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mass transport Flashcards

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1
Q

what is the importance of a transport system?

A

as for larger organisms, the needs of the organism cannot be met by the body surface alone, the distance is too great to only rely on diffusion alone

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2
Q

what are the two types of circulatory systems?

A

single and double

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3
Q

why is the heart called a double circulatory system?

A

This means two pumps that work at the same time to pump blood in two different directions. The right-hand side of the heart collects deoxygenated blood from the body and pumps it to the lungs whereas the left side pumps oxygenated blood to our tissues and cells.

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4
Q

what is meant by a closed circulatory system?

A

the blood remains within the blood vessels

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5
Q

why do mammals require a double circulatory system. explain the importance of this?

A

to manage the pressure of blood flow. the blood flows through the lungs at a lower pressure. this prevents damage to the capillaries in the alveoli and reduces the speed at which the blood flows, enabling more time for gas exchange.
The oxygenated blood from the lungs then goes back through the heart to be pumped out at a higher pressure to the rest of the body. this is important so that all blood reaches respiring cells in the body.

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6
Q

what are the different ypes of blood vessels?

A

arteries, arterioles, capilleries and veins

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7
Q

what are the roles of each blood vessel?
arteries, arterioles, veins, capillaries?

A

arteries- carry oxygenated blood blood away from the heart and into arterioles rapidly under high pressure
arterioles- are smaller arteries that control of oxygenated blood flow from arteries to capillaries under a lower pressure than arteries
veins- transport deoxygenated blood under a low pressure from the capillaries in tissue to heart
venules - are smaller veins
capillaries - to exchange materials such as oxygen carbon dioxide and glucose between the blood and the cells of the body.

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8
Q

draw and label a cross-sectional diagram of an artery
describe
what blood it transports:
pessure of blood:
adaptions to its main function:

A
  • transports oxygenated blood at a high pressure.
    adaptions:
  • thick layer of muscle - this means that smaller arteries can be constricted and dilated to control the volume of blood passing through
  • thick elastic fibres/tissues - which can stretch and recoil so that blood is pushed along with the heart beat and maintained at a high blood pressure
  • narrow/small lumen- withstand high pressures
  • endothelial cells/folded endothelium - allows stretching and is smooth to offer maximum resistance to blood flow
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9
Q

draw and label a cross-sectional diagram of an arteriole
describe
what blood it transports:
pessure of blood:
adaptions to its main function:

A

carry oxygenated blood at a lower pressure than arteries
adaptions:
- muscle tissue is thicker than arteries - the contraction of this muscle layer allows the constriction of the lumen of the arteriole. this restricts the flow of blood and so controls its movement into the capillaries
- the elastic layer is relatively thinner than arteries as blood is pumped at a lower pressure

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10
Q

draw and label a cross-sectional diagram of a capillary
describe
what blood it transports:
pressure of blood:
adaptions to its main function:

A

transports both oxygenated and deoxygenated blood at a low pressure
adaptions:
- thin walls/lining/ one cell thick - so distance over which diffusion takes place is short. allows for the rapid diffusion of materials
- many/numerous capillaries + branching - creating a large surface area for diffusion
- lumen is narrow - that red blood cells are squeezed flat against the capillary. this brings them even closer to the cells to which they supply oxygen reducing the diffusion distance
- spaces between the endothelium - that allow WBC to escape in order to deal with infections within the tissue

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11
Q

draw and label a cross-sectional diagram of a vein
describe
what blood it transports:
pessure of blood:
adaptions to its main function:

A

transports deoxygenated blood
adaptions:
- thin muscular layer - because veins cary blood away from tissue and therefore their constriction and dilation can not control the flow of blood to their tissues
- the elastic layer is thin - because the low pressure within the veins will not cause them to burst and pressure is too low to create a recoil action
- valves - ensures that blood does not flow backwords

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12
Q

explain how valves in the veins prevent the backflow of blood?

A

because the pressure is low, when body muscles contract, veins are compressed, pressureising the bloodwithin them. the valves ensure that this pressure directs the blood in one direction only

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13
Q

Why can a pulse be felt in an artery but not a vein?

A

In a vein the pressure is more constant and there are no pressure surges

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14
Q

how do we maintain our blood pressure in arteries during systole and diastole?

