Unit 4: Energy Flashcards
One of the results of the TCA cycle is the ______________?
a) oxidation of NAD+
b) reduction of NAD+
c) oxidation of NADH
d) reduction of NADH
B) reduction of NAD+
During aerobic cellular respiration, the carbons present in pyruvate are initially derived from _______ and are ultimately converted to _______
glucose and CO2
Which reactant molecule becomes reduced in the following chemical equation?
glyceraldehyde 3-phosphate + NAD+ + Pi –> 1,3-diphsophoglycerate + NADH + H+
NAD+
Substrate level phosphorylation…..
a) requires the presence of oxygen as the terminal electron acceptor
b) happens only in the mitochondria, therefore only occurs in eukaryotic cells
c) refers to the enzyme-catalyzed transfer of an activated phosphate group to form a nucleoside triphosphate
d) a and c
e) a b and c
c)
Two ATP molecule are ‘spent’ in the energy investment phase of glycolysis. Why is this energy necessary to begin the process of glucose catabolism?
a) It isn’t ; glucose contains 686 kcal/mol in its chemical bonds, so its catabolism is spontaneous
b) it is needed to generate the electron carrier NAD+
c) it is needed to prime the enzymes of glycolysis
d) some energy must be invested to make glucose more reactive
d) some energy must be invested to make glucose more reactive
What does the enzyme phosphofructokinase catalyze?
phosphorylation of fructose 6-phosphate to form fructose 1,6-biphosphate
What compound is most likely to inhibit the pyruvate dehydrogenase enzyme complex through a mechanism of feedback regulation?
NADH
Fatty acids are catabolized by a process called beta-oxidation. The end-products of the metabolic pathway are acetyl groups of acetyl CoA molecules. Where would these acetyl groups enter the energy pathway?
Citric Acid Cycle / Krebs Cycle
What importance do fermentation reaction give to cells?
Regenerate NAD+
In a chloroplast of a plant cell actively engaged in photosynthesis, you would expect the pH to be?
lower in the thylakoid space than in the stroma
Why does NADH produce more energy than FADH2?
NADH passes its electrons through 3 proton pumps. FADH2 binds to ubiquinone and passes its electrons through only 2 proton pumps
Why does the oxidation of sugar produce less energy than the direct burning of sugar?
Oxidation of sugar it done through a multitude of steps, each having its own activation energies, each losing heat each time
Is NADH in an oxidized or reduced form?
Reduced
Where does the breakdown of glucose into 2 pyruvate molecules occur?
Cytosol
Do all NADH molecules produce the same amount of energy?
NADH molecules produced during the glycolysis stage produce less energy. Because they are made in the cytosol of the cell, they have to be transported over to the mitochondrial membrane to be used in the ETC