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A-level Biology > Module 2.5 > Flashcards

Module 2.5 Flashcards

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1
Q

In previous videos we saw

A

-We have looked at the strucutres of triglyceriedes nd phospolipids .
-W esw that tirglycerides have three fatty acid moleucles onded to one moleucle of glhycerol .
-Triglyceride moelcules are nonpolar making them hydrophobic (AKA insoluble in water .)

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2
Q

WHEREAS PHOSPHOLIPS

A

-Two fatty acids bonded to a glycerol .
-REMEMBER –> these fatty acids are hydrophillic .
-Flycerol is also bonded toa phosphate group .
-Phosphate group is higly charges , so this part of the moleucle is polar . Menaing the PHOSPHATE goup is hydrophillic .

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3
Q

MEANING WHAT BREH

A

-phospholips have ahydrophobic region consisting of the fatty cid .
-+a hydrophillic region consisiting of the phosphte grup .

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4
Q

Chceck sheet , rather than drawin a phosphatee=lipie , scientsits acc raw iy out like thi .

A

circle with two tails .
-AS a phospholipd contain both hydrohpilic region and hyrdophobic trhio , IF WE place them inw ater they arrange themslevs like this , CHECK SHEET .
-

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5
Q

-the hydrophillic part of the phospholipd moelcules phosphte group can INTERACT WITH WATER .

A

-However ,t he hydrophobic parts in other words the FATTY ACIDS are buried int he center way from th water .
-SCIENTISTS cll this the phospholipid bilayer .

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6
Q

-PHOSPHOIPID bilayer is the BAISSI of ALL CELL mEMBRANES .

A

-Including the cell surface membrane and rhe memranes tha surround organelles , suc as lysosmes and mitochondira .
-Membranes carry out a range of functions inc ells .

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7
Q

One fucntion of phospholipd bilayers

A

-Act as BARRIERS betweent he internal contents of the cell and the external environemnt .
-OR , between the contents of n organele and cytoplasms .
-Someitmes memranes separare one part of an organelle froma nother part (we will see more detai into this when we looka t mitchodnira)/

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8
Q

second fucntion of phospholipid bilhyers

A

Mmebranes are also a locaion for chmeical eaxcctions (stages inr edpirtion )

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9
Q

third funciton of phospholipdi bilayer

A

membranes are also inovved in cell sinalling .

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10
Q

like we said before ,t he cell surfce membrane provides a barriwr between the cytoplasms and the ecternal enviornment of the cell .

A

BECAUSE the cell surfce membrane contrians a hydrophobic center and hydrohpbic moelcules such as steroid hormone can EASILY pass thorugh the cell memerane .

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11
Q

HOWEVER , the hydrohobic cener prevents hydrphillic water soluble moelcules frome sasily passing through /

A

As HYDROHPHILLIC SUBSANCES ARE POLAR AKA THEY HAVE CHARGE ,
-These substances cannot eaisly pass through the non-polar refion of the memrbane .

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12
Q

REMEMBER ; water moelcules can ass thorugh the cell memrbane even htough water moelcuesl re polar .

A

As Water moelcules are extremely smll .
-Even so , gthis tkes plce at a slow rate .

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13
Q

-The cell ,e,brane is based int he phospholipd bilayer , HOWEVER it contains other parts as well .

A

FIRST THING TO NOTIE
-Cells urfaxe memrbane contins a large number of portein moelcuels .
-Som of these portiens are onlyon one side of the memrbaine .
-Whereas oher poreins span the memrane frm onse side to the otoher .

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14
Q

-The cell ,e,brane is based int he phospholipd bilayer , HOWEVER it contains other parts as well . (2)

A

The cells urface memrbane also contains choelstrol (saw int eh videos on lpds .)
-SEE STRCUUTRE OF CHOESTROL ONS HEET .

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15
Q

Cholestrol moelcules hve a polar hydrophillic grouop at the end .

A

-This group cn effect the poar hwad gorups on the phospholipd moleucles .
*The rest f the cholesrrol moelcule is non-polar +hydophobic .
-This part of the cholestrol mopecule cana trxt the non-polar fatty acids int he phospholipds . .

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16
Q

-So ebcuse choelstorl interacts withphospholipids . IT increses the strenght of the cells ufrace merae .

A

Making the memrbane more stbale nd less liekly to et damaged .

