module 6 reds Flashcards
why are some regions of dna described as non coding
not translated or present in mature mrna
why is there more variation in non-coding dna
not selected against
what makes a molecule a suitable resp substrate
bonds contain energy, soluble, bonds can be broke
how can transcription be controlled in eukaryotes
hormone enters cell and binds to transcription factor, transcription factor activated, binds to promoter region, rna p able to bind
how can gene expression be controlled post transcription
removal of introns to produce mature mrna, splicing can produce diff types of mrna, binding of camp alters shape of protein
what is an operon
a cluster of genes under the control of a promoter
what are homeobox genes
contain highly conserved sequence of 180 base pairs, reg expression of structural genes
roles of homeobox genes
determine overall body plan
switch different genes on and off in different cells and tissues
expressed in a set order during development
regulate patterning and positioning of (named) structures
determine polarity
regulate levels of apoptosis and mitosis
what are hox genes
base sequence is similar in all animals, produce polypeptides, mutations are often lethal
explain how failure of the control mechanism for development could lead to deformity
hox gene does not produce transcription factor, molecules signalling apoptosis not produced, apoptosis does not occur
type of speciation that occurs when two populations live in the same location
sympatric
conditions that must be present in order for speciation to occur
reproductively isolated, mutation, natural selection, selection pressure different from other pop
define the term dna sequencing
working out the sequence of bases/ nucleotides
what is needed for dna sequencing
the DNA to be sequenced
short primer sequences specific to the DNA to be sequenced
many normal DNA nucleotides
some chain-terminating DNA nucleotides labelled with coloured dyes
the enzyme Taq polymerase
how can peat bogs be conserved
less planting of trees, no grazing
