B4: Organising Animals And Plants

Question 1

Components of the blood and functions?

Answer 1

• Red blood cells - carry oxygen
• White blood cells - part of the bodies defence system, some make antibodies, and antitoxins, and some digest bacteria and viruses
• Platelets - small fragments of cells. Help blood clot as a wound.
• Plasma - transports all blood cells and some others around body

Question 2

How are red blood cells adapted?

Answer 2

• increased SA:V ratio (biconcave discs)
• packed with haemoglobin that binds to oxygen
• no nucleus to make space for haemoglobin

Question 3

How does the blood clot?

Answer 3

Enzymes help convert fibrinogen to fibrin, which produces a network of protein fibres that captures blood cells and forms a clot to stop excessive bleeding. Dries and gardens to form a scab. Stops bacteria entering body

Question 4

What does the plasma carry? And where does it take them?

Answer 4

• Waste CO2 produces by the cells - lungs
• Urea formed in liver from break down of proteins - kidneys
• Small soluble products of digestion - from small intestine to cells

Question 5

3 main types of blood vessels?

Answer 5

Arteries, vessels, capillaries

Question 6

What direction to arteries carry blood?

Answer 6

Away from heart and to organs. (Oxygenated)

Question 7

What direction to vessels carry blood?

Answer 7

Away from organs to the heart (deoxygenated)

Question 8

Capillaries allow…

Answer 8

The diffusion of substances such as oxygen and glucose into the cells, and substances such as CO2 to diffuse into blood.

Question 9

D. Double circulatory system?

Answer 9

The circulation of blood from the heart to the lungs is separate from the circulation of blood from the heart to rest of body

Question 10

Function of stents?

Answer 10

Keep narrowed or blocked arteries open

Question 11

Function of statins?

Answer 11

Reduce cholesterol levels in blood, reducing risk of coronary heart disease.

Question 12

What is a natural pacemaker?

Answer 12

A group of cells in the right atrium that form a natural pacemaker

Question 13

Adaptions of alveoli?

Answer 13

• rich supply of capillaries which maintain a steep conc gradient in both directions
• very large surface area

Question 14

Examples of plant organ systems?

Answer 14

Roots, stem and leaves form a organ system

Question 15

D. Translocation?

Answer 15

The movement of dissolved sugars from leaves to the plant.

Question 16

Why is transport in plants so important? (4)

Answer 16

• all cells need glucose for respiration
• minerals are needed for production of proteins -“and molecules within a cell
• need water for photosynthesis
• needs water to remain turgid

Question 17

D. Transpiration?

Answer 17

The loss of water vapour from the stomata

Question 18

Through what is water lost in plants? Why?

Answer 18

The stomata as they open to allow CO2 to enter

Question 19

What controls water loss and gas exchange in a plant?

Answer 19

The stomata and guard cels

Question 20

The size of the opening of the stomata is controlled by…..

Answer 20

Guard cells

Question 21

How does the transpiration stream work?

Answer 21

As water evaporates, more is pulled up through the xylem to replace it. It’s driven by evaporation.

Question 22

Factors that increase the rate of photosynthesis?

Answer 22

Humidity, CO2 conc, temperature, light intensity and air flow

Question 23

Transpiration is more rapid in what conditions?

Answer 23

Dry/wind/hot

Question 24

What does the pulmonary artery do?

Answer 24

(Right v.) takes for the Bates blood to the lungs.

Question 25

What does the aorta do?

Answer 25

(Left v.) takes oxygenated blood around the body.

Question 26

What does the pulmonary vein do?

Answer 26

Brings oxygenated blood from the lungs.

Question 27

What does the Vena cava do?

Answer 27

Brings deoxygenated blood into the heart.

Question 28

Adaptations of villi?

Answer 28

• Increased surface area due to folding = max absorption
• Single later of thin cells = small diffusion distance
• Rich blood supply (capillaries) to distribute dissolved food molecules.

Question 29

Adaptations of alveoli? (4)

Answer 29

• Walls are 1 cell thick = short diffusion distance/exchange surface very thin
• Rich blood supply = take oxygen away and bring C02 which maintains max concentration gradient.
• Folded = greater surface area for gas exchange
• Ventilated = removed waste C02 and replenish oxygen levels. Maintain max conc gradient between alveoli and blood.