Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MAD Exam 1 > Vitamins and Cofactors > Flashcards

Vitamins and Cofactors Flashcards

1
Q

cofactors

A

small, non-protein molecules that associate closely with enzymes during enyzmatic reactions and are converted from one form to another in the reaction; metals (zinc, copper, iron, etc)

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

coenzymes

A

organic cofactors (mostly derived from vitamins)

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

vitamins

A

small, organic molecules necessary for cellular functions that cannot be synthesized by an organism
*precursors for co-enzymes

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

water-soluble vitamins

A

the B vitamins and vitamin C
-water soluble because they have lots of negative oxygen and nitrogen atoms to form hydrogen bonds with water
-most wash out in the urine (except B9 and B12, that are stored in the liver)

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

vitamin B1 name

A

thiamine

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

vitamin B1 (thiamine) - where is it found

A

yeast, legumes, pork, brown rice, whole grain cereals
-high temp (cooking) and high pH denatures

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

vitamin B1 - absorption

A

small intestine (esp. jejunum and ileum) via active transport and passive diffusion

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

vitamin B1 (thiamine) - organs with highest concentrations

A

heart and brain

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

vitamin B1 - half-life

A

10-20 days

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

vitamin B1 - populations at risk for deficiency

A
  1. absorption problems (small bowel resection, bariatric surgery, AIDS)
  2. storage problems/insufficiency (alcoholics, hyperemesis gravidarum, eating disorders)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

vitamin B1 (thiamine)- biochemistry

A

*thiamine is a cofactor for a-keto dehydrogenases (pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, branched chain ketoacid dehydrogenase, transketolase)
*vitamin B1 also has a role in the initiation of nerve impulse propagation independent of its coenzyme functions

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

vitamin B1 (thiamine) - deficiency

A

BeriBeri (wet or dry); Wernicke-Korsakoff syndrome

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

Dry BeriBeri

A

*thiamine deficiency
*neurological complications (symmetrical peripheral neuropathy, usually involves distal extremities)

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

Wet BeriBeri

A

*thiamine deficiency
*cardiomegaly and cardiomyopathy
*heart failure and peripheral edema
*tachycardia
*symmetrical peripheral neuropathy

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

Wernicke-Korsakoff syndrome

A

*results from thiamine (B1) deficiency
*a continuum
1. Wernicke enchephalopathy (most severe form)
-acute, life-threatening
-nystagmus, ophthalmoplegia, ataxia, confusion
2. Korsakoff syndrome (least severe form)
-chronic neurologic condition
-impaired short-term memory, confabulation

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

vitamin B1 (thiamine) - treatment for deficiency

A

IV thiamine, followed by oral supplements

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

vitamin B7 name

A

biotin

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

vitamin B7 - where is it found

A

yeast, liver, egg yolk, soybean products, enriched in flour foods

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

vitamin B7 (thiamine) - absorption

A

proximal small intestine and to a lesser extent the cecum
*gut bacteria also synthesize biotin as a byproduct of proteolytic actions

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

how do raw egg white disrupt a vitamin?

A

disrupt B7 (biotin) because AVIDIN binds to biotin and prevents its absorption

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

vitamin B7 - important organs

A

skin and nervous system

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

vitamin B7 - populations at risk for deficiency

A

*fairly uncommon because of how the gut bacteria produce biotin
*people who primarily rely on parenteral nutrition (bypassing the GI tract)
*people who drink raw egg whites
*absorption problems (small bowel resection, bariatric surgery, AIDS)
*storage problems/insufficiency (alcoholics, hyperemesis gravidarum, eating disorders)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

vitamin B7 (biotin) - biochemistry

A

cofactor for many carboxylation rxns
*acetyl-CoA reductase
*proprionyl-CoA reductase
*pyruvate carboxylase

24
Q

vitamin B7 - deficiency

A

*due to fatty acid synthesis disruption
-dermatitis (around eyes, nose, mouth)
-conjunctivitis
-mental status change/lethargy/hallucinations
-allopecia
-myalgias
-anorexia
-nausea

