human bio notes
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Carrier Mediated Transport
• Molecules ind to proteins in the cell memrane to e transported across the
memrane,
• Carrier proteins are specific – the" *ill onl" ind to certain molecules
• Carrier proteins can ecome saturated – the" can onl" ind to a certain numer
of proteins &saturation point)
• Transport is regulated " hormones
• T*o t"pes$ .acilitated +iffusion and Acti(e Transport
/ facilitated diffusion is a passi(e process, It is the mo(ement of molecules
from a high concentration to a lo* concentration " inding to a carrier
protein, The molecule attaches to the inding site on the protein1 the carrier
changes shape and releases the molecule on the other side of the memrane,
/ acti(e diffusion is the transport of molecules from a lo* concentration to a
high concentration, It is an acti(e process and uses AT! molecules, Molecules
tra(el across the memrane similar to those in facilitated diffusion1 onl" going
against the concentration gradient,
Vesicular Transport
• The mo(ement of sustances across the cell memrane is memranous ags
called (esicles, Is an acti(e process,
• Endoc"tosis$ #ringing sustances into the cell, The cell memrane folds
around a droplet of li5uid or a solid particle until the droplet or particle is
completel" enclosed, The (esicle then pinches off and enters the c"toplasm,
/ !inoc"tosis$ Cell drining
/ !hagoc"tosis$ Cell eating
• E'oc"tosis$ %ustances e'iting the cell, Vesicle containing sustances
migrates to the cell memrane and fuses *ith the memrane, The (esicle then
opens and the contents are pushed out,
TY!E 4. TRA6%!4RT !A%%IVE7ACTIVE %U#%TA6CE%
+I..U%I46 !assi(e 8ater1 421 C421 alcohol1 fatt"
acids1 steroids1 ions &6a1 91 Ca)1
lipid solule drugs, 4smosis !assi(e 8ater
CARRIER ME+IATE+ :::::::: :::::::::::::,
.acilitated +iffusion !assi(e -lucose Amino Acids
Acti(e Transport Acti(e Certain ions &glucose1 AA;s)VE%ICULAR TRA6%!4RT :::::::: :::::::::::::,
Endoc"tosis Acti(e Cholesterol1 iron ions1 micro/
organisms and cell deris ut
onl" " certain speciali
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• #ind *ith certain molecules outside the cell and trigger a response7reaction
*ithin the cell
• %pecific – each t"pe of receptor *ill ind *ith one t"pe of molecule &loc and
e" analog")
• +ifferent cells ha(e different t"pes and numers of receptor proteins therefore
there is a (ariation in the sensiti(ities of cells to hormones and other
sustances
• Receptor proteins also help in the communication *ith other cells
+6A
• A +6A molecule is made up of thousands of nucleotides
• Each nucleotide consists of riose &a >/caron sugar)1 a phosphate group and a
nitrogenous ase
• The t*o chains of alternating sugars and phosphates are no*n as the sugar/
phosphate acone
• The ases &once =oined) can e seen as the rungs on a ladder
• The t*o strands t*isted together are no*n as a doule heli'
• A chromosome contains appro'imatel" ?@ million ase pairs
.unctions of !roteins
• %tructure$ %trengthening hair1 nails1 sin &eratin) and strengthening and
maing one1 cartilage1 deep sin la"ers fle'ile &collagen)
• Transport across memranes$ carriers and channels,
• Communication$ 0ormones1 receptors
• Cell metaolism$ en
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• tR6A$ a small R6A molecule that carries an AA to the riosome and places it
in the correct position determined " its corresponding mR6A
• -ene$ part of a +6A molecule that contains all the triplets needed to produce a
specific protein
• +6A$ a molecule in the nucleus of a cell that determines the t"pes of protein
that a cell can mae, 0olds the genetic information
• Chromosome$ rod/lie structures in the cells nucleus that carr" the hereditar"
information
• Triplet$ a section of +6A B ases long
• Codon$ a section of mR6A B ases long1 codes for a particular AA
!rotein %"nthesis
• Translation
The mR6A strand undergoes modification efore it lea(es the nucleus, The introns
&non/coding sections) are remo(ed from the strand1 lea(ing onl" the e'ons &coding
sections),
• Translation
Translation is the production of the protein that is coded in the mR6A strand, The
mR6A tra(els into the c"toplasm and a riosome attaches to one end of the strand
&*here the inding site of ases are – ensures riosome attaches to correct end of
mR6A),
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%ummar" of !rotein %"nthesis$
Transcription$
/ T*o strands of the +6A in a gene separate – coding and templatestrand
/ mR6A forms complementar" to the ases on the template strand
/ modification$ introns are remo(ed to lea(e onl" e'ons
