Proteins

Question 1

What are proteins?

Answer 1

Biological molecules that contain C, H, O, N, and some contain sulfur. They are very large and there are more different types of proteins than carbohydrates or lipids. Proteins differ greatly between species and have a specific shape or structure, which allows them to carry out specific functions.

Example: Hemoglobin is a protein that carries oxygen in the blood.

Question 2

What are Amino Acids?

Answer 2

Amino acids are the building blocks of proteins. They form a polymer called a polypeptide. Amino acids are joined by peptide bonds, and these polypeptides form proteins. There are 20 different naturally occurring amino acids, all with a similar structure.

Additional Information: Amino acids are essential for various biological processes in the body.

Question 3

General structure of Amino acids

Answer 3

Amino acid (-NH2)

Amino acids have an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon, with a hydrogen atom and a variable R group also attached.

Question 4

Dipeptide vs Polypeptide

Answer 4

Dipeptide = 2 amino acids
Polypeptide= more than 2 amino acids

A polypeptide is a chain of amino acids linked by peptide bonds. Proteins are made up of one or more polypeptide chains.

Question 5

What happens when 2 amino acids join in a condensation reaction?

Answer 5

The formation of a dipeptide. A water is formed from the carboxyl group (OH) of one amino acid and from the amino group (H) of the other amino acid. A peptide bond then forms between a C and N.

Question 6

What allows a protein to carry out its specific function?

Answer 6

The structure of polypeptides within a protein.

The tertiary structure

Question 7

Proteins and their functions

Answer 7

Enzymes
Haemoglobin
Hormones
Antibodies

Question 8

What bonds are in the primary structure?

Answer 8

Peptide bonds

Question 9

What is the primary structure?

Answer 9

A sequence of amino acids in a polypeptide chain

Question 10

What is the sequence in the primary structure determined by?

Answer 10

The sequence of bases in DNA

Question 11

Why does the primary structure determine the shape of the protein?

Answer 11

Because the sequence determines the other levels of protein

Question 12

What can the change of 1 amino acid cause?

Answer 12

The protein to function less or not at all

Question 13

The primary structure of a polypeptide chain allows:

Answer 13

*hydrogen bonds to form between different amino acids along a chain

*interactions between R groups of the amino acids along the chain

As a result the polypeptide chain bends and twists

Question 14

What bonds are in the secondary structure?

Answer 14

Hydrogen bonds

Question 15

Why does secondary structure arise?

Answer 15

Due to hydrogen bonding between the C=O group and the NH group on either side of the peptide bond

Question 16

What is the charge of the C=O group?

Answer 16

Delta - charge

Question 17

What is the charge of the NH group?

Answer 17

Delta + charge

Question 18

What does delta + or - usually refer to?

Answer 18

Hydrogen bonds

Question 19

What happens when the bonding occurs within one region of a polypeptide chain? Secondary structure

Answer 19

The chain coils into an alpha helix

Question 20

What happens when the bonding occurs between different parallel regions of a polypeptide chain? Secondary structure

Answer 20

The chains fold into a beta pleated sheet

Question 21

Why does the tertiary structure arise?

Answer 21

When the alpha helixes and beta pleated sheets of many proteins fold and coil into a shape

Question 22

What what holds the shape together in tertiary structure?

Answer 22

Weak and strong covalent bonds between R groups

Question 23

What bonds are in tertiary structure?

Answer 23

Hydrogen, ionic, disulphide bonds

Question 24

Tertiary structure is the final structure of…

Answer 24

Proteins made from a single polypeptide chain

Question 25

Hydrogen bonds

Answer 25

*weakest
*forms between R groups with delta - and + charges

Question 26

Ionic bonds

Answer 26

*less strong(than disulphide bridge)
*forms between R groups with + or - charges

Question 27

Disulphide bridges

Answer 27

*strongest bond
*forms between R groups with sulphides

Question 28

What bonds are there in quaternary structure?

Answer 28

Hydrogen,ionic,disulphide bonds

Question 29

When does quaternary structure arise?

Answer 29

When a protein molecule consists of two or more polypeptide chains

Question 30

What do some polypeptide chains associate with?

Answer 30

a non-protein group called a prosthetic group

This allows it to carry out function