Protein

Question 1

Protein functions

Answer 1

Growth and repair, forms structural and functional elements of body cells

Question 2

1 gram

Answer 2

4kcal - promote satiety

Question 3

Enzymes

Answer 3

Regulating energy production in cells

Question 4

Amino acids

Answer 4

Building blocks
- Side
- Amino
- Carboxyl
Join through peptide bonds making protein through condensation

Question 5

How many different amino acids are there?

Answer 5

20 - 9 essential

Question 6

Are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine essential or non essential amino acids?

Answer 6

Essential

Question 7

What’s the difference between essential and non essential amino acids?

Answer 7

Essential - Amino acids that cannot be made into other amino acids
Non-essential - Amino acids that can be made into others
Body can make non essential, whereas essential have to be obtained through diet

Question 8

How does the body turn non essential amino acids into another non essential?

Answer 8

Transamination

Question 9

Aliphatic vs aromatic

Answer 9

Aliphatic > open chain
Aromatic > unsaturated ring structure

Question 10

Amino acid proteins

Answer 10

Proteins = chains of amino acids
Order and length determines protein type

Question 11

What are linear chains of peptides?

Answer 11

Polypeptides (many peptides) linked by peptide bonds through condensation reaction to make a straight chain (not ring)

Question 12

Metabolic enzymes

Answer 12

Increase the rate of reactions

Question 13

Motor proteins

Answer 13

Initiate movements

Question 14

Structural proteins

Answer 14

Provide support and strength

Question 15

Transporters

Answer 15

Provide movement across membranes

Question 16

Denaturation

Answer 16

Destruction of protein structure through heating, resulting in change of properties (often irreversible)
- Causes loss of enzyme activity
- Molecules change positions but peptide bonds stay the same

Question 17

Protein turnover

Answer 17

Continuous process of breaking down and rebuilding proteins
During growth, turnover is accelerated
In adults, balance between protein synthesis and protein breakdown

Question 18

Protein synthesis

Answer 18

Building of new proteins from amino acids
Regulated by insulin, facilitates uptake of amino acids in tissue

Question 19

Protein degradation

Answer 19

Breakdown of existing proteins into amino acids
Regulated by glucagon, catecholamines and glucocorticoids

Question 20

Amino acid pools

Answer 20

• From the amino acid pools, needed AA are taken by body cells to form proteins (mostly consists of non-essential amino acids as essentials are used quickly)
• Flux between incoming amino acids and those used for synthesis or energy production

Question 21

Transamination

Answer 21

Conversion of one amino acid into another

Question 22

Deamination

Answer 22

Breakdown of amino acid into waste products and energy

Question 23

Digestion and absorption

Answer 23

Digestive system breaks down protein into individual amino acids

Question 24

Mouth

Answer 24

• Teeth do mechanical breakdown
• Salivary glands secrete saliva
• Passes through oesophagus

Question 25

Stomach

Answer 25

- Enters stomach from oesophagus Chemical digestion - Release gastric juices containing hydrochloric acids and pepsin Mechanical digestion - Peristalsis aids digestion (chyme) ' Low pH of stomach causes proteins to denature

Question 26

Small intestine

Answer 26

Chyme enters small intestine - Pancreas secretes digestive juices Chymotrypsin and trypsin breakdown tripeptides, dipeptides and amino acids - Active transport takes single amino acids into the blood stream

Question 27

Once amino acids are transported to the liver, they can be used as:

Answer 27

- Protein synthesis in cells around the body - Making non-essential AA - Making other nitrogen-containing compounds - Rearranged and stored as fat

Question 28

Deamination

Answer 28

Removal of amine group Nitrogen released as ammonia Transported to the kidneys and excreted in the urine

Question 29

Complete vs incomplete proteins

Answer 29

All essential AA in correct proportions vs limited amounts of one/more essential AA

Question 30

Protein quality

Answer 30

Amino acid profile and digestibility determined by essential amino acid content (0-1 score)

Question 31

Recommendations on protein consumptions

Answer 31

15% of dietary energy should come from protein 0.75g per kg

Question 32

Protein is digested in the...

Answer 32

Stomach and small intestine

Question 33

Amino acids are building blocks joined through...

Answer 33

Peptide bonds through condensation