Biotin

Question 1

Biotin is sometimes called:

Answer 1

anti-egg white injury factor

Question 2

-Biotin functions as _____ _____ in carboxylation reactions

Answer 2

carboxyl carrier

Question 3

-4 forms of carboxyl carrier/ enzyme in carboxylation reactions

Answer 3

Pyruvate carboxylase,
acetyl CoA carboxylase,
propionyl CoA carboxylase and
3-methylcrotonyl-CoA carboxylase

Question 4

-Meets the needs for GLUCOSE when not sufficient from the diet.

Answer 4

during Gluconeogenesis.

Question 5

1. Source of energy for RBC and nervous system

2. Only fuel for the muscles during anaerobic conditions

Answer 5

pyruvate carboxylase

Question 6

-is a biotin-dependent enzyme that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-CoA through its two catalytic activities, biotin carboxylase and carboxyltransferase.

Answer 6

Acetyl CoA carboxylase

Question 7

-Converts odd chain fatty acid

Answer 7

-> gluconeogenesis

Question 8

-catalyses the carboxylation reaction of propionyl CoA in the mitochondrial matrix.

Answer 8

Propionyl CoA carboxylase

Question 9

-Food Sources

Answer 9

• Widely distributed in food, synthesized by the microflora*
• ◦Milk, liver, egg yolk, dried soya beans, peanuts, yeast, wheat bran, oatmeal and some vegetables
• ◦Bioavailability varies because of digestibility
• ◦Unstable in oxidizing conditions and heat
• liver glandular organs

Question 10

Deficiency is induced by feeding ____

Answer 10

raw egg white (avidin)

Question 11

Deficiency symptoms

Answer 11

◦seborrhaic dermatitis, alopecia, and paralysis

Question 12

Effects of Deficient Intakes GI tract disorder, infants receiving breastmilk with low biotin, incomplete parenteral nutrition

Answer 12

◦dermatitis, glossitis, anorexia, nausea, depression, fatty liver, and hypercholesterolemia

Question 13

Effects of Excessive Intakes

Answer 13

No toxic effects even in large amounts

Question 14

The chief source of biotin

Answer 14

Coenzyme factor in carbon dioxide fixation

Question 15

biotin together with ______ it helps in the synthesis of purines, pyrimidines, fatty acids and carboxylation reactions.

Answer 15

active acetate (CoA)