Download Document

Lecture 23
Web: pollev.com/ucibio
Text: To: 37607
Type in: 169964 <your question>
Nitrogen metabolism
How does nitrogen enter/exit?
Carbon skeleton source/fate?
Regulation?
Amino acid catabolism - overview
Transfer of Nitrogen to common “carrier”
Two “carriers”
Getting rid of nitrogen…
…as urea
Metabolic compartments
Like the Urea cycle which of the following also
occurs across two cellular compartments?
A. TCA
B. Glycolysis
C. Gluconeogeneis
D. Light reactions of photosynthesis
E. Beta-oxidation of fats
Metabolism is interconnected
Dealing with the C-skeletons
“Glucogenic”?
No net conversion of C from fats  Glc. Why
then, are amino acids “Glucogenic”?
A. Misnomer; they are not
B. They use glyoxalate pathway
C. They make ketone bodies from Glc
D. Enter TCA after loss of C as CO2
E. What is glucogenic?
Diseases
Fixing N2
N2 fixation is energy intensive
Nitrogen fixation
Considering the importance of N2 fixation, do
you think Nitrogenase evolved early or late?
A. Early
B. Late
C. I’m clicking this like a zombie. I don’t
think in class
Nitrogen fixation
Then what might be one problem for Nitrogenase
A. Carbon monoxide
B. Carbon dioxide
C. Oxygen
D. Water vapor
E. Temperature
Legumes & nodules
Symbiosis
Fixing nitrogen
Theoretically, why can’t we develop human
symbionts for N2 fixation?
A. No reason at all; we could!
B. Bacteria would kill us
C. Humans are aerobic
D. We don’t have enough carbohydrates
E. Excess NH3 – BO, dude!