P3.2.1. Protein

Question 1

10 Major Categories of Proteins based on Function:

Answer 1

1. Catalytic
2. Defense
3. Transport
4. Messenger
5. Contractile
6. Structural
7. Transmembrane
8. Storage
9. Regulatory
10. Nutrient

Question 2

• Enzymes are best known for their catalytic role.
• Almost every chemical reaction in the body is driven by an enzyme

Answer 2

catalytic proteins

Question 3

Immunoglobulins or antibodies are central to functioning of the body’s immune system.

Answer 3

defense proteins

Question 4

Bind small biomolecules, and transport them to other locations in the body and release them on demand.

e.g., oxygen and other ligands

Answer 4

transport proteins

Question 5

• transmit signals to coordinate biochemical processes between different cells, tissues, and organs.

1. regulate carbohydrate metabolism
2. regulate body growth

Answer 5

messenger proteins

1. insulin & glucagon
2. human growth hormone

Question 6

• necessary for all forms of movement.
• it makes sperm movement possible.

examples?

Answer 6

contractile proteins

ACTIN & MYOSIN: muscle contain filament-like contractile proteins.

Question 7

• ## Confer stiffness and rigidity

1. component of cartilage
2. gives mechanical strength as well as protective covering to hair, fingernails, feathers, hooves, etc.

Answer 7

structural proteins

1. collagen
2. keratin

Question 8

• Span a cell membrane and help control the movement of small molecules and ions
• have channels - enter & exit
• transport is very selective

Answer 8

transmembrane proteins

Question 9

• Bind (and store) small molecules.

1. saves iron for use in the biosynthesis of new hemoglobin molecules.
2. an oxygen-storage protein present in muscle

Answer 9

storage proteins

1. Ferritin - an iron-storage protein
2. Myoglobin

Question 10

• Often found “embedded” in the exterior surface of cell membranes - act as sites for receptor molecules
• Often the molecules that bind to enzymes (catalytic proteins), thereby turning them “on” and “off,” and thus controlling enzymatic action.

Answer 10

regulatory proteins

Question 11

• Particularly important in the early stages of life - from embryo to infant.

1. are nutrient proteins.
2. provide immunological protection for mammalian young

Answer 11

nutrient protein

1. Casein (milk) & Ovalalbumine (egg white)
2. milk

Question 12

generation of an amine and a carboxylic acid functional groups

Answer 12

Protein Hydrolysis

Question 13

digestion of ingested protein

Answer 13

enzyme-catalyzed hydrolysis

Question 14

what happens to free amino acids?

Answer 14

1. absorbed in the blood stream
2. transported to the liver for synthesis of new proteins

Question 15

TRUE or FALSE?

Hydrolysis of cellular proteins and their re-synthesis is a continuous process.

Answer 15

TRUE

Question 16

• Partial or complete disorganization of protein’s tertiary structure
• UNFOLDING

Answer 16

protein denaturation

coagulation [precipitation] and cooking

Cooking food denatures the protein but does not change protein nutritional value

Question 17

• conjugated proteins with carbohydrates linked to them
• plasma membrane
• blood group marker
• collagen & immunoglobulins

Answer 17

glycoproteins

Question 18

• Glycoproteins produced as a protective response to the invasion of microorganisms or foreign molecules
• antibodies against antigens
• occurs through hydrophobic interactions, dipole – dipole interactions, and hydrogen bonds.

Answer 18

immunoglobulins

Question 19

• they are INSOLUBLE in water like the bloodstream and circulation in our body.
• conjugated protein that contains lipids in addition to amino acids.
• help suspend lipids and transport them through the bloodstream

Answer 19

lipoproteins

Question 20

Four major classes of plasma lipoproteins:

Answer 20

1. chylomicrons
2. VLDL
3. LDL
4. HDL

Question 21

Transport dietary triacylglycerols from intestine to liver and to adipose tissue.

Answer 21

chylomicrons

Question 22

Transport triacylglycerols synthesized in the liver to adipose tissue.

Answer 22

VLDL

Question 23

• Transport cholesterol synthesized in the liver to cells throughout the body.
• bad cholesterol

Answer 23

LDL

Question 24

• Collect excess cholesterol from body tissues and transport it back to the liver for degradation to bile acids.
• good cholesterol

Answer 24

HDL