Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

IHN: Biochemistry 2 > Vitamin E > Flashcards

Vitamin E Flashcards

1
Q

what forms of vitamin E are in the diet?

A
  1. alpha-tocopherol (oils and nuts)
  2. gamma-tocopherol (soybean and corn oil)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

food form of vit E

A

free tocopherol AND
esterified tocotrienols

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

vit E food source

A

bran/germ of grains, nuts, and palm oil

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

do pregnant and lactating women need additional vit E?

A

no

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

what happens when you reach the UL for vit E?

A

increased bleeding and GI distress

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

vit E interferes with absorption and metabolism of __, which is necessary for clotting

A

vit E interferes with absorption and metabolism of vit K, which is necessary for clotting

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

excess vit E in diet can cause __

A

excess vit E in diet can cause bleeding

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

how is vit E metabolized before absorption in enterocyte

A

it is a lipid SO
bile salts required for emulsification, solubilization, and spontaneous packaging into the micelle

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

__ is the only form of vit E that is actively maintained in the human body

A

alpha-tocopherol is the only form of vit E that is actively maintained in the human body

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

__ is the form of vit E found in the largest quantity in blood and tissues

A

alpha-tocopherol is the form of vit E found in the largest quantity in blood and tissues

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

how is vitamin E absorbed into the enterocyte?

A
  1. primarily in jejunum by passive diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the rate of vit E absorption is

A

highly variable (10-80%)

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

factors that interfere with intestinal absorption of vit E

A
  1. retinoids
  2. plant sterols
  3. EPA
  4. alcohol
  5. dietary fiber
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

2 methods of vit E absoprtion into enterocyte

A
  1. passive diffusion
  2. NPC1L1, SR-B1, CD36
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

vit E passive diffusion requires __ for emulsification, solubilization, and __ formation

A

vit E passive diffusion requires bile salts for emulsification, solubilization, and micelle formation

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

micelles carrying vit E __ into enterocyte

A

micelles carrying vit E passively diffuse into enterocyte

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

other receptors that play a role in vit E absorption

A

NPC1L1
SR-B1
CD36

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

how is vitamin E absorbed in the enterocyte?

after absorption, vit E is packaged into __ and released into __

A

after absorption, vit E is packaged into chylomicrons and released into lymph

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

fate of vit E packed into chylomicrons

A
  1. after absorption, vit E packed into chylomicrons and released into lymph
  2. vit E delivered to extra-hepatic tissues as LPL degrades lipoprotein
  3. vit E in chylomicron remnant reaches liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how does enterocyte excrete vit E?

A

exocytosis (bc it is packaged into chylomicrons)

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

fate of vit E that reaches liver (from chylomicron remnant)

A

alpha-TTP selectively transports alpha-tocopherol into liver lipoproteins (mainly VLDL)

  • excess alpha-tocopherols transferred to HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

alpha-tocopherol transfer protein transfers

A

alpha-tocopherol into liver-secreted plasma lipoproteins

23
Q

why does the liver only accept alpha-tocopherol form of vit E

A

bc alpha-TTP

24
Q

excess vit E is __

A

excess vit E is secreted into bile

25
most alpha-tocopherol is incorporated into
VLDL
26
excess alpha-tocopherol is secreted into
bile
27
90% of vit E is stored in __ of __
90% of vit E is stored in **lipid droplets** of **adipocytes**
28
changes in adipose tissue cause problems with
vit E homeostasis
29
alpha-TTP is expressed highly in __ and at lower levels in (4)
alpha-TTP is expressed highly in **liver** and at lower levels in **brain, kidney, lung, and spleen**
30
plasma levels: alpha-tocopherol is __ more elevated than __
plasma levels: alpha-tocopherol is **10x** more elevated than **gamma-tocopherol**
31
mutated or deleted alpha-TTP causes __ and __
mutated or deleted alpha-TTP causes **ataxia** and **AVED (vit E deficiency)**
32
what does vit E do as an antioxidant?
quenches free radicals and absorbs energy of free radicals
33
unlike carotenes, vit E reamins a __ radical
unlike carotenes, vit E reamins a **low-energy** radical
34
alpha-tocopherol has __ properties
alpha-tocopherol has **antioxidant** properties
35
vit C recycles alpha-tocopherol by __
vit C recycles alpha-tocopherol by **accepting alpha-tocopherol radical's electron**
36
regeneration of vit E steps
1. vit E accepts alpha-tocopherol radical's electron 2. vit C --> ascorbate radical (harmless radical) 3. glutathione reduces ascorbate radical to reconstitute vit C 4. NADPH oxidizes reduced glutathione
37
since alpha-tocopherol is an antioxidant, it is found more in tissue with higher rates of __, such as __ and __
since alpha-tocopherol is an antioxidant, it is found more in tissue with higher rates of **oxygen metabolism**, such as **brain** and **lung**
38
2 main functions of vit E in target tissues
1. antioxidant 2. regulatory (non-oxidant) functions
39
__ is necessary for recycling of alpha-tocopherol
**vit C** is necessary for recycling of alpha-tocopherol
40
2 regulatory (non-oxidant) functions of vit E
1. regulation of gene expression 2. cell signaling (PKC, Akt, tyrosine kinases, phosphatases)
41
what form of vit E is excreted in urine?
conjugated form with glucouronic acid
42
main organ responsible for vit metabolism and excretion
liver
43
process for urinary excretion of vit E
1. alpha-tocopherol oxidized into alpha-CEHC 2. alpha-CEHC conjugated with glucouronic acid 3. excreted in urine
44
vit E assessment
1. mainly blood analyses
45
symptoms of vit E toxicity
inhibited platelet aggregation easy bruising and bleeding
46
risks of vit E deficiency
atherosclerosis heart attack cancer
47
populations at risk for vit E deficiency
- preemies - genetic abnormalities (AVED, apolipoproteinemia B) - fat malabsorption syndromes (cholestasis, cystic fibrosis, pancreatic insuffiency) - total parenteral nutrition
48
alpha-tocopherol inhibits oxidation of __ which decreases prevalence of __
alpha-tocopherol inhibits oxidation of **LDL-cholesterol** which decreases prevalence of **atherosclerosis**
49
vit E has __ function that quenches __ and protects from __
vit E has **antioxidant** function that quenches **free radicals** and protects from **cancer**
50
vit E can help prevent formation of __ that can lead to heart attack or venous thromboembolism
vit E can help prevent formation of **blood clots** that can lead to heart attack or venous thromboembolism
51
vit E may prevent formation of __ formed in stomach
vit E may prevent formation of **carcinogenic nitrosamines** formed in stomach
52
4 properties of alpha-tocopherol in disease
1. alpha-tocopherol inhibits oxidation of LDL-cholesterol (decreased atherosclerosis) 2. vit E as an antioxidant prevents cancer development 3. vit E prevents blood clots (could lead to heart attack or venous thromboembolism) 4. vit E blocks formation of carcinogenic nitrosamines formed in stomach
53
HOPE study
long term had increased risk of CVD
54
vit E and cancer risk study
increased risk of prostate cancer with vit E treatment

IHN: Biochemistry 2 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions