Gene regulation

Question 1

inducer

Answer 1

small effector molecule that causes transcription to increase in inducible genes

Question 2

repressible genes

Answer 2

genes affected by corepressors binding to repressor proteins and inhibitors binding to activator proteins and blocking them from DNA

Question 3

operon

Answer 3

a group of two or more genes under the transcriptional control of a single promoter

Question 4

polycistronic mRNA

Answer 4

contains the coding sequence for two or more structural genes

Question 5

operator

Answer 5

sequence of bases that provides a binding site for a repressor protein

Question 6

bacteria attenuation

Answer 6

a sequence is added to the DNA and mRNA is stopped so that the protein being made is not completed

Question 7

catabolic enzymes

Answer 7

enzymes used to break down macromolecules are usually inducible operons turned on by the substance

Question 8

anabolic enzymes

Answer 8

enzymes used to produce macromolecules are usually repressor operons turned off by the product

Question 9

allosteric enzyme

Answer 9

enzyme that contains two different binding sites with a regulatory and catalytic site

Question 10

bacteriophage

Answer 10

viruses that infect bacteria

Question 11

lysogenic phage

Answer 11

acting as temperate phage that integrates its genetic material into bacterial chromosome

Question 12

lytic phage

Answer 12

increases the copies of the virus and lyses that bacteria

Question 13

prophage

Answer 13

the integrated phage DNA into bacteria chromosome

Question 14

general transcription factors

Answer 14

required for the binding of RNA polymerase to the core promoter

Question 15

homodimer

Answer 15

two identical transcription factor proteins or other molecules that come together

Question 16

heterodimer

Answer 16

two different transcription factor proteins or other molecules that come together

Question 17

bidirectional regulatory element

Answer 17

can bind to DNA in the forward or reverse direction

Question 18

transcription factor

Answer 18

proteins that influence the ability of RNA polymerase to transcribe a given gene

Question 19

control elements

Answer 19

DNA sequence located near the core promoter; acted on by regulatory transcription factors; enhancer-silencer sequence

Question 20

transcriptional activators

Answer 20

recruit chromatin remodeling enzymes: ATP dependent chromatin remodeling/histone modification by histone acetyltransferase

Question 21

CpG islands

Answer 21

unmethylated islands are located near promoters of active genes and methylated are near suppressed genes

Question 22

housekeeping genes

Answer 22

encode proteins required and expressed in most cells of multicellular organisms

Question 23

alternative splicing

Answer 23

some pre-mRNAs can have exons spliced to produce dozens of different mRNAs

Question 24

constitutive exons

Answer 24

encode polypeptide segments of acertain protein necessary for general structure

Question 25

alternative exons

Answer 25

encode polypeptide segments of a certain protein that change the function for specific cells

Question 26

splicing factors

Answer 26

exon modulation by repressing or enhancing a specific exons

Question 27

poly A binding protein

Answer 27

binds to the poly A tail; the poly A tail is lossed and exonucleases digest without a binding protein

Question 28

3’ untranslated region

Answer 28

located between the stop codon and the polyA tail

Question 29

AU rich element

Answer 29

ARE; this is a destabalizing element which attracts proteins the rapidly degrades the mRNA

Question 30

pre-miRNA

Answer 30

forms a hairpin structure that is cut by the endonuclease dicer forming double stranded RNA

Question 31

RISC

Answer 31

RNA-induced silencing complex; one of the RNA strands combines with RISC and will degrade the complimentary mRNA strand