3.3.2 Mass Transport

Question 1

Define a closed circulatory system

Answer 1

Blood is enclosed within vessels/diffusion of substances only takes place within vessels

Question 2

Define a single circulatory system

Answer 2

Blood flows through the heart once for each complete circuit of the body
Blood is pumped at a low blood pressure. Suitable for organisms with a low metabolic rate

Question 3

Define a double circulatory system

Answer 3

Blood flows through the heart twice for each complete circuit of the body (i.e simultaneously pumps to lungs and heart)
Maintains a high blood pressure to meet demands of a high metabolic rate

Question 4

Why cant complex multi cellular organisms rely on diffusion to transport substances around the body?

Answer 4

They have a small SA:vol so can’t diffuse substances quickly or efficiently enough to reach all the cells

Question 5

Why is a closed circulatory system more efficient?

Answer 5

The blood is forced through fairly narrow tubes so it remains under pressuse and therefore travels faster, delivering oxygen and glucose to cells more quickly

Question 6

Describe the structure of capillaries

Answer 6

Very narrow lumen for short diffusion distance, single layer of cells so it can lie very close to the cells

Question 7

What is the function of the capillaries?

Answer 7

Where metabolic exchange occurs so substances are exchanged between cells and the blood

Question 8

Describe how blood flows in veins

Answer 8

Blood flow is assisted by the contraction of skeletal muscles during movement of limbs and breathing.

Question 9

State the four chambers of the heart

Answer 9

Left atria/left ventricle/right atria/right ventricle

Question 10

State the four vessels entering/exiting the heart

Answer 10

aorta/vena cava/pulmonary artery/pulmonary vein

Question 11

How is the left side of the heart identified?

Answer 11

Presence of a thicker muscular wall

Question 12

What is present inside the heart to prevent backflow?

Answer 12

AV valves (tricuspid = right, bicuspid = left) and semi-lunar valves.

Question 13

Why are the ventricle walls thicker than atria walls?

Answer 13

Blood needs to be under higher pressure to travel a further distance

Question 14

Why are valves important?

Answer 14

Prevent backflow/allow build up of pressure

Question 15

State what happens to the heart during ventricular diastole and atrial systole

Answer 15

Ventricles are relaxed/atria contract/increases pressure in atria/AV valves open/blood flows into ventricles

Question 16

How does the structure of xylem allow them to transport water?

Answer 16

Hollow as no cytoplasm, vessels have no end walls and pits, vessels are strong so do not collapse, lignin makes the walls waterproof

Question 17

How does no ATP production affect transport of substances in plants?

Answer 17

translocation inhibited but transpiration stream not inhibited. Phloem contains cytoplasm but xylem does not. Cytoplasm has mitochondria involved in metabolism.

Question 18

State the function of xylem vessels

Answer 18

Transport water and mineral ions up the plant and provide support

Question 19

State the function of phloem tissue?

Answer 19

Transport organic solutes from where they are made in the plant to where they are needed

Question 20

Describe the structure of xylem tissue

Answer 20

Long tube-like structures formed from dead cells joined end to end, found together in bundles. Hollow lumen as no cytoplasm and no end walls makes an uninterrupted tube allowing water and mineral ions to pass through the middle easily. Walls thickened with lignin.

Question 21

Describe the structure of phloem tissue

Answer 21

Sieve tube elements (living cells) joined end to end to form sieve tubes. Sieve parts are the end walls which have lots of holes to allow solutes to pass through. There is a companion cell for every sieve tube element

Question 22

Why do plants need water?

Answer 22

For photosynthesis, to transport minerals, maintain structural rigidity and to regulate temperature

Question 23

Why do plants need nitrate ions?

Answer 23

For production of DNA, proteins and chlorophyll. They are required for plant growth, fruit production and seed production

Question 24

If the CO2 concentration increases, which way will the oxygen dissociation curve shift?

Answer 24

To the right - haemoglobin will have a lower affinity and will unload more easily

Question 25

If the CO2 concentraiton decreases, which way will the oxygen dissociation curve shift?

Answer 25

To the left - haemoglobin will have a higher affinity and will load more easily

Question 26

During diastole, which valves are open and which are closed?

Answer 26

semi lunar closed, AV valves open

Question 27

During ventricular systole, which valves are open and closed?

Answer 27

AV valves close, semi-lunar valves open

Question 28

State how the oxygen affinity of haemoglobin changes in a high concentration of CO2 vs a low concentration of CO2. Explain why this is useful for humans.

Answer 28

Haemoglobin has a high oxygen affinity in high in low CO2 concentration and a low affinity in high CO2 concentration. This means oxygen is loaded at the lungs (where CO2 conc is low) and unloaded at the respiring cells (where CO2 conc is high)

Question 29

Answer 29

Question 30

Give the basic structure and function of arteries, veins and capillaries

Answer 30

Question 31

Answer 31

Question 32

Answer 32

Question 33

Answer 33

Question 34

Answer 34

Question 35

Answer 35

Question 36

Answer 36

Question 37

Answer 37

Question 38

Answer 38

Question 39

Answer 39

Question 40

Answer 40

Question 41

Answer 41

Question 42

Answer 42

Question 43

Answer 43

Question 44

Answer 44

Question 45

describe what happens to heart muscle, the blood in the heart and the valves in: atrial systole, ventricular systole, diastole

Answer 45

Question 46

Answer 46

Question 47

Answer 47

Question 48

Answer 48

Question 49

Answer 49

Question 50

Answer 50

Question 51

Answer 51

Question 52

Answer 52

Question 53

Describe the mas flow hypothesis

Answer 53

Question 54

Answer 54