A

During systole (heart contraction), blood is pumped through the aorta and other arteries at high pressure. The elastic fibres of arteries enable them to expand and allow blood through.
During diastole (heart relaxation), the blood pressure in the arteries drops. The elastic recoil of the artery walls help force the blood on.

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15
Q

how does valves in the veins allow blood to flow?
what is the Golden rule?

A

(before valve) when muscles in veins contract, the veins are squashed. this squeezes the blood along. valves open allowing blood to flow to the heart.
valve is closed. (after valve) when the muscles here contract, the increased pressure of the blood, causes the valves to shut. this prevents the backflow of blood.

GOLDEN RULE: Valves OPEN if pressure behind the valve is greater than pressure ahead. They CLOSE if pressure is greatest ahead.

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16
Q

what are varicose veins?

A

If a vein wall becomes weakened, valves may no longer close properly. This allows backflow of blood, causing the vein to become enlarged and bumpy, and become varicose.

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17
Q

where is the heart located?

A

lies in the left centre of the thoracic cavity behind the sternum (breastbone)

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18
Q

what is the pericardium and its role within the heart?

A

The heart is enclosed in a double layer of tough, inelastic membranes called the pericardium. This protects the heart from over expansion.

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19
Q

what is the cardiac muscle?
what is special about this muscle?

A

Cardiac muscle is found only in the heart

It never fatigues, but a lack of oxygen or lack of nutrients will cause the cells to die and stop beating.

It is myogenic which means that it contracts rhythmically even when removed from the body (basis of heart beat)

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20
Q

what is the average human heart rate at rest?

A

72 beats a minute

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21
Q

what are the two chambers in the heart and describe their roles?

A

atrium - is thin walled and elastic and stretches as it collects blood
ventricle - has a much thicker muscular wall as it has to contract strongly to pump blood to some distance, either to the lungs or to the rest of the body

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22
Q

What is the function of the heart?

A

To pump blood around the body

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23
Q

Why do we have two separate pumps? Why not pump blood from lungs to the rest of the body?

A

A problem with this system is that blood needs to be pumped through tiny capillaries in the lungs in order to present a large surface area for the exchange of gases so there is a vary large drop in pressure and so blood flow to the rest of the body will be slow

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24
Q

Why does the left ventricle have a thicker muscular wall than the right ventricle?

A

The right ventricle pumps blood only to the lungs and it has thinner muscular walls then the left v. The left ventricle has a thicker muscular wall enabling it to create enough pressure to pump blood to the rest of the body

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25
Q

describe the blood flow of deoxygenated blood in the heart so it can be taken to the lungs to become oxygenated
i…v..c.. , r..a.., t..v.. ,r..v..,p..v, p..a..,L..

A

blood enters through the right atrium via the inferior vena cava. the right atrium contracts pushing the blood through the tricupsid valves into the right ventricle, the right ventricle then contracts pumping the blood throught the pulmonary valve up through the pulmonary artery where bloood is taken to the lungs

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26
Q

if blood from the lower half of the body enters the heart which vena cava does it come through…?
if blood from the top half of the body enters the heart which vena cava does it come through…?

A
  • inferior as its on the bottom of the heart
  • superior as its on the top of the heart
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27
Q

why does blood need to be returned to the heart (when oxygenated)?

A

because the heart pumps the blood to the rest of the body

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28
Q

describe the flow of oxygenated blood in the heart
p..v.., l..a.., m..v.., l..v.., a..v.., a..

A

now the blood is oxygenated. blood travels through the pulmonmary vein into the left atrium. the left atrium contracts and the blood travels through the micupsid valve into the left ventricle. the left ventricle contracts pushing the blood through the aortic valve into the aorta so can be transpoorted to the rest of the body

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29
Q

explain the role of the conorarty arteries?

A

they branch off the aorta and provides the heart with its own supply of blood

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30
Q

why is it important that these arteries do not get blocked?

A

because a blockage can cause a heart attach or myocardial infarction

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31
Q

suggest why it is important that blood from both sides of the heart does not mix?

A

the mixing of the blood would result in partially oxygenated blood reaching the tissues and the lungs. this would mean that the supply of oxygen to the tissues would be inadequate and there would be a reduced diffusion gradient in the lungs, limiting the uptake rate of oxygen

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32
Q

what is the cardiac cycle?
what are the 3 main stages?

A

describes the series of events that occur during one complete heartbeat. the contraction and relaxation of both the atria and ventricle
- diastole, atrial systole, ventricular systole

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33
Q

how do we know when one cardiac cycle is completed?

