1: BIOLOGICAL MOLECULES - PROTEINS

Question 1

What are amino acids made up of?

Answer 1

• carbon atom
• a carboxyl group (-COOH
• an amine/amino group (-NH2)
• R group (varies depending on amino acid)

Question 2

How many different amino acids are there?

Answer 2

20

Question 3

What are the bonds that form between amino acids called?

Answer 3

peptide bonds

Question 4

What are dipeptides?

Answer 4

2 amino acids joined together by a condensation reaction

Question 5

What are polypeptides?

Answer 5

3+ amino acids joined together by condensation reactions

Question 6

What is the name of the reaction that breaks down dipeptides and polypeptides?

Answer 6

hydrolysis

Question 7

What is the primary structure of a protein?

Answer 7

the sequence of amino acids in the polypeptide chain

Question 8

What bonds are present in the primary structure of a protein?

Answer 8

peptide bonds

Question 9

What is the secondary structure of a protein?

Answer 9

polypeptide chain coiled into α helix/folded into β pleated sheet

Question 10

What bonds cause the secondary structure of a protein to form?

Answer 10

hydrogen bonds

Question 11

What is the tertiary structure of a protein?

Answer 11

coiled/folded more to form 3D structure (final structure for proteins made up of only 1 polypeptide chain)

Question 12

What bonds cause the tertiary structure of a protein to form?

Answer 12

• hydrogen bonds
• ionic bonds
• disulfide bridges

Question 13

What is the quarternary structure of a protein?

Answer 13

more than 1 polypeptide chain bonded together

Question 14

What bonds are present in the quaternary structure of a protein?

Answer 14

• hydrogen bonds
• ionic bonds
• disulfide bridges

Question 15

How are shape and function linked in proteins?

Answer 15

final 3D structure determines function

Question 16

What are some functions of proteins?

Answer 16

• enzymes
• antibodies
• transport proteins
• structural proteins

Question 17

How does the structure of enzymes relate to their function?

Answer 17

specific 3D tertiary structure makes active site complementary to a specific substrate molecule

Question 18

How does the structure of antibodies relate to their function?

Answer 18

specific 3D structure makes antibody specific to antigen

Question 19

How does the structure of transport proteins (eg: channel proteins) relate to their function?

Answer 19

• contain hydrophilic and hydrophobic amino acids which cause the protein to fold up and form a channel
• this allows it to transport molecules and ions across membranes

Question 20

How does the structure of structural proteins (eg: keratin in hair and nails/collagen in connective tissue) relate to their function?

Answer 20

• consist of long polypeptide chains parallel to each other with crosslinks between them
• crosslinks make the proteins strong

Question 21

How do you test for proteins?

Answer 21

• add a few drops of NaOH (to make it alkaline)
• add copper (II) sulfate solution
• if protein is present, solution changes colour to purple if no proteins are present the solution stays blue