Download SI Worksheet #10 (Chapter 9) BY 123 Meeting 10/8/2015 Chapter 9

SI Worksheet #10 (Chapter 9)
BY 123
Meeting 10/8/2015
Chapter 9:
1. Write the overall reaction for cellular respiration.
2. What is the literal meaning of glycolysis?
Sugar splitting
3. Where in the cell does glycolysis take place?
In the cytosol
4. What is the advantage of glycolysis taking place stepwise?
If energy is released all at once it cannot be harnessed. Organic molecules are broken down in a
series of steps to harness all of the energy.
5. How many ATP are used (changed to ADP) in the first half of glycolysis?
2
6. How many ATP are made from ADP in the second half of glycolysis?
4
7. What is the net gain of ATP in glycolysis?
2
8. How many molecules of pyruvic acid are made from a single molecule of glucose?
2
9. What molecule stores the high-energy electrons (and hydrogen) removed from glucose in
glycolysis?
NADH
1. Glucose Activation
During the first four steps of glycolysis, two phosphate groups are transferred to glucose via
phosphorylation, where ATP is converted to ADP. The end product is fructose 1, 6-bisphosphate.
2. Sugar Splitting
Fructose 1,6-bisphosphate gets split into two fragments, dihydroxyacetone phosphate (DHAP)
and glyceraldehyde 3-phosphate (G3P). DHAP then gets converted into G3P by the enzyme
isomerase.
3. Oxidation
Both molecules of G3P become oxidized using NAD+, which becomes NADH. This process
releases energy which is used to attach phosphates to the sugars, making them 1,3bisphosphoglycerate.
4. Formation of ATP
During the last four steps of glycolysis, the phosphate groups of the molecules are transferred to
ADP by the enzyme phosphoglycerate kinase creating ATP. This is done via the process of
substrate-level-phosphorylation.
10. The three metabolic stages of cellular respiration
1. Glycolysis
2. Citric Acid Cycle
3. Electron Transport Chain and chemiosmosis: oxidative phosphorylation
11. In which of the three stages is most of the cell’s ATP produced? Electron Transport Chain
12. Where in the cell does the citric acid cycle take place? Mitochondria
13. What must happen to pyruvate before entering the citric acid cycle? How does this process
occur? It must be converted into Acetyl CoA. It occurs in 3 steps
i. Pyruvates carbonyl group is given to CO2
ii. Remaining carbon oxidized forming acetate
iii. Coenzyme A attached
14. Where does the oxaloacetate that Acetyl CoA combines with come from? What does this joining
produce? It comes from the previous Citric Acid Cycle. Acetyl CoA + oxaloacetate = citrate
15. What do the next 7 steps of the citric acid cycle do to citrate?
Decomposes citrate back to oxaloacetate. 1 ATP generated per pyruvate. We get 2 pyruvates
from glycolysis so 2 ATP are produced.
16. Fill in the table telling the energy rich molecules and amounts of each energy rich molecule
produced in the citric acid cycle.
Energy Rich Molecule
Number produced
NADH
8
FADH2
2
CO2
6
ATP
2
17. Where is the electron transport chain located in an eukaryotic organism? In a prokaryotic
organism? Eukaryote: mitochondria Prokaryote: plasma membrane
18. How does the structure of the mitochondria allow space for thousands of copies of the electron
transport chain? Folding of the cristae increases surface area allowing space for thousands of
copies of the electron transport chain
19. What are most of the components of the electron transport chain? How do these components
exist within the chain? Most components of the electron transport chain are proteins existing in
multiprotein complexes tightly bound with non-protein prosthetic groups
20. Electron carries alternate between reduced and oxidized states as they accept and donate
electrons. https://www.youtube.com/watch?v=kN5MtqAB_Yc
21. As you move down the electron transport chain, each electron carrier becomes more
electronegative with the most electronegative carrier being oxygen.
22. Electrons are transferred from NADH to the first molecule in the electron transport chain in
complex I.
23. What are cytochromes? Prosthetic groups (heme group), that accept and donate electrons
24. FADH2 adds electrons to complex II first.
25. What is chemiosmosis? The movement of ions across a selectively permeable membrane, down
their electrochemical gradient; relates to the generation of ATP by the movement of hydrogen
ions across a membrane during cellular respiration.
26. What is the structure of ATP synthase?
Part of ATP Synthase: catalytic knob, internal knob, rotor, stator
27. What is the role of ATP synthase in chemiosmosis?
Serve as sites that allow protons to diffuse back across the
membrane
28. Fermentation and anaerobic respiration enables cells to produce
ATP without the use of oxygen.
29. Can organisms living in environments without oxygen have electron
transport chains? If so, how? Yes, their final electron acceptor is
something other than oxygen
30. What are the two type of fermentation discussed in this chapter?
1. Alcoholic Fermentation: pyruvate is converted to
ethanol
a. Co2 released from pyruvate  acetaldehyde
b. Acetaldehyde reduced by NADH to ethanol
2.
Lactic Acid Fermentation: pyruvate reduced directly by NADH to form lactate (no
CO2 produced)
31. What is an obligate anaerobe? Cannot survive in oxygen
32. What is a facultative anaerobe? Can make ATP and survive using fermentation or aerobic
respiration in the presence of oxygen.