BIO 202 Study Guide - Midterm Guide: Pyruvate Dehydrogenase, Nadh Dehydrogenase, Oxidative Phosphorylation
16 Jun 2018
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Chapter 9: Cellular Respiration
1. Define oxidation and reduction reactions with respect to electron position or localization.
Oxidation: The charge of molecule goes up, meaning it loses an electron.
Reduction: Decrease in charge of molecule, meaning electron gained.
2. Describe the fate of electrons during a catabolic process.
-During a catabolic process electrons are released and accepted by electron carriers.
3. Know where glycolysis and the Krebs cycle occur in a eukaryotic cell.
-Glycolysis occurs in the cytoplasm outside the mitochrondria. For every glucose, net 2 ATP produced. 2 ATP
used, 4 ATP produced.
-Krebs cycle takes place in the mitochondria
4. Know the fate of glucose in glycolysis under aerobic conditions.
-Under aerobic conditions glucose is turned into 2
pyruvate and 2 H2O through glycolysis
-Needs 2 ATP to work, yields 4, net gain is 2 ATP.
Also yields 2 NADH
-During Energy Investment Phase:
1. Using 1 ATP glucose is phosphorylated to
Glucose 6-phosphate by hexokinase.
2. The enzyme phosphoglucoisomerase then
rearranges the molecule into fructose 6-phosphate.
3. Phosphofructokinase then phosphorylates it
turning into Fructose 1,6-biphosphate.
4. This is then split by aldolase to create 1 G3P and
1 DHAP.
5. Isomerase then converts DHAP into G3P which is
immediately used in the next step.
-During the Energy Payoff Phase:
6. 2 phosphate groups are added to the G3P by
Triose phosphate dehydrogenase and 2 NADH are
created by taking two hydrogen from G3P. This
creates 1,3-bisphosphoglycerate.
7. ADP is phosphorylated by taking a phosphate
group off (with help from phosphoglycerokinase)
1,3-bisphosphoglycerate turning it into 3-phospho-
glycerate. This yields 2 ATP
8. Phosphate group is moved by
phosphoglyceromutase making 2-phosphoglycerate.
9. Enolase releases 2H2O by creating a double bond.
10. Unstable phosphate group is removed by
pyruvate kinase to create high energy molecule
pyruvate.
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5. Know the fate of pyruvate under aerobic conditions and where this reaction occurs in eukaryotic cells.
Pyruvate is oxidized by the pyruvate
dehydrogenase complex. This process is
exergonic. Pyruvate goes inside the
mitochondria to proceed to the Krebs cycle,
but first the pyruvate produced from glycolysis
is oxidized into acetyl coA by pyruvate
dehydrogenase. In this process one molecule
of NADH and CO2 is released.
6. Contrast the fate of glucose under aerobic and anaerobic conditions
-Under anaerobic conditions instead of sending pyruvate to mitochondria, it is reused through fermentation.
There are two types:
1. Alcohol: Pyruvate is converted into ethyl alcohol through NADH donating electrons to pyruvate. This frees
NADH by it getting oxidized to NAD+ which allows continuous glycolysis.
2. Lactic Acid: Pyruvate is converted to lactate through NADH donating electrons back to pyruvate to create this
lactate. This allows NADH carriers to be oxidized to NAD+ which allows the carrier to continuously do glycolysis.
7. Describe the role of NAD+ in the oxidation of glucose under anaerobic conditions.
-NAD+ IS and electron acceptor and converts pyruvate into different molecules through reducing it. This allows
NAD+ to cycle back through glycolysis to keep creating some energy.
8. Defie sustrate leel phosphorlatio.
substrate level phosphorylation: A type of phosphorylation in
which the phosphoryl group is transferred from a
donor compound (a phosphorylated reactive intermediate) to
the recipient compound. Ex: ADP into ATP
9. Know the objectives of the Krebs cycle and how it is
regulated.
-The objective of the Krebs cycle is to continuously oxidize and
reduce the Acetyl CoA molecule (formerly glucose) to
ultimately create electron carriers (NADH, FADH2). Each
glucose molecule yields: 6 CO2, 10, NADH, 2FADH2, and 4ATP.
-The Krebs cycle is always on but slows down or speeds up.
This is done NOT BY HORMONES, but by allosteric regulation
(molecule binding to an enzyme that is not active site which
can inhibit or activate the enzyme) and substrate availability (if
acetyl CoA is available)
-Allosteric inhibitors: NADH, ATP (for citrate and isocitrate)
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10. Describe the fate of NADH and FADH2 in the mitochondria.
-NADH and FADH2 are used in the electron transport chain. The electron transport chain is made of four protein
complexes (NADH dehydrogenase, cytochrome bc-1, cytochrome oxidase, and ATP synthase) which get reduced
and oxidized from the electrons brought by NADH and FADH2. These complexes have small messengers:
ubiquinone and cytochrome C.
-The electrons are transferred through each complex all while pumping H+ ions across the concentration
gradient (higher concentration outside). This concentration gradient allows ATP synthase to generate ATP
through pumping the H+ ions from outside to inside.
11. Describe the anatomy of the mitochondria.
-Cristae allow compartmentalization to create
more ATP by creating more surface area for the
electron transport chain.
-ATP synthase is on the inner membrane and the
Krebs cycle occurs in the mitochondrial matrix.
12. Describe the fate of H+ during cellular respiration.
-H+ is used in the electron transport chain to generate ATP through ATP synthase. They are also used to bond
with O2 to form H2O as a product of the ETC.
13. Describe chemiosmosis and what it achieves.
-Chemiosmosis is the process of ions diffusing across a semi permeable from high concentration to low to drive
cellular work. An example of this process is the ATP synthase of the ETC.
14. Describe the function of the mitochondrial ATPase.
-The mitochondrial ATPase: same as ATP synthase.
15. Summarize the integrative functions of glycolysis, Krebs cycle, and ETC (electron transport chain) in protein
and fat catabolism.
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16. Understand how aerobic respiration is regulated.
Chapter 10: Photosynthesis
1. Describe the structure of a chloroplast, and know what thylakoids and stroma are.
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