/ mR6A tra(els to the c"toplasm
Translation$
/ mR6A attaches to riosome
/ riosome mo(es along strand reading codons until it reached AU-
&start codon) *hen it *ill egin coding the mR6A and maing the
protein
/ for each codon1 a tR6A molecule *ith matching anticodon rings the
correct AA/ AA;s are onded together to form peptide chain &? AT! molecule per
ond) *hich is the protein
!rotein %tructure
!rimar" &?D) %tructure$ A chain of AA;s =oined "
peptide onds, The se5uence of AA;s that mae up
the protein, A protein ma" ha(e ? or more
AA;s in the chain and changing =ust one of these can
significantl" change the proteins properties and in
turn1 the function of the od",
%econdar" &2D) %tructure$ Is either a coiled or folded
shape, Is made " onds et*een different parts of
the AA chain, .orms sheets or spirals,
Tertiar" &BD) %tructure$ Is formed " further ending
and folding of the protein into gloular or firous
shapes,
uaternar" &@D) %hape$ &%ome proteins) Is formed*hen t*o or more AA chains interact7=oin,
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Modif"ing and !acaging of !roteins
• AA chain goes to the -olgi Apparatus &or -olgi #od") *here %U-AR%1
!04%!0ATE%1 sulfates1 fatt" acids and other molecules &depending on the
desired protein) are added to create a functional protein
/ +6A holds info to mae proteins1 *hich mae en
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• Is the determination of the precise order of the nucleotides in a sample of
+6A
• The method most commonl" used to determine this se5uence *as in(ented "
.RE+ERIC9 %A6-ER
• 4ur nucleotides &+eo'"nucleotide Triphosphates) are onded together (ia
their h"dro'"l groups
• The se5uence that has een shortened is then more easil" compared to the
+6A se5uences in 5uestion
• It is also a lot easier *oring *ith smaller1 more manageale sections of +6A
+6A %e5uencing !rocess
• The +6A is separated into t*o strand &" heating)
• The strand to e se5uenced is copied using s"ntheticall" altered ases
&thousands and thousands of copies)
• These altered ases cause the
cop"ing process to stop each
time one particular letter &e,g,
- – guanine) is incorporated
into the gro*ing +6A chain
• The location of that particular
ase can then e located on
the strand of +6A
• This process is carried out for all four ases1 and the
fragments are put together lie
a =igsa* to re(eal the
se5uence of the original piece
of +6A,
• #" comparing +6A se5uences1 changed alleles and mutations can e
identified and *ill sho* *hether an indi(idual has a particular disease,
Electrophoresis
4040
4040
0
00
0
8ithout the 0"dro'"l group1 the nucleotides
can;t ond together,
Therefore1 artificiall" made nucleotides1
ha(e another 0"drogen *here the 0"dro'"l
group should e,
This means that this artificial nucleotide
can;t =oin to another nucleotide1 hence
stopping the +6A molecule from gro*ing
and lengthening,
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• +6% strands can e chopped up into smaller fragments using special en
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• These B steps are repeated as necessar" &efore final step)
• .inal Elongation$ &J – J@DC)
/ after the last !CR c"cle
/ this ensures an" remaining strands are elongated
runs for ?> minutes
• .inal hold$ &@ – ?>DC)
/ allo*s for stoppage and storage of the reaction
Recominant +6A Technologies &aa -enetic Engineering)
• In(ol(es the
introduction of +6A
from one organism
into the +6A of
another organism,
• 0as the huge potential
of replacing fault"
genes *ith health"
ones
• Can help patients
suffering from c"stic
firosis1 rheumatoid
arthritis and certain
cancers
• Transgenic organisms
are those *hose
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genome has een altered " the transfer of a gene or genes from another
organism
• These transferred genes ecome part of the organisms +6A and therefore can
e passed on to the ne't generation
• Recognition site$ a point *here there is a specific se5uence of ases *here
restriction en
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• This process is used e'tensi(el" to detect +uchene muscular d"stroph" and
Thalasseamia
• If the gene in 5uestion is normal7health" the genetic proe *ill ind to the
+6A and the gene *ill e highlighted, If the gene is anormal1 the genetic
proe *ont e ale to ind to the +6A and nothing *ill e highlighted
• Man" techni5ues are used to detect the presence of a mutant gene3
/ +6A se5uencing
/ !rofiling techni5ues
/ !ol"merase Chain Reaction &!CR)
/ -enetic !roes
/ -enetic Engineering &recominant +6A technologies)
Chapter ?@ – I60ERITA6CE
