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Flashcards in Protein Deck (12):
1

What is a protein?

Amino acids joined by peptide bonds

2

how many amino acids are there?

20

3

what is an essential amino acid?

One that must be eaten preformed in the diet

4

Name the essential amino acids

isoleucine
leucine
lysine
methionine
phenylalanine
threonine
tryptophan
valine

5

Give some examples of functional roles and products that amino acids are used for

Neucleotides
Neurotransmitters
Energy transduction - ATP
Membrane structures
Porphyrin
Fat metabolism
Fat digestion
Cellular replication
Hormones

6

What are the inflows and outflows of the amino acid pool?

Inflow - dietro intake, de novo synthesis and protein degradation
Outflow - protein synthesis, oxidation, other metabolic pathways

7

How much protein do we need and how did the WHO come up with this number (in 1973)

0.44g/kg protein
They calculated the loss of nitrogen in an energy balanced, protein free diet. Nitrogen was lost in urine, skin, faeces and misc. This added up to 0.34g.kg protein per day, this was the average so they added on 2 standard deviations.
This has the limitation that it assumes 100% efficiency in metabolising dietary proteins

8

What process might result in protein deficient states?

Increased demand e.g. infection or stress
Increase in losses e.g. burns, diarrhoea, haemorrhage
Failure of conservation systems e.g. impairment or urea salvage within the colon

9

What is the R-group?

The side chain to amino acids, which is the group that varies between amino acids

10

What are the groupings of amino acids based on the nature of their R groups?

1. Glycine - has a H atom as its side chain
2. Those with aliphatic (hydrocarbon) side chains
3. Those with hydroxyl aliphatic side chains - i.e containing an OH side chain
4, Those with aromatic side chains
5. Basic side chains
6. Carboxyl groups in the side chains
7. Those with sulphur containing side chains
8. Those with amide groups in their side chains

11

What is the general structure of a protein?

May be comprised of hundreds of amino acids linked together
Each protein will have a free amino group at one end (the N-terminal) and a free carboxyl group at the opposite end (the C-terminal)

12

How are amino acids linked to each other?

Via peptide bonds
The nitrogen atom in the amino group of one amino acid is linked to the carbon atom of the carboxyl group in the adjacent amino acid.