cellular worlds

8/19/2019 Cellular Worlds

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Cellular WorldsMDSC 1001 PBL Problem 1

Tutor: Dr S. Chase


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List o )be"ti&es

1. Des"ribe the ultrastru"ture o a! a!imal "ell.

2. Des"ribe the stru"ture o the "ell membra!e.

3. Des"ribe the basi" stru"ture a!d properties o lipids.

4. %elate the morpholo,$ a!d relati&e abu!da!"e o &arious "ellular or,a!ellesto the u!"tio!s o the "ell.

5. Dis"uss the !eed or i!tra"ellular "ompartme!talisatio! a!d the basi"pri!"iples o i!tra"ellular metabolism.

6. Dis"uss the diere!t methods used i! the stud$ o "ells a!d the preparatio!o tissues.


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Lear!i!, )be"ti&e 1Des"ribe the ultrastru"ture o a! a!imal "ell.


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Source: Ultrastructure of a Eukaryotic Cell. (2015).Odekunle, Aayo!e


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7ltrastru"ture o a! A!imal Cell 8u"lear e!&elope: double lipid bila$er membra!e whi"h surrou!ds the ,e!eti"

material a!d !u"leolus i! euar$oti" "ells

8u"leus: "o!tai!s most o the "ell9s ,e!eti" material a!d "o!trols thea"ti&ities o the "ell b$ re,ulati!, ,e!e e;pressio!.

Plasma membra!e: surrou!ds the "$toplasm ph$si"all$ separati!, thei!tra"ellular "ompo!e!ts rom the e;tra"ellular o!es.

%ou,h e!doplasmi" reti"ulum: has ribosomes atta"hed to it where protei!s$!thesis taes pla"e.

%ibosomes: lar,e "omple; mole"ular ma"hi!e whi"h ser&es as the site o

biolo,i"al protei! s$!thesis.

Gol,i apparatus: "omprised o "upshaped sa"s that resemble delatedballoo!s< is respo!sible or the i!al pro"essi!, o protei!s a!d lipids withi!the "ell.

Pero;isome: small membra!e e!"losed or,a!elles that "o!tai! e!=$mesi!&ol&ed i! a &ariet$ o metaboli" rea"tio!s i!"ludi!, se&eral aspe"ts o e!er,$metabolism.


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7ltrastru"ture o a! A!imal Cell #!termediate ilame!ts: o!e o the three t$pes o "$toseleto! eleme!ts. The three "ompo!e!ts

wor to,ether to e!ha!"e both stru"tural i!te,rit$ "ell shape a!d "ell a!d or,a!elle motilit$.

Mi"rotubules: lo!, thi! tubes o protei! that mae up the "$toseleto!.

Mi"roilame!t: hi,hl$ &ersatile eleme!ts u!"tio!i!, i! "$toi!esis amoeboid mo&eme!t a!d"ha!,es i! "ell shape.

Mi"ro&illi: mi"ros"opi" "ellular membra!e protrusio!s that i!"rease the sura"e area o "ells a!dmi!imi=e a!$ i!"rease i! &olume a!d are i!&ol&ed i! a wide &ariet$ o u!"tio!si!"ludi!, absorptio! se"retio! a!d "ellular adhesio!.

Ce!trioles: pair o or,a!elles ou!d i! a!imal "ells whi"h build the mi"rotubules to orm thespi!dle duri!, "ell di&isio!.

Mito"ho!drio!: surrou!ded b$ a! e!&elope o whi"h the i!!er membra!e is olded to rom

"ristae where aerobi" respiratio! taes pla"e.

L$sosome: small &esi"le "o!tai!i!, h$drol$ti" e!=$mes surrou!ded b$ a membra!e.

C$tosol

Smooth e!doplasmi" reti"ulum: does !ot ha&e ribosomes asso"iated with it< "arries out &ariousmetaboli" rea"tio!s su"h as the s$!thesis o steroids.

Source: "a!esar, #., $ones, #., % $ones, &. (2011). ioloy Unit 2 for CA*E+ Ea!inations.

Ca!ride Uni-ersity *ress.


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Lear!i!, )be"ti&e 2Des"ribe the stru"ture o the "ell membra!e.


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The Stru"ture o the Cell Membra!eThe fluid mosaic model is used to des"ribe how the "ell membra!e is stru"tured.

The "ell membra!e is a phospholipid bila$er with h$drophobi" tails mai!, up

the i!side o the bila$er a!d h$drophili" heads poi!ti!, outwards.

The bila$er o the membra!e is said to ha&e a luid "o!siste!"$. The mole"ule"holesterol is ou!d i! the membra!e a!d it re,ulates the luidit$ o the bila$er.

The membra!e is "alled mosai" due to the prese!"e o diere!t protei!s.

Protei!s ou!d i! the "ell membra!e are

? #!te,ral protei!s : embedded i! the phospholipid bila$er

? Peripheral protei!s : ou!d o! either side o the phospholipid bila$er

? Tra!smembra!e protei!s: ou!d i! the e!tire width o the two la$ers

Gl$"olipids a!d ,l$"oprotei!s are also ou!d i! the "ell membra!e.

