Chapter 3: Internal Membranes and Enzymes

Question 1

What is the mitochondrial mix?

Answer 1

The gel-like substance enclosed by the inner membrane of a mitochondrion

Question 2

What is the purpose of the mitochondrial mix?

Answer 2

Contains enzymes in solution that are responsible for reactions in another stage of cellular respiration

Question 3

What are catalysts?

Answer 3

A substance that speeds up a chemical reaction without being used up in the reaction

Question 4

Why are enzymes called the organic catalysts?

Answer 4

They act as catalysts and speed up the reactions within a cell

Question 5

What is cellular metabolism?

Answer 5

All of the chemical processes occurring in a living cell

Question 6

What are intracellular enzymes?

Answer 6

An enzyme that functions inside the cell that produces it, to speed up and control metabolic reactions

Question 7

What are extracellular enzymes?

Answer 7

An enzyme that is produced by cells but functions outside of the cells. E.g. digestive enzymes that break down food

Question 8

What is activation energy?

Answer 8

The energy required to initiate a reaction

Question 9

What are biochemical pathways?

Answer 9

Chemical reactions in cells that occur in a series of enzyme-regulated steps

Question 10

What is a substrate?

Answer 10

A substance that enters a reaction, also called reactant or precursor

Question 11

What is an enzyme-substrate complex?

Answer 11

A substance formed when an enzyme and a substrate molecule join

Question 12

What is an activation site?

Answer 12

The place on the surface of an enzyme molecule where substrate molecules attach

Question 13

What is the lock-and-key model?

Answer 13

A model suggesting that the shape of a substrate molecule is an exact fir to the shape of an enzyme’s active site

Question 14

What is the induced-fit model?

Answer 14

A model to explain that the shape of an enzyme’s activation site undergoes specific changes, induced by the substrate to achieve a high degree of specificity with the substrate

Question 15

What is one of the fastest acting enzymes?

Answer 15

Catalase

Question 16

Do enzymes reduce or increase activation anergy?

Answer 16

Reduce

Question 17

What are equilibrium reactions?

Answer 17

A chemical reaction in which the forward and reverse reactions occur at equal rates

Question 18

What are enzymes sensitive to?

Answer 18

Change in temperature, pH, substrate and product concentrations

Question 19

What temperatures do enzymes have an optimal range at?

Answer 19

The temperature of the environment they are found in

Question 20

What are psychrophiles?

Answer 20

An organism that can grow and reproduce at low temperatures, ranging from -20ºC to 10º C

Question 21

What is denaturation?

Answer 21

The process by which the structure of a protein is changed by factors such as pH and temperature, the change in structure often destroys the shape of the active site of the molecule and results in a loss of function

Question 22

What is the optimal pH for an enzyme?

Answer 22

The pH of the environment it is found in

Question 23

What is a non-competitive inhibitor?

Answer 23

A molecule that binds to an enzyme at a site other than the active site, this changes the shape of the enzyme so that the substrate can no longer bing to the active site

Question 24

What is a competitive inhibitor?

Answer 24

A substance that competes with a substrate for an enzyme’s active site

Question 25

What are cofactors?

Answer 25

A small inorganic substance that is required in addition to an enzyme to catalyse a certain reaction

Question 26

What are coenzymes?

Answer 26

A small non-protein organic substance that is required in addition to an enzyme to catalyse a certain reaction