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AQA Alevel Biology > mass transport > Flashcards

mass transport Flashcards

(75 cards)

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1
Q

Haemoglobin

A

quaternary structure protein
2 alpha chains
2 beta chains
4 associated haem groups in each chain containing Fe2+
transports oxygen

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2
Q

affinity of haemoglobin

A

the ability of haemoglobin to attract/ bind to oxygen

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3
Q

saturation of haemoglobin

A

when haemoglobin is holding the maximum amount of oxygen it can hold

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4
Q

loading/ unloading of haemoglobin

A

binding/ detachment of oxygen to haemoglobin
also known as association and disassociation

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5
Q

oxyhaemoglobin dissociation curve

A

oxygen is loaded in regions with high partial pressures
unloading in regions of low partial pressure

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6
Q

oxyhaemoglobin dissociation curve shifting left

A

Hb would have a higher affinity for oxygen
load more at the same partial pressure
becomes more saturated
adaptations in low-oxygen environments

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7
Q

cooperative binding

A

Hbs affinity for oxygen increases as more oxygen molecules are associated with it
when one binds. Hb changes shape meaning others bind more easily
explaining S shape of curve

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8
Q

how CO2 affects haemoglobin

A

When carbon dioxide dissolves
in liquid, carbonic acid forms
decreases pH causing Hb to
change shape
affinity decreases at respiring
tissues
more oxygen is unloaded

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9
Q

Bohr effect

A

High carbon dioxide partial pressure
causes oxyhaemoglobin curve
to shift to the right

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10
Q

oxyhaemoglobin dissociation curve shifting right

A

Hb has lower affinity for oxygen
unloads more at the same
partial pressures
less saturated
present in animals with faster
metabolisms that need more
oxygen for respiration
e.g. birds/rodents

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11
Q

closed circulatory system

A

Blood remains within blood
vessels

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12
Q

name different types of blood vessels

A

Arteries, arterioles, capillaries,
venules and veins

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13
Q

structure of arteries

A

Thick muscular layer
thick elastic layer
thick outer layer
small luman
no valves

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14
Q

capillary endothelium

A

Extremely thin
one cell thick
contains small gaps for small
molecules to pass through (e.g.glucose, oxygen)

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15
Q

capillaries

A

Form capillary beds
narrow diameter (1 cell thick) to slow blood flow
red blood cells squashed
against walls shortens diffusion pathway
small gaps for liquid / small
molecules to be forced out

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16
Q

arterioles

A

Branch off arteries
thickest muscle layer to restrict
blood flow
thinner elastic layer and outer
layer than arteries as pressure
lower

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17
Q

tissue fluid

A

Liquid bathing all cells
contains water, glucose, amino
acids, fatty acids, ions and
oxygen
enables delivery of useful
molecules to cells and removal
of waste

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18
Q

tissue fluid formation

A

At arteriole end, the smaller
diameter results in high
hydrostatic pressure
small molecules forced out
(ultrafiltration)
red blood cells / large proteins
too big to fit through capillary
gaps so remain

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19
Q

reabsorption of tissue fluid

A

Large molecules remaining in
capillary lower its water
potential
towards venule end there is
lower hydrostatic pressure due to loss of liquid
water reabsorbed back into
capillaries by osmosis

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20
Q

role of lymph in tissue fluid reabsorption

A

Not all liquid will be reabsorbed by osmosis as equilibrium will
be reached
excess tissue fluid (lymph) is
absorbed into lymphatic system and drains back into
bloodstream and deposited
near heart

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21
Q

cardiac muscle

A

walls of heart having thick muscular layer
unique because it is:
myogenic - can contract and
relax without nervous or
hormonal stimulation
never fatigues so long as
adequate oxygen supply

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22
Q

coronary arteries

A

Blood vessels supplying cardiac muscle with oxygenated blood
branch off from aorta
if blocked, cardiac muscle will
not be able to respire, leading to myocardial infarction (heart
attack)

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23
Q

adaptation of left ventricle

A

Has a thick muscular wall in
comparison to right ventricle
enables larger contractions of
muscle to create higher
pressure
ensures blood reaches all body
cells

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24
Q

veins that connect to the heart

A

Vena cava - carries
deoxygenated blood from body to right atrium
Pulmonary vein - carries
oxygenated blood from lungs to left atrium

