Gene Regulation

Question 1

how do cells ensure energy is only spent on necessary processes

Answer 1

feedback inhibition - used by many cells to regulate which genes are expressed at different times

Question 2

promoter

Answer 2

dna segment that allows a gene to be transcribed

Question 3

operator

Answer 3

part of dna that turns a gene “on”/”off”

Question 4

what is included in an operon

Answer 4

promoter, operator, one or more sturctural genes that code for all the proteins needed to do a job, terminator

Question 5

repressor

Answer 5

binds to operator sequence –> blocking RNA polymerase from attaching to promoter –> preventing transcription

Question 6

inducer

Answer 6

molecule that attaches to the repressor protein and changes it shape so that it falls off the operator sequence allowing RNA polymerase to do its job
- induces process

Question 7

what is lactose in the lac operon system

Answer 7

lactose = inducer
- binds to repressor and allows transcription to begin

Question 8

what is the role of tryptophan in the regulation of the trp operon

Answer 8

causes repressor to bind to operator –> shuts down production/gene is turned OFF

Question 9

enhancers

Answer 9

speed up rate of transcription

Question 10

silencers

Answer 10

slows down rate of transcription

Question 11

how do prokaryotic cells turn on/off genes

Answer 11

control transcription

Question 12

what is the advantage of an operon

Answer 12

• con