Proteins (Types of proteins - Globular Proteins)

Question 1

Give 3 characteristics of globular proteins

Answer 1

compact
water soluble
roughly spherical

Question 2

Define globular protein

Answer 2

spherical, water-soluble proteins

Question 3

Why are globular proteins water soluble?

Answer 3

TERTIARY structures are folded so that the hydrophobic R-groups are kept away from the aqueous environment -hydrophilic R-groups are on the outside

Question 4

Why is the solubility of globular proteins important?

Answer 4

The solubility allows globular proteins to perform vital functions in the body, such as chemical reactions, immunity, and muscle contraction.

Question 5

What is an example of a globular protein and its function?

Answer 5

Insulin is a globular protein that regulates blood glucose levels. It is soluble in the bloodstream and has a precise shape to bind to specific receptors on cell membranes.

Question 6

What are globular proteins used for?

Answer 6

regulating many processes

Question 7

Give examples of the processes globular proteins regulate

Answer 7

muscle contraction
immunity
chemical processes

Question 8

Are conjugated proteins a type of globular protein?

Answer 8

Yes.

Question 9

What are conjugated proteins?

Answer 9

Conjugated proteins are globular proteins that contain a non-protein component called a prosthetic group. Proteins without prosthetic groups are called simple proteins.

Question 10

What do conjugated proteins contain?

Answer 10

A non-protein prosthetic group

Question 11

What is a prosthetic group and give an example?

Answer 11

A prosthetic group is a non-protein component that binds to a protein, such as a metal ion or molecule derived from vitamins.

An example is the haem group, which contains an iron ion (Fe²⁺).

Question 12

Give an example of 2 conjugated proteins

Answer 12

Haemoglobin
Catalase

Question 13

What is the function of haemoglobin?

Answer 13

Carries oxygen in the blood in erythrocytes

Question 14

What polypeptide sub units is haemoglobin made up of?

Answer 14

2 alpha-helices 2 beta-pleated sheets

Question 15

How many subunits make up haemoglobin?

Answer 15

4

Question 16

What does each haem group contain?

Answer 16

Iron 2+ ion

Question 17

What does each subunit of haemoglobin contain?

Answer 17

A haem group

Question 18

How do haem groups allow erythrocytes to carry out their function?

Answer 18

Iron ions in haem groups can reversibly combine with an oxygen molecule

Question 19

How many oxygen atoms can one haemoglobin molecule carry?

Answer 19

8- remember ATOMS not MOLECULES

Question 20

How does haemoglobin transport oxygen?

Answer 20

Haemoglobin is a quaternary protein with four polypeptide sub units (two alpha and two beta) and prosthetic haem groups.

Each haem group can bind reversibly with an oxygen molecule, allowing haemoglobin to pick up oxygen in the lungs and release it in tissues.

Question 21

What is catalase and how does it function? What does it produce?

Answer 21

Catalase is a quaternary protein containing haem groups, which allows it to catalyse the breakdown of hydrogen peroxide, a harmful by-product of metabolism, into water and oxygen.

Question 22

What type of protein is catalase?

Answer 22

Conjugated

Question 23

What type of prosthetic group does catalase contain?

Answer 23

Haem

Question 24

How many haem groups does catalase contain?

Answer 24

4