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Biology > ✅7 - Mass Transport > Flashcards

✅7 - Mass Transport Flashcards

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1
Q

What is associating?

A

When haemoglobin binds with oxygen

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2
Q

Where does loading take place?

A

In the lungs

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3
Q

What is dissociating?

A

When haemoglobin releases its oxygen

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4
Q

Where does unloading take place?

A

The tissues

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5
Q

Haemoglobins with a high affinity for oxygen…

A

…take it up easily but release it less easily

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6
Q

Haemoglobins with a low affinity for oxygen…

A

…don’t take it up easily but release it easily

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7
Q

What is the role of haemoglobin?

A

To transport oxygen

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8
Q

What features must haemoglobin have to be efficient at transporting oxygen?

A

Readily dissociate with oxygen at the surface where gas exchange occurs
Readily dissociate from oxygen at the tissues requiring it

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9
Q

When does haemoglobin change affinity?

A

Under different conditions, such as O2 and CO2 concentrations

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10
Q

Why do different haemoglobins have different affinities for oxygen?

A

Because they have different shapes as each species produces a different amino acid sequence so the tertiary and quaternary structure are different

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11
Q

What is an oxygen dissociation curve?

A

The graph of the relationship between the saturation of haemoglobin and oxygen partial pressure

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12
Q

At low oxygen concentrations, why does little oxygen bind to haemoglobin?

A

Because the shape of the haemoglobin molecule makes it difficult for the first oxygen molecule to bind to one of the sites on its four polypeptide subunits because they are closely united

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13
Q

Why is it easier for the second oxygen molecule to bind to haemoglobin?

A

Because the binding of the first oxygen molecule changes the quaternary structure of the haemoglobin and uncovers another binding site

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14
Q

What is positive cooperativity?
(Mass transport)

A

Binding the first molecule makes binding of the second easier and so on

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15
Q

What happens after the binding of the third oxygen molecule?

A

It is harder to bind the fourth, as the majority of the binding sites are filled and it is less likely that a single oxygen molecule will find an empty site to bind to

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16
Q

What is the shape of the oxygen dissociation curve?

A

Sigmoidal

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17
Q

The further the curve is to the left…
(oxygen dissociation graph)

A

…the greater the affinity of haemoglobin for oxygen

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18
Q

The further the curve is to the right…

A

…the lower the affinity of haemoglobin for oxygen

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19
Q

How does haemoglobin’s affinity for oxygen change in the presence of carbon dioxide?

A

Its affinity is reduced

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20
Q

What is the Bohr effect?

A

The greater the concentration of Carbon Dioxide, the more rapidly haemoglobin releases its oxygen

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21
Q

Why is a transport system required?

A

To take materials from cells to exchange surfaces and the environment

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22
Q

What factors does the presence of a transport system depend on?

A

The surface area to volume ratio

How active an organism is

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23
Q

What are the features of transport system?

A

A suitable medium in which to carry materials
A form of mass transport
A closed system of tubular vessels
A mechanism for moving the transport medium within vessels

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24
Q

What do animals use as transport mechanisms?

A

Muscular contraction either of the body muscles or of the organs eg heart

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25
Q

What do plants rely on for exchange?

A

Natural, passive processes such as evaporation

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26
Q

What kind of circulatory system to mammals have?

A

A closed, double system

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27
Q

Why does the blood pass through the heart twice for reach circuit of the body?

A

Because pressure is reduced when the blood is passed through the lungs, and it otherwise would circulate the body very slowly

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28
Q

What is the atrium?

A

A thin walled and elastic chamber which stretches as it collects blood

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29
Q

What is the ventricle?

A

A much thicker, more muscular chamber

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30
Q

Why do the ventricles have thicker more muscular walls?

A

Because they have to contract strongly to pump blood a further distance

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31
Q

Where does the right ventricle pump blood to?

A

The lungs

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32
Q

Where does the left ventricle pump blood to?

A

The rest of the body

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33
Q

What are the two valves?

A

The left atrioventricular (bicuspid)
The right atrioventricular (tricuspid)

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34
Q

What is the problem with the large surface area needed for the capillaries in the lungs?

A

There has to be a significant drop in pressure

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35
Q

What is the aorta connected to?

