Houston -we have a problem...HELP!!! Krebs cycle, metabolic pathways, glycolysis....

Fugitive · Nov 6, 2005

So really dummied down...

In glycolysis glucose is converted into 2 molecules of pyruvate. ATP (net 2) and NADH are also formed.

The following is within the mitochondria:

Through anaerobic respiration, pyruvate is either converted into lactate or ethanol.

Through aerobic respiration, pyruvate in converted into acetyl-Coenzyme A.

Acetyl-CoA enters the Krebs Cycle (the citric acid cycle). It goes through a series of 9 reactions. The first reaction combines acetyl-CoA with oxaloacetate. After the nineth reaction, the end product is oxaloacetate. This will then combine with acetyl-CoA to start the cycle over again. NADH and FADH2 are formed at different points in the cycle.

NADH and FADH2 are electron carriers. They deposit their electrons (the hydrogen) into the electron transport chain.

The electrons travel through the chain carried by cytochrome and quinone which are electron carriers.

The electrons, while travelling through the chain, lend their energy to a series of proton pumps. The proton pumps take H+ (proton) out of the matrix and into the intermembrane space creating a gradient.

H+ wants to diffuse (high to low) back into the matrix. Chemiosmosis takes place when an ATPase pumps H+ back into the matrix while simultaneously combining ADP with a phosphate to create ATP.

The low energy electrons exit the chain and combine with oxygen to form water. The theoretical yield of the electron transport chain in 36 ATP.

The is very basic. I hope you understand it. You'll have to use your textbook to fill in the details. You should find out what reactions occur. Also know what products are formed and how much is formed.

Here's something even more simple:

Glycolysis: Glucose -> Pyruvate

Anaerobic Respiration: Pyruvate -> Lactate or Ethanol

Aerobic Respiration: Pyruvate -> Acetyl-CoA -> Kreb's Cycle -> Electron Transport Chain

Good luck!

karmyk · Nov 6, 2005

What may help is actually drawing out what happens step-by-step WHILE explaining to yourself what happens at each step... I remember being confused initially when I first read it in the book, but when I decided to draw out the entire process and try to understand it all, one baby step at a time, it finally made sense to me... it forces you to slow down and allow the information to kind of seep in at a comfortable rate.

Then make note of the primary reactants and products/results of each major reaction (i.e. circle with another color.. or whatever will help it stick out or become emphasized).

Not sure if that will help.. but it really helped me.

onehusbandsevenkids · Nov 6, 2005

Thanks for the help Fugitive & Karmyk!

This exam covers Skeleton, Joints (and diseases & treaments), and Metabolism, I'm a bit overwhelmed but praying I can somehow pass this!!!

Thanks God it all multiple choice, if the lab exam I failed was multiple choice instead of 90% complete fill in the blank, I would have done much better.

So, maybe I have a chance...

**canoehead, BSN, RN** · Nov 6, 2005

I also had the same trouble you did, and although we were told we would have to reproduce the Kreb's cycle on paper the questions were limited to what goes in-"Kreb's cycle"-what comes out. No fancy explaining.

I gotta reassure you; as a nurse you don't have to actually perform the Kreb's cycle, just know it exists. I've been a nurse 16 years and only once heard the word Kreb outside a classroom.

stpauligirl · Nov 6, 2005

I've been having some serious depression and personal problems that past few weeks and hardly studied at all for my latest lab exam in A&P I. First lab exam I got a 96. However the lab exam we took a few days ago was TERRIBLE. The hardest on one of the course we were told...connective tissues, skeleton, joints, articulations, ect....anyhow I'm sure that I failed it -just dont know how badly.
I'm really mad at myself because IF I HAD STUDIED - I would have passed no problem.
Anyhow, We have a lecture exam coming up on Tuesday....alot of the same material plus the integumentary system and krebs, metabolic stuff, glycolysis.
For some reason I can not make my brain understand any of this biochemistry stuff. Its a mental block. I'm terrible at anything chemistry related and I know I need a tutor to back up with me and explain it from the beginning but at this point in time its only a few days from this next exam and I don't have time for that now.
Here it is late Saturday night and I'm still clueless.
So....I HAVE to pass this lecture exam to pass the course.
I've already been accepted into the nursing program and it all hinges on passing this course. If I don't pass with at least a "C" (ugh...I am NOT a C student) I lose my seat for the January class.
Can anyone help me to understand glycolysis, metabolism and the Krebs cycle?
I've even googled it several times and I still can't get it. I need it in simple, super-dummy terms. Just the facts, step by step.
Our instructor assumes that we have some basic understanding of alot of things in this course....I've been out of school almost 20 years - I have NO understanding! LOL
If you understand these subjects and could help a very dense person out here, I would be sooooooooo thankful.
I've got to pass this exam, no if, ands, or butts about it.
Its a "do or die" situation.
We're now starting nerves and muscles and I'm still drowning in this other stuff.

I am sorry to hear that you have a difficult time. I believe that Chem and Biochem need to be a prereq for A&P. but it's the same at our school. You don't need any Chem to take A&P and as a result too many people run into trouble. I am sorry that I can't be of help to you, I understand your frustration.

missninaRN · Nov 6, 2005

I don't have any new advice for you, but just felt so bad to hear that you are having a rough time. I am so sorry that you are suffering right now.