Peptides

Question 1

What is dipeptide?

Answer 1

When two amino acids join together

Question 2

What is the reaction called where amino acids join together?

Answer 2

Condensation

Question 3

What happens in a condensation reaction with amino acids?

Answer 3

Reaction is between COOH and NH2 of Amino acids
Water is lost
Bond between C-H formed

Question 4

What is the bond between amino acids called?

Answer 4

Peptide

Question 5

How many dipeptides can be made?

Answer 5

400 different

20^2

Question 6

What is the terminal where the COOH group is found?

Answer 6

C terminal

Question 7

What is the terminal where NH2 is found?

Answer 7

N terminal

Question 8

What tripeptide?

Answer 8

3 amino acids joined together

Question 9

How many tripeptide are there?

Answer 9

8000

20^3

Question 10

What is polypeptide?

Answer 10

Many, often hundreds, of amino acids joined together

Question 11

What is the primary structure of Amino acid?

Answer 11

The number and sequence of amino acids in a particular polypeptide

Question 12

How does the R group effect the peptide structure?

Answer 12

Sequence of R group determines higher folded structure of the polypeptide

Question 13

What is the secondary structure of an amino acid?

Answer 13

The folding of all of part of a polpeptide

Question 14

What is the most common secondary structure of amino acids?

Answer 14

Extended spiral - alpha helix

Question 15

What is the structure of a alpha helix?

Answer 15

Maintained weak electrical hydrogen bonds formed between the CO group and NH
4 amino acids down chain
11 amino acids long

Question 16

What is made from a alpha helix?

Answer 16

fibrous proteins which have structural functions

• Keratin (Nails, hair)
• Collagen (Tendons, connective tissue)

Question 17

What is the other secondary structure?

Answer 17

Beta pleated sheet

Question 18

What is the beta pleated sheets structure?

Answer 18

Polypeptide chains run parallel to each other

Hydrogen bonds - very strong

Question 19

What is made from beta pleated sheets?

Answer 19

Silk is a protein made completely from beta pleated sheet. Complete beta structures are uncommon.

Question 20

What is needed to produce an alpha helix or beta pleated sheet?

Answer 20

Polypeptide with a regular repeating amino acid in its primary structure

Question 21

What is the tertiary structure?

Answer 21

The compact 3 dimensional shape adopted by most polypeptides

Question 22

What type of shape is the tertiary structure?

Answer 22

Globular

Question 23

What 4 types of bonds are found in tertiary structure?

Answer 23

Hydrogen bonds (between R groups)
Ionic bonds (between R groups of different charges)
Disulphide bonds or bridges (between sulphur containing R groups)
Hydrophobic interactions (hydrohobic R groups near middle)

Question 24

How do we find the 3D structure of a polypeptide?

Answer 24

X ray diffraction

Crystallography

Question 25

What is quarternary structure?

Answer 25

Where 2 or more polypeptide chains are bonded toegther and together they form a functional molecule.

Question 26

What is an example of a protein hormone with a quartenary structure?

Answer 26

Insulin

Question 27

What binds are found in quarternary structure?

Answer 27

Hydrogen bonds 
Ionic bonds 
Disuplide bonds or bridges 
Hydrophobic interactions
= same as tertiary structure

Question 28

What is an example of protein with a quarternary structure?

Answer 28

Haemoglobin
Made of 4 polypeptide chains
(2 alpha chains and 2 beta chains) - not alpha helix of beta pleated sheet