Lec 7-3

Question 1

Gene expression

Answer 1

Process by which a gene creates a gene product that has some kind of cellular/organismal function

Question 2

Gene regulation

Answer 2

Types of mechanisms that control the flow of information

Question 3

Gene regulation responds to

Answer 3

The environment

Question 4

Bacteria gene regulation

Answer 4

Gene regulation maintains internal flexibility, turning genes on and off in response to environmental changes

Question 5

Multicellular eukaryotic organisms

Answer 5

Gene regulation also brings about cell differentiation

Question 6

Structural genes

Answer 6

Encode proteins used in metabolism, biosynthesis, or structural roles in the cell

Not involved in gene regulation

Question 7

Regulatory genes

Answer 7

Encode products that interact with DNA sequences and regulate transcription

RNA or proteins

Often regulatory genes are DNA binding proteins

Can regulate in a positive or negative way

Question 8

Housekeeping genes

Answer 8

Constitutive genes are not regulated and continually transcribed

Question 9

Constitutive expression

Answer 9

Always on

Question 10

Regulatory expression

Answer 10

Gene will only transcribe depending on the environment

Question 11

Regulatory elements

Answer 11

Affect the expression of DNA sequences (genes) they are physically linked to the gene

They are not transcribed

Question 12

Positive control

Answer 12

Regulatory genes acts as an activator and increases transcription

Question 13

Negative control

Answer 13

Regulatory genes acts as a repressor and blocks transcription

Question 14

Transcription is regulated by

Answer 14

Operons

Question 15

Francois Jacob and Jacques Monod

Answer 15

Used classical genetics to uncover the “Operon Model” of how bacteria regulate genes

Question 16

Operon

Answer 16

Multiple genes clustered together under control of a single promoter

Single mRNA but translated into multiple proteins

Question 17

Operon advantage

Answer 17

Allows the cell to coordinate expression of multiple gene products with on promoter

Question 18

Operons are controlled by

Answer 18

Regulatory genes

They can be distant and not physically linked to the operon to control it

Question 19

Negative control on operons

Answer 19

Repressors bind to operators (partially overlap the promoter or beginning of first gene)

Physically blocks RNA polymerase from proceeding with transcription

Question 20

Allosteric proteins

Answer 20

Proteins that change shape and function when binding to another protein or molecule

Question 21

Small molecule that binds to allosteric proteins is called a

Answer 21

Ligand

Question 22

Inducible operon

Answer 22

Ligand increasing operon transcription

Question 23

Repressible operon

Answer 23

Ligand decreasing operon transcription

Question 24

Negative inducible operon

Operon is negative because

Answer 24

Regulator protein inhibits transcription when bound

Ligand causes increased transcription and is called the inducer

Inducer inhibits the function of the repressor

Question 25

Negative repressible operons

Answer 25

Operon is negative because regulator protein inhibits transcription when bound

Ligand causes decreased transcription and is called a co-repressor.

Co-repressor is required for repressor protein function

Question 26

Operons can also be regulated by their

Answer 26

Own products

Inducer is precursor for enzymes produced by the operon, thus transcription itself leads to more enzymes and thus effects levels of inducer

This feedback system allows bacteria to adapt to their environment and function more economically

Question 27

Lactose overview

Answer 27

Glucose preferred energy source for E.coli

Lactose can also be used as energy if broken down by B-Galactosidase, through catabolism, where on of the products is glucose

Question 28

Lac Operon

Answer 28

Used to respond to changing glucose/lactose levels in the environment by efficiently switching on and off lactose metabolism

Question 29

lac Operon structural genes

Answer 29

lacZ- B-Galactosidase
lacY-Permease
lacA- (dont need to know

Question 30

lac regulatory gene

Answer 30

lacl-repressor

It is a repressor putting Lac operon under negative control

Question 31

B-Galactosidase breaks down

Answer 31

Lactose into galactose and glucose

Question 32

Low glucose leads to

Answer 32

High cAMP

Cell responds to low glucose by increasing energy metabolism of lactose

Question 33

Jacob and Monod

Answer 33

Used mutational analysis of a partial-diploid strain of bacteria that contains a F plasmid

Question 34

F plasmid

Answer 34

Contains lac operon that they could mutate