Question

5. Your friend keeps telling you that fatty acids are broken down to sugar in the body and used for energy. You disagree. In a simple explanation of metabolism, tell your friend why this idea is false. (1 point)

6. Vitamin B6 plays many roles in the body, but a very important one ensuring that we aren’t required to eat ALL amino acids directly in the diet. Explain how this works. (2 points)

Answer 1

(1)

The digestion is a catabolic process in which large pieces of food are broken down into small absorbable forms of food by the digestive enzymes like salivary amylase, lipase, trypsin, nucleases, etc.

Digestion of FAT molecules

The fat molecules are broken down into glycerol and fatty acids in the small intestine by the enzyme, lipase present in the pancreatic juice that is secreted by the pancreas after they have been emulsified into fat droplets by the bile salts. The digestion of the fat molecules by the pancreatic enzyme, lipase is shown below:

Therefore, fat needs to be broken down into glycerol and fatty acids before absorption.

Digestion of CARBOHYDRATES

Starch is a polysaccharide whose digestion starts in the mouth by the enzyme, salivary amylase. Starch is broken down into a disaccharide (maltose) in the small intestine by the enzyme, pancreatic amylase present in the pancreatic juice. The maltose is further broken down into glucose by the enzyme maltase. The digestion of the starch is shown below:

Therefore, a polysaccharide like starch is broken down into maltose by the enzymes, salivary amylase, and pancreatic amylase, and maltose is enzymatically broken down into glucose by the enzyme maltase before absorption.

(2)

Vitamin contributes to the following:-

• Fatty acid biosynthesis
• Breakdown of particular or certain storage compounds in plants and animals.
• Biosynthesis of neurotransmitters, plant hormones, and organelle-specific compounds (like chlorophyll).
• Majority of the Vitamin   co-catalyzed reactions are associated with amino acid catabolism and biosynthesis.

Presumably, the most crucial function of active and phosphorylated Vitamin in the cell is associated with the biosynthesis and degradation of amino acids. It is frequently used for transamination reactions where an amino group is carried to a ketoacid for the formation of new amino acids by the formation of an amino acid–PLP Schiff base intermediate. Additionally, Vitamin is also used in reactions like racemizations and decarboxylations.

Since, Vitamin is associated with amino acid catabolism and biosynthesis, the direct intake of all the amino acids in the diet is not essential.