IB Biology HL D2.2 Gene Expression Hl Only Questions

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;

7

Marking guidance:

max

C

methylation/acetylation/phosphorylation/epigenetic tags/modification of nucleosome tails/N-terminal tails