Year 12 Proteins and enzymes Flashcards Preview

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Flashcards in Year 12 Proteins and enzymes Deck (25)
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1

Name the monomer used to make proteins.

Amino acid

2

Name the 2 substances made when 2 amino acids are joined together.

Dipeptide
Water

3

Name the type of reaction used to join 2 amino acids together.

Condensation

4

Name the bond that joins 2 amino acids together.

Peptide

5

How many different amino acids are there and how do they differ?

20
R group is different.

6

Name the molecule made when many amino acids are joined together.

Polypeptide/protein

7

What is the primary structure of a protein/polypeptide?

Specific sequence of amino acids joined by peptide bonds.

8

What is the secondary structure of a protein?

Specific folding of the primary structure held together by hydrogen bonds.

9

What is the tertiary structure of a protein.

Specific folding of the secondary structure held together by hydrogen, ionic or disulfide bridges.

10

What is the quaternary structure of a protein?

Two or more polypeptides joining to make a functional protein.

11

Describe a biochemical test for protein.

Biuret test

Add sodium hydroxide solution and copper sulfate solution.

Positive results - lilac
Negative result - blue

12

Explain the effect of increasing temperature on an enzyme controlled reaction until the optimum temperature is reached.

As temperature increases
The KE of enzyme and substrate increases.
More successful collision between substrate and active site.
More enzyme substrate complexes formed.
Faster rate of reaction.

13

Describe the induced fit model of enzyme action.

Active site and substrate are not complementary.
Active site changes shape to become complementary when an enzyme substrate complex is formed.

14

What is the role of an enzyme?

Catalyses a reaction by reducing the activation energy.

15

Name the structure formed when an enzyme and substrate combine.

Enzyme substrate complex

16

Explain the effect of increasing temperature beyond the optimum temperature for an enzyme.

Enzymes denatures
Hydrogen bonds break
Tertiary structure of enzyme changes.
Active site changes shape.
Active site no longer complementary to the substrate.
No enzyme substrate complexes formed.
Rate of reaction decreases.

17

Explain the effect of changing the pH on the rate of an enzyme controlled reaction.

As the environment becomes too acidic or Enzymes denatures
Hydrogen bonds break
Tertiary structure of enzyme changes.
Active site changes shape.
Active site no longer complementary to the substrate.
No enzyme substrate complexes formed.
Rate of reaction decreases

18

Describe the effect of adding a competitive inhibitor to an enzyme controlled reaction

As concentration of competitive inhibitor increases the rate of reaction decreases

19

Explain how a competitive inhibitor affects the rate of an enzyme controlled reaction.

Competitive inhibitor and substrate have a similar shape.
Competitive inhibitor enters the active site.
Preventing the substrate gaining access to the active site.
Fewer ES complexes formed.
Rate of reaction decreases.

20

Describe the effect of adding a non-competitive inhibitor to an enzyme controlled reaction.

Decreases the rate of the reaction.

21

Explain the effect of adding a non-competitive inhibitor to an enzyme controlled reaction.

Non-competitive inhibitor has a different shape to the substrate.
Non-competitive inhibitor bonds to an allosteric site.
Changes the tertiary structure of the enzymes.
Changes the shape of the active site.
Substrate no longer complementary to active site.
Fewer ES complexes formed
Rate of reaction decreases.

22

Describe the effect of increasing enzyme concentration on the rate of an enzyme controlled reaction.

As enzyme concentration increases the rate of the reaction increases.
The rate then remains constant/plateau/levels off.

23

Explain the effect of increasing enzyme concentration on the rate of an enzyme controlled reaction.

As enzyme concentration increases rate the reaction increases
More successful collisions between enzyme active site and substrate.
More ES complexes formed.

Plateau
Excess enzymes - insufficient substrate available to enter the active sites.

24

Describe the effect of increasing substrate concentration on the rate of an enzyme controlled reaction.

As substrate concentration increases
More successful collisions between enzyme active site and substrate.
More ES complexes formed.

Plateau
Excess substrate available.
All active sites are full at all times.
Rate of reaction cannot increase.

25

Describe how you would work out the rate of an enzyme controlled reaction at 10s from a graph showing time on x axis and amount of product made on y axis

Draw tangent to line of best fit.
Read off graph
Change in time
Change in amount of product made

Amount of product/Time