7.05  General Biochemistry

Exam 4 and grades

Dear Class,

Exam 4 grades have been posted. The average was a 69 with a standard deviation of 13.7.

The calculation for final grades is as follows:

(best 10 problem set grades)*10/100+(4 exams)*90/400+(extra credit 1 + extra credit 2)=final grade

Where the extra credit 1 and extra credit 2 are the extra credit from the first problem set (0.125 percentage points total) and the CRP/paper extra credit (1.25 percentage points total)

The professors will post the final grades soon.

Have a good summer,
Your TAs

Announced on 25 May 2017  6:29  p.m. by Timothy Jonas Eisen

Exam Location

There seems to be some confusion about the location of the exam. It is at 9 am at Johnson Track in the Z center!

Announced on 22 May 2017  10:49  p.m. by Sonia M Scaria

Exam 4 Review Session Notes (Part 1)

Hi guys,

My notes from the first half of the exam review session are posted!

- Sonia

Announced on 22 May 2017  8:50  p.m. by Sonia M Scaria

Practice Exam 4 Key

Dear Class,

The key for the practice exam has been posted.

Best,
Your TAs.

Announced on 21 May 2017  3:36  p.m. by Timothy Jonas Eisen

Notes from Office Hours

Hey all,

I got lots of questions (thru email and in OH) about the following things so I thought I would snd a short note (sorry for 2 emails today!):

1. PPP vs. Calvin Cycle: Calvin only happens in photosynthetic organisms like plants, because they need to fix carbon using RUBISCO (5C starting backbone + CO2 --> ---> 6C sugar to become stored while also regenerating that 5C starting material. for more on this, please read sections posted in the textbook & lecture notes.) The PPP is different because it happens in cytosol of mammals and in the plastids (mostly, in plants). It is a parallel to glycolysis and is used to generate NADPH and 5C sugars to make ribonucleotides. The reactions In PPP are similar to, but not entirely the same as those in the Calvin cycle. PPP evolved from Calvin cycle, and many of regeneration steps are the same in both pathways. But point is, they are two different pathways. PPP does NOT use RUBISCO to fix carbon, that is something special to plants (Calvin Cycle). *(PPP= pentose phosphate pathway)

2. PLP is used in both transamination and also in 1C metabolism (generating the different oxidation states of 1C units that exist within the folate pool to be donated to R--->R-CH3, for example as occurs in methylation reactions.)
Transamination is simply a reaction that takes an amino acid's Nitrogen group --- donates it to another alpha-keto acid to make that a new amino acid , meanwhile the original amino acid itself becomes deaminated.
Both transamination and 1C met. use PLP in analogous ways, and we drew the mechanisms for these in class.

3. urea Cycle. This is a cycle that can take free nitrogen and also nitrogens from amino acids and make them into urea to be taken out of the body in the form of urea. this is needed because excess N in the body is bad. How the cycle works is that it uses transamination reactions and other reactions to move around Nitrogen groups and get them eventually onto urea, which can be taken out of the body through the kidneys which filter it out (urine). Please note that urea cycle also generates amino acid arginine (part of the cycle) and also uses aspartate.

nothing major, just some points that people seemed to be unsure about, so thought it might be helpful.
Happy Studying!

Announced on 21 May 2017  3:31  p.m. by Kimia Ziadkhanpour