Enzymes

Question 1

What type of reactions are anabolic reactions?

Answer 1

Building up.

Question 2

What type of reactions are catabolic reactions?

Answer 2

Breaking down.

Question 3

Enzymes can only increase the rate of reaction up to a certain point. What is this called?

Answer 3

Vmax (maximum initial velocity or rate of the enzyme-catalysed reaction)

Question 4

What will happen to the molecules when high temperatures or pressures are applied to a solution?

Answer 4

The speed of the molecules will increase, increasing the number of successful collisions and therefore the rate of reaction.

Question 5

What is the specificity of an enzyme?

Answer 5

Where each enzyme catalyses one specific biochemical reaction.

Question 6

What is activation energy?

Answer 6

The energy needed for a reaction to start.

Question 7

What is the lock and key hypothesis?

Answer 7

The idea that only a specific substrate will ‘fit’ into the active site of an enzyme.

Question 8

What is an enzyme-substrate complex?

Answer 8

When the substrate binds to the active site.

Question 9

What happens when the R-groups within the active site of an enzyme interact with the substrate?

Answer 9

It forms temporary bonds, which puts a strain on other bonds within the substrate and help speed the reaction up.

Question 10

What is the induced fit hypothesis?

Answer 10

When the active site changes slightly as the substrate enters.

Question 11

What are intracellular enzymes?

Answer 11

Enzymes that act within cells.

Question 12

What are extracellular enzymes?

Answer 12

Enzymes that act outside of cells.

Question 13

Which organisms rely on extracellular enzymes to make use of polymers for nutrition?

Answer 13

Both single-celled and multicellular organisms.

Question 14

Name a large molecule that enzymes break down.

Answer 14

Protein.

Question 15

Name 2 small molecules that enzymes produce.

Answer 15

Amino acids, glucose.

Question 16

Name 2 extracellular enzymes that are involved in digestion in humans.

Answer 16

Amylase and trypsin.

Question 17

What happens to the particles when temperature of a reaction environment is increased?

Answer 17

Kinetic energy of the particles increase and the particles move faster and collide more frequently.

Question 18

What measures how much the rate of a reaction increases?

Answer 18

Temperature coefficient, Q10.

Question 19

As temperature increases, the vibrations increase until the bonds strain then break. What does this cause the enzyme to do?

Answer 19

Denature.

Question 20

What is the optimum temperature?

Answer 20

The temperature at which the enzyme has the highest rate of activity.

Question 21

What is the optimum temperature for enzymes in the human body?

Answer 21

40*C.

Question 22

Which enzymes have more flexible structures and are less stable?

Answer 22

Enzymes adapted to the cold.

Question 23

Which enzymes are more stable?

Answer 23

Enzymes adapted to hot environments.

Question 24

Why are enzymes that are adapted to hot environments more stable?

Answer 24

They have an increased number of hydrogen and sulphur bonds.

Question 25

More hydrogen ions are present in which pH?

Answer 25

Low (acid).

Question 26

Fewer hydrogen atoms are present in which pH?

Answer 26

High (alkaline).

Question 27

What is the optimum pH in terms of ions?

Answer 27

Where a certain hydrogen ion concentration will cause the active site to be the right shape.

Question 28

What is renaturation?

Answer 28

If the pH returns to the optimum then the protein will resume its natural shape and catalyse the reaction again.

Question 29

What does the increased number of substrate particles lead to?

Answer 29

A higher collision rate with the active sites of enzymes and the formation of more enzyme-substrate complexes.

Question 30

What happens when the concentration of the enzyme increases?

Answer 30

More active sites become available which leads to enzyme-substrate complexes forming at a faster rate.

Question 31

Competitive inhibitor.

Answer 31

Binds to the active site of the enzyme, preventing the substrate from doing this.

Question 32

Incompetitive inhibitor.

Answer 32

Binds to the allosteric site of the enzyme, which still allows the substrate to bind to the active site, but prevents any products from being produced.