biological molecules

Question 1

What are proteins made up of?

Answer 1

Amino acids

Question 2

What is the general structure of an amino acid?

Answer 2

Central carbon, amine group (NH2), carboxyl group (COOH), hydrogen, & an R group

Question 3

What is the R group described as?

Answer 3

Variable - the part that changes in all of the 20 different amino acids

Question 4

What are the 4 levels of protein structure?

Answer 4

Primary, secondary, tertiary, & quarternary

Question 5

What is the primary structure of a protein?

Answer 5

The sequence of amino acids in the polypeptide chain

Question 6

What is the secondary structure of a protein?

Answer 6

The sequence of amino acids causes parts of a protein molecule to fold into the alpha helix, or beta pleated sheets

Question 7

What holds the secondary structure together?

Answer 7

Hydrogen bonds

Question 8

Where do the hydrogen bonds in the secondary structure form?

Answer 8

Between the oxygen in the carboxyl group, & the hydrogen in the amine group of different amino acids

Question 9

What is the tertiary structure of proteins?

Answer 9

The further folding to form a unique 3D shape

Question 10

What 4 bonds hold the tertiary structure of proteins together?

Answer 10

• hydrophobic and hydrophilic interactions
• hydrogen bonds
• ionic bonds
• disulfide bonds

Question 11

Where do ionic bonds form in the tertiary structure of a protein?

Answer 11

Between the R groups of different amino acids

Question 12

Where and when do disulfide bonds form in the tertiary structure of a protein?

Answer 12

Between the R groups of different amino acids that contain sulfur

Question 13

What is the quarternary structure in proteins ?

Answer 13

When a protein is made up of more than one polypeptide chain

Question 14

What is the structure of haemoglobin?

Answer 14

• made of 4 polypeptide chains
• has a prosthetic group attached to each polypeptide chain, which aren’t made up of amino acids & contain iron

Question 15

What can a protein with a prosthetic group be described as?

Answer 15

A conjugated protein

Question 16

What shape are globular proteins?

Answer 16

Polypeptide chains which form a spherical shape

Question 17

What are fibrous proteins?

Answer 17

Polypeptide chains which form long twisted strands linked together to form a long chain

Question 18

What are the properties of fibrous proteins?

Answer 18

• stable structure
• insoluble in water
• strength to give a structural function

Question 19

What are 3 examples of fibrous proteins?

Answer 19

Collagen, keratin, elastin

Question 20

What are properties of globular proteins?

Answer 20

• relatively unstable structure
• soluble in water
• metabolic functions

Question 21

What are 4 examples of globular proteins

Answer 21

Enzymes, antibodies, some hormones e.g. insulin, haemoglobin

Question 22

What is the function of collagen?

Answer 22

Forms part of skin, tendons, cartilage, ligaments bone, and connective tissue in the bronchi, bronchioles and trachea

Question 23

What is the function of keratin?

Answer 23

Forms skin, nails, and hair

Question 24

What is the function of elastin?

Answer 24

Makes up elastic fibres around alveoli and blood vessels (arteries, arterioles, venules, and veins)

Question 25

What is the function of haemoglobin?

Answer 25

Responsible for the transport of oxygen

Question 26

What is the function of the enzyme pepsin?

Answer 26

It is a protease enzyme, able to digest other proteins using its specifically shaped active site which is complimentary to its substrate

Question 27

What is the function of insulin?

Answer 27

Produced by beta cells in the pancreas to lower blood glucose concentration, its specific 3D shape is complimentary to the receptors on the cell surface membrane of its target cells (liver and muscle cells)