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Exchange of substances Flashcards

1
Q

structure of fish gills

A

bony fish have four gills, each supported by an arch

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2
Q

why can’t fish survive for long out of water

A

projections are held apart by water- without water they stick together

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3
Q

adaptations of fish for gas exchange

A

many gill fillaments and many lamellae

blood and water flow in a counter-current direction

fillaments made of thin tissue

good ventilation

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4
Q

how do fish maintain good ventilation?

A

fish opens mouth and lowers the floor of the buccal cavity

this increases volume and decreases pressure

so water is forced in

fish closes its mouth, decreasing volume and increasing pressure

so water is forced into the opercular cavity via the gill fillaments

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5
Q

why is transport of oxygen in insects directly to muscles

A

they have no transport system (blood)

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6
Q

why are insects’ exoskeletons waterproof and why is this good/ bad

A

to stop water loss
good- protective
bad- doesn’t allow simple diffusion to occur

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7
Q

what do more active insects use for ventilation

A

mchanical ventilation by contraction of the abdominal muscles

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8
Q

what are spiracles

A

holes on surfact to let air enter or exit
can open or close to control gas exchange

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9
Q

trachea

A

tube lined with chitin
branches into tracheoles

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10
Q

tracheoles

A

deliver oxygen to cells

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11
Q

chitin

A

impermeable rings
impermeable so doesn’t allow diffusion

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12
Q

why is lactic acid in tracheoles

A

oxygen can dissolve in it then move into cells via simple diffusion

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13
Q

how can excess water be removed from tracheoles

A

lactic acid builds up in cells, decreasing their water potential
so water moves into cells from tracheoles via osmosis

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14
Q

how are plants adapted for efficent gas exchange

A

many stomata
large surface area
many leaves
air space so gasses can move throughout leaf

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15
Q

how is friction between the ribs and lungs decreased

A

a lubricating substance is secreted

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16
Q

trachea

A

leads from mouth/ nose to bronchus
lines with goblet cells, mucus and cilia

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17
Q

bronchus

A

lead from trachea to bronchioles

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18
Q

bronchioles

A

lead from bronchus to alveoli
have no supporting cartlidge and are narrow
made of smooth muscle and elastic fibres which relax and contract to control airflow

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19
Q

alveoli

A

many fluid filled sacs with thin walls
allow gas exchange into bloodstream
surrounded by capillaries
constant blood supply

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20
Q

ciliated epithelium

A

found in trachea and bronchi
each cell has cilia which sweep mucus, dust and bacteria away from the lungs

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21
Q

cartlidge in trachea

A

found in rings
keeps trachea open whilst allowing some movement

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22
Q

goblet cells

A

produce mucus to drap dust etc.

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23
Q

describe inspiration

A

external intercostal muscles contract
ribs move upwards
diaphragm contracts and flattens
volume in thorax increases, so pressure decreases
forces air into lungs down concentration gradient

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24
Q

describe expiration

A

internal intercostal muscles contract
ribs move down
diaphragm relaxes and raises
volume in thorax decreases, so pressur eincreases
air is forced out down a concentration gradient