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25
arteries connected to the heart
Pulmonary artery - carries deoxygenated blood from right ventricle to lungs Aorta - carries oxygenated blood from left ventricle to rest of the body
26
valves within the heart
ensure unidirectional blood flow semilunar valves are located in aorta and pulmonary artery near the ventricles atrioventricular valves between atria and ventricles
27
opening and closing valves
Valves open if the pressure is higher behind them compared to in front of them. AV valves open when pressure in atria > pressure in ventricles SL valves open when pressure in ventricles > pressure in arteries
28
the septum
Muscle that runs down the middle of the heart separates oxygenated and deoxygenated blood maintains high concentration of oxygen in oxygenated blood maintaining concentration gradient to enable diffusion to respiring cells
29
cardiac output
Volume of blood which leaves one ventricle in one minute. heart rate = beats per minute heart rate x stroke volume
30
stroke volume
Volume of blood that leaves the heart each beat measured in dm^3
31
cardiac cycle
Consists of diastole, atrial systole and ventricular systole
32
diastole
Atria and ventricular muscles are relaxed when blood enters atria via vena cava and pulmonary vein increasing pressure in atria
32
atrial systole
Atria muscular walls contract, increasing pressure further. pressure atria > pressure ventricles atrioventricular valves open and blood flows into ventricles ventricular muscle relaxed
33
ventricular systole
After a short delay (so ventricles fill), ventricular muscular walls contract pressure ventricle > atria pressure and artery pressure atrioventricular valves close and semi-lunar valves open blood pushed into artery
33
transpiration
Loss of water vapour from stomata by evaporation affected by: light intensity temperature humidity wind can be measured in a lab using a potometer
33
how light intensity affects transpiration
As light intensity increases, rate of transpiration increases more light means more stomata open larger surface area for evaporation
34
how temperature affects transpiration
As temperature increases, rate of transpiration increases the more heat there is, the more kinetic energy molecules have faster moving molecules increases evaporation
34
how humidity affects transpiration
As humidity increases, transpiration decreases the more water vapour in the air, the greater the water potential outside the leaf reduces water potential gradient and evaporation
35
how wind affects transpiration
As wind increases, rate of transpiration increases the more air movement, the more humid areas are blown away maintains water potential gradient, increasing evaporation
36
cohesion in plant transport
Because of the dipolar nature of water, hydrogen bonds can form - cohesion water can travel up xylem as a continuous column
37
adhesion in plant transport
Water can stick to other molecules (xylem walls) by forming H-bonds helps hold water column up against gravity
38
cohesion-tension theory
As water evaporates out the stomata, this lowers pressure water is pulled up xylem (due to negative pressure) cohesive water molecules creates a column of water water molecules adhere to walls of xylem pulling it upwards this column creates tension, pulling xylem inwards
38
root pressure in plant transport
as water moves into roots by osmosis, the volume of liquid inside the root increases therefore the pressure inside the root increases this forces water upwards
39
translocation
Occurs in phloem explained by mass flow hypothesis transport of organic substances through plant
40
sieve tube elements
Living cells contain no nucleus few organelles this makes cell hollow allowing reduced resistance to flow of sugars
41
companion cell
Provide ATP required for active transport of organic substances contains many mitochondria
42
mass flow hypothesis
Organic substances, sucrose, move in solution from leaves (after photosynthesis) to respiring cells source -> sink direction
43
how is pressure generated for translocation
Photosynthesising cells produce glucose which diffuses into companion cell companion cell actively transports glucose into phloem this lowers water potential of phloem so water moves in from xylem via osmosis hydrostatic pressure gradient generated
44
what happens to sucrose after translocation
Used in respiration at the sink stored as insoluble starch
45
investigating translocation
Can be investigated using tracer and ringing experiments proves phloem transports sugars not xylem
46
tracing
Involves radioactively labelling carbon - used in photosynthesis create sugars with this carbon thin slices from stems are cut and placed on X-ray film which turns black when exposed to radioactive material stems will turn black as that is where phloem are
47
ringing experiments
Ring of bark (and phloem) is peeled and removed off a trunk consequently, the trunk swells above the removed section analysis will show it contains sugar when phloem removed, sugar cannot be transported
48
how do small organisms exchange gases
Simple diffusion across their surface
49
why dont small organisms need breathing systems
They have a large surface area to volume ratio no cells far from the surface
50
how alveoli structure relates to its function
Round shape & large number in - large surface area for gas exchange (diffusion) epithelial cells are flat and very thin to minimise diffusion distance capillary network maintains concentration gradient
51
how fish gas exchange surfaces provide a short diffusion distance
Thin lamellae epithelium means short distance between water and blood capillary network in every lamella
52
how fish gas exchange surface maintains diffusion gradient
Counter-current flow mechanism circulation replaces blood saturated with oxygen Ventilation replaces water with oxygen removed
53
name of gas exchange system in terrestrial insects
tracheal system
54
structure of spiracles
Round, valve-like openings running along the length of the abdomen
55
trachea and tracheoles structure
Network of internal tubes have rings of cartilage adding strength and keeping them open trachea branch into smaller tubes - tracheoles tracheoles extend through all tissues delivering oxygen
56
how tracheal system provides short diffusion distance
Tracheoles have thin walls so short diffusion distance to cells
57
how tracheal system maintains concentration gradient
Body can be moved by muscles to move air - ventilation Use of oxygen in respiration and production of CO2 sets up steep concentration gradients
58
amylase
Produced in pancreas & salivary gland hydrolyses starch into maltose
59
enzymes involved in protein digestion
endopeptidases exopeptidases membrane-bound dipeptidases
60
products of protein digestion
larger polymer proteins are hydrolysed to amino acids
61
Double circulatory system
Blood passes through heart twice pulmonary circuit delivers blood to/from lungs systemic circuit delivers blood to the rest of the body
62
coronary arteries
Supply cardiac muscle with oxygenated blood for continued respiration and energy production for contraction
63
Blood vessels entering/ exiting the kidneys
Renal artery carries oxygenated blood to kidney renal vein carries deoxygenated blood to heart
64
Blood vessels entering/ exiting the lungs
Pulmonary artery carries deoxygenated blood to lung pulmonary vein carries oxygenated blood to heart
65
describe the structure of the veins
Thin muscular layer thin elastic layer thin walls valves
66
explain role of elastic layer in arteries
Thick elastic layer to help maintain blood pressure by stretching and recoiling
67
Describe the elastic layer in veins
Thin elastic layer as pressure lower cannot control the flow of blood
68
explain the role of valves in veins
Due to low pressure in veins skeletal muscle usually used to flatten walls of veins for blood flow valves prevent the backflow of blood unidirectional flow
69
What causes the AV valves to open
Higher pressure in the atria than in the ventricles
70
what causes the semi-lunar valves to open
Higher pressure in the ventricles than in the arteries

AQA Alevel Biology (22 decks)

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