Vitamins

Question 1

What are some common properties of fat soluble vitamins?

Answer 1

Isoprene units
Uptake in S.I
Stored in liver/adipose
Deficiencies arise from problems with digesting fats, with pancreatic lipase, or with bile production
Transported via chylomicrons and lipoproteins

Question 2

What are some common properties of water soluble vitamins?

Answer 2

B vitamins + C
Taken up by diffusion or medicated transport in S.I
Little storage, excreted urine
B12 is weird

Question 3

Potenital causes of vitamin deficiency in developed countries

Answer 3

anorexia 
problems with digestion
malabsorption 
increased need (pregnant) 
alcoholism (thiamin) 
smoking

Question 4

common signs of vitamin deficiency

Answer 4

dermatitis
anemia (folate, B12)
neuropathy 
muscle weakness
fatigue
decreased appetite, growth, immunity

Question 5

Modified versions of B vitamins often act as _____________, which are organic molecules required for catalysis by some enzymes.

Answer 5

Coenzymes

Apoenzyme + coenxyme = holoenzyme

Question 6

Niacin co-enzyme carrier

Answer 6

NADH, NADPH

Question 7

Riboflavin co-enzyme carrier

Answer 7

FADH2, FMNH2

Question 8

Pantothenic acid co-enzyme carrier

Answer 8

coenzyme A (CoA), ACP (of fatty acid synthase)

Question 9

Thiamin co-enzyme carrier

Answer 9

Thiamin pyrophosphate (TPP) 
Found in E1 of PDH

Question 10

Biotin co-enzyme carrier

Answer 10

Biotin

Found in ACC

Question 11

B12 co-enzyme carrier

Answer 11

cobalamin derivatives (important for methylation)

Question 12

Folate co-enzyme carrier

Answer 12

tetrahydrofolate (THF)

Question 13

B6 co-enzyme carrier

Answer 13

pyridoxal phosphate

Question 14

Which vitamins are crucial for electron carriers and the ETC?

Answer 14

Niacin

Riboflavin

Question 15

Found in grains and meats, but often not released during digestion. (Corn soaked in solution - tortillas - to allow absorption)

Answer 15

Niacin

Question 16

Deficiency causes pellagra (4Ds: dermatitis, diarrhea, dementia, death)

Answer 16

Niacin

Question 17

Found in meat, dairy, dark green veggies
Deficiency can cause swelling and fissuring of lips, tongue, mouth
FAD, FMN

Answer 17

Riboflavin

Question 18

Found in ALL plant/animal based food, deficiency rare
Sulfhydryl group can form high energy bonds
CoA, ACP

Answer 18

Pantothenic acid

Question 19

Important consideration in alcoholism

Important for enzymes in pentose monophosphate shunt, PDH, Alpha ketoglutaric DH

Answer 19

Thiamin

Question 20

Found mostly in whole grains
Deficiency causes beriberi
Deficiency most common in alcoholics/chemo its (ethanol reduces absorption, pts don’t eat as much) and in countries with white rice diet

Answer 20

Thiamin

Question 21

Found in alcoholics due to Thiamin deficiency

Movement problems, hallucinations

Answer 21

Wernicke-Korsakoff Syndrome

Wernicke (movement), Korsakoff (hallucinations)

Question 22

Dry beriberi

Answer 22

Chronic thiamin deficiency

Wasting, leg weakness, peripheral neuropathies, older

Question 23

Wet beriberi

Answer 23

Acute thiamin deficiency

Edema and heart failure

Question 24

Infantile beriberi

Answer 24

Death from heart failure in a few hours

Question 25

Found in most foods, deficiency rare Used in ATP-dependent carboxylases (PC, ACC) Long arm can bind CO2

Answer 25

Biotin

Question 26

Important for oxidation of odd-chain fatty acids, Met synthesis from homocysteine, production of SAM, methylation (esp. of lipids in myelin)

Answer 26

Vitamin B12

Question 27

Found exclusively in animal products (produced by animal microbiota) Vegans/vegetarians more likely to be deficient

