Module 3 Regulation of Gene Expression at various levels

Question 1

a unit of genetic function common in bacteria and phages;

consists of coordinately-regulated clusters of genes with related functions

Answer 1

OPERON:

Question 2

a specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA

Answer 2

PROMOTER

Question 3

a segment of DNA to which a transcription
factor protein bind

Answer 3

OPERATOR:

Question 4

a gene involved in controlling the expression of
one or more other genes; may encode a protein, or it may work at the level of RNA. In prokaryotes, regulator genes often code for repressor proteins.

Answer 4

REGULATORY GENES

Question 5

protein that physically obstructs the RNA polymerase from
transcribing the genes.

Answer 5

REPRESSOR

Question 6

a gene whose presence prevents the expression of some other gene at a different locus

Answer 6

INHIBITOR

Question 7

a molecule that starts gene expression; can bind to repressors or activators; function by disabling repressors (gene is thus expressed)

Answer 7

INDUCER

Question 8

Transcriptional Control Systems in Prokaryotes

Answer 8

Negative control
Positive control

Question 9

regulatory protein shuts down transcription

Answer 9

negative control

Question 10

regulatory proteins triggers trancription

Answer 10

positive control

Question 11

negative control

a group of genes that are
used, or transcribed, together — that codes for the components for
production of tryptophan; present in many bacteria, but was first
characterized in Escherichia coli.

Answer 11

TRP OPERON (tryptophan operon)

Question 12

an operon required for the
transport and metabolism of lactose in E. coli and some other enteric
bacteria; has three adjacent structural genes: lacZ, lacY, and lacA.

Answer 12

LAC OPERON (lactose operon)

Question 13

T or F

Positive control is also demonstrated by the lac operon.

Answer 13

T

Question 14

CLASSES OF SEQUENCES:

Each producer may have several receptor sites, each responding to one activator so that a single activity
though can recognize several genes. However, different activators
may activate the same gene at different times

Answer 14

. Producer genes or structural genes

Question 15

CLASSES OF SEQUENCES:

one such receptor site is assumed to
be present adjacent to each producer gene or a set of such producer
genes

Answer 15

Receptor site or operator gene

Question 16

CLASSES OF SEQUENCES:

responsible for synthesis of an activator RNA that may or may not give rise to proteins before it activates the receptor site; may also fall in cluster with same sensor
sites.

Answer 16

Integrator gene or regulator gene -

Question 17

CLASSES OF SEQUENCES

regulates activity of integrator gene which can be
transcribed only when the sensor is activated; sensor sites are
recognized by agents which, like hormones and proteins, change the
pattern of gene expression. (ex: hormone-protein complex or a
transcription factor may bind to a sensor site and cause the
transcription of integrator)

Answer 17

Sensor site

Question 18

are DNA sequences that bind to the RNA
polymerase II enzyme. They are binding sites of transcription factors.

Answer 18

PROMOTERS

Question 19

are DNA sequences that, when bound by
transcription factors, enhance the transcription of an associated
gene.

Answer 19

ENHANCERS

Question 20

Addition of 7-methyguanylate to the 5’ end occurs
shortly after the beginning of transcription.

Answer 20

5’ capping

Question 21

After transcription termination, cleavage
and polyadenylation specificity factors (CPSF) bind to a poly(A) signal
sequence, typically AAUAAA, and another protein complex, cleavage
stimulation factor (CStF), interacts with a downstream G/U signal.

Answer 21

3’ polyadenylation

Question 22

he eukaryotic RNA transcript has INTERRUPTED GENES which means that there are alternating introns (non-coding sequences) and exons (coding sequences).

Answer 22

Splicing

Question 23

The cell can select different splice sites by
producing splicing repressor proteins or splicing activator proteins that
bind to alternate splicing sites and therefore, direct the spliceosomes to
different splicing sites or block a site altogether

Answer 23

Alternative Splicing

Question 24

separation of mature rRNA from the primary
transcript (generated by RNA pol I)

Answer 24

Nucleolytic cleavage

Question 25

includes synthesis/regeneration of the CCA sequence
at the 3’ end of tRNA. (For example, modified nucleotides can affect the
way in which a tRNA recognizes different codons.)

Answer 25

Chain extension

Question 26

example: Synthesis of methylated nucleotides
in tRNA or rRNA

Answer 26

Nucleotide modification

Question 27

addition of a phosphate group to specific amino acid
residues on proteins

Answer 27

Phosphorylation

Question 28

addition of a carbohydrate, i.e. a glycosyl donor, to a
hydroxyl or other functional group of another molecule

Answer 28

Glycosylation

Question 29

the addition of ubiquitin to lysine residues of a substrate protein.

‘the kiss of death

Answer 29

Ubiquitination

Question 30

the addition of NO to cysteine residues of proteins

Answer 30

S-Nitrosylation

Question 31

: the addition of methyl groups to proteins

Answer 31

Methylation

Question 32

the addition of an acetyl functional group into a
protein

Answer 32

. N-Terminal Acetylation

Question 33

addition of lipid moieties
to proteins

Answer 33

Lipidation

Question 34

plays a central role in the
modification of protein activity, structure and localization.

Processing of the
inactive proinsulin
to the active
insulin involves
the removal of the
C peptide.

Answer 34

Protein Cleavage