1.1.1 The need for communication

Question 1

Give an example of internal stimuli and how the organism would respond?

Answer 1

As cells undergo metabolic activities thy use up substrates and produce products. Sometimes the products are toxic. Carbon dioxide is an example. If it is alllowed to build up in the tissue fluid it could disrupt the activty of enzymes due to a pH change.

Question 2

What is a response?

Answer 2

A response is a change of behaviour or physiology as a result of a change in the environment.

Question 2

Give an example of external stimuli and how the organism would respond?

Answer 2

When the temperature changes during the seasons, the Arctic Fox changes it’s coat, from thick and white in the winter to thin and brown in the summer.

Question 3

What is the name given to the process by which cells communicate with each other?

Answer 3

Cell signalling.

Question 5

Give four examples of conditions that could affect enzyme activity?

Answer 5

1. Temperature
2. pH
3. Aqueous environment to keep substrates and products in solution
4. Freedom from toxins and excess inhibitors

Question 6

What are the five properties a good communication system will have?

Answer 6

1. It will cover the whole body
2. It will enable rapid communication
3. It will enable cells to communicate with each other
4. It will enable specific communication
5. It will enable both short-term and long-term responses.

Question 7

What is a stimulus?

Answer 7

A stimulus is any change in the environment that causes a response.

Question 8

Give two examples of major systems of communication that work by cell signalling?

Answer 8

1. The hormonal system (long-term responses)
2. The neuronal system (short-term responses)

Question 9

Why must living things need to maintain a certain limited set of conditions inside their cells?

Answer 9

They must maintain certain condtions becuase the cellular activities rely on the action of enzymes, which need a specific set of condtions to work efficiently.