Lecture Quiz 5
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What are vitamins?
organic compounds needed for growth and good health not used for energy
What are the functions of vitamins (vague)?
crucial in helping the body use nutrients often function as coenzymes
What vitamins are synthesized in the body?
D (skin) K (intestine) B (intestine)
What are the water soluble vitamins?
B and C
What is unique about B12 absorption?
it requires gastric intrinsic factor to be absorbed
What are the fat soluble vitamins and how are they digested?
A, D, E, K bind to ingested lipids and are absorbed with their digestion products
What is vitamin B1?
thiamin coenzyme for the pyruvate catalyzed reactions of the pentose phosphate pathway oxidation of alcohol
What does deficiency of B1 do?
reduced capacity of cells to generate. energy Beriberi syndrome - caused by white rice or excessive alcohol
What is vitamin B2?
riboflavin coenzymes FMN and FAD to form FMNH2 and FADH2
What does a deficiency in B2 cause?
dermatitis cheilosis blurred vision light sensitivity
What is vitamin B3?
niacin required for synthesis of NAD+ coenzyme in glycolysis, oxidative phosphorylation, DNA repair
What does a deficiency in vitamin B3 do?
early - headache, loss of appetite late - dermatitis, diarrhea, dementia, death
What is vitamin B5?
required for synthesis of coenzyme A required for the metabolism of carbohydrate via the TCA cycle and all fats and proteins
What does a deficiency in vitamin B5 do?
neuromuscular degeneration loss of appetite mental depression abdominal pains
What is vitamin B6?
pyridoxal efficiently converted to the biologically active form of vitamin B6, pyridoxal phosphate this functions as a cofactor in enzymes involved in transamination reactions and glycogenolysis
What happens during a deficiency of vitamin B6?
infants - nervous irritability, anemia adults - increased risk of heart disease
What is vitamin B7?
biotin coenzyme for carboxylation, decarboxylation, deamination essential for Krebs cycle
What happens during a deficiency of vitamin B7?
scaly skin, muscle pains, nausea, elevated blood cholesterol levels
What is vitamin B12?
cyanocobalamin coenzyme in all cells important in DNA synthesis in bone marrow
What happens during B12 deficiency?
pernicious anemia neurological disturbance
What is vitamin C?
ascorbic acid antioxidant enhances iron absorption and bioavailability essential in conversion of tryptophan to serotonin and of cholesterol to bile salts
What happens during vitamin D deficiency?
joint pains, poor bone growth, poor wound healing, more susceptible to infection
What is vitamin A?
retinol consists of three biologically active molecules (retinol, retinal, retinoic acid) required for photoreceptor pigments synthesis, integrity of skin, and reproductive function antioxidant essential for normal bone development
What happens during vitamin A deficiency?
night blindness epithelial changes increases infections