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Biology year 1 > 7.0 Mass Transport > Flashcards

7.0 Mass Transport Flashcards

(104 cards)

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1
Q

What type of molecule is haemoglobin?

A

Protein

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2
Q

How many polypeptide chains make up a haemoglobin molecule?

A

4

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3
Q

What does haemoglobin transport?

A

Oxygen

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4
Q

What is the primary structure of haemoglobin?

A

The order of amino acids in the polypeptide chains

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5
Q

What is the secondary structure of haemoglobin

A

The coiling of the polypeptide chains into a helix

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6
Q

What is the tertiary structure of haemoglobin?

A

The folding of the polypeptide chains into a precise shape

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7
Q

What is the quaternary structure of a haemoglobin?

A

The linking of the 4 polypeptide chains into an almost spherical molecule. Each polypeptide also has an associated haem group

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8
Q

What ion does a haem group contain?

A

Fe2+

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9
Q

How many oxygen molecules does each Fe2+ ion combine with?

A

1 oxygen per Fe2+

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10
Q

How many oxygen molecules can a molecule of haemoglobin carry in humans?

A

4m one per haem group, 1 haem group in a polypeptide chain, 4 polypeptide chain in a haemoglobin molecule

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11
Q

What is the name given to the process in which haemoglobin binds to oxygen?

A

Loading or associating

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12
Q

What is the name given to the process in which oxygen is released from a haemoglobin molecule?

A

Unloading or dissociating

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13
Q

What does affinity mean with respect to haemoglobin?

A

The chemical attraction between the haemoglobin and oxygen

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14
Q

If haemoglobin has a high affinity for oxygen, what does this mean?

A

Easier to associate, harder to dissociate

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15
Q

If haemoglobin has a low affinity, what does this mean?

A

Harder to associate, easier to dissociate

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16
Q

To be good at transporting oxygen, what 2 characteristics must haemoglobin have?

A

It must readily associate with oxygen where gas exchange occurs. it must readily dissociate from oxygen in respiring tissues which require it

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17
Q

How does haemoglobin change its affinity for oxygen?

A

It will change shape when in the presence of
certain molecules (e.g. carbon dioxide). If
present, the carbon dioxide changes the shape, so
the oxygen nolonger fis as well, and is easily
disassociated

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18
Q

What do we mean by partial pressure?

A

The pressure exerted by one component of a mixture of gases, if it alone occupied the volume. Eg: atmospheric pressure is 100KPa, oxygen is 21% of the atmosphere, so its partial pressure is 21KPa

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19
Q

What does a dissociation curve represent?

A

it is a graph referring to the partial pressure of oxygen, and how saturated the haemoglobin is with oxygen

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20
Q

What shape does the oxygen dissociation curve take?

A

S

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21
Q

Why does the oxygen dissociation curve increase slowly to begin with?

A

The shape of the haemoglobin molecule makes binding the first oxygen molecule difficult

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22
Q

Why does the oxygen dissociation curve increase sharply after a slow beginning>

A

The first oxygen molecule to bind changes the shape of the quaternary structure, this makes binding of subsequent molecules easier

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23
Q

Why does the oxygen dissociation curve increase slowly at the end of the graph?

A

Probability. It is easier for the molecules to bind,
but the likelyhood of the 4th oxygen molecule to
find an empty bionding site is less likely.

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24
Q

What is the name given to the increase in ease of binding for the other oxygen molecules?

