week 4

Question 1

define essential amino acid and name them

Answer 1

essential/ indispensable AAs
The body cannot make them, must come from diet

• threonine
• lysine
• isoleucine
• leucine
• methionine
• valine
• phenylalanine
• tryptophan

Question 2

define non-essential amino acids

Answer 2

The body can make the AAs via transamination

-

Question 3

define conditionally essential amino acids

Answer 3

rate limitations of synthesis in certain times of the lifecycle
histidine in infancy
post trauma and injury
inadequate organ function e.g. tyrosine in phenylketonuria

Question 4

what is a complete protein source

Answer 4

provides all essential AAs in sufficient amount and adequate ratio

Question 5

what is an incomplete protein source, and how do you make it complete?

Answer 5

when one or more essential AAs is missing, the missing AAs is the limiting AAs

protein sources can be combined in the diet to ensure all essential AAs are provided

Question 6

explain the plasma amino acid “pool”

Answer 6

• rises after a meal
• about 150g of endogenous and exogenous AAs
• there are more non-essential AAs in the pool
• “reuse source” is thought to be primary source of AAs for protein synthesis function

Question 7

what are the functions of amino acids

Answer 7

1. building blocks of rigid structures and movement structures
   - collagen in connective tissue/ bone
   - keratin in fingernails/ hair
   - muscle fibres, cilia, spindle fibres in mitosis
2. building blocks of gene products implicated in digestion, absorption, metabolism and transport of nutrients
3. precursors and building blocks of hormones and neurotransmitters
4. factors in acid-base regulation
5. building blocks of immune function proteins
6. building blocks of proteins involved in fluid balance