Topic 6.5 - Regulation of Gene Expression

Question 1

what do the differences in gene expression account for?

Answer 1

account for phenotypic differences between organisms

Question 2

gene expression

Answer 2

the process by which instructions in the DNA are transcribed and translated into a functional protein

Question 3

what regulates gene expression?

Answer 3

different types of chemical reactions

Question 4

what are regulatory sequences?

Answer 4

stretches of DNA that promote/inhibit protein synthesis

Question 5

what are regulatory proteins used for?

Answer 5

used to assist with the promotion/inhibition of protein synthesis

Question 6

how is transcription controlled?

Answer 6

the interaction of regulatory sequences with regulatory proteins

Question 7

what do epigenetic changes involve?

Answer 7

involve reversible modifications of DNA or histones

Question 8

histones

Answer 8

proteins used to wrap around DNA. slight chemical modifications of DNA and histones cause tight/loose packing of DNA

Question 9

what regulates gene expression?

Answer 9

packing/unpacking DNA

Question 10

do all cells within an organism have the same DNA sequences?

Answer 10

yes, but they do not have the same function

Question 11

how is the phenotype of a cell determined?

Answer 11

by the combination of genes that are expressed

Question 12

what is cell differentiation?

Answer 12

cells within the same organism having different phenotypes

Question 13

transcription factors

Answer 13

proteins that promote/inhibit gene transcription

Question 14

what determines how a cell differentiates?

Answer 14

the presence of various transcription factors

Question 15

what is a result of sequential gene expression?

Answer 15

the process of development from an undifferentiated cell to a differentiated cell

Question 16

what is the difference between differentiated vs undifferentiated cells?

Answer 16

differentiated cells are specialized for certain jobs, undifferentiated cells are not yet specialized (ex. stem cells)

Question 17

operons

Answer 17

closely linked genes that produce a single mRNA molecule during transcription

Question 18

what do operons do and what do they include?

Answer 18

operons are under the control of the same regulatory sequence and they include the genes to be transcribed, the regulatory sequence, and the operator

Question 19

operator

Answer 19

a sequence that either inhibits/promotes transcription by binding with regulatory proteins

Question 20

what happens in the genome?

Answer 20

structural proteins with related functions are encoded together. they are controlled by a single regulatory sequence

Question 21

what are the two operons we discussed?

Answer 21

lac and tryptophan operons

Question 22

how is lactose inducible?

Answer 22

when the regulatory protein is bound to the operator, RNA polymerase cannot bind to the regulatory sequence (needs something to induce it)

Question 23

what happens when lactose is absent?

Answer 23

transcription of genes is inhibited

Question 24

what are inducers?

Answer 24

molecules that can bind to the regulatory protein and cause it to change shape

Question 25

what happens when the inducer binds to the regulatory protein?

Answer 25

the protein changes shape and cannot bind to the operator, allowing transcription to occur