A

one cardiac cycle is completed when the heart fills with blood and the blood is pumped out

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34
Q

what happens in the diastole phase?

A
  • both atrial and ventricle muscles are relaxed
  • volume in the atria is high so the pressure is low
  • blood enters the atria from veins with a high pressure
  • semi-lunar valves are shut
  • as pressure rises in the atria due to the entry of blood, blood starts to move into the ventricles where there is a low pressure
  • atrioventricular valves are pushed open
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35
Q

what happens in the atrial systole phase?

A

-atria muscles contract
-volume of atria decreases so pressure increases
- ventricles muscles relaxes so there is a low pressure
- blood is pushed out from atria to ventricles
- atrioventricular valves are open
- semi-lunar valves are shut

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36
Q

what happens in the ventricular systole?

A
  • ventricle muscles contract
  • volume decreases so pressure increases
  • arteries have a lower pressure
  • blood is pushed out of the heart to the arteries
  • semi-lunar valves are open
    atrioventricular valves are forced shut to prevent backflow of blood
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37
Q

how do you calculate the cardiac output?

A

CARDIAC OUTPUT (cm3 min-1) = STROKE VOLUME (cm3) X HEART RATE

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38
Q

what is the stroke volume?

A

the volume of blood pumped by the heart during one cardiac cycle

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39
Q

wehat are the benefits of an increased cardiac output?

A

supply o2 and glucose to muscles faster, remove co2 from the muscles faster , remove lactate away fastewre, remove heat away friom the muscles fater

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40
Q

why do athletes increase their cardiac output?

A
  • Their heart muscle is stronger and the volume of each chamber can be increased.
  • This enables them to increase their stroke volume as thicker muscle can contract with greater force to expel more blood
  • Athletes pump more blood out in each heartbeat so are able to expel the same volume of blood in fewer beats than an unfit person with a smaller cardiac output
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41
Q

what does the cardiac cycle graph show?

A

pressure changes in the heart

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42
Q

cardiovascular diseases (CVD) and Coronary Heart Disease (CHD)

A
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43
Q

what is coronary heart disease?

A

Any condition that interferes with the coronary arteries

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44
Q

why is it important that coronary arteries do not get blocked?

A

These supply the heart muscle with the glucose and oxygen needed for respiration

If the vessels become narrow or blocked, the supply of glucose and oxygen is stopped or reduced.

This may lead to death of the cells resulting in a heart attack (Myocardial Infarction)

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45
Q

what is cardiovascular disease?

A

Cardiovascular disease (CVD) concerns the heart and blood vessels. Principles are the same.

46
Q

what does most cardiovascular disease start with?

A

Most CVD starts with ATHEROMA formation

47
Q

what is an atheroma?

A

formation of fatty deposits in wall of arteries

48
Q

what is thrombis?

A

formation of blood clot

49
Q

what is an Aneurysm?

A

swelling of weakened artery

50
Q

what is angina?

A

disease you get when you have a build up of atheromes

51
Q

what is a stroke?

A

when blood clots reach the brain.
mini stroke - blood clot in small blood vessels

52
Q

what is a risk factor?

A

A risk factor is a factor correlated with a particular disease

53
Q

what are risk factors that increase CVD?

A

Diet

Age and Sex

Genetic factors

Blood cholesterol/ LDL levels in blood

Cigarette smoking

High blood pressure

54
Q

Tissue fluid and lymph

A
55
Q

what is tissue fluid?

A

Tissue fluid is a substance that surrounds the body cells, and provides a constant environment for the cells it surrounds.

56
Q

how do cells get their resources?

A

from tissue fluid

57
Q

what are the components in tissue fluid similar to?

A

the components in plasma

58
Q

why does tissue fluid contain WBC?

A

to fight infections

59
Q

how is tissue fluid formed?
what are the small molecules that can pass through?
which big molecules can not pass through?

A

high hydrostatic pressure at the arteriole end of the capillary pushes fluid out of the blood.

Small pores in capillary walls only the small molecules can pass through. e.g Plasma, Water molecules, Minerals and salts, Glucose and urea, Small proteins and amino acids

Those that don’t!
Large proteins, Red blood cells, Platelets

60
Q

explain fully in detail how tissue fluid is formed?

