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biology year 1 > mass transport > Flashcards

mass transport Flashcards

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1
Q

why is the dissociation curve Sigmoidal s shaped?

A

co-operative binding=
-low partial pressures of O2 haemoglobin has low affinity for O2, doesnt load as readily
-as O2 partial pressures increase affinity of haemoglobin increases. when first O2 molecule loads, changes shape of haemoglobin moleucle =easier
-difficult to become 100% saturated - hard to diffuse and associate into 4th

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2
Q

describe haemoglobin in low oxygen environments

A

-Hb has higher affinity for O2
-Hb loads more readily at low pO2
-curve shifts to left

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3
Q

describe haemoglobin with high activity levels

A

-very active
-aerobically respire faster
-need more O2 per unit mass of tissue
-Hb has lower affinity for O2
-Hb unloads more readily at any given pO2
-curve shifted to the right

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4
Q

describe haemoglobin in smaller organisms

A

-higher SA:V
-transfer heat energy to environment faster
-aerobically respre faster/high metabollic rate
-need more O2 per unit mass of tissue
-Hb loads more readily at any given pO2
-curve shifts to the right

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5
Q

where does the renal artery carry blood from and to?

A

aorta to kidney

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6
Q

why is the left venticle much thicker?

A

need to contract more powerfully to pump oxygenated blood around the body

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7
Q

whats the importance of the septum?

A

separates sides so oxygenated and deoxygenated blood dont mix
also enables different pressures

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8
Q

whats the hearts own blood supply?

A

coronary arteries

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9
Q

in blood vessels how can blood flow be controlled?

A

in arterioles
-when muscle relaxes
arterioles dilate
-lumen become wider
-blood flow increases

-when muscle contracts
arterioles constrict
-lumen narrows
-blood flow decreases

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10
Q

what are the 3 stages of the cardiac cycle?

A
  1. ventricles relax, atria contract
  2. ventricles contract,atria relaxes
    3.ventricles relax, atria relax
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11
Q

when do atrioventricular valves open?

A

when pressure in the atria is greater than the ventricles

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12
Q

when do semilunar valves open?

A

when pressure is higher in the arteries than in the aorta/pulmonary artery

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13
Q

whats the formula for cardiac cycle?

A

stroke volume x heart rate

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14
Q

define stroke volume

A

vol of blood pumped during each heart beat in cm3

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15
Q

give 3 examples of contents of plasma

A

hormones
fatty acids
amino acids

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16
Q

whats the role of tissue fluid?

A

transport oxygen and nutrients from blood to cells and CO2 and other waste products from cells back to blood

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17
Q

where does formation of tissue fluid occur?

A

at a capillary network which surrounds cells

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18
Q

how is tissue fluid formed?

A

at arteriole end:
-blood has higher hydrostatic pressure (due to left ventricle) lower osmotic pressure
-water is forced out of fenestrations
-along with dissolved substances like oxygen and glucose

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19
Q

what is ultrafiltration?

A

filtration under pressure

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20
Q

how is fluid returned to the capillary?

A

at venous end:
-blood has lower hydrostatic pressure
-plasma protiens lower water potential
in blood
-higher hydrostatic pressure
-water moves back in by osmosis
other waste by diffusion
-excess tissue fluid moves into lymphatic capillaries where it drains back into circulatory system via subclavian vein

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21
Q

importance of the lymphatic system

A

-draining excess tissue fluid and returning to blood
-for immune system = lymph nodes produce lymphocytes
-absorp lipids from digestive system into lacteal

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21
Q

describe how not excersizing increases risk of cardiovascular disease

A

high blood pressure
atheroma formation
blood clots
heart attak

21
Q

describe how a diet high in saturated fats may increase risk of cardiovascular disease

A

high blood cholesterol
atheroma formation
blood clots
heart attack

21
Q

stroke symptoms

A

think FAST
Face=distorts one side
Arms=weak limbs on one side
Speech=difficulty speaking,slurring

21
Q

describe 2 ways smoking increases risk of cardiovascular disease

A

1.carbon monoxide
less oxygen in blood
less oxygen to tissues
heat attack
2.fewer antioxidents
damage to coronary artery walls
atheroma formation
heart attack

22
Q

posh word for heart attack?

A

myocardial infarction

23
Q

how to make a study more representative?

