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Exchange of Substances Flashcards

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1
Q

describe microvilli

A

large surface area to increase absorption

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2
Q

what is respiration

A

chemical reaction to release energy in the form of ATP

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3
Q

what happens during inhalation/inspiration

A

diaphgram contracts
external intercostal muscles contract pulling ribcage up and out
volume increases and pressure in thoractic cavity decreases
air pressure decreases
air moves down the trachea down a pressure gradient
active process requires energy

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4
Q

what happens during exhalation/expiration

A

diaphgram relaxes/flattens
internal intercostal muscles relax pulling ribcage moving in and down
volume decreases and pressure in thoractic cavity increases
air pressure increases
air moves out of the trachea down a pressure gradient
its a passive process does not require alot of energy

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5
Q

what is pulmonary ventilation

A

total volume of air moved into the lungs during one minute

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6
Q

how are the alveoli adapted for gas exchange

A

large number of alveoli increases surface area
surrounded by a network of capillaries to maintain a concentration gradient
endothelium and epithelium cells are very thin one cell thick to shortern diffusion distance to increase rate of diffusion
capillaries are narrow to decrease the speed of red blood cells to increase diffusion rate

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7
Q

explain the movement of oxygen and blood in the endothelium cells

A

oxygen diffuses out of the endothileum cell and epithelial cells which are one cell thick to reduce diffusion distance to increase rate of diffusion so they diffuse faster into the blood

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8
Q

what is a spiracle

A

tiny pores that allow gases to diffuse in and out

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9
Q

what is the trachea

A

a large internal network of tubes in insects with supported rings to prevent them from collapsing

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10
Q

what are the tracheoles

A

tubes that extend from the trachea and they allow air to be brought to respiring tissues

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11
Q

how are insects adapted for gas exchange (structure)

A

trachelos have thin walls to shortern diffusion pathway increasing rate of diffusion
tracheoles are highly branched which increases surface area for gas exchange
fluid in the ends which increases surface area
spiracles can open and close to prevent water loss
muscle can bump body and force air out which maintains a concentration gradient

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12
Q

how do insects use gas exchange

A

air moves down the trachea through the spiracles
oxygen travels down a concentration gradient
trachea branches into many tracheoles which have thin walls which means that oxygen can be diffused faster to respiring cells

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13
Q

how do insects use ventilation

A

compress the trachea
pumping raises pressure in the body and forces air out of the spiracles down a pressure gradient

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14
Q

how do insects limit water loss

A

small surface area to volume ratio
they have a waterproof exoskeleton
spiracles can reduce water loss as they can close and open

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15
Q

structure of fish

A

4 layers of gills
gills are made up of gill filaments
contains gill lamealle which is positioned on a right angle to the filament to increase surface area
contain lots of lamellae
gill filaments increase the surface area
many blood capillaries + thin walls for raster rate of diffusion

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16
Q

what is counter-current system

A

where blood flows through the lamealle in one direction and water flows in the opposite direction. this maintains a concentration gradient

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17
Q

how does the fish use ventilation

A

the fish takes in water through the operculum then the buccal cavity which then flows over the pharnyx over the gill filaments

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18
Q

how are the fish adapted for gas exchange

A

large number of filaments and laemale increase the surface area
thin epithelium cells which shortern diffusion distance
countercurrent flow system which maintains a concentratin gradient
large number of capillaries which gives a concentration gradient

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18
Q

why is the countercurrent flow system of fish useful

A

it ensures that a diffusion gradient is maintained across the entire length of the gill lamellae and oxygen cant reach equilibirum so it can keep diffusing/flowing

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18
Q

what is concurrent flow

A

where water and blood flow in the same direction

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19
Q

whats a disadvantage of concurrent flow

A

less oxygen would be absorbed into the blood
concentration gradient decreases

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20
Q

what is the function of operculum

A

maintains constant fresh water flow over gills to replace lost oxygen and to maintain a concentration gradient

