2.1 - Principles of Organisation + Enzymes

Question 1

What is the Order of the Different Levels of Organisation?

Answer 1

Organelles –> Cells –> Tissues –> Organs –> Organ Systems –> Organisms

Question 2

What is the definition of a Tissue?

Answer 2

A group of similar cells that work together to carry out a particular function.

Question 3

What is the definition of an Organ?

Answer 3

A group of different tissues that work together to perform a particular function.

Question 4

What is the definition of an Organ System?

Answer 4

A group of organs that work together to perform a particular function.

Question 5

What is the definition of a Catalyst?

Answer 5

A substance that increases the speed of a reaction, without being changed or used up in the process.

Question 6

What are Enzymes?

Answer 6

Large proteins made up of long chains of amino acids, can fold up to form different shapes which each form a unique enzyme that catalyses a particular chemical reaction.

Question 7

What is a Reactant called in Biology?

Answer 7

A Substrate

Question 8

What is the Active Site on an Enzyme?

Answer 8

A part of the enzyme with a unique shape that’s complementary to the substrates of the reaction.

Question 9

What happens if a Substrate does not fit the Enzyme?

Answer 9

The reaction will not be catalysed. This allows the enzymes to be really specific about which reactions they speed up.

Question 10

What is the Lock & Key Model?

Answer 10

A model showing that the substrate had to fit perfectly into the active site.

Question 11

What is the Induced Fit Model?

Answer 11

A model showing that the enzyme slightly changes shape as it binds to the substrate. The active site is complementary to the substrate

Question 12

What Two Factors affect the Rate of Reaction in Enzymes?

Answer 12

Temperature & pH

Question 13

How does Temperature affect the Rate of Reaction in Enzymes?

Answer 13

The higher the temperature, the more energy in the enzymes and therefore the quicker the reaction. However, if temperature gets too high this can have the opposite effect,

Question 14

What is the Optimum Temperature?

Answer 14

The temperature at which the rate of reaction is highest.

Question 15

Why do Enzymes stop working when the Temperature is too high?

Answer 15

• High Temperatures start to break apart the bonds holding enzymes together.
• The Active Site starts to change shape.
• If it changes shape enough, the enzyme won’t be able to bind to the substrate (The Enzyme has been denatured).

Question 16

Why do Enzymes stop working when the pH is too high or too low?

Answer 16

• Some of the bonds holding the Enzymes together start to break.
• The Active Site starts to change shape.
• If the Active Site changes shape too much, it will become denatured.