A

larger sample size

24
Q

explain how the xylem is adapted to its function

A

-no end walls=continuous flow of water
-no organelle=hollow=eases flow of water
-walls made of lignin=strength prevents collapsing, maintains adhesion
-bordered pits=lateral flow of water

25
Q

describe the cohesion-tension theory

A

1.water evaporates from leaf out of stomata by transpiration
2.lowers water potential of mesophyll cells
3.water is pulled up xylem creating tension
4.water molecules cohere by hydrogen bonds
5.forming continuous water column
6.adhesion of water molecules to walls of xylem

26
Q

define transpiration

A

evaporation of water vapour from arial parts of the plants - stomata

27
Q

importance of transpiration stream

A

as water is lost from xylem in leaves its replace from below

28
Q

why is transpiration important?

A

1.photosynthesis
2.water allows cells to grow and elongate-phototropism
3.turgidity
4.evaporation cooling effect
5.flow of water carries mineral ions up plant

29
Q

how does temperature effect transpiration?

A

increase in temp
more Kinetic energy of water molecules
more water vapor lost via stomata

30
Q

how does humidity affect transpiration?

A

increase
decreases evaporation from leaf
smaller water potential gradient

31
Q

adaptations of xerophytes

A

smaller leaves
thick waxy cuticle
stomata close when hot
hairs
stomata sunk in pits
rolling leaves
loss of leaves high salt concentration in cells

32
Q

how do hairs on leaf help reduce water loss?

A

traps water vapour
decreases water potential gradient

33
Q

how does stomata sunk in pits help reduce water loss?

A

traps water vapour
close to surface of leaf
decreases water potential

34
Q

how does rolling leaves help reduce water loss?

A

traps water vapour
decreases water potential gradient
reduces surface area

35
Q

how does a high salt concentration in cells help reduce water loss?

A

decreases water potential gradient in cells
less water lost between cells

36
Q

what are xerophytes?

A

plants that can survive in dry climates

37
Q

limitations of potometer

A

1.messures water uptake not transpiration
2.cutting plant shoot may damage the plant
3. plant has no roots so no resistance to water being pulled up

38
Q

describe translocation

A

movement of assimilates like sucrose
requires ATP
source to sink

39
Q

define source

A

part of the plant that releases assimilates (makes)

40
Q

define sink

A

part of the plant that receives assimilates

41
Q

structure of seive tube elements

A

-few organelles,no nucleus
-sieve plates form cross walls connect elements
-elements lined end to end
-plasmodesmata link the cytoplasm of companion cells and sieve tube elements

42
Q

structure of companion cell and function

A

-cytoplasm
-many mitochondria for ATP for active transport
-large nucleus so many proteins in plasma membrane and many ribosomes

43
Q

compare structure of xylem and phloem

A

xylem:
-lignin
-one way flow
-no end walls

phloem:
-thin walls
-two way flow
-sieve plates form cross walls

44
Q

describe the mass flow hypothesis/translocation

A

1.active transport is used by companion cells to actively load sucrose into sieve tube elements
reducing water potential
2.water enters the sieve tube elements by osmosis from surrounding tissues
3.this increases hydrostatic pressure in seive tube element
4.sucrose removed from sieve tube and increases water potential
5.water moves out of sieve tube and reduces hydrostatic pressure

45
Q

4 ways of evidence for mass flow

A

1.using aphids
2.ringing a tree
3.radioactive tracers
4.metabolic inhibitors

46
Q

explain how aphids can be used for evidence of mass flow

A

can investigate pressure in phloem
sap flows out quicker nearer leaves than further down stem

47
Q

explain how ringing a tree can be used for evidence for mass flow
(removing a ring of bark including phloem not xylem)

A

bulge forms above ringed area as sugars cant pass
decreases water potential and water moves into the cells
evidence for downwards flow of sugars

48
Q

how can radioactive tracers provide evidence for mass flow?

A

tracers like radioactive carbon- (14C) can be used to track movement of organic substances in a plant

49
Q

how can metabolic inhibitors be used for evidence of mass flow?

A

translocation can be stopped by using a metabolic poison e.g. cyanide that inhibits respiration so ATP cant form
evidence that active transport is used

50
Q

what is evidence against mass flow?

A

1.sugar travels to many different sinks not just the one with lowest hydrostatic pressure
2.sieve plates would create a barrier to mass flow
pressure needed

biology year 1 (8 decks)

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