topic 6.1.1: cellular control Flashcards
what are the three main types of genetic mutations
substitution, insertion, deletion
what is subsititution
one nucleotide changed so only one codon affected
what is insertion
base added, changing all codons downstream
what is deletion
base deleted, affecting all codons downstream
what is a point mutation
may not alter primary structure of protein as genetic code is degenerate
what is a frameshift mutation
change the primary structure of protein
what is a transcription factor
binds to certain genes to turn them on/off to become specialised
what is an example of gene expression regulation at a transcriptional level
lac operon
what is the function of the lac operon
found in e. coli, sequence of 3 genes that aid lactose digestion
how does the lac operon work
lac i- regulatory gene, codes for repressor
repressor protein- inhibits transcription, prevents rnap from binding to promoter
lactose binds to repressor, changes its shape and frees up promoter so can be digested
when is the lac operon needed
when no glucose is present as a respiratory substrate
how is gene expression regulated at a post-transcriptional level
introns removed from pre-mrna strands and exons reordered
what are introns
non-coding dna
how is gene expression regulated at a post-translational level
cAMP binds to receptor proteins in lac operon, non-proteins added in golgi
what are homeobox genes
sequences which create proteins that regulate expression of other genes involved in body plans
what are hox genes
type of homeobox found in animals
what is apoptosis
programmed cell death
how do genes control the cell cycle
through hox genes