A

The left ventricle

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36
Q

What does the aorta do?

A

Carries oxygenated blood to all parts of the body except the lungs

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37
Q

What is the vena cava connected to?

A

The right atrium?

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38
Q

What does the vena cava do?

A

Brings deoxygenated blood back from the tissues of the body

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39
Q

What is the pulmonary artery connected to?

A

The right ventricle

40
Q

What does the pulmonary artery do?

A

Carried deoxygenated blood to the lungs where it is replenished with oxygen and carbon dioxide removed

41
Q

What is the pulmonary vein connected to?

A

The left atrium

42
Q

What does the pulmonary vein do?

A

Brings oxygenated blood back from the lungs

43
Q

Which blood vessels supply the heart?

A

The coronary arteries

44
Q

What is a myocardial infarction?

A

A heart attack

45
Q

Where do the coronary arteries branch off from?

A

The aorta

46
Q

What is systole?

A

Contraction

47
Q

What is diastole?

A

Relaxation

48
Q

What happens in diastole?

A

Blood returns to atria, pressure rises. AV valves open, blood passes into ventricles, pressure drops and semi lunar valves close

49
Q

What happens in atrial systole?

A

Contraction of atrial walls forces blood into ventricles from atria

50
Q

What happens in ventricular systole?

A

Ventricles fill with blood, wall contract, increasing pressure. AV valves shut and backflow prevented. Blood forced out into arteries

51
Q

Where are the atrioventricular valves located?

A

Between the left atrium and ventricle and the right atrium and ventricle

52
Q

What do the atrioventricular valves do?

A

Prevent backflow of blood when contraction of ventricles means that ventricular pressure exceeds atrial pressure

53
Q

How do atrio ventricular valves maintain uni-directional flow of blood

Exam Q

A

Pressure in (left) atrium is higher than in ventricle/B causing valve to open;

Pressure in (left) ventricle/B is higher than in atrium causing valve to close;

54
Q

Where are the semi-lunar valves?

A

In the aorta and pulmonary artery

55
Q

What do the semi-lunar valves do?

A

Prevent backflow of blood into ventricles when pressure in the vessels exceeds the pressure in the ventricles

56
Q

Where are the pocket valves?

A

In veins

57
Q

What is cardiac output?

A

The volume of blood pumped by one ventricle of the heart in one minute?

58
Q

How would you calculate cardiac output?

A

heart rate x stroke volume (volume of flood pumped out of left ventricle per cardiac cycle)

59
Q

What do arteries do?

A

Carry blood away from the heart to the arterioles

60
Q

What do arterioles do?

A

Smaller arteries that control the blood flow from arteries to capillaries

61
Q

How can arterioles reduce blood flow into capillaries

A

Muscle contracts;
Constricts/narrows arteriole/lumen;

62
Q

What do capillaries do?

A

Tiny vessels that link arterioles to veins

63
Q

What do veins do?

A

Carry blood from capillaries back to the heart

64
Q

What is the basic structure of arteries, arterioles and veins?

A 
Tough fibrous outer layer
Muscle layer
Elastic layer
Thin inner lining
Lumen
65
Q

What is the function of the tough fibrous layer?

A

Resists pressure changes from both within and outside

66
Q

What is the function of the muscle layer?

A

Can contract and so control the flow of blood

67
Q

What is the function of the elastic layer?

A

Helps maintain blood pressure by stretching and springing back smoothing blood flow

68
Q

What is the function of the thin inner lining?
(Blood vessels)

A

Smooth to reduce friction and thin to allow diffusion

69
Q

What is the function of the lumen?

A

The central cavity, allows blood to flow

70
Q

How are arteries adapted to their function?

A

Thick muscle layer to constrict and dilate
Thick elastic layer to come with high blood pressure
Thick wall to resist pressure
No valves

71
Q

How are arterioles adapted for their function?

A

Muscle layer is thicker to allow constriction

Thin elastic layer because blood pressure is lower

72
Q

How are veins adapted for their function?

A

Muscle layer is relatively thin as constriction and dilation can’t control blood flow
Elastic layer is thin due to low pressure
Overall thickness is small, low pressure
Valves throughout

73
Q

How are capillaries adapted for their function?

