)D synthesis

27
Q

1,25(OH)2D3 plays a role in (5)

A
  1. muscle and skeletal development
  2. renin-angiotensin regulation
  3. neuronal development
  4. inhibits cell cycle
  5. increases insulin secretion
28
Q

US intake of vit D
__ doesn’t matter
highest =
lowest =
are most ppl deficient?

A

US intake of vit D
latitude doesn’t matter
highest = summer
lowest = spring
are most ppl deficient? NO

29
Q

high __ diet affects lowers serum levels

A

high fat diet lowers serum levels

30
Q

__ ppl respond better to supplementation

A

deficienct (lower baseline vit D) ppl respond better to supplementation

31
Q

do we consume a lot of vit D?

A

no, sunlight helps us though

32
Q

3 main sources of vit D

A
  1. sunlight (carinogen issue)
  2. endogenous production (after sun or diet)
  3. diet (minor, so we fortify milk)
33
Q

dietary vit D sources

A
  1. fatty fish and oil
  2. mushrooms (more sunlight = better)
  3. fortified foods
34
Q

what foods are fortified with vit D

A

milk (not cheese or yogurt)
cereal
bread
OJ

35
Q

vit D toxicity caused by (2)

A
  1. Ca2+ serum build-up
  2. manufacturing errors with supplements or fortification
36
Q

vit D toxicity symptoms

A

drowsiness
vomiting
peptic ulcers
increased BP
tachycardia
kidney issues

37
Q

VITAL study looked at

A

vit D supp and cancer and CVD disease prevention

38
Q

VITAL study effect

A

no effect
supp don’t help elderly people in high doses

39
Q

VITAL
high dose = __ rxn time

A

VITAL
high dose = decreased rxn time

40
Q

VITAL
vit D supp may help __ by __
relevant in preventing __

A

VITAL
vit D supp may help cognitive decline by increasing neuron development and helping beta-amyloid clearance
relevant in preventing dementia

41
Q

vit D is a risk factor for __

A

vit D is a risk factor for mobility after hip fracture

42
Q

vit D deficiency increases __ and __

A

vit D deficiency increases autoimmunity and infection

43
Q

vit D receptor is located in __, so it may affect __ function

A

vit D receptor is located in pancreas, so it may affect beta-cell function

44
Q

who is at special risk for vit D deficiency

A

African Americans
pregnant and lactating
older ppl with risk of falling or fracture
obese (low vit D = increased body weight)

45
Q

is the primary function of vitamin D to support bone health?

A

NO

46
Q

are most ppl vit D deficient?

A

NO

47
Q

do we get enough vit D in diet?

A

no, supp help

48
Q

should we just supp with a ton of vit D

A

no bc it could be toxic

49
Q

__ min sun exposure __x per week is enough

A

10-20 min sun exposure 2-3x per week is enough

50
Q

what percent of ppl are vit D deficient?

A

33%

51
Q

excess sun exposure makes us make large amounts of __
will this become toxic?

A

excess sun exposure makes us make large amounts of D3
will this become toxic? prob not bc it is further metabolized

52
Q

3 inactive forms of vit D

A

lumisterol
tachysterol
suprasterol I and II

53
Q

summer has __ vit D production
__ and __ decrease amount of vit D produced in skin

A

summer has high vit D production
sunscreen and clothing decrease amount of vit D produced in skin

54
Q

ability to produce vit D in skin varies with (2)

A
  1. pigmentation (melanin = decreased UVB to skin)
  2. age = decreased with older age

IHN BIOCHEMISTRY FINAL (15 decks)

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