Proteins

Question 1

What do proteins contain?

Answer 1

Carbon, Hydrogen, Oxygen, NItrogen and sometimes Sulphur

Question 2

What are proteins composed of?

Answer 2

They are cmoposed of long chains of monomers called amino acids

Question 3

What do each amino acids contain?

Answer 3

They contain a central alpha carbon linked to an amine group, carboxyl group, and variable (R) group and a hydrogen atom.

Question 4

What do amino acids differ by?

Answer 4

Amino acids differ in the composition of their variable side chain (R)

Question 5

How are dipeptide formed?

Answer 5

Two amino acids joined by condensation

Question 6

How are polypeptide formed?

Answer 6

They are formed by more amino acids being added to the dipeptide

Question 7

What catalyzes the condensation reactions?

Answer 7

Ribosomes

Question 8

What is a peptide bond?

Answer 8

Bond linking amino acids together (C-N bond, -NH2 of one amino acid and -COOH of the other)

Question 9

Define essential amino acid

Answer 9

Acids that animals cannot synthesize (make) and must be obtained from diet

Question 10

Define non-essential amino acids

Answer 10

Acids that can be made by animals using pathways that transform one amino acids into another

Question 11

What can shortage of one or more essential amino acids in diet cause?

Answer 11

They can prevent the production of specific proteins

Question 12

Ribosome’s function in amino acids?

Answer 12

Ribosomes can join amino acids between any pair of the 20 different amino acids

Question 13

Functions of R groups?

Answer 13

R groups stabilize the 3D shape of proteins

Question 14

Define denaturation

Answer 14

When there is a conformational change in a protein, they don’t normally return to their original structure, it’s usually permanent

Question 15

What can cause denaturation?

Answer 15

Heat, due to vibrations in the molecule
Extreme pH

Question 16

What do R groups determine?

Answer 16

They determine the vehicle properties of amino acids

Question 17

Define Conformation

Answer 17

3D shape

Question 18

What decides which level the proteins conforms to

Answer 18

It’s decided by it’s amino acid structure

Question 19

What do each proteins conforms into determine

Answer 19

It deterines the fuction of the protein?

Question 20

What are four levels of protein structure?

Answer 20

Primary Structure
Secondary Structure
Tertiary Structure
Quaternary Structure

Question 21

Primary Structure

Answer 21

Sequence of amino acids
Formed by peptide bonds
Determines/controls the other levels

Question 22

Secondary Structure

Answer 22

Folds/turns of amino acid sequence upon themselves
Pattern of H bonds between amine and carboxylic groups creates the secondary structure
H bonds give stability
Fibrous proteins

Question 23

Tertiary Structure

Answer 23

3D folding pattern due to side chain interactions
Polypeptide folds and coils (complex)
Caused by interactions between R groups
Tertiary shape is very important for function
Globular proteins

Question 24

Quaternary Structure

Answer 24

Interaction between multiple polypetides
Sometimes prosthetic (part that is not an amino acid) groups involved
Classified as fibrous or globular

Question 25

Define Alpha helix

Answer 25

The structure when the chain coils

Question 26

Define beta-pleated sheet

Answer 26

The structure when teh chain pleats

Question 27

Is C=O polar or non-polar

Answer 27

Polar

Question 28

Is N-H polar or non-polar

Answer 28

Polar

Question 29

Where are H bonds formed

Answer 29

H bonds are formed readily along a polypeptide chain

Question 30

Functions of H bonds in polypeptide chain

Answer 30

Although individually H bonds are weak, there are so many that it helps to stabilize

Question 31

Types of bonds in tertiary structure

Answer 31

Ionic bonds - between + and - R groups Hydrogen bonds - between polar R groups Disulfide bridges Hydrophobic interactions

Question 32

What can amino aicds in proteins broadley be catagorized as?

Answer 32

They can be catagorized as being either hydrophobic (non-polar) or hydrophilic (polar/charged)

Question 33

Example of polar and non-polar amino acids on tertiary structure of globular proteins

Answer 33

Globular proteins need to be soluble in water so the outside/surface amino acids are hydrophilic where they contact water and center is hydrophobic

Question 34

What do the arrangement of polar and non polar amino acids affect?

Answer 34

Tertiary structure, they help them stabilize and ensure position is maintained that suits the proteins function

Question 35

Define non-conjugated proteins

Answer 35

They have only polypeptide subunits

Question 36

Example of non-conjugated proteins

Answer 36

Insulin is 2 polypeptides joined by a disulphide bridge

Question 37

Define conjugated proteins

Answer 37

Have one or more non-polypeptide chains called prosthetic groups, in addition to teh polypeptides

Question 38

Example of conjugated proteins

Answer 38

Haemoglobin - 4 polypeptide chains and each with a haem group. Increasing the diversity of the protein, allowing more function

Question 39

Define fibrous proteins

Answer 39

Contain elongated polypeptides that lack folding or alpha helices

Question 40

Example of fibrous proteins

Answer 40

Collagen, rope like structure giving high tensile strength

Question 41

Define Globular proteins

Answer 41

Rounded shape due to folding, intricate shape stabilized by R group bonds, exact shape closely related to its function

Question 42

Example of globular proteins

Answer 42

Enzymes, receptor sites. Only insulin hast he right shape to connect to the insulin receptor

Question 43

What does the connection between insulin and insulin receptor cause

Answer 43

They cause signals to be sent that open channels to move glucose into cells