Download Make It – Break It

MICRB 201: Metabolism Assignment (F06)
Make It – Break It (4 %)
Goal:
Familiarize your self with some examples of how metabolic pathways are used to break down
compounds for energy or reform new metabolites. Recall that catabolic pathway intermediates
may be substrates for biosynthesis, and visa versa.
Objective:
Using catabolic and anabolic pathways make a new compound from another compound, and then
you will break down (oxidize) the new compound formed to CO2 and capture energy as ATP.
The Assignment:
Complete both the Make It and Break It portions for one option (see below). You are
responsible for thinking through all four scenarios, but you are only required to hand in one
option. You may work with others to learn the other three options, and be able to prove to me
that we don’t need to have a quiz.
Make It Portion:
From the indicated starting compound(s) use metabolic pathways to make one molecule of the
indicated compound. For this assignment portion, you can assume that you have all ATP or
NAD(P)H and non-organic substrates (e.g. ammonia) needed for biosynthetic reactions.
Diagram the pathways involved, clearly indicating intermediates used as a pathway exit or entry
points. What is the net energy expenditure in units of ATP and any NADPH.
Make It Options:
i) Glutamine from 2 x alanines
ii) 6C-fatty acid from glucose
iii) Tyrosine from glucose
iv) Aspartate from 4C fatty acid
NOTE: There will be amination and deamination reactions involved for amino acids; you must
include these in your pathway diagrams.
Break It Portion:
Using your new compound and catabolic pathways, determine the number of net ATPs formed
from complete catabolic oxidation of one molecule of your new compound to CO2. List the
pathways used, clearly indicating intermediates used as a pathway exit or entry points. Give the
net yield of NADH or FADH2 and ATP by SLP for each pathway or partial pathway. Recall that
NADPH can reduce NAD+ to NADH. Convert your reduced electron carriers to ATP by
assuming a P/O ratio of 2 for NADH and 1 for FADH2. What is the total net ATP yield?