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21
Q

how does the stomata reduce water loss

A

it closes at night when photosynthesis is not occuring

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22
Q

adaptation for spongy mesophyll

A

large surface area

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23
how are xerophytic plants adapted for water loss
a layer of hairs on the epidermis to trap water waxy cuticle to reduce evaporation
24
what enzymes break down carbohydrates
amylase mebrane bound disaccharidases
24
what is the function of AMYLASE ENZYME
catalyses the conversion of starch into maltose this involves hydrolysis of the glycosidic bonds in starch
25
where is amylase produced
salivary glands then mouth pancreas then small intestine
26
what are membrane bound disaaccharidases
enzymes which attach to cell membranes of epithelial cells lining the ileum
27
how can monosaccharides be transported across the cell membranes of the ileum epithelial cells
via cotransporter proteins
28
what is the function of the enzyme peptidase
catalyses the conversion of proteins into amino acids by hydrolysing the peptide bonds between amino acids
29
what is the function of endopeptidases
hydrolyses the peptide bonds between the amino aids in the middle of a polymer chain
30
what is the function of exopeptidase
hydrolyses the peptide bonds between the amino aids at the end of a polymer chain
31
what is the function of membrane bound dipeptidases
hydrolyses the peptide bonds between 2 amino acids
31
what is the function of the enzyme lipase
catalyses the breakdown of lipids into monoglycerides and fatty acids. this involves the hydrolysis of ester bonds
32
what is a monoglyceride
a glycerol molecule with one fatty acid attached
33
what do micelles do
increase the surface area for lipase to act on
34
how are micelles formed
emulsification of lipids monoglyceride and fatty acids stick with the bile salts
35
how do micelles help with lipid absorption
increase the surface area for lipase to act on which increases hydrolysis they make the fatty acids more soluble in water they carry the fatty acids to the epithelial cells of the ileum they help to maintain a higher concentration gradient of fatty acids compared to the epithelial cells of the ileum fatty acids leave the micelle and enter the epithelial cells by simple diffusion
36
why do fatty acids enter by simple diffusion
they are non-polar (lipid soluble) so they can dissolve and diffuse through the phospholipid bilayer
37
what happens when the fatty acids are in the epithelial cells
the fatty acids and monoglycerides are modified back into triglycerides inside of the endoplasmic reticulum and golgi body which can form vesicles
38
what are micelles made of
bile salts monoglycerides fatty acids
39
what do micelles do for lipase?
they increase the surface area for lipase to act on which increases hydrolysis
40
adaptations of the villi
thin walls for short diffusion pathway surrounded by a network of capillaries epithelial cells have microvilli which increase surface area maintaining a concentration gradient
41
what is haemoglobins structure
quaternary 4 polypeptide chains each chain made up of a haem group can carry 4 oxygen molecules
42
explain the oxyhaemoglobin dissociation curve
oxygen is loaded in regions with a high partial pressure of oxygen e.g. alveloi and is unloaded in regions of a low partial pressure of oxygen e.g respiring tissues
43
what is cooperative binding (s shape)
when the first oxygen binds to the haemoglobin it changes it shape which makes it easier for further oxygens to bind
44
when does haemoglobin have a high affinity for oxygen
when the partial pressure is high
45
what happens to the affinity when the partial pressure is low
haemoglobin has a lower affinity for oxygen
46
where is the partial pressure high and low
high in lungs, alveoli because more oxygen is being loaded low in respiring tissues because more oxygen is being unloaded
47
explain the Bohr effect
when a high carbon dioxide concentration causes the oxyhaemoglobin curve to shift to the right. the affinity for oxygen decreases because the acidic carbon dioxide changes the shape of haemoglobin slightly
48
what happens when there is a low partial pressure of CARBON DIOXIDE IN THE ALVELOI
curve shifts to the left, increased affinity and therefore uploads more oxygen
49
what happens when there is a high partial pressure of CARBON DIOXIDE IN THE respiring tissues
curve shifts to the right, decreased affinity and therefore unloads more oxygen
50
explain haemoglobin in different organisms
organisms that live in environments with a low concentration of oxygen have a high affinity for oxygen (curve is to the left) organisms that are very active e.g. dove and have a high oxygen demand have a lower affinity for oxygen (curve shifts to the right)
51
what does a closed circulatory system mean
the blood remains within the blood vessels
52
what does double circulatory system
blood passes through the heart twice in each circuit one circuit delivers blood to the lungs whereas the other circuit delivers blood from the heart to the rest of the body
53
why do mammals require a double circulatory system
to manage the pressure of blood flow
54
why does the blood flow through the lungs at a lower pressure
to prevent damage to the capillaries in the alveoli and also reduces the speed at which the blood flows enabling more time for gas exchange
55
why is it important that the heart is pumped out at a higher pressure
to ensure the blood reaches the respiring tissues in the body
56
properties of cardiac muscle
thick muscular layer myogenic - it can contract and relax never fatigues
57
what happens when the coronary arteries are blocked
cardiac muscle wont receive oxygen therefore will not be able to respire and the cells will die this results in a myocardial infarction heart attack
58
adaptations of the atria
thin muscular walls elastic walls to stretch when blood enters
59
adaptations of the ventricles
thick muscular walls for contraction creates a higher blood pressure to enable blood to flow longer distances to the lungs and to the rest of the body
60
function of vena cava
carries deoxygenated blood from body to right atrium
61
function of pulmonary vein
carries oxygenated blood from lungs to left atrium
62
function of arteries
carry blood away from heart
63
function of pulmonary artery
carries deoxygenated blood from right ventricle to lungs to become oxygenated
64
function of aorta
carries oxygenated blood from left ventricle to rest of body
65
function of valves
prevent blackflow of blood
66
function of atrioventicular valve
prevent backflow of blood
67
function of semi lunar valve
prevent backflow of blood
68
function of septum
maintains high conc gradient of o2 enables diffusion to occur at respiring cells
69
function of veins
carry blood back into the heart
70
ADAPTATIONS OF ARTERIES
thick and muscular walls and have elastic tissue to stretch and recoil as the heart beats which help maintains high pressure narrow lumen for high blood pressure single celled layer of endothelium allowing the artery to stretch
71
ADAPTATIONS OF VEINS
wider lumen than artery thin elastic walls and thin walls because the pressure is lower so low risk of bursting contain valve to prevent backflow of blood thin muscular layer
72
what happens in the diastole in the cardiac cycle
the atria and ventricular muscles are relaxed this is when blood will enter the atria via the vena cava and pulmonary vein the blood flowing into the atria increases the pressure within the atria
73
what happens in the atrial systole in the cardiac cycle
atria muscular walls contract, increasing the pressure. this causes the atrioventricular valves to open and blood to flow into the ventricles the ventricular walls are relaxed
74
what happens in the ventricular systole in the cardiac cycle
the ventricle muscular walls contract, increasing pressure. this causes the atrioventricular valves to close and the semi-lunar valves to open
75
what is tissue fluid
fluid containing water, glucose, amino acids, fatty acids, ions and oxygen which bathes the tissues
76
how is tissue fluid formed
as blood enters the capillaries from arterioles, the smaller diameter results in a high hydrostatic pressure so water, glucose, amino acids, fatty acids, ions and oxygen are forced out. this is known as ultrafiltration
77
how is capillary reabsorbed
large molecules remain in the capillaries and therefore create a lower water potential water re-enters the capillaries by osmosis
78
where is the rest of the tissue fluid absorbed
lymphatic system

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