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17
Q

Another unction of choelstrol .
-CholesroL ALSO REDUCES THE SIDE WAYS MOVMEMNT OF THE PHOSPHOLIPDS AND OTHER MOECLUSL ITHIN THE MERBAEN.
-Helping to cotnrol the fulididty of the memrbane .

A

-Preventing the memrane from becoming too fluid under wam condirons and too rigid under cool conditons .

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18
Q

final dfucntion of cholestrol

A

-by packing the spaces begtwween the phosphoipds , cholesrol helps o reduce he movemnt of warer soluble sacorss hr cells urfce memrane .

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19
Q

Scienitsts call the strucutre of the cell surface memrbane the FLUID MOSIC MODEL.
-Need to be able to describe wht his means .

A

-The word “fluid” because the phospholipd molcule cn mvoe around wit each layer .
Menang the moelcule is flexbile nd cn change shape .
-The word “mosic” as the membranes is studed with protien moelcules .
-The rrangeemtn of the poretein molcuels varies like tile in amosaic .

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20
Q

-Looking into detail into the porteins we find in the cell memranes
-All membanes can be divided into two different catgeories

A

-Intrinsi or intergal proteins .
-Extrinsic or perpherl protins .

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21
Q

Intrinisc porteins

A

are fully EMedded from onse side to the toehr .
-As they pass right thorugh the ipid bilayer . Inrinisc proteins hae hydrohphobic amino cids ont heoutside surface of hte portein .
-The h ydrohpbic aminoa cids cna interact with the hydrohllic fatty acid tils in phospholipd bilayer .

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21
Q

rane porteins can be divided into two categories

A
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22
Q

There are two types of intrinsic porteins . Wchi is one of them
-PROTEIN CHANNLESLS

A

-potein channels contain a channel running thoruhgh he center .
-This channel is lines with the hydrohpillic amino acids and filled with water moleucles .
-Protein channels allow water-soluble moelcules nd ions o diffus htourgh .

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23
Q

Another type of intrinsic porteins

A

Carruer porteins .
-These can change thier or postion to transger moelcules or ions fromo ne side of the merbane to theo hter .

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24
Q

IN CONTRAST TO ITNRISNC PROTEINS EXTRISNIX porteins DO NOT spn the memrbane .

A

-Instea are found on one side od rh wmwmenW OE OTHER .
-Someiime extrinsic protein are attached to intrinsic proteins .

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25
Q

Extrinisc porteins ahev a range of functions

A
  1. some play a strcutural role within the mebrne .
    2.others can act as enzymes
    3.some are recepros for other moelcules like hormones .
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26
Q

Many membrnaes protiens lso contain a carbhodhyrate moelule atached . Scientitss call these GLYCOPROTEINS .

A

-GLycoprotein have a range of functions within thr ell .
1.some glycoprotens allows cell to attach to echothe to form tissues such as nervous tisue.

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27
Q

glycoproteins (2)

A

-other glycoproteind play a role in the immuneytem , prsenting antigentd to vrlls .

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28
Q

glycoproteins (3)

A

-Other glycoproteins act as rece[tprs fpr hormoenes .
-Carbodhyrates can aspp e found attached to phosholipid moelcules .
-These are called GLYCOLIPIDS.

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29
Q

GLYCOLIPDS

A

-glyclipds are oftrn used when cells come into contact with rsvhother .
-glycoipids on the surfce of onne cell , csn be recognised by anothder cell
-we can deeterminr ehenever cells come into c ontact
2.glycolipds can alo act a antigrns —>determining bloood group.

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30
Q

diffusion box
-btir in hr vrner
-bpth dsides of the brrier contain the sme concentrtionn of gs A .
-The cocnentrationo f gas A i he ame across oth sides of of the barrie r.

A

-However , oe side of the brrier contins a higher concenration of a different gas (gasB).
-Bear in mind all the prticles have kinetic energy , as they are moving ranodly .
-Particles are consttntly collidign with eachother .

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31
Q

If we was to remove the barrier …

A

-we now have a higher concentration of gas b on the left hand side and a low concnetrtion of gas b on the right hand side .
-scientists call this concentration grdient.
-overtime , as particles move randomlu , the particles of gas b will spread out through the container .
-at a certain point ,t he concneration of gas B will br yhr dsmr rveryehre . THERE IS NO CONCNETRATION GRADIENT .

