3.3.4 Mass transport

Question 1

Explain how following risk factors influence onset of CHD
High blood cholesterol
High blood pressure
Smoking

Answer 1

HBC- Fatty deposition in artery walls
Arteroma formed
Increase bp
Lumen of arteries narrowed
HBP-
Damage to artery lining
Risk of aneurysm
Increased risk of blood clot blocking coronary arteries
Smoking-
Increase bp
Risk of aneurysm
Increases risk blood clot blocking coronary arteres
Reduced blood supply to heart
Increased risk of heart attack

Question 2

Suggest + explain 3 ways risk factors cause cardiovascular disease

Answer 2

Smoking-
Co reduces O2 transport/ nicotine increases blood pressure
Saturated fat-
Raises blood cholesterol level
Alcohol/ salt-
Increases blood pressure

Question 3

Suggest how high bp can result in less O2 reaching heart muscle

Answer 3

damage to artery walls
ref. to blood clot
blood clot can block arteries
ref. to coronary arteries;
lack of (oxygenated) blood flow to heart muscle

Question 4

Suggest + explain why a low cholesterol diet might not result in a lower blood cholesterol level

Answer 4

cholesterol synthesized by the body
further detail e.g. made in liver / cholesterol made from
saturated fats;
genetic factors;
further detail e.g. hypercholesterolaemia / number of LDL receptors

Question 5

Haemoglobin structure

Answer 5

Protein with quaternary structure

Question 6

The Bohr effect

Answer 6

Cells produce CO2 when respiring
Increases rate if oxygen unloading
Dissociation curve shifts right but stays same shape
Saturation of blood with oxygen is lower for given pO2 meaning more oxygen is released

Question 7

Animals adaption (haemoglobin)

Answer 7

Many animals adapted for their environment by possessing different types of haemoglobin with different oxygen transport properties

Question 8

General pattern of blood circulation in mammal

Answer 8

Low SA:V ratio
Heart pumps blood through blood vessels to reach different parts of body
Body transports respiratory gases, products of digestion, metabolic waste, hormones
2 circuits
Heart to lungs and back to heart
Round the rest of the body
Heart has on blood supply- coronary arteries

Question 9

Blood vessels entering and leaving heart, lungs and kidney

Answer 9

Coronary arteries- heart’s blood supply
Pulmonary vein - lungs to heart
Vena cava - body to heart
Pulmonary artery - heart to lungs
Aorta - heart to body
Renal vein - kidneys - heart
Renal artery - heart - kidney

Question 10

Artery adaptions

Answer 10

Elastic tissue in wall
Thick muscle layer
Lumen - space at centre
Folded endothelium

Question 11

Arteriolar adaptions

Answer 11

Arteries divide into arterioles
Thick walls
Narrow lumen
Elastic fibres

Question 12

Vein adaptions

Answer 12

Thin muscle wall
Valves
Endothelium
Large lumen

Question 13

Capillary adaptions

Answer 13

One cell thick endothelium
Leak due to tissue spaces
Lots of them

Question 14

Tissue fluid

Answer 14

Small molecules that leave blood plasma like oxygen, water, nutrients
No big proteins as too large to be pushed through capillary walls

Question 15

The rise and fall in blood pressure in the aorta is greater than in the small arteries. Suggest why.

Answer 15

Aorta is directly linked to to the heart so pressure is very high
Aorta has elastic tissue
Aorta has stretch/recoil

Question 16

Humans and grasshoppers have very similar percentages of each base in their DNA but they are very different organisms
How is this possible?

Answer 16

Have different genes
So bases are in a different sequence
So different amino acids and therefore proteins

Question 17

The DNA of the virus is different from that of other organisms.
Use your knowledge of DNA to suggest what this difference is.

Answer 17

Virus DNA
A not equal T, C not equal G
So no base pairing;
So DNA is not double stranded/is single stranded;

Question 18

Give three ways in which courtship behaviour increases the probability of successful mating

Answer 18

Recognise species
Simulate release of gametes
Indication of sexual maturity

Question 19

Tissue fluid formation and return

Answer 19

Start capillary bed- hydrostatic pressure greater in capillary than tissue fluid
The difference in hydrostatic pressure forces fluid out of capillaries into spaces around cells forming tissue fluid
At end of capillary bed, hydrostatic pressure low so water potential now lower than in tissue fluid so some is returned to capillaries by osmosis
Excess is drained by lymphatic system- from tissues back to circulatory system

Question 20

Heart beat process

Answer 20

Blood enters atrium
Atrium wall contracts
Increases pressure in atrium
Causes atrioventricular valves to open
Blood passes into ventricle
Ventricle contracts increasing pressure
Atrioventricular valve closes when pressure greater than atrium
When ventricle has higher pressure than aorta semilunar valve open
After contraction higher pressure in aorta than ventricle cause semilunar valve to close

Question 21

Formation of oxyhaemoglobin

Answer 21

Haemoglobin – a protein with a quaternary structure. Binds with oxygen to form oxyhaemoglobin
At lungs oxygen binds to haemoglobin
Difficult for first oxygen to bind.
Binding causes a change in the tertiary/quaternary structure of protein Exposes another oxygen binding site
Further oxygen molecules bind to haemoglobin more easily.

Question 22

Bohr affect

Answer 22

Increased rate of respiration
Increase of carbon dioxide in blood.
Increase carbonic acid/decrease in pH.
Changes quaternary/tertiary structure of haemoglobin Oxygen dissociates more rapidly
Delivers more oxygen to respiring tissues.

Question 23

Suggest why a lack of protein in the diet causes swelling (tissue fluid)

Answer 23

Less protein in blood
Water potential in blood too high
Water not drawn into capillary by osmosis
Fluid stays in tissues

Question 24

Why is the water potential of the blood plasma is more negative at the venule end of the capillary than the arteriole end of the capillary ?

Answer 24

Water leaves capillary
Proteins in blood too large to leave capillary
Increases concentration of blood proteins so water potential

Question 25

High absorption of salt from the diet can result in a higher than normal concentration of salt in the blood plasma entering capillaries. This can lead to a build-up of tissue fluid.
Explain how

Answer 25

Lower water potential of tissue fluid
Less water returns to capillary by osmosis

Question 26

Explain 3 ways in which an insect’s tracheal system is adapted for efficient gas exchange

Answer 26

Tracheoles have thin walls so short diffusion distance to cells
High branched tracheoles so large surface area
Abdominal pumping moves air to maintain diffusion gradient