TOPIC 1- Proteins

Question 1

What are the monomers of proteins?

Answer 1

Amino acids

Question 2

What is a dipeptide?

Answer 2

When two amino acids join together

Question 3

A polypeptide

Answer 3

When two or more amino acids join together

Question 4

What is the structure of an amino acid?

Answer 4

-A carbocyl group (COOH)
-Amine/aminogroup (NH2)
-R group attached to a carbon atom

Question 5

Which is the only R group which does not contain carbon?

Answer 5

Glycine

Question 6

What makes all living thing different?

Answer 6

Their R group

Question 7

How many amino acids are there?

Answer 7

20

Question 8

How are amino acids linked together to form dipeptides and polypeptides?

Answer 8

Condensation reactions

Question 9

What is the bond formed between amino acids?

Answer 9

Peptide bonds

Question 10

What reaction happens when dipeptides and polypeptides breakdown?

Answer 10

Hydrolysis

Question 11

What is the primary structure?

Answer 11

The sequence of amino acids in the polypeptide chain

Question 12

What is the secondary structure?

Answer 12

-Polypeptide chain chain does not remain flat and straight
-Hydrogen bonds form between the amino acids in the chain
-This makes it coil into an alpha helix or fold into a beta pleated sheat

Question 12

What is tertiary structure?

Answer 12

-Coiled/folded chain of amino acids is coiled/folded futher
-More bonds form between different parts of the polypeptide chain including hydrogen and ionic bonds
-Disulfide bridges also form when two molecules of the amino acid cysteine come close together- the sulfur atom in one cysteine bonds to the sulfur atom in the other
-For proteins made from one polypeptide chain the tiertry structure forms tehir final 3D structure

Question 13

What are ionic bonds?

Answer 13

Attractions between negative and positive charges on different parts of the molecule

Question 14

What is quaternary structure?

Answer 14

-The way several polypeptide chains are assembled together with bonds
-Final 3D structure

Question 15

A proteins 1_ determines its function

Answer 15

1. Shape

Question 16

How is an enzymes shape related to its function?

Answer 16

-Spherical due to tight folding of their polypeptide chains
-Soluble
-Have roles in metabalisism

Question 17

How does an antibodies shape related to its function?

Answer 17

-Made up of two light (short) polypeptide chains and two heavy (long) polypeptide chains bonded togther
-They have variable regions

Question 18

How does a transport proteins shape related to its function?

Answer 18

-Channel proteins contain hydrophobic and hydrophillic amino acids which cause the protein to fold up and form a channel

Question 19

How do structural proteins shape relate to its function?

Answer 19

-Physically strong
-Long polypeptide chains lying parallel to each other with cross links between them
-Polypeptides coiled together

Question 20

What si the test for proteins?

Answer 20

Biuret

Question 21

What is the method for the Biuret test?

Answer 21

-The test solution needs to be alkaline so add a few drops of sodium hydroxide solution
-Add some copper (II) sulfatre solution

Question 22

What will the resulst be?

Answer 22

Positive-purple
Negative-Blue

Question 23

Do peptide bonds have all 3 structures?

Answer 23

Yes

Question 24

What structures do hydrogen bonds have?

Answer 24

Secondary and tertiary