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32
Q

THE spreading of [articles is clled diffussion .

A

diffuion if thr net movement of partices , from an area of higher concentration to a region of lower cocnentrtion (downwn the cocnetraiton grdien t) .

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33
Q

meaning of net movement .

A

-in diffusion , mor prticles re movng in one direction than another .
-so netmovement just men overll movement .

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34
Q

co2 levels wthn cell

A

-co2 is higher on theiside than on the outside .
-we have a oxnxentrrion gradient for co2 molecules whixh diffuse from an area of high concnetraauon \9in the cell) to an area of lower ocnenctration (otuside the cell ) , .
Eventully the concentraation of co2 iwll be the same ont he outside and th einside of the cell ., EQUILLIBIRUM WILL BE REAACHED - AT EQUILIRUM , T HERE IS NO NET MOVEMNT OF PARTICLES DO DIFFUSION DOES NOT TAKE PLACE.

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35
Q
  1. key poit aout diffusion
A

difusion is a passive processs .
-Meaning it does not require metabolic energy to take place .
-Metbaolic enetgy means energy released by respiration .

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36
Q
  1. key point bout diffusion
A

As some chemicals can eeasily diffuse thorught he cell membrane while other chemcils cann;t the cel membrne is described as partilly permemable .

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37
Q

FCATROS AFFECING RATE OF DIFFUION (1)

A

Gretaer the concnetration grdient , thr greater the rate of difusion .

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38
Q

FCATROS AFFECING RATE OF DIFFUION 2

A

-AS THE CEell membrnae contains hdyorphobic center , chrged partilcles like ions will noy be bale to diffuse htourgh the memrnae
-eter meolcule alhotugh they re polar yhry cn pass htourhg as they re very small .
-contrasting ot uncharged moelcules lieke oyxgen where it candiffuse rpildy xross the membrn

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39
Q

FCATROS AFFECING RATE OF DIFFUION 3

A

size o th prticles is lso impront as wlel
-generally smaller particles will iffuse faster than lager one s.

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40
Q

FCATROS AFFECING RATE OF DIFFUION 4

A

temeprtrue
-inw rmer condtions , particles hae more kineti eegry nd diffuse at fasterrate t codler contions . (nt porblem or mammals and birds however as they maintain constn body temperature .)

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41
Q

FCATROS AFFECING RATE OF DIFFUION 5

A

Surface area
-diffusion takes plce more reaplidly if he memrne has aLARGER surface aew compared toa smlle sufrce area .

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42
Q

FCATROS AFFECING RATE OF DIFFUION 6

A

distance that diffusion tkaes palce over .
-greater the istnce ,s lwoer the rate of diffusion . explaining why CELL MEMRBANES ARE EXTREMEENT THIN .

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43
Q

THIN .FCATROS AFFECING RATE OF DIFFUION 7

A

lastly the presence of PROTEIN CHANNELA (facciliatte diffusion) , or carrrier porteins in the membrnae .
KEY we are looking at specical type of ddiffusion clled FCILITTED DFFUSION .

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44
Q

-not all susbtnaces diffus e across the cell memrbane at the same rate .

A

as the center of the cell membrane is hydorphobic due to the fatty aicd tials of the phospholipd moelcules .

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45
Q

-Hydrophobic susbtnaces - steroid homroes can diffuse RAPIDLY across the memrbane .

A

-However , hydrohphillic substnses ,s uch as ions + polar moelcules , cnnot diffuse across the memrbane .
-An excpetionto this is wtaer as ti is small.

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46
Q

-HYdro[hillic susbtances cannot diffue across membranes .
-This is a porblem forcells as many of thee subsagnces are required fo rporceses isnisde the cell .

A

-to solve this problem , cells use facillitated diffusion

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47
Q

-In faciliated diffusion , hydroophillic suvstances iddfuce acreoss he cell memrbne via portein moelcuels .

A

-These portein moelcules allow the hydrophillic susatcnes to cross the memrbae without interacting with the hdyrophobic cente rof the phospholipid bilayer .

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48
Q

There are two tpes of protien movlueles involed in fcilaited diffusio .

