Lecture 16

Question 1

Transcriptional Regulation

Answer 1

the change in gene expression levels by altering transcription rates

Question 2

Operon

Answer 2

Multiple genes made as one mRNA from a single control region. Each gene in the operon has its own Shine-Dalgarno sequence

Question 3

Promoter

Answer 3

a region of DNA that initiates transcription of a particular gene.

Question 4

Control Protein

Answer 4

Controls whether or not the mRNA can be transcribed. Turns the genes on or off

Question 5

Negative Control

Answer 5

Prevents mRNA synthesis when binded

Question 6

Operator

Answer 6

The binding site of the protein regulators

Question 7

Repressor Protein

Answer 7

Binds downstream(after) the promoter. When binding it prevents mRNA synthesis

Question 8

Positive Control

Answer 8

Allows mRNA synthesis when binded

Question 9

Activator Protein

Answer 9

Binds upstream(before) the promoter. When binding it allows mRNA synthesis

Question 10

Environmental signal

Answer 10

How the genes turn on or off with the environment. Proteins bind to the Repressor or Activator Protein to change what it does

Question 11

Inducer

Answer 11

Can bind to repressor proteins and block the operator and mRNA is made

Question 12

Induction

Answer 12

Small molecule or environmental signal that turns the gene on, without it the gene is off

Question 13

Inducible

Answer 13

mRNA is not produced by default(repressor protein), but can be turned on by certain conditions

Question 14

Co-Repressor

Answer 14

It is a defect in the protein to make it not be able to bind, so a co-repressor comes in and fills the gap so it can bind

Question 15

Repression

Answer 15

A small molecule or environment signal that turns the gene off. Without it the gene is turned on

Question 16

Repressible

Answer 16

mRNA is produced by default(activator protein) but can be turned off by certain conditions

Question 17

Lac Repressor

Answer 17

Allows the bacterium to respond to the environmental presence of lactose and glucose. If lactose is present the bacterium wants to break it down to get energy, but if it isn’t it is wasteful to transcribe and translate the genes the cell would use in its catabolism. If glucose is present the cell will shut off lactose catabolism until it runs out of glucose

Question 18

Negative Control with Induction

Answer 18

Lactose is not present, it is wasteful to transcribe and translate the genes that cell would use in its catabolism

Question 19

Catabolite Activator Protein

Answer 19

a regulatory protein in bacteria. CRP protein binds cAMP, which causes a conformational change that allows CRP to bind tightly to a specific DNA site in the promoters of the genes it controls

Question 20

cAMP

Answer 20

When cAMP goes up Glucose goes down. Senses the absence of glucose

Question 21

Positive Control with Induction

Answer 21

if glucose is present if it more efficient to use glucose, so the cell will shut off lactose catabolism until it has run out of glucose

Question 22

Two Component Regulatory System

Answer 22

Sensor kinase and response regulator

Question 23

Sensory Kinase

Answer 23

senses the environment

Question 24

Response Regulator

Answer 24

Usually an activator protein that regulates the cell’s response to the environment

Question 25

Quorum Sensing

Answer 25

More bacteria = higher concentration of Quorums

Question 26

Homoserine Lactone (HSL)

Answer 26

a class of signaling molecules involved in bacterial quorum sensing. Quorum sensing is a method of communication between bacteria that enables the coordination of group-based behavior based on population density.

Question 27

Cassette Switching

Answer 27

a manipulable fragment of DNA carrying, and capable of expressing, one or more genes of interest between one or more sets of restriction sites. It can be transferred from one DNA sequence (usually on a vector) to another by ‘cutting’ the fragment out using restriction enzymes and ‘pasting’ it back into the new context.

Question 28

Silent (cryptic) gene

Answer 28

Don’t have promoters

Question 29

Expressed Gene

Answer 29

The full use of the information in a gene via transcription and translation leading to production of a protein and hence the appearance of the phenotype determined by that gene.