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A Level Biology > Exchange and Transport Systems (Topic 3) > Flashcards

Exchange and Transport Systems (Topic 3) Flashcards

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1
Q

which has a bigger SA : volume ratio - smaller organisms or large organisms?

A

smaller

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2
Q

in single-celled organisms substances diffuse…
across the…

A

directly into the cell
cell surface membrane

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3
Q

in mammals ‘mass transport’ refers to

A

the circulatory system which uses blood to carry glucose, oxygen, hormones, antibodies and waste

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4
Q

mass transport in plants involves the transport of….

A

water and solutes in the xylem and phloem

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5
Q

heat exchange is influenced by..

A

body size
body shape
adaptions for heat exchange

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6
Q

gas exchange occurs over a…

A

gas exchange surface

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7
Q

what three factors increase the rate of diffusion?

A
  1. large surface area
  2. short diffusion distance
  3. steep concentration gradient
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8
Q

in fish the gas exchange surface is..

A

the gills

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9
Q

describe the structure of the gills

A

each gill is made out of gill filaments
gill filaments are covered in lamellae

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10
Q

gill filaments and lamellae in fish increase _____ so speed up the rate of ______

A

surface area
diffusion

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11
Q

how do the lamellae speed up diffusion?

A

they have a large SA
they have lots of capillaries and thin surface layer of cells

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12
Q

the counter current system in fish maintains a….

A

steep concentration gradient between the water and the blood

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13
Q

why is a steep concentration gradient between the water and blood and fish important?

A

so as much oxygen as possible diffuses from the water into the blood

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14
Q

in a counter current system water with a ____ concentration gradient flows next to ____ with a _____ concentration of oxygen

A

high
blood
lower

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15
Q

the main gas exchange surface in a plant is….

A

mesophyll cells

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16
Q

how are mesophyll cells adapted for gas exchange?

A

large surface area

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17
Q

in plants gases move in and out the leaf via the…
which opens to allow…

A

stomata
gas exchange

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18
Q

why would the stomata in a leaf close?

A

if the plant is losing too much water

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19
Q

what controls the opening and closing of the stomata?

A

guard cells

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20
Q

in insects air moves into the ____ through ______ . oxygen travels ___ the concentration gradient towards the _____ . tracheae branch off into ______ that go to ______ cells

A

trachea
spiracles
down
cells
tracheoles
individual

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21
Q

in insects how is CO2 removed from the organism?

A
  1. moves down its concentration gradient
  2. towards spiracles
  3. to be released
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22
Q

insects use ______ _______ ______ to move air in and out of the spiracles

A

rhythmic abdominal movements

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23
Q

if insects are losing too much water they will…

A
  1. close their spiracles using muscles
  2. the waxy cuticle and tiny hairs reduce evaporation
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24
Q

in plants the stomatal pore is opened by…

A

water moving into guard cells making them turgid

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25
Q

in plants the stomatal pore is closed by…

A

the plant becoming dehydrated so guard cells lose water and become flaccid, which closes the pore

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26
Q

plants that are adapted against water loss are called…

A

xerophytes

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27
Q

examples of xerophytic adaptions are:

A
  1. reduced no. of stomata
  2. thicker waxy waterproof cuticles
  3. curled leaves with stomata on the inside
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28
Q

what happens during inspiration?

A
  1. external intercostals and diaphragm contract
  2. causing the ribcage to move up and out and the diaphragm flattens
  3. increasing the volume of the thoracic cavity so pressure decreases
  4. air moved from high to low pressure down the pressure gradient into the lungs
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29
Q

is inspiration an active or passive process

A

active

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30
Q

what happens during expiration?

A
  1. external intercostals and diaphragm relax
  2. ribcage moves down and in
  3. decreasing the volume of the thoracic cavity so pressure increases
  4. air moves from high to low pressure down the pressure gradient so is forced out of lungs
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31
Q

is normal expiration active or passive?

A

passive

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32
Q

where does gas exchange occur in the lungs?

A

alveoli

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33
Q

what are the alveoli surrounded by?

A

a network of capillaries

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34
Q

the walls of alveoli contain _____ which….

A

elastin
helps them recoil to their normal shape after inhaling or exhaling air

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35
Q

describe gas exchange of oxygen at the alveoli

A

O2 diffuses out pf the alveoli across the alveolar epithelium and capillary epithelium into haemoglobin in the blood

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36
Q

describe gas exchange of carbon dioxide at the alveoli

A

CO2 diffuses out of the blood into the alveoli

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37
Q

what is the pathway of O2 when breathed in?

A
  1. trachea
  2. bronchi
  3. bronchioles
  4. alveoli
  5. alveolar epithelium
  6. capillary endothelium
  7. blood
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38
Q

how are alveoli adapted for fast diffusion?