A

At the arterial end of capillaries, the high hydrostatic pressure forces many of the components of the blood through small pores in the capillary walls, such as glucose, amino acids, mineral and salts, and plasma

Rbc and large proteins are unable to move out, therefore remain in the blood

Reducing the fluid in the capillaries, reduces the pressure.

At the venous end of the capillary, Hydrostatic pressure is lower, Solute potential is higher (due to proteins remaining in blood) .

Water potential in the capillaries is MORE NEGATIVE (low) compared to the tissue fluid.

Fluid drains back into the blood by OSMOSIS.

90% of the fluid drains back in,

10% is returned to the blood by the lymphatic system.

61
Q

When is tissue fluid returned to the blood?

A

once tissue fluid has exchanged metabolic materials with the cells it bathes.

62
Q

how is lymph formed?

A

Not all tissue fluid returns to the capillaries. The excess drains
into the lymphatic system, where it forms lymph.

63
Q

what colour is lymph and does it differ to tissue fluid?

A

Lymph is a colourless/pale yellow fluid similar to tissue fluid but containing more lipids AND LESS PROTEINS.

64
Q

what is the role of lymph?

A

It helps to keep the volume of tissue fluid constant.

65
Q

where does the lymph drain back into?

A

The lymph drains back into the blood near the vena cava.

66
Q

the contents of lymph are not moved by the pumping of the heart. instead they are moved by..?

A
  • hydrostatic pressure of tissue fluid that has left the capillaries
  • contraction of body muscles that squeeze the lymph vessels - valves in the lymph vessels ensure that fluid inside them moves away from the tissues in the direction of the heart.
67
Q

what is the lymphatic system?
what does it consists of?

A

The lymphatic system is a secondary circulatory system and a
major part of the immune system.
It consists of:

Made up of blind-ending vessels, which allow tissue fluid to flow passively into them. Flow is helped by muscle contraction and one-way valves.

lymph nodes – sac-like organs that trap pathogens and foreign substances, and which contain large numbers of white blood cells

68
Q

describe the differences between the cardiovascular system and the lymphatic system?

A
  1. Blood is responsible for collecting and distributing oxygen, nutrients and hormones to the tissues of entire body.
  2. Lymph is responsible for collecting and removing waste products left behind in the tissues.
  3. Blood flows in a closed continuous loop
    throughout the body via the arteries, capillaries, and veins.
  4. Lymph flows in an open circuit from the tissues into lymphatic vessels. Once within these vessels, lymph flows in only one direction due to valves in the lymph vessels.
  5. Blood is pumped. The heart pumps blood into the arteries that carry it to all of the body. Veins return blood from all parts of the body to the heart.
  6. Lymph passively flows from the tissues into the lymph capillaries. Flow within the vessels is aided by other body movements such as deep breathing and the action of nearby muscles and blood vessels.
  7. Blood consists of the liquid plasma that transports the red and white blood cells and platelets.
  8. Lymph that has been filtered and is ready to return to the cardiovascular system is a clear or white fluid.
  9. Blood is visible and damage to blood vessels causes obvious signs such as bleeding or bruising.
  10. Lymph is invisible and damage to the lymphatic system is difficult to detect until swelling occurs.
  11. Blood is filtered by the kidneys. All blood flows through the kidneys where waste products and excess fluids are removed. Necessary fluids are returned to the cardiovascular circulation.
  12. Lymph is filtered by lymph nodes located
    throughout the body. These nodes remove some fluid and debris. They also kill pathogens and some cancer cells.
  13. Blood vessel damage or insufficiency produces swelling that containing low protein fluid.
  14. Lymphatic vessel damage or insufficiency produces swelling containing protein-rich fluid.
69
Q

Not enough food in the body (malnutrition) results in
very little protein in the blood.

Why is this a problem?

A

Proteins lower the water potential in the blood.

Smaller molecules leave the blood to join the tissue fluid and lymph, without protein there are no larger molecules left behind.

The water potential of blood is not lowered sufficiently to cause tissue fluid to return to the blood.

This results in lymph build up in the tissues of the person.

70
Q

what is elephantitis?

A

Elephantiasis is due to obstructions of the lymphatic vessels by a parasitic worm (or sometimes consistent contact with volcanic ash).
Due to the blockage of the lymphatic ducts the tissue fluid cannot return to the blood system and so collects in the limbs of the sufferer

71
Q

what is Hodgkinson disease/ lymphatic cancer?

