PROTEINS

Question 1

what is proteins made up of

Answer 1

amino acids

Question 2

what does the NH2 represent in an amino acid

Answer 2

amine group

Question 3

what does the COOH represent in an amino acid

Answer 3

carboxylic group

Question 4

what bond is formed in a condensation reaction between amino acids

Answer 4

peptide bonds

Question 5

what are dipeptides

Answer 5

two amino acids joined together

Question 6

what are polypeptides

Answer 6

multiple amino acids joined together

Question 7

what is the structure of a primary protein

Answer 7

it is a straight chain of amino acids

Question 8

structure of secondary protein

Answer 8

its is joined by hydrogen bonds when straight chain of amino acids have folded

Question 9

structure of tertiary protein

Answer 9

3d structure when the the secondary protein has folded again causing ionic bonds disulphide bridges and more hydrogen bonds.

Question 10

structure of quaternary protein

Answer 10

when two or more polypeptide chains have joined together held together by more ionic bonds , disulphide bridges,

Question 11

how do you test for proteins

Answer 11

biuret test

Question 12

explain the test for protein method

Answer 12

place biuret solution into a test tube with substance

Question 13

what result do you expect to see if a protein is present

Answer 13

it will turn purple

Question 14

what is the function of protein in relation to its structure.

Answer 14

it is involved in metabolic reactions. eg an enzyme has a tertiary structure which has a specific shape

Question 15

what do enzymes do

Answer 15

they are biological catalysts which lower the activation energy.
- increase rate of reaction

Question 16

list the properties of an enzyme

Answer 16

it has a tertiary structure so it is able to change shape

Question 17

what affect does the – enzyme concentration have on the rate of reaction `
what happens after a few minutes to the ror

Answer 17

enzyme concentration increases the rate of reaction

• this is because there is more active sites to fit with the substrate
• over time is decreases as the substrates have all been used up and is in excess

Question 18

what affect does the substrate concentration have on the rate of reaction

Answer 18

increases rate of reaction

• as there are more substrates to fit into the active sites.
• enzyme limiting factor- as there might not be enough active sites to fit into substrates so rate of reaction decreases.

Question 19

what affect does the concentration of competitive inhibitors on the rate of reaction

Answer 19

it decreases rate of reaction as competitive:
- bind to active site as it has a similar substrate shape so less enzyme substrate complexes are formed so less reactions

Question 20

what affect does the concentration of the non competitive inhibitors rate of reaction

Answer 20

non competitive:
changes the shape of active sites so less substrates can fit into it.
so less substrates will fit into the active site

Question 21

what affect does the PH have on the rate of reaction

Answer 21

the ph. increases the rate of reaction until it has reached its optimum level
- after optimum level the rate of reaction decrees as the enzymes denature

Question 22

what affect does the temperature have on the rate of reaction.

Answer 22

it increases as there are more kinetic energy causing more collisions
after optimum temp the rate of reaction decreases as the enzymes denature.

Question 23

what is competitive and non competitive inhibitors

Answer 23

competitive:

• bind to active site as they have a similar substrate shape
• this causes less substrates to bind to the active site of enzymes.

non competitive:

• bind to other site of enzyme
• causes active site to change shape
• less substrates can fit into active site as there are different shapes.