Topic 1.4 Proteins

Question 1

Proteins consist of:

Answer 1

Hydrogen (H), Carbon (C), oxygen (O) and Nitrogen (N)

Protein containing foods - the only source of nitrogen

Question 2

Amino acid structural formula:

Answer 2

All have the same structure:
central carbon bonded to one:

- hydrogen
amino group (NH2)

• Carboxylic acid group (COOH)

Question 3

What distinguishes amino acids?

Answer 3

The fourth attachment or side group - alters shape, size, charge etc.

May involve a single atom or group of atoms.

Question 4

Why are proteins more complex out of carbs and lipids?

Answer 4

The side-group as each side group varies from one amino acid to the next.

Question 5

How many amino acids are required by the body?

Answer 5

20

Question 6

Essential amino acids

Answer 6

9 essential amino acids

Cannot be synthesised by the body or cannot produce them in amounts sufficient for meeting the body’s requirements.

*must be consumed

Question 7

Non-essential amino acids

Answer 7

Can be synthesised by the body.

Question 8

Essential amino acids

Answer 8

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Question 9

Conditionally essential

Answer 9

non-essential amino acids become essential.

• injury, stress, illness

Question 10

Complete protein

Answer 10

• contains all 9 essential amino acids
• may not contain all non-essentials
• high biological value

Question 11

Incomplete proteins

Answer 11

• do not contain one or more essential amino acids

- low biological value

Question 12

Complementary protein

Answer 12

Combination of incomplete proteins to obtain all essentials.

Question 13

How are excess amino acids stored?

Answer 13

They cannot be stored; thus dietary protein is vital to consume on a daily basis.

Question 14

Complete proteins sources

Answer 14

Animal sources: meat and eggs

Vegan: chia seeds

Question 15

Incomplete protein sources

Answer 15

Tofu and soybeans

Question 16

Is gelatin a complete protein?

Answer 16

No. It does contain the essential amino acid tryptophan.

Question 17

Complementary protein sources

Answer 17

Beans on toast or peanut butter on wholegrain bread.

Question 18

Protein structure

Answer 18

Polypeptide bond links each amino acid forming a polypeptide chain.

• through a condensation reaction, similar to when monosaccharides combine to form Di’s.

Question 19

Condensation

Answer 19

combination of two molecules to form a larger molecule by producing water as a by-product.

Question 20

Synthesising enzymes

Answer 20

Synthesize enzymes that act as catalysts to speed up biochemical reactions in the body, aiding in metabolism.

Question 21

Synthesising hormones

Answer 21

that regulate heart rate, blood glucose levels, growth and development.

Question 22

Synthesising antibodies

Answer 22

Which defends the body against invading antigens or viruses.

Question 23

Regulating fluid and acid-base levels

Answer 23

Produces albumin which controls and regulates the movement of liquids into and out of cells.

Question 24

Functions of Proteins

Answer 24

Structurally required for growth, maintance and repair of body tissue.

Bones, muscle, nerves