A

Hodgkin disease can spread through the lymphatic vessels in a stepwise fashion from lymph node to lymph node.

72
Q

treatment for elephantitis?

A
  • A drug called diethylcarbamazine
  • Simple cleansing - Has been shown to alleviate the symptoms of elephantiasis.
73
Q

treatment for lymphatic cancer?

A

Chemotherapy - New drugs and combinations are being studied. Some are already used to treat other cancers,

Stem Cell Transplants - Used for recurrent or advanced-stage Hodgkin disease.

Monoclonal Antibodies - (manmade antibodies) have been made to target cancer cells.

74
Q

mass transport in plants

A
75
Q

explain the movement of water out through the stomata?

A
  • the humidity of the atmosphere is usually less than the air spaces next to the stomata. as a result there is a water potential gradient from the air spaces through the stomata to the air.
  • provided that the stomata is open, water vapour molecules diffuse out of the air spaces into the surrounding air
  • water loss by diffusion from the air spaces is replaced by water evaporating from the cell walls of the surrounding mesophyll cells. by changing the size of the stomatal pores, plants can control their rate of transpiration
76
Q

explain how water moves through the leaf?

A
  • mesophyll cells lose water to the air spaces by evaporation due to heat supplied by the sun
  • these cells now have a lower water potential and so water enters by osmosis from neighbouring cells.
  • the loss of water in neighbouring cells lowers their water potential
  • they in turn take water from their neighbours by osmosis
77
Q

what is transpiration?

A

Transpiration is the loss of water vapour via the stomata.

78
Q

what is the transpiration stream?

A

The “stream” of water flowing up through the plant

79
Q

what type of process is this?

A

a passive process so requires no energy

80
Q

what are xylem vessels?

A

tubes that transport water and minerals through a plant

81
Q

what are the properties of these vessels?
cells -dead or living?
walls of the cell?
flow?

A
  • cells are dead (from end to end)
  • thick walls impregnated with lignin
  • one-way flow only
82
Q

explain how water moves up the xylem?

A

Capillarity. - Adhesion of water to the side of a tube.

Root pressure - caused by this accumulation of water in the xylem.

The cohesion-tension theory

83
Q

explain the cohesion-tension theory of water transport through a leaf?

A
  1. Water evaporates from the stomata in the leaf. This creates a LOWER pressure
  2. This loss of water by TRANSPIRATION more water is pulled up the xylem vessel to replace it (moves due to negative pressure)
  3. Due to Hydrogen bonds between water molecules (cohesion) this creates a column of water.
  4. Water molecules also adhere to the walls of the xylem. This helps to pull the water column upwards
  5. As the column of water is pulled up is creates tension, pulling the xylem in to be narrower
  6. Water enters the roots by OSMOSIS to replace water moving up the xylem
84
Q

why when transpiration is fast, the diameter of a tree will noticeably reduce?

A

Transpiration is at its highest during the day, so xylem vessels are at greatest tension, so tree shrinks in diameter.

85
Q

what are the factors that effect the rate of transpiration?

A

Wind (air movement)
Humidity
Temperature
Light

86
Q

potometer - PRACTICAL

A
87
Q

what does the bubble potometer measure?

A

the transpiration rate/ water uptake by the plant

88
Q

how do we measure the water uptake?

A

water loss by transpiration + water consumption for cell expansion and photosynthesis

89
Q

potometer method?

A
  1. the leafy shoot must be cut underwater, the apparatus must be filled underwater and the shoot fixed to the potometer under water to prevent air locks in the system
  2. allow the plant to equilibrate (5 mins) before the introduction of the air bubble. take at least 3 readings of rate of bubbles of rate of bubbles movement, and use the reservoir to return bubble to zero on each occasion. calculate the mean of readings. records air temperature.
  3. scale can be calibrated by introducing a know mass of mercury into the capillary tubing and using p=m/v (p=mercury, m=measured v= measured distance of bubble movement can be determined).
  4. rate of water uptake per unit area of leaves can be calculated by measurement of leaf area
90
Q

why does the rubber tubing (connected to the leafy shoot) need to be greased and wired?

A

to prevent leakage of air

91
Q

why does the capillary tube need to be kept horizontal?

A

to prevent the bubble moving due to its density compared with water

92
Q

why do we have a reservoir of water?

A

this is used to prevent the air bubble entering the plant, and to move the bubble back along the capillary tube

93
Q

how is an air bubble inserted?

