B4 Organising Animals & Plants

Question 1

Some students investigated the effect of nitrates on the growth of seedlings.

The students set up three test tubes.
• Tube A contained pure water.
• Tube B contained all the mineral salts that a seedling needs for healthy growth.
• Tube C contained all the mineral salts that a seedling needs for healthy growth,
but no nitrate.

Why did the students set up tubes A and B?

Answer 1

As controls to see if nitrate was necessary for growth.

Question 2

Some students investigated the effect of nitrates on the growth of seedlings.

The students set up three test tubes.
• Tube A contained pure water.
• Tube B contained all the mineral salts that a seedling needs for healthy growth.
• Tube C contained all the mineral salts that a seedling needs for healthy growth,
but no nitrate.

To make it a fair test, what should each of the tubes, A, B and C contain?

Answer 2

The same volume of culture solution.

Question 3

Explain the role of the diaphragm in breathing.

Answer 3

The diaphragm (located below the lungs) contracts and flatterns when we breathe in

…and relaxes and bows upwards when we breathe out.

Question 4

Explain the role of the rib cage in breathing.

Answer 4

The rib cage moves upwards and outwards when we breathe in

…and downwards and inwards when we breathe out.

Question 5

Alveoli are adapted for…

Answer 5

gas exchange.

Question 6

How are alveoli adapted for gas exchange?

Answer 6

Large surface area.
Moist.
Thin walls.
Good blood supply.

Question 7

Which part of the blood transports oxygen?

Answer 7

Red blood cells

Question 8

Which part of the blood helps blood to clot at the site of a cut?

Answer 8

Platelets

Question 9

Which part of the blood transports urea?

Answer 9

Plasma

Question 10

What are the pores on the lower surface of the leaf called?

Answer 10

Stomata

Question 11

How is water lost from the leaves of a plant?

Answer 11

Water vapour diffuses out the stomata.

Question 12

What type of food should people with diabetes avoid?

Answer 12

Foods with high sugar or starch content.

Question 13

What are the advantages and disadvantages of treating a patient with an artificial heart?

Answer 13

Advantages:
• useful where no other treatment available
• extends lifespan

Disadvantages:
• low success rate
• device has limited lifespan
• discomfort
• risk of infection

Question 14

Describe the structure of the leaf and the functions of the tissues in the leaf.

Answer 14

Structures and functions:

1. Waxy cuticle - coats leaf to reduce water loss
2. Epidermis - surface cells, no chloroplasts to allow light through
3. Palisade mesophyll - many chloroplasts to trap light
4. Spongy mesophyll - air spaces for gas movement
5. Stomata - allow gas exchange and controls water loss

Question 15

Most water enters a plant through…

Answer 15

root hairs.

Question 16

The water is transported up the stem to the leaves in the…

Answer 16

xylem.

Question 17

Carbon dioxide enters leaves through…

Answer 17

stomata.

Question 18

Sugars are transported to storage organs through the…

Answer 18

phloem.

Question 19

What is the name of the process through which water is lost from a plant?

Answer 19

Transpiration

Question 20

During a breathing cycle, the volume of the air in the lungs increases then decreases.

How do the diaphragm and ribcage cause these changes?

Answer 20

When we inhale the ribcage moves upwards and outwards and the diaphragm flattens. This reduces pressure and draws air into the lungs.

When we exhale the ribcage moves downwards and inwards and the diaphragm bows upwards. This increases pressure and pushes air out the lungs.

Question 21

A modern ventilator uses a tube to force air into and out of the lungs. Old ventilators were large and used to apply pressure to the patient’s chest to cause breathing.

What are the advantages and disadvantages of using a modern ventilator?

Answer 21

Advantage:
The patient has more freedom of movement.
The modern ventilator is more portable.

Disadvanage:
The tube inserted into the trachea may be uncomfortable and make eating/talking difficult.