topic 4 - genetic infomration, variatoin and relationships between organisms Flashcards
why do different specieslook the same?
similar environmnents
similar selction pressures
similar alles with selctive advantage
similar protiens produced
similar charachteristcs
3 domains
eukaryotes
prokaryotes
archea
why do we clasify organisms?
understand relationships between organisms
universal
treack changeswhy
why do we not clasify off the basis of physical characteristcis?
some members of the same specifies look different e..g idfferent dog breeds
some different species look similar, may accidently class htem as the same speciies.
phylogenic clasifcation
tells us about evolutionamlry origins and relsationships
who and how closely related
what do we classify on the basis of?
mrna sequence
dna seqeunce
amino acid sequence
immunological - shape of self anti bodies
what are the taxes
domian
kingdom
phylum
class
order
family
genus
species
hierarchy defenition
smaller groups within larger groups, no overlap between groups.
binomial name.
what is it ?
why do we use it?
genus. species
universal and gives us a better understnaidn gof how species are related
what are some of the ways bioldiversity is decreased?
destriction of hegerows
selective breeding
monocultures
draining weltsnds
over grazing
fillings ponds
what is genetic diversity?
variety of genes within all indivuduals of a population of one species
ecosystem diversity
range of different habitats
species richness
number of species in a particilar area at a parcticluar time
species diversity
number of soecies and indivudlas within each species in a comunity
what is an index of diversity?
measure of soecies diversity measures the relationship between the number ofspecies in a comunity and numbr of indiviuduals in a species.
what are mutations
alteratoin of base dna
what are the mutagenic agents
alpha or beta
x rays or gamma rays
carcinogens
outline additoin ( mutatoin )
nucleotide is added in
frame shift altering amino acid sequence
akk triplets byone mutation are altred
outline deletion ( mutation )
backwards frame shift
outline substitution ( mutation )
one base is swapped for another
degenrate - possibly no change
outline inversion ( mutatin )
selection of bases leave and return inversted
outline transolcation ( mutatin )
leave and attatch onto different chromozones
what is directional selection
extreme trait has sleective advantage due to a chnage in the envoronment
3 different adaptation types
anatomical
physical
behavioural
evolution - defentiotn
change in allele freuencey over many generations in a population
how to identiify meiosis
2n - n
diploid - haplopid
4 steps to crossing over:
when facing eachoher parts of chormatids become twisted around eachother
this puts tention on the pars of chromatids causing them to break
broken portions of chromatids rejoin wiht another chormatid
new allele combos
oitline indepandant segregatoin
randomly paternal and paternal pairs line up on the qeuator of the cell
pairs are seperated and one of each pair ends up in the daughter cell
how is variatoin is mitosis produced?
crossing over
independatn segrgation
what is 2n
number of homogenous pairs
indenedant segregatoin
random fertlaisatoin…
produced vsristion in chromozones (2^n)^n
what are three main features of the genetic code
universal degenrate non overlapping
what are start codons
start of the polype[tide chain
what are stop condons
end of the polypeptide chain
dont code for amino acids ( so no completmeentry anti codons )
atc, act, att
caude ribsolsome to detatch and stop translocatoin
what is degenerate. advantage why?
each amino acid is coded for by mroe than one triplet of bases
point mutatoin - change in one base
trieplet dsifference, may still code for the same aa ( silent mutastion )
what is universal. advanatge?
same base triplety codes for the same amino acid ine every organism
adv - genertic engenering is possible e.g inserting human gene for insulin into basvteria
what is non overlapping. advantage?
each base is only part of one trplet, triplets read as one discrete unit
advantage? - point muation only affects one codon / triplet - 1 aa
what are introns
non conding section of dna
not in bacteria
spliced out of mrna
what are exons
coding section of dna
code for animo acid therefore polypetide chain
what is genome
compete set of dna
what is a proteome
range of protiens that is constantly changing
what are homologous pairs of chromozones
same genes different allels
dna is wrapped around? to creat?
histomes, neucleozomes
( only in eukaeyontes )
what is a gene
seoction of dna conding for a polypeptide and functional rna
what is a locus
location of a particalr gene on a chromozone
alle what is
a version of a gene
transciption - defenition
copy of one gene onto mrna
translation - defenition
mrna joins with ribosome and trna beings specific amino acid
steps - transciption
- dna helix unwinds
- one strand used as a template
- done by dna helicasse catalisng the reaction breaking hydrogen bonds
- free mrna neucleotides join wiht template strand
- rna polymerase bings erna neucolotides
what happens after transcription
pre mrna is made into mrna
introns spliced out vias splicezome
steps to translatoin
mrna attatvhed to ribosome in cytoplasm at start codon
trna wirth completmentry anti codons aligns oposite mrna
polymerase
contunies till stop codon ( doesnt code for mrna ) so ribosome detatches