A

when we remove the end of the capillary tube, movement corresponds to water uptake by the cut shoot.

94
Q

Translocation

A
95
Q

what is translocation?

A

The movement of organic substances around a plant e.g. SUCROSE (most important) to where they are needed.

96
Q

draw and label a phloem vessel

A
  • Two main components - sieve tube elements and companion cells
97
Q

what are sieve tube elements?
describe some of their features?

A
  • living cells that form the tubes for transporting solutes.
  • No nucleus
  • few organelles. - to block liquid
98
Q

what are companion cells?
describe their features?

A

Each sieve tube element has a companion cell.

They carry out living functions for sieve cells.

Lots of mitochondria - provide ATP for active transport of organic substances

99
Q

in translocation solutes are moved from …? to…?

A

sources to sinks

100
Q

what is a source?

A

Where the substances are being PRODUCED, so are at a HIGH CONCENTRATION

101
Q

what is a sink?

A

WHERE SUBSTANCES BEING USED UP OR CONVERTED TO OTHER MOLECULES, SO AT A LOW CONCENTRATION. (therefore used by respiring cells)

102
Q

what is the mass flow hypothesis?
at the source and the sink?

A

At the SOURCE:
Sucrose is actively transported into sieve tube elements, using companion cells (using ATP from the mitochondria)

Increased concentration of sucrose, lowers the water potential of sieve cells in phloem, therefore water enters by osmosis from xylem vessel.

The increase in volume of water, creates a high hydrostatic pressure at the source end of the phloem.

At the SINK:

At the sink, sucrose are removed from the phloem to be used up for respiration and or converted into insoluble starch for storage.

These cells have a low sucrose content and so sucrose is actively transporting into sink cells from the sieve tubes, which cause the water potential to decrease, therefore water moves into these cells by osmosis from sieve tube elements

the removal of water, decreases the volume of the sieve tube elements, and therefore hydrostatic pressure decreases.

PRESSURE gradient causes flow of solute from source to sink.

103
Q

Why might translocation be from root to leaves at sometimes, but at others be from leaves to root?

What might the direction depend on at any
one time?

A

Because solutes move from source to sink, form a high concentration to a low concentration, where they’re are needed

104
Q

Evidence for and against mass flow

A
105
Q

How are radioactive tracers used to investigate mass-flow?

A

14CO2 will be used as normal in photosynthesis and the
14C is incorporated into new sugars.

Because the 14C is radioactive, it can be traced.

Autoradiograph shows where the radioactive tracer has travelled to.

106
Q

How ringing experiments done?

A

Outer section of the stem is removed around the complete circumference.
This removes the bark and phloem.

107
Q

explain what would happen after two weeks?

A

tissue above the ring are swollen and tissue below the ring is beginning to wilt. this is because at the top half there will be a build up of sucrose and the bottom half will wilt because no sugar can reach the roots

108
Q

how are aphids used to investigate mass flow?

A
  • aphids feed on plant tissue by penetrating the stem with their mouthparts. and then we use the aphids to check the amount of sucrose taken in.
109
Q

what stops translocation?

A

metabolic inhibitors reduces the productivity of an enzyme by (usually) forming a weak bond to an enzyme so no pressure gradient can be formed.

110
Q

evidence against mass flow

A

Function of sieve plates is unclear- would be
a hindrance?

Not all solutes move at the same speed- how
would that be possible if mass flow? - they should do so if movement is by mass flow

Sucrose is delivered to all regions at the same
speed, regardless of their concentrations.

111
Q

what are xerophytes?

A

plants which are adapted for hod dry weather conditions by minimising the the transpiration rate

112
Q

how are xerophytes adapted for their function?

A

sunken stomata - trap a layer of moist air. the water vapour in the moist air reduces the water potential gradient between the the leaf air spaces and the exterior therefore decreases the rate of transpiration by evaporation.

waterproof thick waxy cuticle layer - acts as a barrier so less water can escape to reduce water loss by evaporation

shiny cuticle - helps to reflect a lot of the sunlight way

less stomata - less stomata means less water loss but they can also respond to low water availability by closing the stomata

thick stems - store water in their stems which minimises water loss

large root systems - allow them to maximise the amount of water they get from the ground to reduce water loss

pointed spines - reduce the surface area for water loss

Biology Y12 (20 decks)

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