8B: #! a! ele"tro! mi"ro,raph the "ell membra!e appears as 3 la$ers.


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The Stru"ture o the Cell Membra!e

"eference: ifiore/s Atlas of istoloy it 3unctional Correlations (11t Edition) y

4ictor * Eroscenko.


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Lear!i!, )be"ti&e 3Des"ribe the basi" stru"ture a!d properties o lipids.


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The basi" stru"ture a!d properties olipids

Lipids are biolo,i"al mole"ules that are i!soluble i! water. The$ "a! be "lassiiedi!to three maor orms:

1. Tri,l$"erides

2. Phospholipids

3. Cholesterol


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Tri,l$"erides

The stru"ture o a tri,l$"eride "a! be des"ribed as three att$ a"id "hai!satta"hed to o!e ,l$"erol mole"ule b$ deh$dratio! s$!thesis. Two maor u!"tio!s

i!"lude i!sulatio! a!d e!er,$.


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PhospholipidsThe stru"ture o phospholipids "a! be des"ribed as ha&i!, two att$ a"id "hai!satta"hed &ia a phosphodiester li!a,e to a phosphate mole"ule. Phospholipids

are both h$drophili" @water lo&i!, at the phosphate head a!d h$drophobi"@water hati!, at the tail< be"ause o this propert$ it is able to orm a bila$er i!membra!es.


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CholesterolThe stru"ture o "holesterol "a! be des"ribed as ha&i!, our h$dro"arbo! ri!,s:three o them are si;"arbo! ri!,s a!d o!e o them is a i&e"arbo! ri!,. #t is a

wa;$ atlie substa!"e that is ou!d i! all "ells o the bod$.


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CholesterolCholesterol is !eeded to mae hormo!es &itami! D a!d substa!"es whi"h helpus di,est oods. )ur bod$ is able to ma!ua"ture all the "holesterol it !eeds.+owe&er "holesterol is also ou!d i! some o the oods we eat. Cholesterol

tra&els throu,h $our bloodstream i! small pa"a,es "alled lipoprotei!s. Thesepa"a,es are made o lipids o! the i!side a!d protei!s o! the outside.

There are two i!ds o lipoprotei!s whi"h "arr$ "holesterol arou!d our bod$:lowde!sit$ lipoprotei!s @LDL a!d hi,hde!sit$ lipoprotei!s @+DL. +a&i!,health$ le&els o both t$pes o lipoprotei!s is importa!t.

LDL "holesterol sometimes is "alled ad "holesterol. A buildup o "holesteroli! the arteries is due to lar,e amou!ts o LDL.

+DL "holesterol sometimes is "alled ood "holesterol. This is be"ause it"arries "holesterol rom other parts o the bod$ ba" to $our li&er whi"hremo&es the "holesterol rom the bod$.

Sour"e: http:www.!ewsmedi"al.!ethealthWhatisCholesterol.asp;

http://www.news-medical.net/health/What-is-Cholesterol.aspxhttp://www.news-medical.net/health/What-is-Cholesterol.aspx


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Lear!i!, )be"ti&e 4%elate the morpholo,$ a!d relati&e abu!da!"e o &arious "ellularor,a!elles to the u!"tio!s o the "ell.


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Structure Description & Function

Plasma Membrane

Membra!e bou!dar$ o "ell< re,ulates the e;"ha!,e o substa!"es with a sempermeable phospholipid bila$er @h$drophili" head a!d h$drophobi" tail #t allosmall parti"les or parti"les with !o "har,e to pass throu,h.

Protei!s prese!t i! the stru"ture allow mole"ules to diuse throu,h bi!di!,that tri,,er "ell respo!ses.

Cholesterol allows the "ommu!i"atio! o !ei,hbouri!, "ells throu,h bi!di!, a!d mai!tai!s luidit$ o membra!e.

Nucleus

Lar,e stru"ture surrou!ded b$ double membra!e< spe"ies "ellular

Stores D8A

Produ"es %ibosomes

Nucleolus Gra!ular bod$ withi! !u"leus< site o r%8A s$!thesis @produ"tio! o ribosomes

Nuclear envelope

The !u"lear e!&elope is a doublemembra!e stru"ture that "o!stitutes theoutermost portio! o the !u"leus. Both the i!!er a!d outer membra!es o the!u"lear e!&elope are phospholipid bila$ers. The !u"lear e!&elope is pu!"tuatpores that "o!trol the passa,e o io!s mole"ules a!d %8A betwee! the !u"lea!d "$toplasm.


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Endoplasmic reticulum(ER)

8etwor o i!ter!al membra!es: Smooth '% is a tubule !etwor a!d rou,h '%series o latte!ed sta"s whi"h "o!tai!s ribosomes o! its sura"e< site o melipid protei! s$!thesis. Produ"es a!tibodies a!d e!=$mes.