25
vitamin B7 - treatment of deficiency
-dietary changes -oral supplementation *not IV b/c we have endogenous supplementation via GI tract
26
vitamin B9 name
folate
27
folate vs. folic acid
folate = what is found in nature folic acid = synthetic form
28
vitamin B9 (folate) - where is it found
foods like dark green leafy veggies, liver; cereals and grains are fortified with folic acid *heat destroys folate in food
29
vitamin B9 - absorption
small intestine, esp jejunum, via carrier-mediated processes *must be reduced to dihydrofolate and then to tetrahydrofolate to be biochemically active
30
vitamin B9 - important for?
DNA and RNA synthesis -esp hematopoietic cells -neuronal function
31
vitamin B9 - half-life
have some store but can deplete within weeks
32
vitamin B9 - populations at risk for deficiency
*absorption problems (small bowel resection, bariatric surgery, AIDS) *storage problems/insufficiency (alcoholics, hyperemesis gravidarum, eating disorders) *people who only eat canned foods (elderly, exclusive canned food diet) *people with increased requirements (pregnancy and lactation: chronic hemolytic anemias; hemodialysis)
33
vitamin B9 - biochemistry
*must be reduced (using NADPH as a cofactor) to be active *coenzyme for 1-carbon methylation 1. used for dUMP -> dTMP formation 2. used for conversion from homocysteine to methionine (deficiency = buildup of homocysteine)
34
vitamin B9 (folate) - deficiency blood signs
*macrocytic (RBCs are larger), megaloblastic anemia *pancytopenia (low counts of all cell types) *hypersegmented neutrophils
35
vitamin B9 (folate) - treatment of deficiency
-increase dietary sources -folic acid supplementation
36
vitamin B12 name
cobalamin
37
vitamin B12 - where is it found
meats, dairy products, eggs, clams; breakfast cereals are fortified
38
vitamin B12 (cobalamin) - absorption
1) need R protein in saliva and gastric juice to bind B12 2) need acidic environment in stomach to release B12 from foodstuff 3) need pancreatic proteases to release B12 from R protein and allow it to bind to IF 4) need IF to bind B12 and facilitate absorption in the terminal ileum 5) need a terminal ileum
39
pernicious anemia
autoantibodies to gastric parietal cells cause no IF (intrinsic factor) production, so you can't absorb B12
40
vitamin B12 (cobalamin) - populations at risk for deficiency
*people who eat primarily canned foods *people on chronic proton pump inhibitors (need the acidic environment) *people with pancreatic enzyme deficiency *people with pernicious anemia *people with functional or surgical absence of their terminal ileum
41
vitamin B12 (cobalamin) - biochemistry
***could lead to buildup of homocysteine or methylmalonic acid if B12 deficient *cofactor for methyl transfer in homocysteine/methionine pathway *cofactor to make succinyl CoA from methymalonyl-CoA, needed for TCA cycles and heme
42
vitamin B12 (cobalamin) - important functions
*DNA and RNA synthesis -esp hematopoietic cells -neuronal function
43
vitamin B12 - half-life
takes ~10 years to deplete stores
44
vitamin B12 - deficiency
*macrocytic, megaloblastic anemia *pancytopenia *hypersegmented neutrophils
45
vitamin B12 - presentation of deficiency
progressively worsening neurological finding *symmetric paresthesias, numbness, gait problems (typically more in the legs) *subacute combined degeneration of columns of spinal cord due to demyelination *can progress to spasticity and paraplegia *can be irreversible if not found and corrected
46
vitamin B12 - treatment of deficiency
depends on how severe the symptoms AND why they are deficient (do you need to bypass GI tract?) *IM injections *oral supplementation
47
B9 (folate) vs. B12 (cobalamin) deficiencies
-B9: elevated homocysteine, normal methylmalonic acid -B12: elevated homocysteine AND elevated methylmalonic acid
48
vitamin C name
ascorbic acid
49
vitamin C - where is it found
foods such as citrus fruits, tomatoes, potatoes, brussel sprouts, cauliflower, broccoli, strawberries, cabbage, and spinach *oxidative conditions destroy vitamin C in these foods (heat/light)
50
vitamin C - absorption
absorbed in the distal small intestine via active transport
51
vitamin C - important processes
***collagen synthesis *fatty acid transport *neurotransmitter synthesis *prostaglandin metabolism *nitric oxide synthesis
52
vitamin C - populations at risk for deficiency
*absorption problems (small bowel resection, bariatric surgery, AIDS) *storage problems/insufficiency (alcoholics, hyperemesis gravidarum, eating disorders)
53
vitamin C (ascorbic acid)- biochemistry
*donates electrons to enzymes prolyl hydroxylase and lysyl hydroxylase to form hydroxyproline and hydroxylysine, which aid in COLLAGEN FORMATION *reversible biologic reducing agent (electron donor for iron- and copper-containing enzymes) *antioxidant *cofactor for folate activation *aids in fatty acid transport
54
vitamin C - deficiency
SCURVY -perifollicular hyperkeratotic papules -ecchymoses -gingivitis with bleeding gums -impaired wound healing -anemia
55
vitamin C - treatment of deficiency
*IV supplementation *oral supplementation

MAD Exam 1 (20 decks)

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