6.1.1 Cellular Control Flashcards
Mutation definition
a change to the quantity or structure of the dna of an organism
chromosomal mutations definition
change in the number or structure of whole organisms
gene mutations definition
result in a change in sequence of nucleotides in dna molecule
types of gene mutations
indel and point
point mutations
one base is substituted for another
types of point mutations
nonsense
silent
mis-sense
nonsense mutation
change results in stop codon
Mis-sense mutation
different amino acid is coded for
silent mutation
different base occurs in the triplet but it codes for the same amino acid
indel mutation definition
extra base is added or deleted leading to a frameshift
types of indel mutations
addition
deletion
deletion mutation
remove a base so all codons could be different changing the sequence of amino acids and therefore the protein produced
addition mutation
add a base so it can be read in a different form to make a different amino acid
all codons past that point can be different
Beneficial mutation
gives you a selective advantage for survival
harmful mutation
gives you a selective disadvantage for survival
neutral mutation
no effect on survival
Regulation of protein production steps
transcriptional control
post-transcriptional control
post-translation control
transcription factors
proteins that bind to sections of dna to either switch genes on or off
there encoded by regulatory genes
can either activate or repress genes
during lac operon what proteins must be present to metabolize lactose
B-galactosidase
lactose permerase
why are structural genes in operons transcribed together
share promotor
work together to make simular protein
function of regulatory gene
regulate the production of a transcription of genes using transcription factors
function of structural gene
code for structural proteins
Lac I
a repressor
the protein binds to the operator when lactose is not present
RNA polymerase in Lac Operon
bind to promotor but due to Lac I being bound to the operator RNA Polymerase cannot get past and transcribe the genes
what happens to Lac I when lactose is present
Lac I binds to lactose resulting in a conformational change
the lac i lactose complex then drops off the operator so rna polymerase can transcribe genes for lactose metbaboloism so lactose can be broken down for energy
Name of mRNA strand formed after transcription
primary mRNA transcript
B-galactosidose
hydrolyses lactose into galatose and glucose
Lactose Permease
transport protein that becomes embedded into E.Coli membrane to transport more lactose into the cell
Post transcriptional regulation
splicing
remove introns and leave exons behind
splicing
non coding introns are removed leaving behind RNA exons which are complementary to the original DNA exons
Alternative splicing
can produce slightly different proteins so one strand of dna can code to multiple proteins
can remove some exons aswell as intons so protein is slightly different
post translational gene regulation
after proteins are produced by translation some must be activated by molecules before they become functional
some bind to cell membrane to trigger production of cAMP which is used to alter the 3D shape of proteins by changing the active site shape
Homeotic genes
set of genes that regulate morphogenesis the shape that an organism forms
Homebox genes
subset of homeotic genes
180 base pair sequence excluding introns
homeotic product protein bind to dna + indicates transcription
homeodomain sequence
encodes for a 60 amino acid sequence
Hox genes
subset of homebox genes found in animals
what do hox genes do
control polarity and where organs are
switch genes that control the development of a body plan on or off
Do hox genes mutate
very little as they’re very important and it can be lethal
Regulating body genes
time and sequence of gene expression determines the development of the body parts
Gap genes
regulate regulatory genes
Apoptosis
type of programmed cell death and is integral to development of the body parts
what does apoptosis lead to
orderly tidy cell death
nucrosis
leads to release of harmful hydrolytic enzymes
only occurs when cells are too damaged to survive
- uncontrolled cell death
what happens if theres not enough apoptosis
leads to cancer
formation of tumors
what happens if theres too much apoptosis
cell loss and degeneration
