Homeostasis Flashcards

1
Q

why does phased seperation occur

A

contact is minimised between polar and non-polar components by grouping polar together so they can have as many polar interactions as possible

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2
Q

why does phased separation occur

A

contact is minimised between polar and non-polar components by grouping polar together so they can have as many polar interactions as possible

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3
Q

what is added to the phospholipid bilayer to prevent it freezing at body temperature

A

cholesterol

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4
Q

which kind of molecules cannot cross the lipid bilayer

A

hydrophilic

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5
Q

examples of what can pass through the phospholipid bilayer

A

CO2, steroids (testosterone), some drugs

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6
Q

4 types of diffusion transport

A

direct free diffusion
uniporter
co-transporter
antiporter

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7
Q

where are high sodium levels found? where are high potassium levels found?

A

sodium - outside cell
potassium - inside cell

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8
Q

what does the Na+/K+ ATPase do

A

3Na+ out, 2K+ in

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9
Q

example on how the NA+/K+ ATPase can be used

A

lower concentrations of Na+ in cell cause it to diffuse in through other receptors, providing energy for eg glucose to enter with it

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10
Q

4 classifications of paths?

A

autocrine
juxtacrine
paracrine
endocrine

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11
Q

autocrine?

A

signalling to itself

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12
Q

signalling in general to another cell

A

paracrine

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13
Q

juxtacrine

A

signalling to an immediate neighbour

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14
Q

endcrine?

A

passing via blood to otherc ells

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15
Q

are steroids hydrophobic or hydrophilic

A

hydrophobic

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16
Q

how do steroid signals alter gene expression?

A

pass through lipid bilayer, bind to transcription factor, affects transcription of DNA

17
Q

what are steroids generally used for? examples?

A

long term things:
sex determination
menstrual cycles and puberty
stress
inflammation
etc

18
Q

signals which cannot pass through the cell membrane (too hydrophilic)

A

neurotransmitters, peptide hormones

19
Q

two ways hydrophilic signalling molecules pass on their signals into the cell?

A

binds to receptor causing conformational change

dimerization - each half of signal holds together two receptors which act on each other if held together long enough

20
Q

G-protein signalling? - example for calcium

A

G-protein coupled receptor activates, binds G-protein which is activated then can activate another enzyme - phospholipase, which breaks many phospholipids (amplification) which bind to calcium channels in the ER releasing Ca2+ down conc gradient and calcium activates various proteins

21
Q

how can calcium blood concentration levels be raised

A

PTH from parathyroid gland causes reabsorption from urine and reabsorption called bone.

22
Q

integral control?

A

how far wrong something is and for how long - more and more active the longer something is in error

23
Q

proportional control?

A

looks at how far wrong something is

24
Q

differential control?

A

how quickly things are changing

25
Q

what kind of control for PTH control of renal absorption and intestinal absorption

A

intestinal absorption - integrational control
renal absorption - proportional control

26
Q

what physiological changes are anticipative

A

signalling via sympathetic nervous system - brain recognises danger, adrenaline kicks in

27
Q

anticipatory signalling common in what

A

fleeing, fighting mating

28
Q

damage to effectors solution

A

substitute artificial version of effector

29
Q

damage to control systems solution

A

use drug that mimics missing signal or blocks pathways that shouldn’t be active