Topic 2 Organisation

Question 1

What is tissue?

Answer 1

Tissues are groups of similar cells that act together to perform a certain function It can include more than one type of cell.

Question 2

Give 4 examples of tissues and say whether they are found in animals, plants or both.

Answer 2

• Epidermal tissue(both animals and plants)
• Epithelial tissue(both animals and plants)
• Mesophyll (just plants)
• Muscular Tissue (just animals).

Question 3

Define Organs.

Answer 3

Organs are groups of different tissues that work together to perform a specific function.

Question 4

Give the function of Mesophyll.

Answer 4

Mesophyll is capable of Photosynthesis.

Question 5

Give examples of Epidermal tissue.

Answer 5

Human skin and the waxy covering of plants.

Question 6

Give the three types of tissue that the stomach is composed of.

Answer 6

Muscular Tissue, Glandular Tissue and Epithelial tissue.

Question 7

Give the order of development from cells to organisms.

Answer 7

1) Cells
2) Tissue
3) Organs
4) Organ systems
5) Organisms

Question 8

What process does muscular tissue carry out in mammals?

Answer 8

• It contracts to move whatever it’s attached to.

Question 9

What process does Glandular tissue carry out in mammals?

Answer 9

• It makes and secretes chemical such as enzymes and hormones.

Question 10

What process does Epithelial tissue carry out in mammals?

Answer 10

• It covers some parts of the body e.g. inside of the gut

Question 11

What function does Muscular tissue carry out in the stomach?

Answer 11

• Muscular tissue moves the stomach wall to churn up food.

Question 12

What function does Glandular tissue carry out in the stomach?

Answer 12

• It makes digestive juices to digest food.

Question 13

What function does Epithelial tissue carry out in the stomach?

Answer 13

• It covers the outside and inside of the stomach.

Question 14

Give the 5 organs that make up the digestive system which breaks down and absorbs food and give their overall basic functions.

Answer 14

1) Glands ( e.g. the pancreas and salivary glands) these produce digestive juices.
2) The stomach and the small intestine which digest food.
3) The liver, which produces bile.
4) The small intestine which absorbs soluble food molecules.
5) The large intestine which absorbs water from undigested foods leaving faeces.

Question 15

What is the order in which food passes through the digestive system?

Answer 15

1) Mouth
2) Oesophagus
3) Stomach
4) Small intestine
5) Large intestine
6) Rectum
7) Anus

Question 16

What specifically is the function of the mouth in digestion?

Answer 16

• To mechanically break up food into smaller pieces to make it easier to swallow thus increasing surface area.

Question 17

What are two functions of saliva in digestion?

Answer 17

1) To moisten food to allow easier swallowing.

2) To start chemical digestion by containing salivary amylase.

Question 18

What is the function of stomach acid in digestion?

Answer 18

• To kill potentially pathogenic microorganisms in food.

Question 19

What specifically is the function of the small intestine in digestion?

Answer 19

• To absorb carbohydrates, lipid, amino acids, vitamins and minerals from digested foods.

Question 20

What specifically is the function of the large intestine in digestion?

Answer 20

• To absorb water from digested food.

Question 21

Give an adaptation of a) the small intestine and b) cells lining the small intestine to aid absorption of digested molecules.

Answer 21

• a) Small intestine has structures called villi which increase the surface area
• b) Epithelial cells lining the villi have microvilli on their surface which further increase surface area.

Question 22

What specifically is the functions of the liver in digestion?

Answer 22

• To produce bile, an emulsifying and neutralising substance.

Question 23

What specifically is the functions of the gall bladder in digestion?

Answer 23

• To store bile until it can be released into the small intestine.

Question 24

What generally is an enzyme?

Answer 24

• It is a protein that can catalyse a reaction without being used up itself. They are biological catalysts.

Question 25

What is a substrate?

Answer 25

A molecule or atom which is acted upon by an nenzyme.

Question 26

How does an enzyme “recognise” its specific substrate?

Answer 26

• It has a complementarily shaped active site.

- An active site is a region on the enzyme which fits the substrate.

Question 27

Explain the lock and key model of enzyme action.

Explain why this is simpler than how enzymes actually work.

Answer 27

• It is a simple model whereby the substrate fits into the active site in the enzyme and the products are formed.
• This is simpler than how enzymes actually work as the active site changes shape slightly as the substrate binds to it to get a tighter fit, this is called the ‘induced fit’ model of enzyme action.

Question 28

What is an active site?

Answer 28

• It is a unique shape on the enzyme that fits onto the substrate.

Question 29

What would happen if the substrate didn’t match the enzyme’s active site?

Answer 29

• The reaction would not be catalysed.

Question 30

What is a way we can usually catalyse a reaction without enzymes and how is this flawed?

Answer 30

• We can usually make the reaction happen more quickly by increasing the temperature but this would speed up the useful reactions and the unwanted ones too.
• Further more there is a limit to how much you can increase the temperature inside a living creature before its cells start to get damaged.

Question 31

What happens as we begin to increase the temperature on an enzyme catalysed reaction?

Answer 31

• Like any reaction a higher temperature increases the rate of reaction at first but if the temperature gets too high some of the bonds holding the enzyme together break.
• This changes the shape of the enzymes active site, so the substrate won’t fit anymore. The enzyme is now DENATURED.
• All enzymes have an OPTIMUM TEMPERATURE that they work at best.