Answer 27

Vitamin B12

Question 28

Secreted by parietal cells of stomach Required for B12 absorption in SI Lack leads to pernicious anemia due to gastritis - autoimmune

Answer 28

Intrinsic factor

Question 29

Deficiency can cause anemia AND neurological symptoms | Treat with injection

Answer 29

Vitamin B12

Question 30

Important for THF

Answer 30

Folate

Question 31

Found in green veggies, mushrooms | Deficiency around conception time responsible for many neural tube defects (spina bifida, anencephaly)

Answer 31

Folate

Question 32

Needed for DNA synthesis | Deficiency can cause anemia

Answer 32

Vitamin B12 AND Folate (B12 helps convert folate to active) Can treat anemia with folate, but may miss neurological problems if B12 def.

Question 33

Coenzyme for many, many enzymes (aa metabolism, NTs, glycogen phosphorylase) Found in many foods Reason why glycogen phosphorylase does not need ATP energy and can just use Pi

Answer 33

Vitamin B6

Question 34

Fat soluble Found in green leafy veggies, but sig. proportion made by our gut bacteria Newborns susceptible to def. - given a supplement Involved in coagulation

Answer 34

Vitamin K

Question 35

How does Vitamin K contribute to coagulation?

Answer 35

Coenzyme for Vit K Dep Carboxylase Carboxylation of Glu residues allows clotting factors to bind Ca2+, which allows them to bind phospholipids on platelets and endothelial cells (clot)

Question 36

Patients taking warfarin (coumadin) need to constantly maintain a steady state of _______ because:

Answer 36

Vitamin K Coumadin reduces clotting ability Dosage is set based on dietary intake Balance of active K and epoxide form determines clotting ability

Question 37

Beta-carotene is provitamin (green, orange, yellow veggies) Found in eggs, milk, meat Active forms are retinoic acid, retinal

Answer 37

Vitamin A

Question 38

This form of Vitamin A promotes epithelial differentiation (nuclear receptors) Important for growth and immunity Deficiency can cause scaly skin and keratinization of cornea

Answer 38

Retinoic acid

Question 39

This form of Vitamin A is found in rods and cones attached to rhodopsin Deficiency causes night blindness and blindness

Answer 39

Retinal

Question 40

Fat soluble vitamins that are hormones that act as transcription factors, can be stored in liver

Answer 40

Vitamin A and Vitamin D

Question 41

AKA calcitriol Found in animal products, fortified milk Can get all from UV exposure, or else must get from diet

Answer 41

Vitamin D

Question 42

Absolutely necessary to allow Ca2+ absorption in intestines

Answer 42

Vitamin D

Question 43

Hormone that is activated under low Ca2+ levels to activate osteoclasts to break down bone and to cause kidney to increase resorption of Ca2+

Answer 43

PTH (parathyroid hormone)

Question 44

Deficiency becoming for common, causes rickets in children (softening of bones, bow legs), osteomalacia in adults (increased fragility of bones)

Answer 44

Vitamin D

Question 45

Ascorbic acid, water soluble antioxidant Important in collagen (hydroxylation of Pro and Lys to stabilize triple helix) Deficiency causes scurvy

Answer 45

Vitamin C

Question 46

Why is Vitamin C important for collagen and prevention of scurvy?

Answer 46

Important for hydroxylating enzymes of Pro and Lys residues in collagen triple helix Defects lead to collagen dysfunction and capillary and blood vessel problems

Question 47

Found in many fats Active form: alpha tocopherol Fat soluble antioxidant (present in membranes and fat deposits) Floating around fats (not really stored in liver)

Answer 47

Vitamin E

Question 48

``` What do each of the following mean? EAR RDA AI UL ```

Answer 48

``` EAR = estimate average requirement (50% of population deficient, 50% sufficient) RDA = recommended dietary allowance (97-98% sufficient) AI = adequate intact (best guess, not enough data) UL = upper intake level (highest amount you can eat to be assured of no negative effects) ```