A

-Both of these are example iof intrinsic / integral membranes plrotiens (compelelys pan the memrane from one side to the other )

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49
Q

Carrur oriteus

A

-Carrier porteis hae a bining site for a specific chemical .
-When thar chemial bind s, it causes the tertairys trcutrue of the carrier porein toc hange .
-This chnage in tertiary trucutre , broings the CHEMICAL ACROSS the memrbne where the chemical is no released /

50
Q

Protein channels

A

A protein channel is a portein witha central pore .
-Thsi pore or channle is lined with a hydrohillic amino acid + contians water .
-Hydrophilic substances can pass thorgh the channels from ONE SID EO FTHE MEMERBAN ETO THE OTHE R.

51
Q

IMPORTANT POINT BOUT PROTIEN CHNNELS 1

A

-Protrien channels are selectie for the chemical tht can pass thoruhg .
-Menaing onlyc ertain chemicals can pass thoruh each rype of portein chnnel .

52
Q

IMPROTANT PROTEIN ABOUT PROTEIN CHANNELS 2

A

-While soem types of protein channels are always open , othe rporteinc hannels only open in repsonse to certain trigger .
-This could be a chemicla bdinging to the protein channel .. For exmpale a neurotransmitter .
-Or a change int he voltage across the mwwbrane (see in enrvou system ).

53
Q

KEY THINGS TO REMEMBER BAOUT FACILITATED DIFFUSION.

A

Facilitated idffusion is STILL idffusion .
-Eventhough cttier proteins and channel protiens are used to diffus echemcials .
-Chemcials still moe forma n area of highc onc to an area of low conc .
-SECONDLY metabolic energy is not required .

54
Q

-Looking at direct active transport

A

exmpale
-lrge cocnentrio of lacium ions outise the celll and lwoer inside the cell .
-This is a=common as calicum ions play a role in cell signlling .

55
Q

-So cells re cosntntl trsnsferring calicum ions fromt he cytoplstm to outside the cell

A

-Int his case , calcium ions are moving orm a reion witha lwoer concentration to a region with a higher cocnentration .
-Cells use active transprot to do this .

56
Q

-In active tranpsort , crrier proteins in the memrbane tranpsort a chemical froma reion o lower concenration to a region of higher concentration ( agains tthe cocnentration fradient ,)

A

…

57
Q

Active tranpsort requires metbolic enery –> porvided by ATP MOLECLE .

A

Actie tranpsort used to mvoe lots of dierent meolcuels + ions .. Both into + pt of cells ut always against the cocnetrationg raidient .

58
Q

How does active tranpsort work (1)

A

-durign acrive tranpsort ,t hemoleucle or ion to be rransported ,a ttaches to a receptror ont he site of the crrier portein .
-This takes palc eont he side of the meebrance which the chemical is ata a LWOER concnertation

59
Q

How does active transport owrk (2)

A

A m oelcule of ATP then binds to the catier potein .

60
Q

How does active transport work (3)

A

-Next ATP moelcules undergoes hydrolysis and porduce phospahte +a moelcue of ADP
-Phospahr attaches to a carrrier portein + causes it to change shape .

61
Q

How does active transport work (4)

A

-This shape chnge cuses the carrier protein to transport the moelcule or ion to the other side of the membrane where it is releasse d.

62
Q

How does active transport work (5)

A

Phosphagte now leaves hte portien , causing it to reutn to it previous shap e.

63
Q

How does active tranpsort work m(6)

A

Th adp + phsophte will alet retun into ATP inr espirtion /

64
Q

key thing about active transport (1)

A

-active tranpsort uses A LTO OF TP .
-So we find lots of it in mitochodnira in cells that carry out active tranpsort .

65
Q

Key thing about active tranpsort (2)

A

-Carrier portiens used ina ctive tranpsort are specific .
-So each carrier portein willonly transport one type of moelcule or ion .

66
Q

one differenebtween faicliated idffusiona nd active transport .

A

Carrier porteins are DIFFERENT betweent he two prcesses

67
Q

another difference betwen facilaited iffusiona dn active tranpsort

A

Howeve rin fiscliated idffusio , chemical sare moved odwn the conentration grandient and fcilited iffusion as a passiv process .

68
Q

check sheet

A

on the left hand ide ,w e have pure water .
-Right hand side we have a solution .
-partially permemabme memrbane .
-SKS s dolute is dissolved inw ter .
-AS we said , the mwemrbane is partially permemabel , so the water meolcules can pass frelly around the meemrbane .
-But the solultemoelcules cannot menaing they have to stya ont he right hand side of teh memrane.

