Topic 7-3

Question 1

the process by which a gene creates a “gene product” (ex: proteins, RNA) that have cellular/organismal functions

Answer 1

gene expression

Question 2

mechanisms that have evolved to control gene expression, controlling the flow of information

Answer 2

gene regulation

Question 3

provides the molecular basis for the relationship between genotype and phenotype

Answer 3

gene expression

Question 4

encoding products that interact with other sequences and affect the transcription and translation of these sequences

Answer 4

regulatory genes

Question 5

DNA sequences that are not transcribed but play a role in regulating other nucleotide sequences

Answer 5

regulatory elements

Question 6

encoding proteins

Answer 6

structural genes

Question 7

continuously expressed under normal cellular conditions

Answer 7

constitutive expression

Question 8

in bacteria, gene regulation maintains internal ________, turning genes on and off in response to _________.

Answer 8

flexibility, environmental changes

Question 9

in multicellular eukaryotic organisms, gene regulation also brings about __________.

Answer 9

cell differentiation

Question 10

transcription in bacterial cells is regulated by:

Answer 10

operons

Question 11

is composed of a promoter + additional sequences that control transcription (operator) + structural genes

Answer 11

operon

Question 12

a DNA sequence which encodes products that affect the operon function but are not part of the operon

Answer 12

regulator gene

Question 13

inducible and repressible operons

Answer 13

negative and positive controls

Question 14

list two examples of operons in E.coli

Answer 14

• the lac operon
• the trp operon

Question 15

used classical genetics to uncover the”operon model” of how bacteria regulate genes

Answer 15

Francois Jacob and Jacques Monod

Question 16

operons allow the cell to coordinate:

Answer 16

expression of multiple gene products with one promoter

Question 17

usually, the structural genes in an operon have:

Answer 17

a related function

Question 18

DNA binding proteins that can bind to DNA in the operon to regulate transcription either negatively (repressors) or positively (activators)

Answer 18

regulatory proteins

Question 19

repressors bind operators and blocks RNA pol. and transcription

Answer 19

negative control

Question 20

activator ususally do not bind operators, and frequently bind to promoters and facilitate RNA pol. binding and transcription

Answer 20

positive control

Question 21

proteins that change shape and function upon binding other proteins

Answer 21

allosteric proteins

Question 22

transcription is usually off and needs to be turned on

Answer 22

inducible operon

Question 23

transcription is normally on and needs to be turned off

Answer 23

repressible operons

Question 24

the control at the operator site is negative. molecule binding is to the operator inhibiting transcription. such operson are usually off and need to be turned on.

Answer 24

negative inducible operons

Question 25

a small molecule (allosteric modulator) that turns on transcription

Answer 25

inducer

Question 26

the control at the operator site is negative. but such transcription is usually on and needs to be turned off

Answer 26

negative repressible operons

Question 27

a small molecule (allosteric modulator) that binds to the repressor and makes it capable of binding to the operator to turn off transcription

Answer 27

co-repressor

Question 28

- the inducer is a precursor for enzymes produced by the operon, thus transcription itself leads to more enzymes and effects levels of inducer - feedback system allowsbacteria to adapt to their environment and function more economically - some genes are only made if the precursor/inducer is present (less wasteful production of enzymers) these are characteristics of:

Answer 28

a negative inducible operon

Question 29

- a negative inducible operon - invovled in lactose metabolism - inducer: allolactose these are characteristics of:

Answer 29

the lac operon

Question 30

what is the lac operon repressor encoding gene?

Answer 30

lacI

Question 31

what is the lac operon promoter?

Answer 31

lacP

Question 32

what is the lac operon operator?

Answer 32

lacO

Question 33

what are the encoding beta-galactosidases of the lac operon?

Answer 33

lacZ

Question 34

what is the encoding permease of the lac operon?

Answer 34

lac Y

Question 35

what is the encoding transacetylase of the lac operon?

Answer 35

lacA

Question 36

true or false: the repression of the lac operon completely shuts down transcription

Answer 36

false

Question 37

bacterial cells utilize the lac operon to respond to changing ________ levels in the environment by efficiently switching on and off _________.

Answer 37

glucose/lactose, lactose metabolism

Question 38

what is the preferred energy source for E.coli?

Answer 38

glucose

Question 39

can be used as energy for E.coli if it is broken down via catabolism

Answer 39

lactose

Question 40

catabloizes lactose into galactose into glucose, or into allolactose

Answer 40

beta galactosidase

Question 41

allolactose acts as an _______

Answer 41

inducer

Question 42

an activator protein that binds just upstream of the lac operon promoter and promotes transcription. requires binding to cAMP to bind the DNA

Answer 42

catabolite activator protein (CAP)

Question 43

occurs where in a high concentration fo the catabolite, transcription is repressed

Answer 43

catabolite repression

Question 44

CAP is an example of ________ of an operon

Answer 44

positive control

Question 45

Jacob and Monod used ______ strains of bacteria that contain plasmid F (which would carry a second copy of the lac operon that they could mutatue).with different combinations of mutations in the bacterial genome adn plasmid F, they could determind if mutations had a ________ of ________ effect on lactose metabolism

Answer 45

partial-diploid, dominant, recessive

Question 46

a situation where a gene on a separate piece of DNA affects the transcription of another gene.

Answer 46

trans-acting factor

Question 47

a situation where one gene will affect the transcription of another gene on the same strand of DNA

Answer 47

cis-acting factor

Question 48

lacZ, lacY - mutations affected amounts of beta-galactosidase or permease independently

Answer 48

structural mutations

Question 49

mutations in lacI affect both beta-galactosidase and permease levels

Answer 49

regulator gene mutations

Question 50

some mutations in lacI resulted in lac proteins being produced all the time regardless of lactose levels. this is called a:

Answer 50

constitutive mutant

Question 51

if mutations occured in only one copy of lacI (either plasmid or genome), both lac operons functioned normally. this indicated that the lacI+ gene was:

Answer 51

- dominant over the lacI- gene - lacI was a trans-acting factor (encodes regulatory protein)

Question 52

some constitutive mutations of lac proteins were evident only if the structual genes on the same DNA (plasmid or genome) were not mutated. these mutations were found to be in the _______ and prevent the binding of the regulator protein --> thus are ________ elements. overall this is a ________ mutation.

Answer 52

lacO operator, cis-regulating, operator gene