2(f, g)

Question 1

Function of Trachea?

Answer 1

Airway leading from throat to lungs.

Question 2

Function of Ribs?

Answer 2

Create the ribcage which move during respiration but also protect heart and lungs from major damage.

Question 3

Function of Intercostal muscles?

Answer 3

Muscles which when contracted pull ribcage up and out creating space for air in lungs.

Question 4

Function of Bronchi?

Answer 4

Airway leading from trachea into each lung.

Question 5

Function of Alveoli?

Answer 5

Small air sacs adapted for gas exchange key part of lung.

Question 6

Function of Diaphragm?

Answer 6

Can contract during inspiration to become flat.

Question 7

Function of Pleural membranes?

Answer 7

Keep the thorax airtight and reduce friction during ventilation.

Question 8

Function of Goblet cells in trachea and bronchi?

Answer 8

Secrete mucus which trap pathogens (disease causing microorganisms, e.g. bacteria) and dirt (e.g. dust) in the lungs.

Question 9

Function of Ciliated cells in trachea and bronchi?

Answer 9

Ciliated cells have tiny hair-like projections called cilia, which beat rhythmically to waft the mucus up the bronchi and trachea to the throat where it is swallowed.

Question 10

What is the use of cartilage in the bronchi and trachea?

Answer 10

To hold airways open and prevent collapse when the air pressure inside is low during inspiration.

Question 11

What is the use of the smooth muscle in the trachea, bronchi and bronchioles?

Answer 11

To constrict the airways to control the flow of air to the alveoli; this may be important of there are harmful substances in the air by contracting.

Question 12

What is the use of the elastic tissue in the trachea, bronchi, bronchioles and alveoli?

Answer 12

Recoil to allow the airways to spring back to their normal size after airway constriction so the airways dilate (widen); also allow the alveoli to spring back to normal shape during expiration.

Question 13

State 3 adaptations of the Alveoli for gas exchange.(3)

Answer 13

Sac shaped = increased surface area for faster diffusion.
Thin wall = shorter distance for diffusion.
Capillaries wrapped around alveoli = moving blood creates steep concentration gradient for faster diffusion.

Question 14

Cause of lung cancer?

Answer 14

Carcinogens in the tar of tobacco smoke can enter cells and cause them to divide out of control causing tumours.

Question 15

Cause of chronic bronchitis?

Answer 15

Tar in tobacco smoke causes goblet cells to secrete more mucus, which causes the cilia to be paralysed – this means any pathogens cannot be wafted out of the lungs and can cause infection.

Question 16

Cause of emphysema?

Answer 16

The body􏰂s white blood cells attempt to kill these pathogens but in doing so damage the elastic fibres in the walls of the alveoli – the alveoli burst which reduces the surface area available for gas exchange.

Question 17

State the effects of tar on the body?(3)

Answer 17

Tar can include carcinogens as well as other chemicals.
Lines airways and alveoli with tar.
Paralyses cilia cells.
May cause smooth muscle in airways to contract restricting air flow.

Question 18

State the effects of nicotine on the body?(3)

Answer 18

Very addictive and stimulates release of adrenaline.
Reduces diameter of arterioles.
Increases heart rate and blood pressure.
Increases risk of blood clot and reduces oxygen supply to hands and feet.

Question 19

State the effects of carbon monoxide on the body?(2)

Answer 19

Diffuses across alveoli where it combines with haemoglobin to form carboxyhemoglobin because carbon monoxide outcompetes with oxygen because it has a 200x higher affinity than oxygen with haemoglobin.

Question 20

When guard cells fill with water and become turgid…

Answer 20

The stomata open to allow gases in and out of the plant.

Question 21

When guard cells lose water and become flaccid…

Answer 21

The stomata close.

Question 22

State three ways the structure of the leaf is adapted for photosynthesis(externally).(3)

Answer 22

1 Large surface area to absorb sunlight
2 Green chlorophyll to absorb light
3 Supported by stalk that allows leaf to be angled towards light

Question 23

State six ways the structure of the leaf is adapted for photosynthesis(internally).(6)

Answer 23

1 Upper epidermis is transparent to allow light to pass trough.
2 Waxy cuticle to prevent water loss by evaporation and entry of pathogens.
3 Lower epidermis has stomata to allow CO2 to diffuse into the leaf.
4 Palisade mesophyll (mesophyll = middle of leaf) has elongated cells packed with chloroplasts close to the source of light.
5 Palisade cells have large vacuoles which push chloroplasts to the edge of cell.
6 Good supply of water from xylem to mesophyll.

Question 24

Explain two ways how the structure of the leaf is adapted for gas exchange?(2)

Answer 24

1 Leaf is thin therefore diffusion distance is fairly short
2 Stomata and air spaces in the spongy mesophyll contribute towards efficient gas exchange(rate of diffusion greater in air than water)

Question 25

Explain what ATP is?

Answer 25

A lot of the processes in the cell require a small amount of energy, but a small amount only. In respiration glucose is broken down into many small molecules of ATP for these processes.

Question 26

State the differences between Aerobic and Anaerobic respiration.(3)

Answer 26

1 Less ATP produced in Anaerobic respiration
2 Aerobic starts in cytoplasm, ends in mitochondrion, Anaerobic is in cytoplasm alone
3 Anaerobic requires no oxygen, but releases toxic chemicals

Question 27

Describe the process of glucose breaking down into ATP.(2)

Answer 27

Glucose alone can break down into a small amount of ATP and two molecules of pyruvate. However if Oxygen is present these two molecules of pyruvate can break down in the mitochondrion into lots of ATP.

Question 28

State word equation for Aerobic respiration as well as balanced symbol equation.(3)

Answer 28

Glucose + Oxygen(+ enzymes) »» Water + Carbon Dioxide + ATP.
(C6)(H12)(O6) + 6(O2) »» 6(H2O) + 6(CO2) + ATP

Question 29

Explain the phrase ‘excess post-exercise oxygen consumption’ or ‘oxygen debt’?(2)

Answer 29

Someone doing very heavy exercise will probably respire anaerobically, creating lactic acid.
Lactic acid is toxic and needs to be broken down which requires extra oxygen.

Question 30

State the net gain of ATP molecules per molecules of glucose aerobically and anaerobically.

Answer 30

32 and 2 respectively.

Question 31

Explain how the net exchange of carbon dioxide and oxygen depends on the intensity of light on a plant?

Answer 31

When the light intensity is high, a plant carries out photosynthesis at a much higher rate than it respires. So in bright light there will be a net uptake of carbon dioxide from the air around a plant’s leaves and surfeit of oxygen.
A plant only produces more carbon dioxide than it uses up in dim light.

Question 32

How can we investigate the effect of light of net gas exchange from a leaf?(3)

Answer 32

Hydrogen carbonate indicator solution is very sensitive to changes is carbon dioxide concentration, in concentrations > 0.04% it is yellow, in concentrations of 0.04%(normal air) it is orange, in concentrations < 0.04% it is purple.
In four boiling tubes, 10ml of indicator is placed at the bottom and three leaves are placed in three of the tubes.
One in dark(covered), one in light, and one covered by a translucent material(dim light).
The four tubes are set under a bright light and the colour of the indicator is recorded. The leaf in light should be have indicator coloured purple, leaf in the dark; yellow, leaf in dim light; orange.