Module 3A and some 3B Flashcards
what is coat color determined by
two pigments eumalanin (dark) and pheomelanin (light)
syntheis of pigments is controlled by which gene
Mc1r gene
wildtype produces which type of melanin more
pheomelanin (light)
mutant produces which time of melanin more
eumelanin (dark)
where is the receptor of Mc1r gene embedded
in the membrane of meloncytes
what is triggered by the bindg of alpha MSH and Mc1r
eumelanin
what is produced by the absence of alpha MSH binding
phaeomelanin
what are mutations a source of
genetic variation
For dark and light pigment phenotypes how do the proteins differ
protein for brown pigment: enzyme required for pigment synthesis
protein for no pigment: enzyme required for pigment synthesis does not work
what is a gene
nucleotide sequence that codes for the primary strcture of a specific polypeptide
central dogma
process in which the genetic information flows from DNA to RNA to make functional product protein
Dogma
principles or rules that facilitate phenomenons
proteins _____ traits while DNA _____ proteins
produces; encodes
replication
synthesis of a new DNA strand
transcription
syntheis of RNA using information from DNA; information is transcribed or rewritten from DNA to a complimentary strand of RNA (mRNA)
mRNA
carries a genetic message from DNA to the ribosome
ribosome
protein syntheisizing machinery of the cell
translation
syntheis of a polypeptide using infor from the mRNA; carried out by ribosome
codon
mRNA nucleotide triples (UGG - > tryptophan
start codon
first codon of an mRNA trascript translated by a ribosome
mutation
change in the nucleotide sequence of an organisms DNA or a virus’s RNA
silent mutations
have no effect on the amino acid encoded because of the redundancy in the genetic code
missense mutations
still code for an amino acid, but not the correct amino acid
nonsense mutations
change in amino acid codon into a stop codon nearly always leading to a nonfunctional protein
insertion
adding protein
substitution
exhanging proteins
deletion
getting rid of protein
why do insertions and deletions have a greater effect than substitution
due to downstream consequences
transcription and translation are compartmentalized in eukaryotic cells but not in
prokaryotes
what represents the first stage of gene expression
transcription
RNA polymerase
catalyzes RNA synthesis
What is the newly made RNA complementary to
DNA template strand
what is stage one of transcription
initiation: RNA polymerase unwinds and initiates RNA synthesis
promoter
specific nucleotide sequence of a gene that binds RNA polymerase. helps position the start point of transcription
what does a eukaryotic promoter include
TATA box
stage 2 of trasncription
Elongation: after RNA polymerase binds to the promoter, it unwinds a short segment of DNA (transcription bubble) and starts forming the RNA transcript
what may insertions and deletions lead to
frameshift mutations: lead to nonfunctional proteins unless frameshift is near the end of the gene
frameshift mutation
mutation occurring when nucleotides are inserted in or deleted from a gene and the number inserted or deleted is not a multiple of three, resulting in the improper grouping of the subsequent nucleotides into codons
stage three of transcription
termination: transcription continues until RNA polymerase reaches a termination signal in the DNA sequence which releases the RNA polymerase and newly synthesized RNA
