cellular control Flashcards
wat does it mean for a gene to be ‘expressed’
transcribes and used to make functional protein
not all genes in a cell are expressed
how is gene expression controlled at transcription level
altering rate of transcription
- through transcription factors
- affected by certain molecules
what is an intron
section of gene in eukaryotic DNA that doesn’t code for amino acids
how is mRNA editted
during post-transcriptional level
- introns + axons both copied int primary mRNA
- introns removed through splicing
- exons join forming mature mRNA
how are proteins activated
in post-translational level
- mol.s (e.g. hormones) bind to cell membrane
- trigger cAMP production
- changes 3D structure of proteins
how are body plans developed
coded for by Hox genes
- have highly conserved homeobox sequences
- code for homeodomain in protein
- binds to sites on DNA allowing protein to work as transcription factor
what is apoptosis and its stages
highly controlled programmed cell death
- enzymes break down cell components
- cell shrinks and breaks up
- fragments engulfed by pathogens
name the 3 types of mutation
sustitution
deletion
insertion
how can mutations have a neutral effect
different triplet codes for same amino acid
new amino acid is chemically similar to original
amino acid doesn’t code for function
give an example for beneficial mutations
enzymes in bacteria break down certain antibiotics
makes them work on wider range of antibiotics
bacteria is more resistant- survival
give a example of a negative mutation
cystic fibrosis= deletion of 3 bases
leads to excess mucus production which affects the lungs
define nonsense mutation
codon becomes stop codon instead of coding for amino acid
define missense mutation
addiction of amino acid into primary structure
what is the difference between gene and chromosome mutations
gene-affects single gene/ section of dna
chromosome- affects whole chromosome
