Everything a cell does involves proteins. seven classes of proteins are discussed in
module 3.11. match each of the classes with one of the descriptions below.
1. hemoglobin carries oxygen in the blood.
2. a protein in muscle cells enables them to move.
3. antibodies fight disease-causing bacteria.
4. collagen gives bone strength and flexibility.
5. insulin signals cells to take in and use sugar.
6. proteins in seeds provide food for plant embryos.
7. a protein called sucrase promotes the chemical conversion of
sucrose into monosaccharides.

Explanation:

1. Hemoglobin carries oxygen in the blood

Class: Transport or carrier protein. Function: Carries molecules from one part to another in the body; like hemoglobin carries oxygen in the blood and transports to different parts of the body.

2. A protein in muscle cells enables them to move

Class: Contractile protein. Function: Facilitates muscle contraction and relaxation for movement; actin and myosin present in muscle cells which enables them to move.

3. Antibodies fight disease-causing bacteria

Class: Defensive protein. Function: Specialized in defending and protecting the body against antigens which are the pathogenic foreign invaders; like the disease-causing bacteria, viruses, fungi, protozoa, etc.  

4. Collagen gives bone strength and flexibility

Class: Structural protein. Function: Provides structural framework, support, strength, flexibility, as well as protection to different parts of the body; like collagen, elastin, keratin.

5. Insulin signals cells to take in and use sugar.

Class: Hormonal/messenger/signal proteins. Function: Messenger proteins in the form of hormones which helps the body to coordinate a number of activities; like insulin signals cells to take in and use sugar during glucose metabolism.

6. Proteins in seeds provide food for plant embryos.

Class: Storage proteins. Function: Act as biological reserve which stores nutrients; like casein in milk, ferritin in hemoglobin, albumin in egg white, and proteins in seeds that provide food for plant embryos.

7. A protein called sucrase promotes the chemical conversion of sucrose into monosaccharides

Class: Enzyme protein. Function: Acts as a catalyst to promote and accelerate biochemical reactions of the body by acting as a catalyst; like sucrase promotes the chemical conversion of sucrose