69
Q

LHS –> high cocnenraiton of wate r.
-RHS has a low cocnentraion of water .

A

Menaing water moelcuels will diffuse fromt he lHS to the right hand side .
-This diffusion of water -osmosis .
RMEMEBER - OSMMOSIS IS A PASSIVE PORCESS .

70
Q

Defention of osmosis

A

Omosis si the movoemet of water moleucles froma region of HIGH WATER POTENITAL to a region of lwoer water potential through a partially (or selectively)permemwbael memrbane .

71
Q

Go back to the drawn diagram on the sheet

A

-Got water moelcules on both sides of the memrbne .
-These water moeluels are COLLDIIGN WITHT HE MEMBRBANE .
-These collisosns means that the water moelcles apply a PRESSURE ot the ememrbe .
-Sciensits cllt hsi pressure the WATER POTENTIL .
-Water potentil has a symbol SAI chek sheet .
-bECAUSE WATER POTENITAL IS A MEASUR EOF PRESSURE THE UNIT IS kilopadscals.

72
Q

Like we saw , the LHS od the memerbane has more water molecules than the rhs .
-Menaing the pressure due to the waer moelcules is GREATER on the LHS than on the right .
-Due to this ,t he water potential is GREATER ont he LEFT than on the RIGHT .

A

-HIgh water potenital on the LEFT than ont her ight .
-Watermolcuels will moe by osmiss formt he left hand side to the right .
-at soe point , boths ides of the emmbrane will ahve the same wate rpotential ,a t this point we have reched equlibrim so osmosis stops .

73
Q

-Water moelcules will still be moving acorss the membrane , but hte SAME NUMBER of water moelcules will be moving in each direction .

A

-so the net . ocerall moememnt of eater moelcules =zero.

74
Q

-Pure water has the highest possible water poteintal .

A

-This is becaus eprue water has the highest possible concnetration of water movlues .

75
Q

Scienitsts have set the wate rporteital of pure water as 0 .
-Meanign that the wate rpotential of an solution , MSUT BE less than zero (a negative numer)

A

-A MORE COCNENTRATED SOULTIOn ahs a lower wter potenital than a LESS COCNENTRATED SOLUTOIN .

76
Q

CHEKC SHEET , what side willw aer move to .

A

water movlues iwll move by osmsosis froma reion of highw ate potenitl to a lwoer wate rpotential .

77
Q

IN ODLER TEXTBOOKS

A

may see osmsos sdescriebs a s hyeprtonoc hyptonic isotonoci .
-No longer used as osmsosis is descirbed int erm sof waterpotenital .

78
Q
A
79
Q

an animal cell example - red blood cell
-the cytoplasm of all animal cells contains a number of solutes dissolved in water.

A

-these solutes include sugar glucose+ mineral ions sucha sthe sodium ion .
-these dissolves solutes means that the cytoplasms has a negaite water poeintioal.

80
Q

red blood cells are surroudned by w watery soltuion called blood plasma ,

A

-The water potenital of the blood plasma is the same as thee water potenital of the cytoplasms in red blood clls .
check sheet for ysmbol erion .

81
Q

as the water potenital is the same both INISDE + Outisde the red blood cll .
-osmosis is not taking place.

A

-however , water oelcues are still moving across the cell memmbrnae .
-but the rate of movement inwarss is the same as the movement outwards .
-so no net , overall movment of water molecles as occured .

82
Q

-now if we was o take an animal cll ,r ed blood clls nd plce into prue water which we know hs th ehighests water potential .

A

-the water potentila otuside the cell is now greater thsn the wter [ptenital isnide .
-meniang water molcues now move inside the cell by somsosis .
-this mvomeemnt of wate r movleucles , causes hte pressure inside ht eclel to iocnrease .
-Scienitss call this h ydrstaic pressure .

83
Q

What is the probelm with this ?

A

Cell emmrbane is not strong enough tow ithstand a significan tincreas eint he hysrostatic pressures isndie the cell . #-So if , wter emoclues move isnide the cell , this can cause hte cll memrbante to RUPTUTRE AND CELL to burst (check sheet)

84
Q

-In the case of a rd blood cell , this is haemolsis .

