Exam 1 Review: Chapter 3 Flashcards
how does cellular respiration operate under aerobic and anaerobic conditions? in other words, what is the role of oxygen, and how is ATP produced in its absence?
role: final electron acceptor
how: regenerating NAD+
why is the amount of ATP produced from NADH made in glycolysis not always the same?
short answer: glycerol-phosphate shuttle.
medium answer: NADH –> glycerol 3 phosphate –> FAD –> FADH2 –> coenzyme Q –>located at stage 2 of ETC , which does not pump protons !
long answer: NADH passes its 2e- to dihydroxyacetone-PO4 to make glycerol 3-phosphate; a transporter takes G3P across the outer mitochondrial membrane.
why is it said that triglycerides are built for energy storage?
- no enzymatic activity
- no proteins made
what is the source of gluconeogenesis in normal conditions?
glycogen
what is the source of gluconeogenesis in starvation conditions?
proteins
what are two other sources of gluconeogenesis?
glycerol, lactate
why can’t carbon from fatty acids be used to make glucose in gluconeogenesis?
carbons are lost as CO2, enter TCA as acetyl CoA.
why can’t acetyl CoA be used to make glucose?
large negative delta G to make it in the first place. not favorable to put that much energy back in.
how can protein be used to make glucose?
reverse from carbon skeleton to make AA intermediates for TCA
what sources are used to make acetyl CoA
what happens to all the carbon that enters the TCA cycle as acetyl CoA?
released as CO2
what does the TCA cycle ultimately do?
finishes the oxidation of glucose that was started during glycolysis
what hormone is released in response to low blood glucose and why do you need to maintain blood glucose levels?
glucagon.
glucose and oxygen to the brain…
why is excessive ketone body formation potentially dangerous?
more acetyl CoAs —> form ketone bodies –> extra acidic cause they release protons into the body and pH drops.
what effect would a compound that inhibits PFK have on tumor growth and why?
limits most important regulatory step of glycolysis. back half of glycolysis will not accelerate.