A
  1. thin exchange surface
  2. large surface area
  3. steep conc gradient of O2 and CO2 between capillaries and alveoli
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39
Q

tidal volume is…

A

the volume of air inspired or expired per breath

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40
Q

ventilation rate is…

A

the no. of breaths per minute

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41
Q

forced expiratory volume is…

A

the maximum volume of air that can be breathed out in one second

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42
Q

forced vital capacity is…

A

the maximum volume of air possible to breathe out forcefully out of the lungs after a deep breath in

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43
Q

lung diseases reduce the rate of gas exchange in alveoli which means…

A

less O2 diffuses into the blood and body cells receive less O2 and rate of aerobic respiration is reduced

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44
Q

risk factors are…

A

factors that increase a persons chance of getting a disease

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45
Q

why do large biological molecules need to be broken down?

A

they are too large to be absorbed

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46
Q

what enzyme catalyses the breakdown of starch?

A

amylase

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47
Q

where is amylase produced?

A

salivary glands and pancreas

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48
Q

how do amylase work?

A

catalyses hydrolysis reactions that break the glycosidic bonds in starch to produce maltose

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49
Q

membrane bound disaccharides are..

A

enzymes that are attached to the cell membranes of epithelium cells lining the ileum

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50
Q

sucrose is broken down by…
to produce what two monosaccharides?

A

sucrase
glucose + fructose

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51
Q

maltose is broken down by….
to produce what two monosaccharides?

A

maltase
glucose + glucose

52
Q

lactose is broken down by….
to produce what two monosacchrides?

A

lactase
glucose + galactose

53
Q

what enzyme catalyses the breakdown of lipids?

A

lipase

54
Q

when lipids are digested what bond is hydrolysed in the molecule?

A

ester bond

55
Q

where are lipases produced?
then secreted to the….

A

pancreas
small intestine

56
Q

where are bile salts produced?

A

liver

57
Q

what do bile salts do and why is this useful for digestion?

A

emulsify lipids increasing the surface area for lipases to work on

58
Q

once a lipid has been broken down,
the _______ and ____ ___ stick with the bile salts to form ______

A

monoglycerides
fatty acids
micelles

59
Q

what do micelles do?

A

help the products of lipid digestion to be absorbed

60
Q

what two peptidases are involved in digestion of proteins?

A

endopeptidases
exopeptidases

61
Q

what do endopeptidases do?

A

hydrolyse peptide bonds within a protein

62
Q

what do exopeptidases do?

A

hydrolyse peptide bonds at the end of proteins. they remove single amino acids from proteins

63
Q

what are dipeptidases?

A

two exopeptidases that work specifically on dipeptides

64
Q

how many molecules of oxygen can each haemoglobin molecule carry?

A

4

65
Q

when there is a high pO2 oxygen…

A

loads onto haemoglobin to form oxyhaemoglobin

66
Q

when there is a low pO2 oxygen…

A

unloads from oxyhaemoglobin

67
Q

where pO2 is high does haemoglobin have high or low affinity for oxygen?

A

high

68
Q

where pO2 is low does haemoglobin have high or low affinity for oxygen?

A

low

69
Q

the pulmonary artery carries blood from the….
to the….

A

heart
lungs

70
Q

the pulmonary vein carries blood from the….
to the…

A

lungs
heart

71
Q

the aorta carries blood from the…
to the…..

A

heart
body

72
Q

the vena cava carries blood from the…
to the….

A

body
heart

73
Q

the renal artery carries blood from the….
to the…..

A

body
kidneys

74
Q

the renal vein carries blood from the….
to the….

A

kidneys
body

75
Q

does the aorta carry oxygenated or deoxygenated blood?

A

oxygenated

76
Q

does the vena cava carry oxygenated or deoxygenated blood?

A

deoxygenated

77
Q

does the pulmonary artery carry oxygenated or deoxygenated blood?

A

deoxygenated

78
Q

does the pulmonary vein carry oxygenated or deoxygenated blood?

A

oxygenated

79
Q

arteries carry blood from the….
to the….

A

heart
body

80
Q

describe the structure of an artery and what this does?

A
  1. thick walls with elastic tissue
  2. inner lining is folded
    which maintains a high pressure
81
Q

arteries divide into….

A

arterioles

82
Q

veins carry blood from the…
to the….

A

body or lungs
heart

83
Q

in veins blood travels at a _____ pressure

A

low

84
Q

describe the structure of a vein

A
  1. have valves to stop backflow of blood
  2. wider lumen than arteries
85
Q

arterioles branch into….

A

capillaries

86
Q

describe the structure of a capillary..

A

one cell thick

87
Q

in a capillary bed, substances move out of the capillaries into the tissue fluid by….

A

pressure filtration

88
Q

where is pressure highest in the capillary bed?

A

at the start

89
Q

what has thicker walls atria or ventricles?

A

ventricles

90
Q

what is the function of AV valves?

A

stop blood flowing back into the atria when the ventricles contract

91
Q

what is the function of semi-lunar valves?

A

stop blood flowing back into the heart after the ventricles contract

92
Q

what are the three stages of the cardiac cycle?

