13.2

Question 1

molecules in the enviroment may affect transcription

Answer 1

molecules may induce transcription

Question 2

transcriptional control mechanisms

Answer 2

induction
repression
positive control
negative control

Question 3

induction

Answer 3

molecule in environment stimulates transcription

Question 4

repression

Answer 4

molecule in environment inhibits transcription

Question 5

positive control

Answer 5

transcription regulated by activator protein

Question 6

negative control

Answer 6

transcription regulated by repressor protein

Question 7

regulation by general and specific transcription factors

Answer 7

general transcription factors assemble at the core promoter and recruit RNA polymerase to enable basal transcription
changing the availabilty or binding ability of these transcription factors can be one way to regulate transcription in eukaryotes

Question 8

specific transcription factors increase gene expression

Answer 8

may not always bind near to the core promoter, particularly in eukaryotes

Question 9

chromatin structure influences gene expression

Answer 9

in eukaryotes, DNA and histone proteins are organized into nucleosomes, which are then assembled into a chromatin struutre
changes in chromatin structure occur by chemical modification of histones
or by ATP dependent movement of nucleosomes
both affect the accessibility of the DNA for transcription