DNA Part 2

Question 1

Where are the control mechanisms in Eukaryotes?

Answer 1

DNA to RNA is a control point5 prime G cap is a control point 3 prime Poly A tail is a control point A splicing reaction to connect exons together and to remove introns, this is a control pointIf we take the messege out of the nucleus is a control point. TRANSCRIPTIONAL CONTROL POINTS If DNA is packaged there is NO TRANSCRIPTION If DNA is mentholated there is NO TRANSCRIPTION

Question 2

What are Histones?

Answer 2

Are proteinA

They package DNA

They are positive - Lysine, Arginine, histidine

Question 3

What is Histone Acytlease?

Answer 3

is going to cover up the positive charges, it also unwinds DNA

Question 4

What do we have to do in order to start transcription?

Answer 4

If we want to start transcription we have to unwind DNA which means we have to cover up the positive charges with Histone Acytlase.

Question 5

Histone acytlase adds an acytle group to the histone, the acytle group then removes the possitive charge

Answer 5

Histone acytlase adds an acytle group to the histone, the acytle group removes the possitive charge

Question 6

Once we cover up the positive charges the TF and the RNA polymerase can start binding to the DNA, they cant do that until we unwind the structure of the DNA.

Answer 6

Once we cover up the positive charges the TF and the RNA polymerase can start binding to the DNA, they cant do that until we unwind the structure of the DNA.

Question 7

What needs to happen in oder for transcription to occur?

Answer 7

we have to unwind the DNA and remove the methol groups

Question 8

What is a promoter?

Answer 8

Is that region of DNA that tells us where transcription is going to occur and it is bound by RNA Polymerase. (it has a fixed location it is always going to occur just upstream of where transcription is going to start where RNA Polymerase

Question 9

What is an Enhancer?

Answer 9

The enhancer does not have a fixed location, it can lie anywhere within the structure of DNA, and the enhancer is not bound by RNA Polymerase. It is bound by activators and inhibitors. It can either turn the process on or off.

Question 10

The enhancer can lie anywhere in the DNA sequence in the linear form, but when DNA is folded the enhancer and the promoter lie side by side, this is going to help RNA Polymerase bind to the promoter site

Answer 10

The enhancer can lie anywhere in the DNA sequence in the linear form, but when DNA is folded the enhancer and the promoter lie side by side, this is going to help RNA Polymerase bind to the promoter site

Question 11

Why are cells different than each other?

Answer 11

Because of the enhancer ,the activators and the inhibitors. Each type of cell will have a different set of activators and inhibitors.

Question 12

If DNA is packaged there will be no transcription, if it is methylated there will be no transcription, we also have to see what activators and inhibitors are present this will determine what genes will be turned off or on.

Answer 12

If DNA is packaged there will be no transcription, if it is methylated there will be no transcription, we also have to see what activators and inhibitors are present this will determine what genes will be turned off or on.

Question 13

Post Transcriptional Control - What do we do to the RNA after we have made RNA,

Answer 13

we add a 5 prime Gcap, we had 3 prime Poly Tail, we add these two so we know when transcription is over, and we have to have this so that we have transportation out of the nucleus and into the cytoplasm and it prevents derogation. We also have to think of the splicing reaction, this is where we connect the exons together and we cut out and throw away the introns.

Question 14

Translational control

Answer 14

Getting the message to a ribosome and having translation occur.

Question 15

Post Translational Control - What happens to the protein after we have made it?

Answer 15

We have to fold it into its correct 3d shape, because when a proteins first comes off the ribosome it is linear, but linear proteins cant do anything it must fold into its complex 3d shape. (example insulin)

Question 16

What is Ubiquitin?

Answer 16

is the protein that marks other proteins for degradation, if a protein is labeled with ubiquitin it will be destroyed.

Question 17

What is the most important control point and which one occurs most often (in Eukaryotes)

Answer 17

Transcriptional Control

Question 18

Silent Mutation

Answer 18

Silent mutation base is exchanged for another, but the same amino acid is interoperated into the protein ( this will never have an effect on the protein)

Question 19

Missense Mutations

Answer 19

Missense mutations one base is exchanged for another resulting in the wrong amino acid being Incorporated into the protein (it may or may not have a problem)

Question 20

Nonsense Mutations

Answer 20

C) Nonsense mutations change in the base results in the appearance of a stop codon so the protein ends pre maturely

Question 21

Frame Shift Mutations

Answer 21

Frame shift mutation happens when you add or subtract one or two bases, this disrupts the triplet codon sequence so you end up with a totally different proteins (this is the worst type this will have a lot of problems)

Question 22

How are frames read?

Answer 22

Frames are read three bases at a time

Question 23

Operon System

Answer 23

this is where we can produce a family of proteins all at the same time that are doing a specific job. This system makes all the enzymes at the same time. This makes the enzymes at the same amount as well.

Question 24

How do we turn these enzymes on or off

Answer 24

with promoters and operators

Question 25

Operator

Answer 25

This is an off and on switch that is bound a repressor (the system is repressed of shut off)

Question 26

Promoter

Answer 26

the site that tell us where transcription is going to occur , and it is bound by RNA Polymerase