By what process are LDL particles removed selectively from the blood serum?
A. through targeted digestion by serum lipases
B. by receptor-mediated endocytosis
C. They are replenished with triacylglycerols and never removed.
D. They form atherosclerotic plaques. correct answers by receptor-mediated endocytosis
The sterol regulatory element (SRE) is a(n) __________ and the sterol regulatory element
binding protein (SREBP) is a(n) __________.
allosteric activator; enzyme
transport activator; transport protein
receptor; hormone
DNA promoter; transcription activator correct answers DNA promoter; transcription activator
Nitrogen in biological compounds ultimately comes from what source?
ammonia
nitrate
nitrogen gas
bacteria correct answers nitrogen gas
What is the net reaction of nitrogen assimilation in plants?
Glutamate + ADP + Pi + NADP+ -Ketoglutarate + NH4+ + ATP + NADPH + H+
-Ketoglutarate + NH4+ + ATP + NADPH + H+ Glutamate + ADP + Pi + NADP+
-Ketoglutarate + NH4+ + ADP + NADPH + H+ Glutamate + ATP + Pi + NADP+
-Ketoglutarate + NH4+ + ATP + NADP+ + H+ Glutamate + ADP + Pi + NADPH correct
answers -Ketoglutarate + NH4+ + ATP + NADPH + H+ Glutamate + ADP + Pi + NADP+
How does atmospheric fixation occur given the high energy barrier to convert nitrogen to
nitrogen oxides?
through the oceans that break the triple bond of nitrogen and allow for the combination with
water
through clouds that allow for nitrogen to combine with oxygen
in the soil by bacteria that reduce nitrogen to ammonia
through lightning that breaks the triple bond of nitrogen and allows for the combination with
oxygen correct answers through lightning that breaks the triple bond of nitrogen and allows for
the combination with oxygen
, The Haber process is 98% efficient. How does it achieve that level of efficiency?
low temperatures and atmospheric pressure
low pressures and recycling unreacted nitrogen
high pressures and recycling nitrogen
high pressures and high concentrations of nitrogen correct answers high pressures and recycling
nitrogen
Using nitrogenase to reduce N2 should require 2 ATP to be invested, but it actually takes 16
ATP. Why?
It is harder to break the nitrogen triple bond than expected and requires more energy input.
Extra energy is required to produce H2.
To regenerate the MoFe protein requires the input of ATP.
To keep the nitrogenase complex associated requires an input of 4 ATP. correct answers Extra
energy is required to produce H2.
Because nitrogenase is inhibited by oxygen, under what conditions can the enzyme operate to
reduce N2?
aerobic conditions
anaerobic conditions
high pressure
high temperature correct answers anaerobic conditions
Bacteria in the genus Nitrosomonas are able to oxidize ammonia to what final product?
NO2
NO3
NO4
NO2 correct answers NO2
Both Nitrosomonas and Nitrobacter have a key role in nitrification. Nitrosomonas produces
__________, whereas Nitrobacter produces __________.
ammonia; nitrite
nitrite; nitrate
nitrate; nitrite
nitrite; ammonia correct answers nitrite; nitrate
If plants and bacteria were unable to produce glutamate from ammonia, a possible outcome
would be that plants would