Biology

Question 1

What is a cell?

Answer 1

Cells are the basic building blocks of all living organisms.

Question 2

What is a tissue?

Answer 2

A tissue is a group of cells with a similar structure and function

Question 3

What is an organ?

Answer 3

Organs are aggregations of tissues performing specific functions.

Question 4

What is an organ system?

Answer 4

Organs are organised into organ systems, which work together

Question 5

What is the function of the digestive system?

Answer 5

To digest and absorb food.

Question 6

Name 6 facts about enzymes, including what they are.

Answer 6

1. are biological catalysts that speed up chemical reactions in living organisms
2. are large proteins
3. catalyse a specific reaction due to the shape of the active
   site
4. are denatured by high temperature and extremes of pH
   due to changes in the shape of the active site
5. have an optimum temperature
6. have an optimum pH.

Question 7

What is the role of digestive enzymes?

Answer 7

Digestive enzymes convert food into small soluble molecules that can be absorbed into the bloodstream.

Question 8

What are carbohydrases? Give an example and what it breaks down.

Answer 8

Carbohydrases break down carbohydrates to simple sugars. Amylase is a carbohydrase which breaks down starch.

Question 9

What are proteases?

Answer 9

Proteases break down proteins to amino acids.

Question 10

What are lipases? Give an example.

Answer 10

Lipases break down lipids (fats) to glycerol and fatty acids

Question 11

What are the products of digestion used for?

Answer 11

The products of digestion are used to build new carbohydrates, lipids and proteins. Some glucose is used in respiration.

Question 12

Where is bile made and stored?

Name 3 functions of bile.

Answer 12

Bile is made in the liver and stored in the gall bladder.

1. It is alkaline to neutralise hydrochloric acid from the stomach. 2. It also emulsifies fat to form small droplets which increases the surface area.
2. The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.

Question 13

What is metabolism?

Answer 13

Metabolism is the sum of all the reactions in a cell or the body.

Question 14

What is energy from respiration used for?

Answer 14

The energy transferred by respiration in cells is used by the organism for the continual enzyme controlled processes of metabolism that synthesise new molecules.

Question 15

Describe the 5 metabolic reactions that make up cellular metabolism?

Answer 15

1. conversion of glucose to starch, glycogen and cellulose
2. the formation of lipid molecules from a molecule of
   glycerol and three molecules of fatty acids
3. the use of glucose and nitrate ions to form amino acids
   which in turn are used to synthesise proteins
4. respiration
5. breakdown of excess proteins to form urea for excretion.