1. Glycolysis & Kreb’s Cycle
Cellular Respiration Lecture 2

2. Cellular Respiration Overview Review
What are the major reactants of cellular respiration?
What are the major products of cellular respiration?
In what organelle in eukaryotes does cellular respiration occur?

3. Match the following names to the structures:
Mitochondrial matrix
Inner membrane space
Inner Membrane
Outer Membrane

4. The first step in cellular respiration
= _______________
happens in the ________________
outside the mitochondria
occurs _________________________
GLYCOLYSIS
CYTOPLASM
with or without oxygen

5. Glycolysis
Requires ____________to get it started.
ENERGY

6. Evolutionary Significance
Most widespread metabolic pathway
ancient prokaryotes probably used glycolysis to make ATP before oxygen was present
Glycolysis happens in cytoplasm
Evidence:
Earliest fossil bacteria present 3.5 billion years ago
large amounts of oxygen not present until 2.7 billion years ago
eukaryotes appeared 1 billion years after prokaryotes (Endosymbiotic theory)

7. SUBSTRATE LEVEL PHOSPHORYLATION
= creating ATP from removing a phosphate
from the substrate and adding it directly to ADP
MITOCHONDRION

8. Redox Reactions Oxidation is loss of electrons
Glucose is oxidized
Reduction is gain of electrons
NAD+ is reduced to NADH
Used as an electron carrying molecule to store energy until later steps

9. Glycolysis
What are the reactants?
What are the products?

10. PYRUVIC ACID MOVES TO NEXT STEP
IF THERE IS NO OXYGEN (______________)
IF THERE IS OXYGEN (_____________)
= ANAEROBIC
= AEROBIC

11. Pyruvate is transported into mitochondrion and Acetyl CoA produced
For each pyruvate converted into acetyl CoA
1 molecule of CO2 is released;
NAD+ ---> NADH;
Coenzyme A (from B vitamin)

12. Kreb’s Cycle = Citric Acid Cycle occurs in mitochondrial matrix
OAA
CITRIC ACID
Reactants?
Products?

13. Kreb’s Cycle 2 C atoms from pyruvate → exit as CO2
For each pyruvate that enters:
2 CO2 released 3 NAD+ reduced to 3 NADH; 1 FAD+ reduced to 1 FADH (riboflavin, B vitamin); 1 ATP molecule