• -ene$ Coding sections1 for the factors that determine hereditar" diseases1 on
the chromosomes• Allele$ Alternati(e forms of the same gene
• Chromosome$ Rod/shaped structures that carr" the hereditar" information
• Loci7lucus$ The location of a gene7 genes on a chromosome
• -ene Linage$ Certain characteristics tend to e inherited as a set
Multiple Alleles
• %till one gene1 ho*e(er there are more than 2 alleles and more than 2
phenot"pes
• E,g, #lood T"pes
A#4 #lood T"ping
• A;s1 #;s and 47s code for antigens that are present on the cell memrane ofR#C;s
• Antigen A K IA Antigen A # K IAI#
• Antigen # K I# 6o Antigen K i
• IA and I# are co/dominant – lending of characteristics
• i is recessi(e
Monogenic Inheritance
• There are man" alleles ut the pattern of inheritance is one *ith discrete
characteristics
• Each person has onl" one pair of alleles for the characteristics &e,g lood t"pe)
!ol"genic Inheritance• The inheritance of the characteristic is dependent on man" genes1 not =ust one
pair
• The en(ironment ma" also influence the e'pression of these characteristics
&e,g, diet1 e'ercise1 UV radiation1 disease causing organisms)
• 0air colour1 *eight1 height and sin colour
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• -ene !ool$ the collection of genot"pes of all the indi(iduals that are capale
of reproduction ¬ infants) in a particular population
• Allele .re5uencies$ the occurrence of alleles of a gene in a population studied
• %pecies$ a group of indi(iduals that share man" characteristics and are ale to
interreed under natural conditions to produce fertile offspring
• There are @ *a"s to change the allele fre5uencies in a population$
/ Mutations
/ 6atural %election
/ Random -enetic +rift
/ #arriers to -ene .lo*
Mutations
• Random1 non/inherited (ariations appearing *ith no precursor and purel" "
chance
• Mutant$ an organism *ith a mutation
• -ene mutation$ change in a single gene so the traits normall" produced " that
gene are changes or destro"ed• Chromosomal mutation$ all or part of a chromosome is destro"ed
• %omatic mutations$ mutations occurring in somatic &od") cells that are not
passed on to the ne't generation
• -ermline Mutations$ mutations that occur in the reproducti(e &germinal) cells
that are passed on to the ne't generation
6atural %election
• Charles +ar*in$ .ather of E(olution, A naturalist *ho proposed and pro(ed
*ith scientific e(idence that all species of life ha(e e(ol(ed o(er time from
common ancestors through the process of natural selection
• .orms the asis of the modern e(olutionar" theor"• Can e (ie*ed as the selection of genes in a population that gi(e an organism
a greater chance of sur(i(al, The organisms that sur(i(e can pass on their
genetic information &*ith these fa(ourale characteristics) and graduall" o(er
a long period of time1 the population *ill ecome etter suited to the
en(ironment
• 6atural selection CA664T occur in a changing en(ironment
• There are B oser(ations that for the theor" of 6atural %election$
/ Variation$ All memers of a species (ar" and these (ariations are passed on
from generation to generation
/ #irth rate$ all li(ing things increase their numers at a rate greater than theira(ailale resources allo* &food1 shelter1 *ater etc)
/ 6atures #alance$ although the irth rate of organisms *as (er" high1 the
species tended to maintain their numers at a relati(el" constant le(el
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• %ocio/cultural arriers$ +e(eloped as human cultures ecame more comple',
Religion1 economic status1 education1 social position &main @) and language
&to some e'tent),
• -ene .lo*$ The transfer of genetic information from one population to
another, If isolation has een e'treme and o(er an e'tended period of time1 itma" not e possile for populations to interreed if the" come together again
• %peciation$ The formation of ne* species, .or a ne* species to form &e,g,
et*een t*o separated populations)1 there needs to e (ariation *ithin oth
populations1 isolation of the t*o populations1 en(ironmental pressures
&*eather1 UV1 diet1 chemicals) and it needs to occur o(er an e'tended period
of time,
• .ounders Effect$ %imilar to -enetic +rift &e'cept change is more immediate),
8hen a small population mo(es a*a" from the original population and
estalishes a ne* communit", This ne* communit" is not geneticall"
representati(e of the homeland population and usuall" sho*s non/t"pical &forthe original population) characteristics,
E,g, the ount" mutineer descendents &*ith nati(e Tahitian men and *omen)
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