14 - Protein

Question 1

What should I know?

Answer 1

1. The role of nitrogen containing compounds in nutrition. The nature and quality of proteins in the diet
2. Outline how dietary proteins are denatured and digested
3. Outline how digestive products are transported into the enterocytes, further digested if required and transported into the portal blood
4. Determine nitrogen balance

Question 2

what are 8 roles of proteins?

Answer 2

> building materials for growth and maintenance 
enzymes
hormones 
regulators of fluid balance 
acid-base regulators 
transporters 
antibodies 
source of energy when glycogen depletes (aa's can be used to make glucose)

Question 3

What are the organic compounds that we need for health?

Answer 3

9 essential amino acids
2 FAs
13 vitamins

Question 4

Difference between essential and non essential amino acids

Answer 4

essential - need to get from diet

non - consume and make

Question 5

What is a conditionally essential aa

Answer 5

Non essential aa’s can become essential under certain conditions i.e. premature infants don’t have the formed pathways to make some of the non essential AAs so they become conditionally essential i.e. arginine and cystiene

Question 6

What are proteins?

Answer 6

Chains of AAs linked by peptide bonds via a dehydration reaction to form polypeptides. long chains are also bound around each other by strong sulphide bonds

Question 7

Sickle cell?

Answer 7

Dna sequence determines AA sequence determine shape and folding determines function. I.e. in HB it is normally folded to tightly carry heme iron to carry oxygen. Abnormal sequence causes abnormal folding and abnormal sickle shape so can’t carry out its function resulting in sickle cell anaemia

Question 8

2 examples of when your protein needs increase

Answer 8

athlete

burns

Question 9

If you eat more protein does this mean you get bigger muscles?

Answer 9

NO as protein is tightly regulated
To grow muscle you need to work the muscle i.e. resistance training and have a load against the muscle in order to hypertrophy the muscle
If you increase exercise than you need to increase protein intake to replace those lost by breakdown and rebuild

Question 10

What happens if you eat more protein than you need? Do you get bigger muscles?

Answer 10

No- the excess protein is utilised as energy before it is added to body mass

Question 11

Why is it important that we consume high quality protein?

Answer 11

High quality protein provides all of our essential amino acids
Protein quality also determines growth and health maintenance

Question 12

What 2 things determine protein quality?

Answer 12

Digestibility and amino acid composition

Question 13

Digestibility?

Answer 13

• ANIMAL protein is more digestible than plant protein
• depends on the protein source AND the other foods eaten with the protein
• quality depends on the proteins digestibility because it can only provide AAs once it has been digested!

Question 14

AA availability?

Answer 14

• animal > plant
• proteins need to supply at least the 9 EAAs and enough nitrogen containing AAs and energy to synthesise the others!
• if the AA composition is too low of EAAs, nitrogen containing AAs and energy then protein synthesis will be limited

> is why there is a pop guideline of 1-2 servings to ensure people are getting adequate types and QUALITIES of proteins