B3- Organisms exchange substances with their environment

Question 1

What happens to the surface area to volume ratio as the size of an organism, increases?

Answer 1

Decreases

Question 2

What happens to the rate of diffusion as the SA:Volume ratio increases?

Answer 2

Increases

Question 3

What happens to the rate of diffusion as the size increases?

Answer 3

Decreases

Question 4

Why do animals in a cold environment experience less heat loss?

Answer 4

Larger volume therefore smaller ratio, reduced heat loss/diffusion

Question 5

Why do animals in a hot environment experience increased heat loss?

Answer 5

Have large features to maximise SA. Increased ratio, more heat loss/diffusion

Question 6

Factors affecting the rate of diffusion? [3]

Answer 6

• (decreased) diffusion distance
• (increased) concentration gradient
• (increased) Surface area

Question 7

What two features on a fish’s gills maximise SA?

Answer 7

-Gill lamella
-Gill filaments

Question 8

How does a fish maximise concentration gradient?

Answer 8

The counter current system

Question 9

How does the counter current system work? [3]

Answer 9

• Blood flows in the opposite direction to water in the fish’s gills
• This ensures a steep concentration gradient of oxygen is maintained
• Maintained along the entire length of the gill filament

Question 10

How does a fish minimise diffusion distance?

Answer 10

Thin lamella

Question 11

How does the alveoli reduce diffusion distance to maximise gas exchange?

Answer 11

Alveoli and surrounding capillares are one cell thick

Question 12

How does the alveoli maximise concentration gradient to maximise gas exchange?

Answer 12

Constant blood supply by capillaries

Question 13

What two things does ventilation consist of?

Answer 13

Inspiration and Expiration

Question 14

Process of inspiration [6]

Answer 14

-External intercostal & diaphragm muscles contract
- Rib cage moves upwards & outwards
- Diaphragm flattens
- Increased volume of thoracic cavity
-Lung pressure decreases
- Air flows into lungs (from area of high pressure to area of low pressure)

Question 15

Process of exspiration [6]

Answer 15

-External intercostal & diaphragm muscles relax
- Rib cage moves downwards & inwards
- Diaphragm becomes curved
- Decreased volume of thoracic cavity
-Lung pressure increases
- Air flows out of lungs (from area of high pressure to area of low pressure- down pressure gradient)

Question 16

Is inspiration active or passive?

Answer 16

Active

Question 17

Is expiration active or passive?

Answer 17

[Normal]- passive
[Forced- e.g blowing out candle]- active

Question 18

What is the thoracic cavity?

Answer 18

Lung space

Question 19

What do insects use for gas exchange?

Answer 19

The Tracheal system

Question 20

Process of gas exchange in insects [3]

Answer 20

-Air moves into tracheae (microscopic air-filled pipes) through pores called spiracles
-The tracheae branch into smaller tracheoles
Carbon dioxide moves into spinacles and is released
-Use Rhythmic Abdominal movements

Question 21

How does gas exchange occur in plants?

Answer 21

Gases enter and leaves via the stomata in the leaves.

Question 22

How does air enter into the alveoli in the human/mammalian respiratory system. [4]

Answer 22

• Air enters via nasal cavity, into the trachea
• The trachea splits into two bronchi
• The two bronchi branch into many smaller bronchioles
• Bronchioles end with small ‘air sacs’ called alveoli.

Question 23

What is the pharynx?

Answer 23

The throat- a passageway for air from the nose to the larynx

Question 24

What is the larynx?

Answer 24

The voice box- contains vocal cords and helps direct air from your throat to the trachea to your lungs

Question 25

Three adaptations of the alveoli to increase gas exchange?

Answer 25

- Large SA - Thin alveolar walls (one cell thick) - Good blood supply (surrounded by dense capillary network)

Question 26

what is a xerophytic leaf?

Answer 26

a leaf adapted to survive in dry environments by minimising water loss

Question 27

What is a dicotyledonous leaf?

Answer 27

a leaf adapted to survive in hot and wet environments by maximising water loss

Question 28

Adaptations of xerophytes?

Answer 28

- Thick cuticle - Rolled up leaves - Hairy leaves - Sunken stomata - Reduced SA/V radio - Deep roots

Question 29

Types of lung diseases

Answer 29

-Cancer -Emphysema -Tuberculosis -Asthma -Fibrosis

Question 30

Causes of lung diseases

Answer 30

Smoking, asbestos, bacterial infection, allergic response, dust and dirt particles

Question 31

Symptoms of lung diseases

Answer 31

- Coughing mucus or blood - Faster, shallower breathing - Blood oxygen saturation readings below 90% - Fatigue

Question 32

How are the lungs affected by asthma?

Answer 32

Asthma increases the production of mucus by the epithelial cells. The increased mucus increases the length of the diffusion distance. The greater diffusion distance decreases the rate of gas exchange. An asthma attack also causes the smooth muscle in the bronchioles to contract. This makes it difficult to breathe.

Question 33

How are the lungs affected by emphysema?

Answer 33

Emphysema is caused by smoking or air pollution. Dirt and bacteria become trapped in the alveoli which damages the alveoli walls. The alveoli provide a large surface area for gas exchange. Damage to the walls decreases the surface area and rate of gas exchange declines.

Question 34

How are the lungs affected by tuberculosis?

Answer 34

Tuberculosis bacteria can infect the lungs, damaging the lung tissue. The cells of the immune system can also damage the lungs. The damaged lungs lead to a decreased tidal volume.

Question 35

Which blood vessel does deoxygenated blood enter the heart via?

Answer 35

Vena Cava

Question 36

What valve connects the atrium to the ventricle

Answer 36

Atrio-ventricular valve

Question 37

What valve connects the right ventricle to the pumonary artery?

Answer 37

Pulmonary valve

Question 38

What valve connects the left ventricle to the aorta?

Answer 38

Aortic valve

Question 39

Which blood vessel carries blood away from the heart to the rest of the body?

Answer 39

Aorta

Question 40

Which blood vessel does deoxygenated blood travel to the lungs via?

Answer 40

Pulmonary artery

Question 41

Which blood vessel does oxygenated blood travel into the heart from the lungs via?

Answer 41

Pulmonary vein

Question 42

Where do arteries carry blood from and to?

Answer 42

Fro the heart to the rest of the body

Question 43

Artery adaptations [3]

Answer 43

Elastic tissue, thick muscular walls- maintains high blood pressure- stretches and recoils as heart beats. Folded inner lining (endothelium)- allows artery to stretch and maintains high pressure Narrow lumen- maintains high blood pressure

Question 44

Where do veins carry blood?

Answer 44

Back to heart under low pressure.

Question 45

Adaptations of veins

Answer 45

Wider lumen and very little elastic tissue- accommodates a large volume of blood Contains valves- prevents back flow of blood

Question 46

What are the arterioles?

Answer 46

Network that arteries divide into Blood directed to different areas of demand by muscles in arterioles Muscles contract and relax to control blood flow to organs

Question 47

What are capillaries

Answer 47

Smallest blood vessel that exchanges substances between cells and capillaries

Question 48

Adaptations of capillaries

Answer 48

Found near cels in exchange tissues- short diffusion pathways Walls are one cell thick- shortens diffusion pathway Large number of them- increases surface area for exchange

Question 49

What are capillaries made of?

Answer 49

Endothelium cells