Proteins

Question 1

What is a condensation reaction?

Answer 1

A reaction where two molecules combine to form a larger molecule, and H2O is a by-product.

Question 2

What is a hydrolysis reaction?

Answer 2

Water is used to BREAK-down a molecule.

Question 3

What are the two types of secondary structure?

Answer 3

Alpha helix (vertical H bonds) and beta sheets (horizontal H bonds)

Question 4

What does protein denaturation do? What are the effects?

Answer 4

Causes loss of structure/function.
Disruption of both secondary and tertiary bonds, but not peptide bonds.

decreases solubility, loss of biological activity, improves digestion.

Question 5

What are Glycoproteins?

Answer 5

compound composed of protein and carbohydrate. Sugar bound via amino acid.

Question 6

What can cause protein denaturation?

Answer 6

Acids
heats
solvents
disulphide bond reducers.

Question 7

What does glycosylation produce and where does it occur?

Answer 7

Glycoproteins (sugar and protein) and in the Endoplasmic reticulum ad Golgi apparatus of the membrane.

Question 8

What are Glycohaemoglobin levels measured to determine?

Answer 8

Type 2 diabetes.

Question 9

What are lipoproteins? What are their functions?

Answer 9

A protein and lipid. transport of water insoluble fats and cholesterol in blood.

Question 10

What molecule transports hydrophobic lipids in blood/water?

Answer 10

lipoproteins

Question 11

Give examples of lipoproteins

Answer 11

LDL and HDL

Question 12

What are metalloproteins?

Answer 12

protein and metal ion. 1/3 of proteins require a metal ion to carry out their function.

Question 13

What are the 3 classes of proteins?

Answer 13

Globular, membranous and fibrous.

Question 14

What are Globular proteins?

Answer 14

Functions vary, circular in shape, water soluble, e.g haemoglobin.

Question 15

What fibrous proteins?

Answer 15

Insoluble in water, rod/wire like, reated structe. E.g muscle fibres, tendons, keratin, collagen , elastin.

Question 16

What happens in protein digestion?

Answer 16

Cleavage by peptidases.

Question 17

What has happened in sickle cell anaemia?

Answer 17

An altered base in AA chain. Haemoglobin is deoxygenated.

Question 18

What is collagen?

Answer 18

A fibrous protein, makes up 25% of protein in all humans. 3 polypeptides wrap around one another - very strong.

Question 19

What is scurvy?

Answer 19

A deficiency in vitamin C - required to convert one AA to another - crosslinks between polypeptides weak.

Question 20

What is osteogenesis imperfect?

Answer 20

When middle AA glycine in chain is substituted for larger AA. Cannot fold as tightly - brittle bones.

Question 21

What is LDL and what does it do? What about the receptor?

Answer 21

lipoprotein, transports cholesterol. The receptor is a glycoprotein, present on surface of all cells. Breaks down LDL into lysosomes.

Question 22

What is a lysosome?

Answer 22

It digests things. contains degradative enzymes.

Question 23

What is familial hypercholesterolaemia?

Answer 23

Deficiency in LDL receptors - build up of cholesterol in the wrong places.

Question 24

Give 3 examples of fibrous proteins?

Answer 24

Keratins, elastins and collagens.