MIDTERM PRACTICE QUESTIONS
The midterm is approaching, and Craig provided us with a number of old midterm exams. I don't know if they will be up on the website, so I will put a FEW COPIES in my mailbox for you to TAKE, LOOK AT AND/OR PHOTOCOPY, AND BRING BACK (so that others can see have access to them).
My mailbox is located in the biosci (biology) building, outside the zoology office, opposite room 2361. Look below the tag with my lastname (Kalas) on Friday.
Happy studying!
Pam
Quick facts and a couple of practice questions on techniques can be found here
posted by pam39 @ 1:44 PM
13 Comments:
Thanks Pam! You're the best!
Pam, is it possible for you to go over the posted-practice midterm, either during tutorial or other time? Thanks!
we can do that. I'll be posting some info, Q&A that came up, and hints to solve those questions after Tuesday's tutorial.
Cheers!
Pam
Question:
When do you know which type of blot to use? (southern, northern) Does it matter?
Thanks
Oh yes, which type of blot to use DOES matter!
(you can find some info under the link "techniques, chapter 11 and 12 stuff").
In a Southern blot you run restriction digested DNA on a gel, blot it on a membrane, and probe it. What you are detecting is a DNA molecule that has a very high sequence identity with your probe.
In a northern blot you run RNA on the gel (your probe is still DNA, but you will detect an RNA that hybridizes to your probe).
Southerns give you information about DNA, northerns about RNA. For example, if you do a Southern using DNA extracted from bacteria growing under condition A, and then under condition B, you won't see any differences because the bacteria's DNA does not change depending on growing conditions.
However, if you do a northern, you may see differences, because different RNAs are produced (different genes are expressed) under different conditions.
In western blots you run proteins on a gel, blot on a membrane, and probe with an antibody to your protein of interest.
Hope this helps
Cheers
Pam
hey Pam,
You told our tutorial that you'll have more office hours on Thursday 4-6 but unfortunately I can't make it due to work commitments. Can I meet with you to discuss some questions on Wednesday afternoon instead?
Thanks,
Ada
HELP!!!! I don't understand this restriction mapping at all!!! Am I the only one??? HELP!!!
no...youre not the only one..but just try re-reading the notes again..and do the textbook questions...they are a great start and might help you understand a bit more.
Ada, Wed pm does not work for me, but Thu or Fri am would be OK.
Restriction mapping, here's a start:
- start by looking at the results of cutting/digestions with each single enzyme. This tells you how far apart the sites recognized by each enzyme are.
- look at a digestion with 2 enzymes and compare to each of the 2 single enzymes. Any 'sizes' in common?
A more complete explanation will be posted on Tue night.
Goodnight!
Pam
By 'overlaps' I mean, bands that have the same size. For example, if with enzyme A you got a band that is 7kb, one that is 4kb and one at 1 kb, and with enzymes A+B you get 3kb, 1.5kb, 2.5 kb, 0.8kb, 0.2 kb and 4 kb...well, the 4 kb band is in common between the 2 samples, so it's very likely that there are 2 restriction sites for enzyme A that are 4kb apart, and no sites for enzyme B are within this 4kb region.
If you have partiaal maps (one for digestion with A, one for digestion with A+B), try to 'superimpose them' so that all sites for enzyme A correspond exactly to sites in the double digest. At this point you can 'assign' these sites, in the double digest, to enzyme A. So, the remianing sites must be sites for enzyme B
Hi Pam
I just checked your box today, and I dont' see any more of the photocopies. :( Do you have any more copies I can grab to photocopy?
I think people are not returning them and just taking them :(
leave your e-mail adress and one of us can send you a scanned copy that Belinda was kind enough to send us:)
The email addresses are listed under "Extra Help Session(s)" comments. Thanks again! I really don't want to bomb this midterm!!!
Post a Comment
<< Home