Lecture 9- Protein Energy Storage Flashcards Preview

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Flashcards in Lecture 9- Protein Energy Storage Deck (10)
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0
Q

What is protein turnover?

A

Idea that proteins are constantly being degraded and re-synthesised.

1
Q

What is positive nitrogen balance?

A

Nitrogen input > Nitrogen output

2
Q

List the essential amino acids in the diet.

A

Leucine, isoleucine, lysine, tryptophan, threonine, valine, phenylalanine, methionine.

3
Q

What is transamination?

A

When the amino group of an amino acid is transferred to a Keto-acid.

4
Q

What do high levels of ALT and AST enzymes indicate?

A

Liver damage.

5
Q

What is Deamination?

A

The removal of the amine group from an amino acid.

6
Q

Why must proteins be gradually re-introduced into the diet of a starving person?

A

Because the activity of their urea cycle will be slow, therefore if too much protein is introduced too quickly, excess amino acids will be degraded, causing hyperammonaemia.

7
Q

Why is ammonia toxic to cells?

Three points.

A
  1. It reacts with alpha Keto-glutamate to form glutamate which slows the TCA cycle and therefore disrupts energy supply.
  2. It is alkaline in pH. (enzyme activity)
  3. Affects neurotransmitter synthesis and affects CNS.
8
Q

What is Phenylketonuria (PKU) and how does it arise?

A

It is when excess phenylketones are excreted in the urine.

It arises when there is a defect in the enzyme that converts phenylalanine to tyrosine.

9
Q

What is the clinical importance of creatinine excretion?

A

Creatinine levels can be measured in the urine. The levels over 24 hours are directly proportional to muscle mass, therefore can be used to determine an individual’s muscle mass as well as urine dilution.