exchange systems

Question 1

How to calculate SA:V

Answer 1

SA / V

Question 2

what organisms have a large SA:V?

Answer 2

Smaller organisms/ single cell organisms given that their cell membranes are relatively thin

Question 3

How are larger organisms exchange systems specialised for high activity demands?

Answer 3

xylem and phloem transport water and solutes and the blood and circulatory system transports glucose, oxygen and carbon dioxide

Question 4

Why is heat exchange required in organisms?

Answer 4

So that enzymes don’t denature causing the 3D tertiary protein structure to be damaged

Question 5

What is a suitable medium to transport substances in organisms?

Answer 5

Blood

Question 6

What are blood vessels?

Answer 6

Closed systems to transport the medium with branches to reach all parts of the organisms body

Question 7

What is the role of the heart in transport systems?

Answer 7

Mechanism to provide a pressure difference between parts of the system to keep things moving

Question 8

What is the role of the valves?

Answer 8

A mechanism to maintain the movement of the medium

Question 9

How is the alveoli adapted for efficient exchange?

Answer 9

Thin walls for a short diffusion pathway
Alveolus with a low CO2 conc and high O2 conc to maintain a concentration gradient

Question 10

How does a partially permeable membrane benefit exchange rates?

Answer 10

Allows selected materials to diffuse easily

Question 11

How does a moist and warm environment benefit exchange rates?

Answer 11

Warmth increases the kinetic energy of particles, moisture allows gasses to diffuse

Question 12

How does movement of internal and external mediums allow exchange of gasses?

Answer 12

Maintains a diffusion gradient

Question 13

Why do terrestrial insects suffer with dehydration?

Answer 13

They have a waterproof covering and a small SA:V, minimising gas exchange

Question 14

What are tracheae and what do they do?

Answer 14

Tubes that penetrate in the body carrying air to each tissue- maintaining a diffusion gradient

Question 15

What are tracheoles?

Answer 15

Branched tissues

Question 16

What are spiracles?

Answer 16

Openings in the body surface leading to the tracheae- can be closed to prevent water loss

Question 17

What is abdominal pumping?

Answer 17

Body contractions that speed up the gasses from the tracheae to the cells

Question 18

Why must water flow continuously in fish?

Answer 18

To maintain a concentration gradient for the exchange of oxygen and carbon dioxide

Question 19

Role of gill filaments

Answer 19

To provide fish with water providing them oxygen

Question 20

Role of lamellae?

Answer 20

Stacked to increase surface area

Question 21

What is a counter current flow?

Answer 21

Water is taken in through the mouth, and passed over the gills and out the openings in the body. Water flows in the opposite direction to blood maintaining conc gradient

Question 22

What is a concurrent flow and why is in not efficient?

Answer 22

Blood and water flow across the body in the same direction and will eventually reach an equilibrium meaning fish will not gain oxygen and die

Question 23

How are leaves thin a benefit for photosynthesis?

Answer 23

Short diffusion pathway so gasses can reach cells easily

Question 24

How do lots of chloroplasts help photosynthesis?

Answer 24

Located at the top of the cell to absorb light and air

Question 25

How do veins help photosynthesis?

Answer 25

Carry water to cells and glucose carried away

Question 26

Role of stomata?

Answer 26

Open and close through guard cells to let water and air pass in and out

Question 27

What are xerophytes?

Answer 27

Plants adapted to live in dryer conditions

Question 28

How do thick waxy cuticles benefit xerophytes?

Answer 28

Increase the diffusion distance so less chance of gasses leaving

Question 29

How do hairs on leaves benefit xerophytes?

Answer 29

Traps water vapour next to the surface- water potential is reduced

Question 30

How do curled leaves benefit xerophytes?

Answer 30

stomata's are trapped so transpiration is reduced

Question 31

How do sunken stomata's benefit xerophytes?

Answer 31

Traps water vapour on the underside of the leaf

Question 32

How to work out Frick's law of diffusion?

Answer 32

Diffusion = (surface area x difference in concentration) / length of diffusion pathway

Question 33

What is each alveoli lined with?

Answer 33

Flattened layer of epithelial cells

Question 34

Why is it beneficial that capillaries are narrow?

Answer 34

So that travelling RBC's are flattened and can squeeze through. It also helps to slow down the pace of RBC's increasing surface area for diffusion

Question 35

Describe the squamous epithelia and where it is found

Answer 35

they are found in the tissues and are the only cells which are; Flat, smooth, thin, packed closely together and found in the linings of cheeks, blood vessels and heart chambers

Question 36

Why is it important that the surface of the epithelial cells are low friction?

Answer 36

Decreases the chance of clots forming

Question 37

How does slow passing RBC's increase diffusion rate?

Answer 37

More time for gas exchange

Question 38

How do flattened RBC's help diffusion rate?

Answer 38

reduces the distance between alveoli and capillaries creating a short diffusion pathway

Question 39

How do thin wall help diffusion rate?

Answer 39

Decrease diffusion pathway

Question 40

How do alveoli folds help diffusion rate?

Answer 40

increases the surface area

Question 41

How does ventilation and circulation help diffusion rate?

Answer 41

Maintains a concentration gradient

Question 42

Describe the process of inspiration

Answer 42

The internal intercostal muscles and the diaphragm contract whilst internal muscles remain relaxed Volume of thorax increases as diaphragm flattens Pressure of the thorax decreases as volume increases The pressure of the air is higher pressure than in the thorax Active process and requires energy

Question 43

Describe the process of expiration

Answer 43

external intercostal muscles and diaphragm relax Volume of the thorax decreases as diaphragm becomes domed Pressure in the thorax increases as volume decreases Pressure in air is lower than in the thorax Air is forced out the lungs

Question 44

What is pulmonary ventilation?

Answer 44

The measure of the amount of air moved into the lungs in a minute

Question 45

Calculation of pulmonary ventilation

Answer 45

tidal volume x ventilation rate