Practise identifying promoter function and explaining how transcription factors at specific DNA sequences let activators and repressors alter RNA polymerase activity in IB Biology HL D2.2.2.
The genome is the total of all the DNA in an organism, containing all the genetic information required for development and growth.
Explain how gene expression can be regulated during transcription to determine an organism's phenotype.
a. transcription factors bind to DNA and can be activators or repressors OR
transcription factors promote or block transcription;
b. protein/transcription factor/TF binds to promoter to activate transcription OR
promoter indicates where RNA polymerase binds to begin transcription;
c. transcription factor/activator/protein binds to enhancer to increase the rate of transcription
OR
transcription factor/repressor/protein binds to silencer to decrease the rate of transcription;
d. epigenic tags can alter gene expression / methylation can alter gene expression;
e. methylation of cytosine in the DNA of a promoter represses transcription;
f. methylation of amino acids/protein in histones can cause transcription to be repressed or activated;
g. thereby regulating the production of proteins from the gene
OR
proteins from gene expression display/create phenotypic traits;
h. gene expression may be altered by (steroid) hormones/biochemicals that act as chemical signals to activate receptors that promote transcription;
i. alteration of methyl tags on DNA in response to air pollution or in response to the environment;
j. valid example of gene regulation;