A

Positive cooperativity

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25
If an oxygen dissociation curve is shifted to the left does that affect the affinity for oxygen?
Higher affinity for oxygen, loads more readily, unloads less readily
26
If an oxygen dissociation curve is shifted to right does that affect the affinity for oxygen?
Lower affinity for oxygen, loads less readily and unloads more readily
27
What affect does carbon dioxide have on the affinity of haemoglobin?
The higher the concentration of carbon dioxide, the lower the affinity of haemoglobin to oxygen. Haemoglobin releases oxygen more readily
28
What effect does a lower concentration of carbon dioxide have on the oxygen dissociation curve?
Shifts the curve to the left
29
What is the name given to the shifting of the oxygen dissociation curve due to carbon dioxide?
The Bohr effect
30
What affect does a higher concentration of carbon dioxide have on the oxygen dissociation curve?
Shifts it to the right
31
What effect does the Bohr effect have at the gas exchange surface?
Low carbon dioxide concentrations. Affinity of haemoglobin for oxygen is increased, curve is shifted to the left
32
What effect does the Bohr effect have at the respiring tissues?
High carbon dioxide concentrations. Affinity of haemoglobin for oxygen is decreased, curve is shifted to the right.
33
Why does the carbon dioxide cause the haemoglobin to lose oxygen more readily?
Dissolved carbon dioxide is acidic. The low pH causes the haemoglobin to change shape.
34
How might the oxygen dissociation curve appear for an animal adapted to live in an area with a low partial pressure of oxygen?
They would require haemoglobin with a higher oxygen affinity, so the curve would be further to the left
35
Why do large organisms require a transport system?
Diffusion is fast enough for short distances, but large organisms need to transport nutrients over a greater distance
36
Why are specialist exchange surfaces required in large organisms?
Large organisms require a large amount of nutrients and create a large amount of waste. This requires greater surface area than the surface of the organism creates.
37
What happens to the surface area to volume ratio as the size of an organism increases?
The surface are to volume ration decreases.
38
What two factors determine whether an organism requires a specialised transport medium or a pump to circulate it?
The surface area to volume ratio and the activeness.
39
What are the main features of all transport systems?
A suitable medium (e.g. blood); A form of mass transport to move the medium great distances; A closed system of branching vessels; A mechanism for moving the medium in the vessels by pressure differences. A way of controlling the direction of mass transport (e.g. valves) A way of controlling the flow of medium to suit changing needs of the organism A mechanism to control the mass flow of water or gases. (E.g. intercostal muscle and diaphragm)
40
How do animals move their transport medium around their bodies?
Muscular contraction, either body muscles or specialised pump (heart).
41
How do plants move their transport medium?
Passive process such as evaporation:
42
How is the heart described in terms of a pump?
A double pump
43
What does the left side of the heart deal with?
Oxygenated blood from the lungs
44
What does the right side of the heart deal with?
Deoxygenated blood from the body
45
What are the two chambers that each side of the heart has?
Atrium and a ventricle
46
What is the structure and role of the atria?
Thin walled and elastic, stretches as blood enters
47
What is the structure and role of the ventricles?
Thick muscular wals to pump blood a good distance (Lung or body)
48
Why is the heart a double pump system?
As the blood flows through the cappilaries of the lungs, there is a massive drop in pressure. This would decrease the speed at which the blood would flow through the rest of the body.
49
What valve separates the left atrium and ventricle?
Left atrioventricular (bicuspid) valve
50
What valve separates the right atrium and ventricle?
Right atrioventricular (tricuspid) valve
51
Which chamber has the thickest walls and why?
Left ventricle because it has to pump blood through the aorta at high pressure all round the body
52
What supplies the blood to the heart?
Coronary arteries
53
What happens if the coronary arteries are blocked?
Myocardial infarction / heart attack as the muscle cells have no oxygen so die as are unable to respire aerobically.
54
What is the contraction of the atria known as?
Atiral systole
55
What is the relaxation of the heart called?
Diastole
56
What is the contraction of the ventricles known as?
Ventricular systole
57
What is the main job of the valves?
Prevent backflow of blood
58
How do atrioventricular valves close?
As the ventricles contract, the ventrical pressure exceeds atrial pressure.
59
Where are the semilunar valves?
In the aorta and pulmonary artery
60
How do the semilunar valves close?
When the elastic walls of the arteries recoil, causing the pressure to exceed that of the relaxed ventricle. This forces blood through the artery.
61
What are pocket valves?
These are valves located through the veinous system.
62
How do pocket valves close?
When the skeletal muscles contract, and the veins are squeezed, the valves only allow blood to flow towards the heart
63
How do you calculate cardiac output?
heart rate x stroke volume
64
What are the four type of blood vessel?
Arteries; Arterioles; Capillaries; Veins
65
What is the second most inner layer found in both arteries and veins called?
Elastic layer
66
What is one adaptation of arteries which allows them to withstand high pressures?
Thick elastic tissue which allows them to stretch and recoil
67
Which blood vessel carries blood from the heart to the body?
Aorta
68
