Chapter 4 - Proteins & Nucleic Acids

Question 1

Some types of tasks proteins do:

Answer 1

Enzymes, 
Structural Proteins, 
Contractile Proteins (muscles),
Transport Proteins 
Hormonal Proteins
Receptor Proteins
Storage Proteins (e.g. Casein)
Defensive Proteins (immune system)

Question 2

What is a polypeptide

Answer 2

Another word for protein.

String (polymer) of amino acids.

Question 3

What is an amino acid made up of?

Answer 3

Alpha carbon in the middle.

A carboxyl group
A amino group
A hydrogen
A side group (R)

Question 4

What is a peptide bond?

Answer 4

Amino acids linked together by peptide bonds (covalent bond).

Amino acid links to the carboxyl group of another.

Water molecule is lost when a piptide bond is formed. Dehydration reaction.

Bond is planar - can’t rotate.

Question 5

What is the backbone sequence of a protein?

Answer 5

N-C-C-N-C-C-N-C-C..

Question 6

What happens after a protein is formed?

Answer 6

Then it becomes a functional protein.

Question 7

What are the four levels of protein structure?

Answer 7

1. Primary
2. Secondary
3. Tertiary
4. Quaternary

Question 8

What is the 1. Primary level?

Answer 8

The primary structure is just the sequence of amino acids.

Question 9

What is the 2. Secondary level?

Answer 9

Hydrogen bonding between parts of the backbone.
N-C-C-N-C-C-N-C-C
Doesn’t include the R group - just the backbone.
Can be of two types: coils (helixes), and sheets (pleated sheets).

Question 10

What is the 3. Tertiary level?

Answer 10

The side groups sticking to each other.

Includes all interactions between amino acid side groups.

Water molecules pull polar side groups to the outside and push nonpolar side groups to the inside.

Question 11

What is the 4. Quaternary level?

Answer 11

Whole polypeptides (proteins) sticking together to form a macro protein.

Question 12

What are pleated sheets?

Answer 12

Full name is: beta pleated sheets.

Two or more straight regions of the backbone of the protein are held together side by side.

They can be parallel or antiparallel.

Held together by hydrogen bonds.

Side groups stick out from both sides of the sheet.

Question 13

What are helixes?

Answer 13

Common form of protein helix is called alpha helix.
Backbone is coiled up and the coils are held together by hydrogen bonds.

Side groups of amino acids in a coil stick out from the sides in all directions.

Question 14

Proteins & Ions

Answer 14

Many proteins need to incorporate ions internally such as Ca++ & Zn++ to help them form the right structure.

Question 15

What are proteins that have oligosaccharides attached to them called?

Answer 15

Glycoproteins