Goli !omple"Sta"s o latte!ed membra!e sa"s< modiies pa"a,es se"retes protei!s. Gl$"oprotei!s

L#sosomes

Membra!ous sa"s< "o!tai!s e!=$mes to di,est waste material a!d "ellular de

L$sosomes di,est e;"ess or wor!out or,a!elles ood parti"les a!d e!,uledor ba"teria.

$acuoles Membra!ous sa"s< tra!sport a!d store water other mi!erals &ital to "ells h

Mitoc%ondria

Sa"s "o!tai!i!, 2 membra!es< The outer membra!e "o&ers the or,a!elle a!d"o!tai!s it lie a si!. The i!!er membra!e olds o&er ma!$ times a!d "reate

la$ered stru"tures "alled "ristae< site o *rebs "$"le ele"tro! tra!sport s$ste"hemiosmosis.

ATP is produ"ed here a!d the "ristae "reates a lar,e sura"e area or ma;imuprodu"tio!.

Plastids Sa"lie stru"tures with i!ter!al th$laoid membra!es< photos$!thesis

Microbodies orPero"isomes

Membra!ous sa"s "o!tai!i!, e!=$mes "o!tai!s e!=$mes that produ"e +$dropero;ide as a b$produ"t.

7ses o;$,e! to brea dow! ats a!d orms bile a"id


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!%romosomesComposed o D8Aprotei! "omple;< "o!tai!s ,e!es

Eou!d i! the 8u"leus

Ribosomes

Gra!ular or,a!elles "omposed o %8A protei!< s$!thesi=e protei!s

Carr$ them to the ,ol,i bod$

Microtubules +ollow tubes o tubuli!< stru"tural support or or,a!elles o mo&eme!t

Microfilaments Solid rodlie stru"tures o a"ti! stru"tural support

!entrioles Small hollow "$li!ders< i!&ol&ed i! "ell di&isio! a!"hors la,ellae "ilia

!ilia Short hairlie stru"tures< mo&eme!t ood i!tae usuall$ FF1 o! a "ell.

!#toplasmEluid part "alled the "$tosol< Co!tai!s "$toseleto! that ,i&es the "ell its shapCo!sists o dissol&ed !utrie!ts that aids to dissol&e waste produ"ts.

Flaella Lo!, proe"tio!s< "ellular lo"omotio! usuall$ 15 o! a "ell.


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Lear!i!, )be"ti&e 5Dis"uss the !eed or i!tra"ellular "ompartme!talisatio! a!d the basi"pri!"iples o "ellular metabolism.


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#!tra"ellular Compartme!talisatio!

Compartme!ts ha&e 3 mai! roles:

1. To establish ph$si"al bou!daries or biolo,i"al pro"esses that e!ables the "ellto "arr$ out diere!t metaboli" a"ti&ities at the same time.

2. To isolate the rea"tio! happe!i!, i! o!e or,a!elle rom ae"ti!, the rest othe "ell.

3. To establish a spe"ii" lo"atio! or whi"h pro"esses should o""ur.


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#!tra"ellular Metabolism

The basi" pri!"iple o i!tra"ellular metabolism is to allow the euar$oti" "ellto "arr$ out its u!"tio! a!d &ital pro"ess at the same time i! order tou!"tio! as it should. This mea!s that spe"iali=ed or,a!elles are ormed.


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Lear!i!, )be"ti&e 6Dis"uss the diere!t methods used i! the stud$ o "ells a!d thepreparatio! o tissues.


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'le"tro! Mi"ros"opes

Tra!smissio! 'le"tro!Mi"ros"ope @T'M

7ses a &olta,e to pass a! ele"tro! beam emitted b$ a "athode throu,hthe sample

Produ"es 2D ima,es

%esol&i!, power 0.2!m

S"a!!i!, 'le"tro!Mi"ros"ope @S'M

Produ"es ima,es b$ dete"ti!, dis"har,e o ele"tro!s rom thespe"ime!

Produ"es 3D topo,raphi" @detailed ima,es

%esol&i!, power 2!m


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TissueSample Preparatio! Ei;atio!: Preser&atio! o sample at a spe"ii" poi!t to pre&e!t de,radatio!

be$o!d that poi!t

Cr$oi;atio!: %apid ree=i!,

Deh$dratio!: %emo&i!, all aueous solutio!s rom sample usi!, or,a!i"sol&e!ts

'mbeddi!,: #!iltratio! o tissue with resi! @as opposed to wa; used or li,htmi"ros"op$

Se"tio!i!,: Produ"i!, @"utti!, a &er$ thi! se"tio! o the spe"ime!. T$pi"al

si=e H0!m Stai!i!,: 7ses hea&$ metals su"h as lead a!d ura!ium

Sputter "oati!,: Ier$ thi! la$er o ele"tro!i"all$ "o!du"ti!, material is usedto "oat spe"ime!. Do!e to pre&e!t "har,i!, o the spe"ime!.


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Disad&a!ta,es

'le"tro! mi"ros"opes are &er$ e;pe!si&e to bu$ a!d mai!tai!

The$ reuire si,!ii"a!t e;pertise a!d te"h!i"al trai!i!, i! order to operate

The e!er,$ reuireme!ts or operatio! are hi,h

cellular worlds

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