Which blood vessel carries blood from the body to the heart?
Vena cava
69
Which blood vessel carries blood from the body to the kidneys?
Renal artery
70
Which blood vessel carries blood from the kidneys to the vena cava?
Renal vein
71
Which blood vessel carries blood from the heart to the lungs?
Pulmonary artery
72
Name three substances found within tissue fluid
glucose amino acids fatty acids ions in solution oxygen.
73
Describe how tissue fluid is returned to the circulatory system?
1 - Loss of tissue fluid causes a drop in hydrostatic pressure 2 - Therefore at the venous end of the cappillary network pressure is lower than the tissue fluid outside 3 - Fluid is forced back in 4 - Also plasma which has lost water has a lower water potential 5 - water moves from tissue fluid down a water potential gradient
74
How does water move up the stem?
Cohesion-tension
75
How is water lost through a leaf?
Water is lost through a stomata
76
How is water lost through the stomata?
Diffusion as the humidity of the atmosphere is lower than inside the leaf
77
How does water move through the cells of a leaf?
Mesophyll cells lose water through evaporation. This lowers their water potential This causes movement of water via osmosis from neighbouring cells. due to water potential difference.
78
How does water move up the stem in the xylem?
Water evaporates from the mesophyll causing evaporation The hydrogen bonds between water molecules cause cohesion Water makes an continuous chain from the mesophyl down the xylem The loss of water draws up new water molecules - transpiration pull
79
What is cohesion-tension theory?
The idea that the xylem is under tension, as the pull from transpiration puts them undernegative pressure.
80
What is the evidence that supports cohesion-tension theory?
Change in the diameter of tree trunks based on the rate of transpiration If air enters the xlem, transpiration no longer occurs as there is no continuous column of water Water doesn't leak out if the xylem is broken. The negative pressure draws air in instead.
81
Why is transpiration pull a passive process?
It occurs due to evaporation, it requires no metabolic energy
82
Where does the energy come from to drive the process of transpiration?
The sun
83
When talking about the movement of water in plants, what is the cell wall pathway?
The movement of water around the cells, through the cell walls (water doesn't enter the cells.
84
When talking about the movement of water in plants, what is the cytoplasmic pathway?
The movement of water through the cells via osmosis as the water potential changes.
85
Does sucrose affect water potential and if so how does the plant combat this?
Lowers water potential in the phloem sieve tubes, water moves from the xylem to sieve tubes.
86
What is a potometer?
A piece of equipment used to measure the movement of water into a plant
87
What is it that moves in a potometer?
Water moves through the potometer, this is observed by trapping an air bubble than is drawn through a capillary tube.
88
Why is the plant to be investigated, cut underwater?
So as not to get air trapped in the xylem vessels
89
What is measured when using a potometer?
The movement of a trapped air bubble along a capillary tube, and the time taken. Then the volume of water taken in by the plant can be calculated, and the time taken used to calculate the rate of uptake as well.
90
How does sucrose enter the sink from the phloem?
Active transport
91
How is sucrose moved from the source to the sieve elements?
1- Diffuses down the concentration gradient by facilitated diffusion into companion cells 2 - H+ ions actively transported out of companion cells 3 - H+ ions and sucrose molecules are transported into seive tube elements by co- transport
92
How is sucrose moved through the sieve elements?
1 - Sucrose that moves in at the source decreases water potential 2 - Water moves in from the xylem 3 - At the sinks, sucrose moves into the respiring cells, as does water 4 - This creates a hydrostatic pressure difference, so the sucrose solution is forced from source to sink
93
How is sucrose moved from the sieve elements to the storage or sink cells?
Active transport
94
Why is mass flow described as passive?
It does not use metabolic energy to directly move the substances
95
Is translocation active or passive, why?
It is active, as it is driven by the active transport of sugars.
96
In a woody stem, what lies just under the bark?
The phloem
97
What happens in a ringing experiment?
A complete ring of bark and phloem is removed from the stem.
98
What would you observe after a ringing experiment?
There is a swollen region in the bark just above the where the ring of stripped stem is.
99
What happens to the parts of a plant above and below the stripped area of bark in a ringing experiment?
The non-photosynthetic parts below the ring start to die. those above stay alive.
100
How does removing the phloem affect the plant? What does it mean?
Sugars accumulate above the ring causing the swelling. The interruption of the sugers cause the parts below the ring to die. It shows that the pholem not the xylem is involved in the movement of sugars.
101
What is an isotope?
An element with the same number of protons and electrons, but a different number of neutrons.
102
What are radioactive isotopes used for in plant investigations?
They can be used to trace the moevement of these iosotopes and the substances they become through the plant
103
What is an example of a radioactive isotopes used? What happens to it in a plant?
14C is different to typical 12C. It can be converted to CO2 which is then used in the plant to create sugars.
104
What can be used to identify the presence of the radioisotopes?
X-ray film. it will be blackened when exposed to the radiation

Biology year 1 (10 decks)

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