6.1 - cellular control Flashcards
mutation
change in dna base sequence caused by mutagens
types of mutations
- point (sub)
- indel - insertion/deletion
point mutation
affects only 1 base
3 types - silence, missense, nonsense
could have no effect - dna code is degenerate
whats a frameshift mutation
occurs in indel mutation
disrupts triplet code reading
what effect can a mutation have
- neutral/silent - no effect (degenerate code)
- beneficial - enhanced function of protein
- damaging - malfunctioning protein made
nonsense mutation
codon has changed into a stop codon
missense
change to triplet code which alters amino acid sequence
transcription factors
**proteins which can bind to different base sequences on dna and initiate transcription of genes
HAS TO ENTER NUCLEUS AND BIND TO DNA TO WORK
OPERON
group of simultaneously controlled genes that are either all expressed or not
what is a lac operon
found in e coli.
aid lactose digestion
lactose induces the production of….
what does the lac operon look like
IF LACTOSE IS PRESENT
LACTOSE ISNT PRESENT
HOW IS CYCLIC AMP USED
INCREASES RATE OF TRanscription of lac operon
Activate proteins inside the cell at the post translational level by altering 3-D structure
introns
non coding regions of dna
exons
coding regions of dna
post transcriptional level
intond are removed from primary mRNA by splicing
Exons join together form mature mRNA strands
Mature mRNA leaves the nucleus for translation
homeobox genes
sequences of genes which create proteins that regulate expression of other genes involved in the formation of embryo
hox genes
responsible for correct body development and positioing of body parts
only animals9
How do hox genes control development?
homeobox sequences code for a part of the protein called homeodomain
Domain binds to specific DNA enabling the protein to work as a transcription factor
Proteins bind to DNA at the start of developmental genes activating/ repressing transcription
alters The production of proteins involved in the development of the body plan
how is apoptosis and mitosis involved in the development of body plans?
Mitosis and differentiation create the body parts and then apoptosis refines by removing the unwanted structures TOES