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25
what is a spirometer and how does it work
device used to measure lung volume person breathes in and out of an airtight chamber chamber moves up and down trace on a graph is left which can be interpreted
26
vital capacity
maximum volume of air which can be inhaled/exhaled in one breath varies with age, gender etc.
27
tidal volume
volume of air inhaled/exhaled at rest
28
breathing rate
breaths per minute number of peaks on spirometer
29
residual volume
volume of air which is always present
30
endopeptidases
hydrolyse peptide bond in middle of the amino acid chain
31
exopeptidases
hydrolyse the peptide bond at the end of the amino acid chain
32
dipeptidases
hydrolyse the peptide bond between two amino acids
33
define digestion
hydrolysis of large, insoluble molecules into smaller, soluble ones
34
where are amylase, lactase, maltase and sucrase found in the body
amylase- mouth others- membrane of small intestine
35
what are lipids hydrolysed into
glycerol and three fatty acids
36
describe lipid absorption
lipids are hydrolysed into glygerol and fatty acids these associate with bile salts and are emulsified to form micelles this increases surface area and makes the molecules more soluble these micelles can diffuse through PLB fatty acids recombine with monoglycerides and glycerol to form triglycerides in the ER triglygerides are packaged into lipoproteins called chylomicrons these move out of the cell via exocytosis
37
what is the ileum
end of the small intestine
38
structure of haemoglobin
water soluble globular protein 2 beta polypeptide chains and 2 alpha helixes each molecule contains a haem (Fe2+) group which can bind to and carry oxygen
39
effect of increased partial pressure on haemoglobin
the haemoglobin's affinity for oxygen increases so oxygen is loaded
40
how is oxygen released at respiring tissues
there will be a low pp of oxygen so it will be unloaded for haemoglobin as the affinity between oxygen and haemoglobin decreases
41
how does oxygen saturation affect affinity
after the first oxygen molecule binds to haemoglobin, affinity increases as it is then easier for the second molecule to bind after the third oxygen molecule binds, it becomes harder for the fourth to do so as it is harder to find a fourth binding site
42
what is the difference between adult and foetal haemoglobin and why
foetal haemoglobin has a higher affinity for oxygen as it needs to absorb oxygen from the mother's blood when it reacher the placenta, but by this time pp oxygen has decreased
43
describe the Bohr effect
at high pp carbon dioxide, the affinity of haemoglobin for oxygen decreases so oxygen is unloaded at respiring tissues
44
how does the Bohr effect happen
the carbon dioxide creates slightly acidic conditions which change the shape of the haemoglobin
45
what are the right and left AV valves also known as
tricuspid and bicuspid valves, respectively
46
name of valves between ventricles and pulmonary artery/ aorta
semilunar valves
47
why is the heart known as myogenic
it can initiate its own contraction
48
what is located in the right atrium and what does it do
specialised fibres called the sionatrial node (pacemaker) sends electrical impulses so atria contract
49
cardiac diastole
atria and ventricles relax pressure in chambers lowers vena cava and pulmonary vein fill atria until AV valves open and blood moves into ventricles due to pressure gradient
50
atrial systole
atria contract forcing any remaining blood into the ventricles
51
ventricular systole
ventricles contract semilunar valves open and AV valves close blood leaves hear
52
structure and function of arteries
thick walled, narrow lumen- withstand pressure elastic fibres- stretch and recoil to smooth bloodflow muscle tissue- can vary bloodflow lined with smooth endothelium- reduces friction and eases bloodflow
53
arterioles
branch off arteries and lead to capillaries thinner, less muscular walls
54
capillaries
one cell thick wall for faster exchange
55
venules
lead from capillaries to veins larger than capillaries but smaller than veins
56
veins
wide lumen valves to stop backflow of blood little muscle or elastic tissue as low pressure so no need for recoiling
57
which substances are small enough to move into the tissue fluid
glucose, amino acids, oxygen etc.
58
what is tissue fluid formed from
blood plasma
59
function of tissue fluid
remove waste from cells and supply them with essential solutes
60
function of lymph fluid
remove waste products form cells
61
describe the movement from the capillaries to the lymphatic system
there is high hystrostatic pressure at the arteriole end so molecules move from capillary into the tissue fluid large molecules such as proteins are too large to move out so remain in blood this gives the blood a more negatice water potential (concentrated) so some water moves by osmosis back into the capillaries but overall more moves into the tissue fluid
62
describe the difference in hydrostatic pressure and water potential in arteriole end and venous end of capillaries
arteriole end has a higher hydrostatic pressure than venous end (but bothe higher than tissue fluid) arteriole end has a similar water potential to venous end (but both lower than tissue fluid)
63
features of xylem
transports water and soluble minerals long cylinders made of dead cells no sieve plates etc. so can form a continuous column spiral lignin for strength
64
adaptations of xerophytes to reduce water loss
sunken stomata and curled leaves- humid layer formed so reduces water potential gradient, less wind fewer stomata thicker waxy cuticle smaller leaves stomata open in the night
65
describe the cohesion-tension theory
water evapourates out the mesophyll cells due to a water potential gradient water molecules stick together due to cohesion caused by hydrogen bonds water forms a continuous column from xylem to mesophyll cells column of water is pulled up the xylem (transpiration pull) this puts the xylem under negative pressure (tension)
66
evidence for cohesion-tension theory
tension causes trunk diameter to shrink when transpiration is occuring during the day if air enters xylem, column is broken so water can't be drawn up no end walls in xylem- continuous column energy needed is derived from sun causing transpiration
67
describe movement of water cells across leaf
mesophyll cells lose water via evapouration from air spaces water potential gradient between air spaces and outside loss of water from mesophyll cells reduces their water potential so water moves in via osmosis from neighboring cells this continues
68
structure and adaptations of phloem
used to transport sugars and insoluble nutrients living cells with companion cells for ATP production have sieve plates cytoplasm of phloem cells and sieve cells is linked through plasmodesmata so they can exchange minerals etc.
69
describe the process of translocation (mass flow theory)
companion cells use ATP to transport hydrogen ions into the surrounding tissue there is now a diffusion gradient between surrounding tissue and companion cells H+ ions move back into the cell with sucrose via facillitated diffusion sucrose moves from the high concentration in companion cells to sieve elements there is now a high water potential in sieve tube elements so water moves into them via osmosis there is now high hydrostatic pressure so water moves down to a lower hydrostatic pressure sucrose is unloaded at the sink water potential is now higher in the sieve elements so water moves out of these via osmosis into xylem
70
ringing experiements
phloem are removes but xylem left in tact after a week there is swelling above the ring leaves are unaffected and there's reduced growth below the ring so sugars must be transported downwards in the phloem
71
radioactive tracer experiment
expose a leaf to radioactive C14 carbon dioxide which is radioactive C 14 is used to produce glucose then sucrose autoradiograph shows the location of the radioactive carbon this shows sugars are transported downwards
72
evidence contradicting the mass flow hypothesis
amino acids appear to travel more slowly than sucrose different substances in sieve element flowing in one direction sieve tubes function unknown- appear to slow down flow.
73
three adaptations of an insect's trachiole system
thin tracheole walls highly branched trachea- more surface area muscles contract to move air so maintains concentration gradient
74

Biology (8 decks)

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