A

Walls consist mostly of the lining layer
Numerous and highly branched
Narrow diameter to permeate tissues
Narrow lumen to squeeze RBCs flat

74
Q

What is tissue fluid?

A

A watery liquid that contains glucose, amino acids, fatty acids, ions in solution and oxygen

75
Q

How is tissue fluid formed?

A

High hydrostatic pressure at the artery end forces the fluid out through the capillary

76
Q

What is ultrafiltration?

A

Filtration under pressure

77
Q

How is tissue fluid returned to the circulatory system?

A

The loss of tissue fluid reduces hydrostatic pressure in capillaries, so higher hydrostatic pressure outside forces fluid back in. Water also leaves the tissue by osmosis.

78
Q

How are fluids moved around the body?

A

Hydrostatic pressure of the tissue fluid

Contraction of body muscles

79
Q

How does water move across the cells of the leaf?

A

Water from mesophyll cells is lost by evaporation from their cell walls to the air spaces in the leaf, then water moves by osmosis into the drier cells

80
Q

What is the main factor responsible for the movement of water up the xylem?

A

Cohesion tension

81
Q

How does water move up the xylem?

A

Water evaporates from mesophyll
Water molecules form hydrogen bonds and have cohesion
Water forms a continuous column down the xylem
The column is pulled up the xylem

82
Q

What is transpiration pull?

A

When a column of water is pulled up the xylem as a result of transpiration

83
Q

What evidence supports cohesion-tension theory?

A

Tree trunks change in diameter according to the rate of transpiration
If a xylem vessel is broken and air enters, a tree can no longer take up water
When a xylem vessel is broken, water does not leak out as it would if it was under pressure

84
Q

What is needed to drive the process of transpiration?

A

Energy from the sun

85
Q

What is translocation?

A

The process by which organic molecules and some mineral ions are transported from one part of a plant to another

86
Q

What is the phloem?

A

The tissue that transports biological molecules in flowering plants

87
Q

What is evidence for the fact that translocation occurs in the phloem?

A

When phloem is cut, a solution of organic molecules flows out
Plants provided with radioactive carbon dioxide can be shown to have radioactively labelled phloem

88
Q

Explain the cohesive-tension theory

A

Water evaporates from mesophyll cells due to the sun and transpiration
Water molecules form hydrogen bonds between one another and therefore stick together (cohesion)
Water from a continuous unbroken column column which is pulled up

89
Q

Describe the mechanism for translocation

A

Sucrose is actively transported into phloem
By companion cells
Lowers the water potential in the phloem and water enters by osmosis
Produces high pressure
Mass transport towards the sink
At sink, sugars are removed

90
Q

What are ringing experiments

A

Cut a ring of bark from around the stem of a plant.
After a period of time, the section of stem above the removed area will start to swell
This is because sugars are accumulating above the ring

91
Q

What are tracer experiments

A

Radioactive isotopes are put in CO2 (e.g. carbon 14). The plant will then incorporate this into its sugars which can be tracked through the plant

92
Q

Evidence for the mass flow hypothesis

A

When a phloem is cut, stuff flows out
Plants provide with radioactive CO2 have radioactive carbon in the phloem after a short time
Aphids which feed out of the phloem show sucrose conc. variation changes each day
A ring experiment leads to accumulation of sugars around the stem

93
Q

2 ways cell surface membranes are adapted for rapid transport

A

Membrane folded to increase S.A
Large number of protein channels/carriers for facilitated diffusion

94
Q

Why should a person be treated with an experimental and established drug at the same time

A
  1. New/old antibiotic does not kill all bacteria;
  2. Resistant bacteria will reproduce to produce (more) resistant bacteria;
  3. One antibiotic will kill bacteria resistant to the other antibiotic;
95
Q

How do micelles work

A
  1. Micelles include bile salts and fatty acids;
  2. Bring/release/carry fatty acids to cell/lining (of the ileum);
  3. Fatty acids (absorbed) by diffusion;
  4. Triglycerides reform in cells
  5. Vesicles move to cell membrane
96
Q

What is a hierarchy

A

groups within groups with no overlap

Biology (23 decks)

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