Biotin/Vitamin B7

Question 1

Biotin Structure, Digestion & Absorption
* 2 rings + _____ acid side chain
* Used to be called Vitamin _
* Often bound to protein in foods – freed by
________ & ________ _______
* Absorbed throughout the _____ Intestine

Answer 1

• valeric
• H
• intestinal & pancreatic enzymes
• Small

Question 2

Biotin Functions
* Coenzyme for multiple carboxylase enzymes
(enzymes that catalyze carboxylation or
decarboxylation reactions)
* Carboxylic acid = -COOH group
Actions of enzymes requiring biotin:
* Form components of _____ _____ (oxaloacetate & acetyl
CoA)
*______ ____ synthesis
* Catabolise odd chain _____ _____
* Catabolise _____

Answer 2

• carboxylase
• TCA cycle
• Fatty acid
• fatty acids
• leucine

Question 3

Biotin Deficiency
* Deficiency of biotin alone is _____ EXCEPT
* Is induced when large amounts of
_________ _____ _____ are consumed
* The protein _____ in raw egg white binds
biotin preventing ________
* Thereby impairs lipid and energy
metabolism
- Lethargy, paraesthesia in extremities, hypotonia, depression, hallucinations, red dermatitis. Anorexia, nausea, hair loss, brittle nails, muscle pain
- Fatal if untreated

Answer 3

• rare
• uncooked egg white
• avidin, absorption

Question 4

Biotin Food Sources
* Almost every food contains biotin
* ____,____ & _____ particularly good sources
* Also produced by bacteria in the intestine
(uncertain absorption)

Answer 4

• Nuts, Eggs and Bran
• bacteria