Answers to Cellular Respiration Worksheet
1. Where does each reaction take place?
- Glycolysis – cytosol
- Fermentation – cytosol
- Acetyl CoA formation – Mitochondria
- Krebs Cycle – Mitochondria (Matrix)
- ETC – Mitochondira (cristae & intermembrane compartment)
2. What goes in/comes out of each reaction/name of each reaction?
- Glycolysis
reactants: Glucose, NAD+, ADP
products: pyruvate, NADH, ATP
- Fermentation
reactants: pyruvate, NADH
products: Lactate, NAD+ OR Ethanol, CO2, NAD+
- Acetyl CoA formation
reactants: pyruvate, CoA, NAD+
products: CO2, NADH, Acetyl CoA
- Krebs Cycle
reactants: Acetyl CoA, NAD+, FAD, H2O
products: CO2, CoA, NADH, FADH2
- ETC
reactants: NADH, FADH2, O2, ADP
products: ATP, H2O
3. What are the electron carriers? Where are the electrons actually located?
- NADH, FADH2, they are nucleic acids, the H-covalent bond contains the
electrons.
4. What are the energy carrying molecules? Where is the energy actually located?
- ATP, a nucleic acid. The energy is between the last two phosphate groups
5. Where is oxygen used? Where’s CO2 released in cellular respiration?
- Oxygen (O2) is used in the electron transport chain. The oxygen atoms
combine with electrons and H+ to form water
- CO2 is released from two reactions of cellular respiration: Formation of
Acetyl CoA and the Krebs Cycle
6. Where is most of the ATP made?
- The Electron Transport Chain along with the H+ transport protein
7. What is the point of fermentation?
- To regenerate NAD+ that is needed for Glycolysis
8. Why does bread have holes?
- As fermentation takes place, the empty pockets are ethanol that has
evaporated
9. How is beer/wine made? What is the live organism that does this?
- Yeast is a fungus that can undergo fermentation if no O2 is present. Sugar
is added (grapes, barley, etc.) and the yeast goes through fermentation,
producing ethanol and CO2
10. Do humans do fermentation? Why?
- Lactic Acid fermentation, when there is a lack of O2 during rigorous
exercise
11. What limits us from doing cellular respiration?
- Amount of O2 that our lungs can carry and deliver to our cells
12. What limits prokaryotes from doing cellular respiration?
- For some, lack of mitochondria. Except if they are prokaryotes that
function themselves as mitochondria, in which case they can do cellular
respiration.
13. How are photosynthesis & cellular respiration related? Which came first?
- If you look at the general reaction for photosynthesis, it’s the opposite of
cellular respiration. Photosynthesis derived first, and as O2 accumulated in
the atmosphere, cellular respiration derived, using the O2