test 2 Flashcards
what is autosomal dominent
the allele for the trait is dominant and is carried on an autosome
what is autosomal recessive
the allele for the trait is recessive and is carried on an autosome
what is x linked recessive
the allele for the trait is recessive and is carried on the sexual chromosome x
what is x linked dominant
the allele for the trait is dominant and is carried on the sexual chromosome x
what is transcription and what do you get
the process of converting DNA to RNA
from a template strand from 3’ to 5’, you get a complementary strand from 5’ to 3’
what is translation and what do you get
translation is the process of converting RNA to a protein (comes after transcription)
from a complementary strand you get a protein of the form
N Met-Pro C
what are the letters changing to in transcription
A to U
C to G
G to C
T to A
what is the orientation of mRNA (messenger)
always 5’to3’
when translating mRNA what do you get
protein
what is a missence mutation
-type of base substitutions
-alters the identity of the amino acid
-effects the reactive site of enzymes (moderate effects)
what is a nonsense mutation
-type of base sub
-generates an early stop codon so protein is truncated
-has severe effects on protein function
silent mutation
-type of base sub
-generates no change because protein identical so does not have an effect
what are frameshift mutations
-insertions or deletions
-changes the reading frame
-the remainder of the protein after is changed
-a premature stop codon will end translation
what is a deletion in Large chromosomal rearrangement
-occurs if a broken segment is lost from a chromosome
-ex: deletion on human chromosome 5 normally leads to severe cognitive impairment and a malformed larynx (cris du chat)
what is a duplication
-type of large chromosomal rearrangements
-a segment is broken from one chromosome and added to its homologue
-in the receiving homologue the alleles of the inserted fragment are added to the ones already there
-may be good or bad depending on the genes and or alleles in the duplicated region
-ex: mammals have genes that encore several types of hemoglobin that are not present in vertebrates such as sharks that evolved earlier
what is a translocation
-type of lcr
-occurs when a segments of a chromosome breaks and attaches to another non-homologous chromosome
-ex: cancer burkitt lymphoma happens in humans when part of chromo 8 goes to the end of chromo 14
what is an inversion
-type of LCR
-part of a chromo breaks and reattaches on the other side
-ex 5 human chromo show signs oof inversions that our nearest relative the gorilla doesn’t have so is a big part of evolution
what are transcription factors
proteins that need to bind to DNA and regulate gene expression by promoting or suppressing transcription to recruit rna polymerase II
what is the difference in the mRNA of eukaryotes and prokaryotes
eukaryotes have pre-mRNA that needs to be transformed to go through translation
prokaryotes have their rna ready to go from transcription to translation
there are no transcriptionfactors in prokaryotes
what is epistasis
many genes that interact with each other where one or more alleles of one gene can mask the effect of other genes
what is incomplete dominance
both phenotypes show up to create a new one (pink flower from a red and a white)
what is codominance
both phenotypes are expressed
what is a lethal recessive allele
-phenotype for heterozygous individual is normal
-lethal for homozygous individual
f2 ratio 3:0
what are multiple alleles
small differences in the sequence of the DNA at one or more points of a gene
what is polygenic inheritance
traits that are conferred by multiple genes
what is the SRY
the switch that directs development toward maleness at an early point in embryonic developpement
the disease skips generations
probably recessive
more men than women affected
probably x linked recessive
more women that man affected
on autosome
affected mother has an unaffected son in a recessive trait
rule out X linked
when will an affected father always have affected daughter
x linked dom
dna base pairs
adenine
thymine
guanine
cytosine
rna base pairs
adenine
uracil
guanine
cytosine
what is a codon
a section with three base pairs
what does every protein start with
methionine
what are the 3 stop codons
UAA
UAG
UGA
what are chaperones
chaperones are protein complexes that fold the proteins
what are the mRNA start codon
AUG
what are the mRNA stop codons
UAA
UAG
UGA
what’s the use of rRNA
rRNA form with proteins the ribosomes that translation happens in
what’s the use of tRNA
tRNA is what brings the amino acids to their respective codons
it has on one side an amino acid and on the other the anticodon that pairs with the codon on the mRNA
summarize transcription
1 initiation -transcription factors bind to the promoter on the TATA box and they recruit RNA polymerase.
2 elongation- dna is unwound and rna base pairs are added to the new mRNA strand in the 5’ to 3’ direction. behind the rna polymerase the DNA rewindsthe newly synthesized pre mRNA molecule is elongated by adding new bases to the RNA strand.
3 termination- the RNA polymerase is removed
summarize translation
1 initiation- the ribosome scans the mRNA until it finds the start codon
2 elongation- tRNA brings the amino acid that is correct for the codon in the A site. The codon must fit the anticodon on the tRNA. each added amino acid start forming a polypeptide in the P site. The empty tRNA exists at the E site
what are polysomes
They are a chain of ribosome so many ribosomes can translate a mRNA chain at the same time making it faster
what is the transcription start codon
TAC
what is an operon
A sequence of genes plus a promoter and an operator involved in the same metabolic pathway
unique to prokaryotes
what is a catabolism reaction and which operon does it go with
It is the ensemble of reactions that lead to the degradation of molecules. Produces energy
Lac operon
what is an anabolism reaction and which operon does it go with
It is the ensemble of reactions that lead to the construction of molecules. Consumes energy
Trp operon
what is RNA polymerase I
a type of rna that transcribes DNA into rRNA
what is RNA polymerase II
a type of rna that is an enzyme and transcribes protein coding genes
what is RNA polymerase III
a type of rna that is an enzyme that transcribes DNA into tRNA and some parts of rRNA
what happens in initiation of translation
the ribosomes scan the mRNA strand until it finds the start codon
what happens in elongation of translation
the tRNA brings in the amino acid attached to it’s anti codon to match each codon of the mRNA. a polypeptide chain forms.
lac operon induced or repressible and what type rxn
induced and catabolic
trp operon induced or repressible and what type rxn
repressible and anabolic
what happens to the lac operon when no lactose
the Lac repressor encoded by the LacI gene is active and binds to the operator so no transcription really occurs (basal level)
what happens to the lac operon when lactose present
the lactose is converted to allocate which inactivates the repressor so it does not bind to the operator so transcription can occur
what happens the trp operson when there is no trp
the repressor is inactive, so it is prevented from binding to the operator so transcription can happen
what happens to the trp operon where trp is present
repressor gets activated by the tryptophan which allows him to bind to the operator blocking transcription
what’s the difference between an snp and an lcr
an snp changes only one base pair of the chain whereas an lcr changes a whole part of chromosome
what are activators
regulatory proteins that bind to the promoter proximal effects to stimulate or inhibit transcription
