Proteins

Question 1

Proteins are made of elements…

Answer 1

C,H,O,N and some S and P

Question 2

Proteins are po…

Answer 2

polymer molecules.

Question 3

There are millions of…

Answer 3

different proteins

Question 4

Proteins make up more than…

Answer 4

50% of a cell’s dry mass.

Question 5

How many essential amino acid is there?

Answer 5

8

Question 6

General structure of protein

Answer 6

• carboxyl group (-COOH)
• amino group (-NH2) and H attached to C atom
• variable group R

Question 7

Functions of proteins

Answer 7

• enzymes
• carrier proteins transport molecules across membranes
• antibodies
• structural proteins support cells and tissues
• transport proteins(hameoglobin)
• contractile proteins enable muscles to contract

Question 8

Peptide bond

Answer 8

• by condensation reaction

- H2O is removed using OH from COOH group and H from the amino group of another amino acid.

Question 9

Dipeptide

Answer 9

Two amino acids joined together.

Question 10

Tripeptide

Answer 10

3 amino acids joined together

Question 11

Polypeptide

Answer 11

Made of many amino acids joined together.

Question 12

Proteins have 4…

Answer 12

structural levels.

Question 13

Primary structure determines…

Answer 13

the eventual shape of the protein, hence its function

-peptide bonds

Question 14

Primary structure

Answer 14

The particular amino acids contained in the chain and the sequence in which they are joined.

Question 15

Secondary structure

Answer 15

Hydrogen bonds form between the amino acids in the chain between the O of -CO- group of one amino acid and the H of the -NH- group of the amino acid four places ahead.

Question 16

Secondary structure due to hydrogen bonds…

Answer 16

coil into an alpha helix or fold into a beta sheet.

Question 17

Hydrogen bonds are easily broken by…

Answer 17

high temperatures and pH changes.

Question 18

Tertiary structure

Answer 18

Way in which a protein coils up to form a precise 3-D shape.

Question 19

Tertiary structure is held in these shapes by…

Answer 19

bonds between amino acids in different parts of the chain.

Question 20

In tertiary structure more bonds…

Answer 20

form due to interactions between R-groups of the polypeptide chain.

Question 21

(Tertiary structure)For proteins formed from a single polypeptide chain…

Answer 21

this is the final 3D structure of the protein.

Question 22

Bonds in tertiary structure

Answer 22

• hydrogen
• ionic
• disulfide
• weak hydrophobic interactions

Question 23

Hydrogen bond

Answer 23

Between strongly polar groups

e.g. -NH-, -CO- and -OH groups

Question 24

Ionic bonds

Answer 24

Between ionised amine (NH3+) groups and carboxylic acid (COO-) groups.
Can be broken down by pH changes.

Question 25

Disulfide bonds

Answer 25

Between cysteine molecules Strong covalent bonds Can be broken down by reducing agents.

Question 26

Weak hydrophobic interactions

Answer 26

Between non-polar R groups. Interactions are weak but groups tend to stay together as they are repelled by watery environment.

Question 27

Quaternary structure

Answer 27

Made up of several polypeptide chains held together. It is how different chains are put together.

Question 28

Hydrogen bonds are found in...

Answer 28

Secondary and tertiary

Question 29

Ionic bonds are found in...

Answer 29

tertiary

Question 30

Disulphide are found in

Answer 30

tertiary

Question 31

Hydrophobic and hydrophilic interactions are found in

Answer 31

tertiary

Question 32

Quaternary structure depends on the...

Answer 32

tertiary structure of the individual polypeptides, so it is influenced all these types of bonds.