Genetic Regulation

Question 1

How do eukaryotes modify their mRNA?

Answer 1

5’ cap
3’ poly-A tail
removal of introns

Question 2

What method(s) do prokaryotes use to control gene expression?

Answer 2

Operons

Question 3

What method(s) do eukaryotes use to control gene expression?

Answer 3

Regulation through Chromatin
Regulation of Transcription
Post-Transcriptional Regulation

Question 4

In prokaryotes, genes are “___” unless turned ___.

In Eukaryotes, genes are “___” unless turned ___.

Answer 4

on/off

off/on

Question 5

What is a promoter?

Answer 5

A “switch” that turns an operon on. It’s where RNA polymerase binds.

Question 6

What is a classic example of a negative operon?

Answer 6

Trp

Question 7

What must be present to repress the lac operon?

Answer 7

Lactose

Question 8

In the lac operon, what does the inducer do?

Answer 8

The inducer binds to the repressor, inactivating it

Question 9

In the lac operon, the ______ is already bound.

Answer 9

repressor

Question 10

What is VDJ recombination?

Answer 10

A method T cells use to recombine multiple alternative exons that are found in the gene in three places (V, D, and J). However, VDJ recombination changes the genome of the cell forever as it changes the actual DNA.

Question 11

What two mechanisms are used to regulate chromatin structure?

Answer 11

Methylation of histone tails

Acetlyation of histone tails

Question 12

What does methylation do? How long is it retained?

Answer 12

It down-regulates

Is maintained after cell division

Question 13

What does acetylation do?

Answer 13

Up regulates

Question 14

In eukaryotes, ______ ________ won’t bind and do transcription unless it is recruited and stabilized by other _____ already bound to the DNA.

Answer 14

RNA polymerase

proteins (promoters)

Question 15

What is a proximal promoter?

Answer 15

Up to 250 bp upstream from gene. Has TATA box as part of the basal promoter.

Question 16

What is a distal promoter?

Answer 16

An enhancer, that is turned on by “activators” that can be far upstream from the gene

Question 17

What is the most important factor in turning eukaryotic genes on?

Answer 17

Proximal control elements

Question 18

How do proximal control elements work?

Answer 18

We aren’t sure how they work – so there’s no picture.

We do know that they bind transcription factors (proteins that help start transcription).

Question 19

What is RNA splicing?

Answer 19

Not using all the exons in mRNA, choosing some and discarding others.

Question 20

What do miRNA do?

Answer 20

MicroRNA (miRNA) molecules bind to the complementary sequences on the target mRNA, either blocking ribosomes from translation, or attracting cellular machinery to destroy that particular mRNA molecule.

Question 21

What do snRNA do? How do scientists use it?

Answer 21

We use snRNA in the lab to silence specific genes. This is vastly easier and faster, in most cases, than making a “knock-out” organism, that has had a specific gene destroyed.

Question 22

What is a proteasome?

Answer 22

Protein complex that destroys proteins

Question 23

What are the three stages of development?

Answer 23

Mitotic cell division
Differentiation of cells
Morphogenesis

Question 24

What is induction?

Answer 24

Once two different types of cells exist (because of cytoplasmic determinants), next to each other, they can send each other signals about how to next develop.

Question 25

What are homeotic genes?

Answer 25

Homeotic genes are responsible for the formation of structures such as legs, wings, and antennae.

Question 26

What two types of things can go wrong in transcription and cause cancer?

Answer 26

1) Making too many signal molecules that tell the cell to divide
2) Not making enough molecules that tell the cell not to divide.