A
  1. ventricles relax and contract
  2. ventricles contract and atria relax
  3. ventricles relax and atria relax
93
Q

cardiac output =

A

stroke volume x heart rate

94
Q

how is an atheroma formed?

A

if the endothelium is damaged by high blood pressure, white blood cells and lipids clump together under the lining to form fatty streaks. more builds up and hardens to from atheroma

95
Q

what is an aneurysm?

A

a balloon-like swelling of the artery

96
Q

what is thrombosis?

A

the formation of a blood clot

97
Q

what is the scientific term for heart attack?

A

myocardial infarction

98
Q

what causes a heart attack?

A

when a coronary artery is completely blocked and an area of the hearts blood supply is completely cut off and receives no oxygen

99
Q

what are the risk factors for cardiovascular disease?

A

high blood pressure
high blood cholesterol & poor diet
cigarette smoking

100
Q

what tissues are involved in mass transport in plants?

A

xylem
phloem

101
Q

what does xylem tissue transport?

A

water and mineral ions in solution

102
Q

what does phloem tissue transport?

A

organic substances like sugars

103
Q

describe the structure of the xylem

A

xylem vessels are long tube like structures formed from dead cells joined end to end

104
Q

How does water move up a plant?
4 marks

A
  1. transpiration occurs at the leaf
  2. creating tension, pulling more water into the leaf
  3. water molecules stick together so the whole column of water in the xylem moves upwards
  4. water enters the stem through the roots
105
Q

what is transpiration?

A

the evaporation of water from a plants surface

106
Q

what 4 factors affect rate of transpiration?

A
  1. temperature
  2. humidity
  3. light intensity
  4. wind
107
Q

what affect does light intensity have on transpiration?

A

the lighter it is the faster the rate of transpiration

108
Q

what affect does temperature have on transpiration?

A

the higher the temperature the faster the rate of transpiration

109
Q

what affect does humidity have on transpiration?

A

the lower the humidity the faster the rate of transpiration

110
Q

what affect does wind have on transpiration?

A

the windier it is the faster the rate of transpiration

111
Q

describe the structure of the phloem

A

formed from cells arranged in tubes and contains sieve tube elements and a companion cell for each sieve tube

112
Q

what is the function of the sieve tube element of phloem?

A

they form the tube for transporting solutes

113
Q

what is the function of the companion cell element of the phloem?

A

they carry out the living functions for sieve cells

114
Q

translocation is….

A

the movement of solutes to where they are needed in the plant, from sources to sinks

115
Q

what is the source in translocation?

A

where solutes are produced, so are at high concentration

116
Q

what is the sink in translocation?

A

where solutes are used up, so are at a lower concentration

117
Q

the concentration gradient in translocation is maintained by…

A

enzymes breaking down or converting solutes into something else at the sink

118
Q

give evidence for the mass flow theory

A
  1. if a metabolic inhibitor is put into the phloem translocation stops - proving active transport is used
  2. a radioactive tracer can be used to track movement of organic substances in the plant
119
Q

give evidence against the mass flow theory

A
  1. sugar travels to many different sinks not just the one with the highest water potential
  2. the sieve plates would create a barrier to mass flow
120
Q

what is the mass flow hypothesis?

A

the theory for how dissolved substances (solutes) are transported from source to sink by translocation

121
Q

Describe the mass flow hypothesis for the mechanism of translocation in plants

4 marks

A
  1. In source sugars are actively transported into phloem
  2. By companion cells
  3. Lowers water potential of sieve cell and water enters via osmosis
  4. Increase in pressure causes mass movement
122
Q

Use your understanding of the mass flow hypothesis to explain how pressure is generated inside a phloem tube

3 marks

A
  1. sucrose actively transported into phloem
  2. lowering water potential
  3. water moves into phloem via osmosis
123
Q

Describe how a high pressure is produced in the leaves

3 marks

A
  1. water potential becomes lower
  2. water enters phloem via osmosis
  3. increased volume of water causes increased pressure
124
Q

Explain three ways in which an insects’s tracheal system is adapted for efficient gas exchange

3 marks

A
  1. tracheoles have thin walls so short diffusion distance to cells
  2. highly branched so short diffusion distance
  3. highly branched so large surface area
125
Q

The concentration of oxygen in the surface water than it is in water close to the seabed. Explain why

3 marks

A
  1. mixing of air and water at surface
  2. air has a higher conc. of O2 than water
  3. oxygen diffuses in
126
Q

Explain how the countercurrent system in fish ensures max volume of O2 passes into the blood

3 marks

A
  1. water and blood flow in opposite directions
  2. blood passing water with higher oxygen concentration
  3. diffusion gradient maintained throughout gill length
127
Q

Explain how the gills of fish are adapted for efficient gas exchange

6 marks

A
  1. large SA provided by lamellae
  2. thin distance between blood and water
  3. water and blood flow in countercurrent
  4. which maintains high conc. gradient
  5. circulation replaces blood saturated with oxygen
  6. ventilation replaces water

A Level Biology (19 decks)

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