A

…

85
Q

-now palce the cell ina soluton with a LOWER WATER POTNEITL THAT CYTPOPLAMSS (OLUTIO OF GLCUOSE0

A

-int hsi case , water will move OUT of tcell by osmsosis causing the clel to SHRINk ,.
-RHIS EFFECT WILL HAOE TI ALLC ELLS NOT JUST RED BLOOD CELLS .

86
Q

-In animals , the water potential , of the lqiuid round the cells is TIGHTLY CONTROLLED .
-SO its the same as the water potneital of the cytoplasms

A

…

87
Q

PLANT CELLS SIMPLEID DIAGRAM
-omitted evpeyreying apart fom vacuole and nucleus .

A

-unlike animal cells , plant cells are surroudned by a cellulose cell wll .
-[lant cells contain a large permanent cvacuole with a soltuoin of susgar + minerla ions .
-Beteeen the vacuole and clel wall , we have the PORTOPLAST .

88
Q

-Tne protopoalst consists of the clel memrban e, the cytoplasms and the orgnelles found in the cytoplasms .

A

-due to the dissoles solids , the ienteriorr of the palnt cell ahs a relarivley LOW wate rpotneital .
-Unliek in amimals , plants CANNOT eaislyc otnrol the enviornemtn aroun hteir cells .
-SOmeitmes , plant cells ar surroudned bya very ILUTE solution or COENCNTRAD oslution .

89
Q

What happens if we palce a paltn cell in a pure water ?

A

-Becuse te water potenital outside the cell is greater than insid e,w ater ENTERS the cell bys osmsis s .
-Causing the hdyrostatic pressure inside the cell to icnrease .
- BECAUE OF THIS , the portopolaast passes outwards agaisnt the cell wal .

90
Q

REMEMBER ,T HE CELL WALL is amde of cellulsoe which is ery DSTRONG .
-So rather than nrsing , the plant cell eocmesFIRM .

A

SCIENITSTS AY THE PLANT CELL IS TURGID .
-The itneral pressure called turgor pressure.
-At cetrain point ,t he turgpr pressur epreents anymroe wate enetring the clel by osmsis .

91
Q

-Plant cell is placed ina solution which has a Lower WATER POTENITAL THAN INSIDE HTE CELL (CONCENTRATED GLUCOSE SOLUTION )

A

Int his case ,w ater moves OUT of the cell by osmosis , causing hte ortoplast ot PULL AWAY FROM THE CELL WALL .
-Scienitsts all this plasmolyiss .
-The plant vell is sid to be plasmolsyed .

92
Q

-Whrn plsymolssis occurs ,t he space between the cell membrane + cellwall is now filled iwth asoltuoinw hich surrounds the plant cell

A

…

93
Q

-IN many cases , cells require larg particles or moelcules o pass aross the cell memrbane .

A

-Inclluding large protein moeluls which are exported from the cell - e.g enzymes + anitobdies .

94
Q

Larhe particles can also pas into th cell
.
Like antignes + bacteira

A

Ina ll of these cases , the particles or moelcules are TOO LARGE to cross t cell memerane , nu coaoted diffsion +active tranpsort .

95
Q

Instead cells sue endocytosis and exocytossi .
-In both processes , alrhe particles or moelcuels are transferred across the cell memrbane .

A

-Both processses can transfer a lrge uanitth of mateiral .
-so scineittsts refer to these poresses as BULK transport .

96
Q

What happens in endocytoiss ?

A

-Particles or moelcules are tranpsorted into the cell .
-including large moelules such as proteins+ cells like bacteira.

97
Q

s1 of endocytoiss

A

-cell memrbane folds inwards a form a cavity around the particles .
-sceinitsts clal this porcess invaginaition.
-the aprticles to be ransported are now in the cavity .

98
Q

s2 of endocytosis

A

the particles to be transportd sre now int he cavity .

99
Q

s3 of endocytoiss .

A

next the meembrane compeltely encicrcles the particles to form a vesicle like this .

100
Q

s4 of enodcytosis

A

now the vescile movies into the cell . At this stage , what takes palce depends ont he mateirl int he vesciel .
-for exmple acteria re diegsted in lssosmes .

101
Q

s5 of endocytosis

A

other materials can eb delievred to differen tprt of ht ecellw here htey are needed .

102
Q

there are two types of endocytsois .
NUMBER ONE phagocytosis

A

-when solid mteirals sucha sbacteria are tkane into cells by endocytossis .

