(SBI4U1) Regulation of Gene Expression

Question 1

What is a gene?

Answer 1

Act as instructions to make proteins

Question 2

What are genes made of?

Answer 2

DNA

Question 3

Human genome contains how many genes that code for proteins?

Answer 3

~35000

Question 4

For a cell to function properly, what must be made at the proper time and place?

Answer 4

Proteins

Question 5

What is the process of turning on a gene to produce RNA and protein called?

Answer 5

Gene expression

Question 6

All _____ control the _________ of proteins using the ___ code

Answer 6

Cells
Synthesis
DNA

Question 7

For gene expression to occur, there must be a mechanism that controls what? (3)

Answer 7

When to make RNA and protein
How much to make
When to stop making it

Question 8

In __________, gene expression can be _________ or ___________ at different points along the ________ _________ _______

Answer 8

Eukaryotes
Inhibited
Accelerated
Protein synthesis pathway

Question 9

Methods of Regulating Gene Expression (Eukaryotes):

What is transcriptional control?

Answer 9

Speed up/slow down rate of transcription (less mRNA = less protein)

Question 10

Methods of Regulating Gene Expression (Eukaryotes):

What is post-transcriptional control? (2)

Answer 10

mRNA may be broken down if protein is not needed

Length of poly-A tail/5’ cap can change (shorter protective caps means mRNA is destroyed faster in cytoplasm)

Question 11

Methods of Regulating Gene Expression (Eukaryotes):

What is post translational control? (2)

Answer 11

Polypeptide may be degraded

Cell may slow down the folding of the polypeptide into a functional protein (if it is not needed right away)

Question 12

Prokaryotes are _____ and lack a true _______; _____________ and ___________ happen nearly ______________

Answer 12

Simple 
Nucleus
Transcription
Translation
Simultaneously

Question 13

Therefore, in prokaryotes protein production is controlled solely by what?

Answer 13

Transcriptional regulation

Question 14

In prokaryotes:

If more protein is needed, what happens?

Answer 14

Transcription occurs

Question 15

In prokaryotes:

If no protein is needed, what happens”

Answer 15

Transcription stops

Question 16

What are operons?

Answer 16

All proteins needed for a specific function (or that are part of the same biochemical pathway) encoded together in blocks

Question 17

What are the 3 important regions of operons?

Answer 17

The coding region
Promoter/Transcription start site
Operator

Question 18

Describe the coding region of the operon

Answer 18

Has codons to build the protein

Question 19

Describe the promoter/transcription start site in the operon

Answer 19

Where transcription starts (TATA box - where RNA polymerase binds)

Question 20

Describe the operator in the operon

Answer 20

DNA region that determines if transcription happens

Question 21

What are the 3 types of molecules that can affect the operon?

Answer 21

Repressors
Activators
Inducers

Question 22

What are repressors?

Answer 22

Proteins that bind to operator regions to block/prevent transcription

Question 23

What are activators?

Answer 23

Proteins that bind to the promoter to increase transcription of a gene

Question 24

What are inducers?

Answer 24

Small molecules that can either activate or repress transcription depending on the needs of the cell