Ua, Microbiology For Engineers, Exam2, Lecture 19 (Incomplete)

Front 1

How would one regulate gene activity (5 types):

Back 1

Regulate Transcription (synthesis of mRNA)
Regulate Translation (synthesis of proteins)
Regulate Post-translational modifications
Regulate Enzyme activity
Regulate how much enzyme is degraded

Hint 1

How much enzyme is produced
How much enzyme is modified
How active the enzyme is
How much enzyme is degraded

Front 2

Allostery (Describe enzyme and what it does):

Back 2

An enzyme that binds to inhibitor (allosteric site)

Hint 2

Causes conformation of enzyme whose new shape at no longer allows substrate binding

Front 3

What happens when an corepressor is bound to a repressor?

Back 3

When corepressor is bound –modifies repressor.
RNA polymerase path is blocked halting transcription

Front 4

What happens when an inducer is bound to a repressor?

Back 4

When inducer is bound -modifies repressor.
RNA polymerase path is unblocked allowing transcription

Front 5

Housekeeping Genes:

Back 5

Genes required in virtually all cells at all times

Front 6

Constitutive gene expression (Describe how often they are expressed and what 'kind' of genes should these be grouped in):

Back 6

Always expressed at all times (not regulated)

Front 7

Describe Regulated Gene Expression:

Back 7

Gene expression rises and falls as needed

Front 8

Repressible gene expression:

Back 8

Expression is dampened-off in response to a signal

Front 9

Inducible gene expression:

Back 9

Expressed in response to a signal

Front 10

What is the Promotor and how can the Promotor effect expression (Name two means):

Back 10

Regulation can be effected by changing the interactions of RNA polymerase
Frequency of gene transcription can be changed by variable promotor nucleotide sequence

Hint 10

Promotor: site where RNA polymerase binds.

Front 11

Name the two types of regulatory proteins:

Back 11

Activators: proteins that enhance interaction RNA polymerase with promoter

Hint 11

Repressors:impede access RNA polymerase to promoter

Front 12

What is the operator?

Back 12

Region on DNA nearby promoter where repressors bind

Front 13

Name the two effectors:

Back 13

Inducer: substance that increase enzyme production (Positive)

Hint 13

Corepressor:substance that decreases enzyme production (Negative)

Front 14

Describe negative and positive regulation:

Back 14

Positive facilitates transcription

Hint 14

Negative inhibits transcription

Front 15

What are operons?

Back 15

Multiple genes transcribed together with a single promoter

Hint 15

Are polycistronic and regulated together

Front 16

Name three genes involved in lactose metabolism (Lac Operon), and describe what do they do:

Back 16

galactoside permease (Y): transport lactose into cell
β-galactosidase (Z): cleaves lactose into galactose and glucose
thiogalactosidetransacetylase(A): no known physiological function

Front 17

Name three lac operon inducers:

Back 17

Lactose (via its isomer Allolactase)
Isopropylthiogalactoside(IPTG)

Front 18

Name a lac operon repressor:

Back 18

glucose

Front 19

Is repression absolute?

Back 19

No, some transcription will always occur

Front 20

What is Cyclic adenosine monophosphate's (cAMP) role in repression or inducement of lactose:

Back 20

Accumulates when glucose is low (formed from hydrolysis of ATP and ADP)

Hint 20

Biochemical indicator of “low energy reserves”

Front 21

What is a catabolite activator protein:

Back 21

An allosteric protein that binds to DNA which enables binding of RNA polymerase to promoter

Hint 21

Only binds to DNA if an inducer is bound to the protein

Front 22

What does a cAMPReceptor Protein (CRP) do:

Back 22

CRP binds to site on DNA near lac promoter and stimulates transciption 50-fold (Binds best when cAMP is high)

Hint 22

Helps anchor the RNA polymerase onto promoter site