103
Q

second type of endocytoiis
pinocytosis .

A

when endocystosis is used to transfer FLUID into the cells .
-for example liwuid surroudning the cell . this is called pinoccystosis .

104
Q

what is exocytosis

A

-exocytosis moves material out of the cell .
-This incldues secreted porteins uscha s hormoens +c eretain enzymes .

105
Q

s1 of exocytosiss

A

-At the start of exocytosis ,t he proteins are found in the golgi apparatus .
-Here the porteins are modifieded before beindg ecreted .

106
Q

s2 exocytosis

A

next vesicles contain the portein , bud off the golgi apparatus + amk thier way towaeds h cell memabne .
-the vescles hen fuse with the cell memrbane + the porteins secretd .

107
Q

KEY ; borh endocytosis +exocytoiss require energy .

A

e.g to move esicles to + from the cell emrbane ,
-this enegry is produces by the molecule ATP .

108
Q

inorganic ions are charged atoms / molecules that fall into two categories

A

-Cations - positively charged
-anions -negaively charged

109
Q

What is the purpose of inorganic ions ?

A

-Inorganic ions are essential for life because ;
-DNA -phosphate ions
-Haemoglobin FE2+

110
Q

Inorganic in respiration .

A

-Inorganic ions are classed also as macronutrients (large NO3) traces of micronutrients

111
Q

if organisms do not manage to acquire enough of a particular ion , they become deficent .

A

calcium = ca2+ cation
FUNCTION ;
-Helps with the movement of organisms by regulating , transmission of impulses , from neurone to neurone .
-helps to harden body part such as bones , teeth and exoskeleton .

112
Q

other functions of calcium

A

-Helps with the movement of organisms by regulating transmisssion of impusles from neurone to neurone .
-stimulates muscle contraction .
-Also helps to regulate protein channels , which affects the permeability of cell membranes .
-many enzymes are activated by calcium , making it a key regulation in many biolgivla reactions .

113
Q

other improtant roles of calicum

A

also0 important for formation of blood clots .
-calcium also has an important role in plants , development of the middle lamella in-between plant cell walls .

114
Q

Sodium ions

A

important inorganic ions na+, plays an important role in regulating osmotic pressure which is important in .
-Helping planta remain turgid .
-regulating absorption of water in the kidneys / nerves .
-also important for the transmission of nervous impulses

115
Q

sodium ions (2)

A

-Also important in maintaining PH levels (7)
-Sodium also involved in active transport and aids it and glucose + amino acids in the intestine .

116
Q

Potassium ions

A

important role in neurones transmissions \9like sodium ) .
-Also involves in osmotic pressure +active transport .
-also needed to help grow healthy leaves flowers in plants .
-Plays roles in synthesising proteins + glycogen and breakdown of glucose .

117
Q

Hydrogen ions

A

-In photosynthesis and respiration in driving the production of ATP .
-Hydrogen ions also determine the Ph of bodily fluids .
-Blood Ph which affects its function of haemoglobin .
ctyoplasmic ph which affects the function og enzymes .

118
Q

ammonium ions (inorganic ion )

A

-ammonia is a source of nitrogen which is many biological molecules subtles .
-amino acids , which make proteins .
-organic base which are components of nucleic aics liek DNA+Rna .
-nirgoen makes vitamins lie vitamin B .
-Chlorphylll

119
Q

ammonium ions

A

are also a formed from ammonia by accpeting a h dyorgen ions so they help maintain ph .
-ammonium ions are also a aprt of the ntirogen cylve .

120
Q

nitrate ions

A

no3-
-like ammonium nitrate ions are also used as a sorce of nitrogen for making .
-aminoa cids which make up proteins /
-ORGANIC BASES , whcih are components of nucliec aicd dna + rna

121
Q

vitamins also need nitorgen + used in chlorphyll

A

nitrogen ions are also a part of the nitrogen cycle .

122
Q

Hydrogen carbonate ;HCO3-

A

hydrogen carbonate ions -why co2 dissolves in blood.
-Hydrogencarbonate ions therefore important in transport of co2 in the blood and regualtion of the .

123
Q

phopshate

A

-important in components of many biological molecules such as ;
NUCLEOTIDES ; making nucleic acids like NDA /RNA
ATP -Phosphoric acid .
-Phosphate also important in the breakdown of glucose in respiration .

A-level Biology (18 decks)

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