B4

Question 1

Components of blood

Answer 1

Plasma, red blood cells, platelets, white blood cells

Question 2

Plasma

Answer 2

carries red blood cells, white bloodcells and platelets and other disolved substances around the body.
Also carries waste carbon dioxide to the lungs and urea formed in your liver from excess protien to the kidneys

Question 3

Red blood cells

Answer 3

pick up oxygen from the lungs and carry it to cells around the body.
They are concave discs, giving them a large surface area : body ratio for diffusion.
Contain haemoglobin which binds to oxygen.
No nucleus to contain more haemoglobin.

Question 4

White blood cells

Answer 4

protect the body against harmful microrganisms (and contain a nucleus). There are different types including: lymphocytes, phagocytes, and others which produce antitoxins.

Question 5

Lymphocytes

Answer 5

Form antibodies against microorganisms.

Question 6

Phagocytes

Answer 6

Engulf and digest bacteria and viruses

Question 7

Platelets

Answer 7

small fragements of cells that cause the blood to clot at the site of a wound. This causes enzyme reactions and creates protien networks to form a scab.

Question 8

Arteries

Answer 8

Carries oxygenated blood away from the heart and to the organs of the body. Arteries stretch as bright red oxygenated blood is forced through them by the muscle surrounding the lumen.

Question 9

Veins

Answer 9

Carries purple-red low in oxygen blood away from the organs towards the heart. They have thinner walls than arteries and often have valves in them to aid in the movement of blood by preventing backflow.

Question 10

Capillaries

Answer 10

Capillaries form a huge network around the body, allowing blood to reach every cell, and linking veins and arteries. They have very thin walls so substances can diffuse into and out of cells.

Question 11

The heart

Answer 11

pumps blood around the body in a double circulatory system. The right ventricle pumps blood to the lungs where gas exchange takes place. The left takes it around the rest of the body

Question 12

Xylem cells

Answer 12

Specialised to carry water and minerals by having long hollow tubes, and are supported by spiral structures made of the chemical lignin. Also supports the plant’s stem.

Question 13

Pholem cells

Answer 13

Specialised to let food (made by photosynthesis) travel around a plant by having tubes to carry food, sieve plates which allow dissolved food to move through tubes. They are supported by companion cells.

Question 14

Palisade mesophyll

Answer 14

Contains lots of chloroplasts which carry out photosynthesis

Question 15

Spongy mesophyll

Answer 15

Has some chloroplasts, but is mainly big open air spaces and has large surface area for diffusion.

Question 16

Aveoli

Answer 16

In the lungs, have large surface areas for gas exchange. Absorbs oxygen for the blood stream as they contain many capillaries.

Question 17

Transpiration

Answer 17

When water leaves a plant, through stomatas on leaves, into the air.

Question 18

Transpiration stream

Answer 18

Water moving through the plant to the leaves, through xylem cells.

Question 19

Stomata

Answer 19

The openings on leaves where oxygen enters the plant and carbon dioxide and water vapour exits.

Question 20

Measuring transpiration rate

Answer 20

Using a potometer, we can see the distance an air bubble in a tube has travelled within a selected amount of time.

Question 21

How temperature affects transpiration

Answer 21

The kinetic energy of water molecules increases so they diffuse faster.

Question 22

How wind affects transpiration

Answer 22

Removes water molecules as they pass out of the leaf maintaining a steep concentration gradient for diffusion.

Question 23

How does humidity affect the rate of transpiration

Answer 23

The concentration of water molecules outside the leaf. Steepness of gradient for diffusion.

Question 24

How light intensity affects transpiration

Answer 24

Stomata open to allow gas exchange for photosynthesis so water vapour can diffuse out of the leaf.