B3

Question 1

What is a tissue with an example?

Answer 1

A tissue is a group of cells with similar structure and function working together e.g. muscular tissue can contract to bring about movement

Question 2

What are organs with an example?

Answer 2

Organs are collections of tissues. Each organ contains several tissues all working together to perform a specific function. e.g. the stomach containing muscular tissues to churn the food, the glandular tissue to produce digestive fluids and the epithelial tissue which covers the surface

Question 3

What is an organ system?

Answer 3

Groups of organs that work together to perform specific functions. There are many in one organism

Question 4

What is the digestive system?

Answer 4

The digestive system in a mammal is an organ system where several organs work together to digest and absorb food

Question 5

What do the glands in the digestive system do?

Answer 5

They release digestive juices containing enzymes to break down your food.

Question 6

What is the small intestine and what does it do?

Answer 6

It is a long tube where the soluble molecules that have been broken down are absorbed into your blood. Then it can be transported in the bloodstream around your body. It is adapted to have a large surface area with lots of villi. It also has good blood supply and short diffusion distances which increases the rate of active transport.

Question 7

What is the liver?

Answer 7

The liver is a large organ that carries out the production of bile which helps in the digestion of lipids.

Question 8

What are carbohydrates?

Answer 8

They are made up of units of sugars. They either contain one sugar unit-called a simple sugar or many sugar units known as complex carbohydrates which need to be broken down to be absorbed.

Question 9

What are lipids?

Answer 9

They are fats and oils and are the most efficient energy store in your body. They are made up of tree molecules of fatty acids joined o a molecule of glycerol.

Question 10

How do you test for lipids?

Answer 10

Through the ethanol test.

Question 11

How do you test for simple sugars?

Answer 11

If there are it turns blue Benedict’s solution brick red on heating.

Question 12

How do you test for complex carbohydrates?

Answer 12

Starch turns yellow-red iodine solution blue-black

Question 13

What are proteins made up of?

Answer 13

Long chains of small units called amino acids.

Question 13

How to test for protein molecules?

Answer 13

Biuret reagent turns from blue to purple in the presence of proteins.

Question 14

What happens if the bonds between the amino acids are heated?

Answer 14

They become denatured and it may not be able to function anymore in your cells.

Question 15

What is a catalyst?

Answer 15

They increase the rate of chemical reaction without changing chemically themselves.

Question 16

What are enzymes?

Answer 16

They are large protein molecules that are special biological catalysts that speed up reactions. Each enzyme reacts with a particular substrate as their active site is moulded to fit the substrate.

Question 17

How do enzymes work?

Answer 17

It is when a moulded enzyme joins to a substrate because the active site fits onto the substrate. The reaction then happens and breaks down the substrate.

Question 18

What is metabolism?

Answer 18

It is the sum of all the reactions in the cell or in the body.

Question 19

What effect does temperature have on enzymes?

Answer 19

Up until 37 degrees Celsius the rate of reaction speeds up with an increase of temperature but then it sharply decreases in reaction time when the enzyme becomes denatured.

Question 20

What effect does pH have on enzyme action?

Answer 20

A change in pH affects the forces that hold the folded chains in place

Question 21

What are digestive enzymes?

Answer 21

They are enzymes that work outside your cells and are produced by specialised cells in your glands

Question 22

What are enzymes that break down carbohydrates called?

Answer 22

Carbohydrase’s, an example of this is starch being broken down by amylase

Question 23

What breaks down proteins?

Answer 23

Proteases are produced by your stomach and other areas and the breaking down of you proteins into amino acids take place in your stomach and small intestine.

Question 24

What breaks down fats?

Answer 24

Lipase enzymes break the lipids down into fatty acids and glycerol, these enzymes are made in your pancreas and small intestine.

Question 25

What is bile?

Answer 25

Bile is an alkaline liquid that is needed to turn the acidic liquid inside your stomach into an alkali to enter the small intestine. It is stored in your gall bladder. The bile also emulsifies the fats in your food so it breks up large drops of fats into smaller drops so there is a much larger surface area for lipase enzymes to act upon.