METABOLISM EXAM REVIEW

Terms to know

Redox- an electron transfer reaction 

coupled reaction- type of reaction in which 2 reactant molecules are bonded together

Endergonic- a chemical reaction that absorbs free energy the products have more free energy than the reactants 

Exergonic- a chemical reaction that releases free energy the products have less free energy than the reactants

Isomerase- the enzyme that converts DHAP to G3P in glycolysis

Isomers- a molecule that has the same composition as another but a different arrangement of atoms 

Phosphorylated- the transfer of a phosphate group, usually from ATP to another molecule

SLP- the formation of ATP by the direct transfer of a phosphate group from a substrate to ADP

Chemiosmosis- way to make ATP chemiosmosis→ proton pump→ gradient across membrane 

Dehydrogenase- performing enzymes

Decarboxylation- a chemical reaction that removes a carboxyl group to form CO2 

CoA- shuttles to the cac 

Impermeable- can’t pass through the membrane 

Aerobic- must have o2

Anaerobic- organisms that can live without o2 (yeast) 

Facultative anaerobe- can do either aerobic or anaerobic (muscle cells) 

MITOCHONDRIA

1. Draw and label a diagram of the mitochondria. 

its double membraned

same size as bacteria
outer membrane- barrier to mitochandria

cristae- highly folded to higher surface area

matrix- jelly like substance (cytoplasm)

2. Show where each cycle takes place. 

Glycolysis 

• In cytoplasm 

• 10 reactions 

• Convert glucose to pyruvate 

• Every cell uses this pathway 

ETC

• In cristae 

• Converts O2 to H2O 

• Makes 32 ATP

CAC 

• In matrix 

• 10 reactions 

• Make NADH + FADH 

• Cyclic 

Lactic acid fermentation 

• In cytoplasm 

• Muscle cells 

• Anaerobic 

Ethanol fermentation 

• In cytoplasm 

• Yeast cells 

• Anaerobic 

3. What is the endosymbiotic theory?  What evidence supports this theory?

Mitochondria + chloroplasts once existed on their own as bacteria 

Mitochondria are the same size as bacteria 

Have circular DNA  like bacteria 

Double membraned like bacteria 

Believed mitochondria existed on own as bacteria

GLYCOLYSIS

1. Where does glycolysis occur?

Cytoplasm 

2. Is glycolysis considered aerobic or anaerobic?

Anaerobic 

3. What type of cells use glycolysis?

All 

Eukaryotic e.g., animal, plant, fungi, and yeast cells)

Prokaryotic (e.g., bacteria)

4. State the sets of isomers in glycolysis.

Glucose 6 phosphate- fructose 6 phosphate

DHAP-G3P 

3 phosphoglycerate- 2 phosphoglycerate 

5. State the products of glycolysis.

2 pyruvate 

2 H2O 

2 ATP

2 NADH

6. How is ATP made in glycolysis?

Made by SLP reactions 

7. What is a coupled reaction?

transfer of energy from one reaction to another in order to drive the second reaction

8. Know the glycolytic pathway.

CITRIC ACID CYCLE

1. Where does CAC occur?

Matrix of mitochondria

2. What is the main theme of the CAC?

is to oxidize acetyl-CoA to generate high-energy molecules (NADH, FADH₂, and GTP/ATP) for energy production in the cell.

To strip electrons 

3. What is the recycled molecule in the CAC?

Oxaloacetate 

4. What are the products per glucose?

8 NADH 

6 CO2 

2 FADH 

2 ATP 

5. Explain what happens in the oxidation of pyruvate

Decarboxylation, NADH formation, Acetyl-CoA product

6. Know the CAC pathway

7. What is the purpose of NADH and FADH?

NADH- Generate energy- will carry electrons to transport chain use redox reactions to convert 

• These electrons help produce ATP, the cell’s main energy source.

FADH- also carries high-energy electrons to the electron transport chain.

• It comes from the breakdown of food, especially during the citric acid cycle (Krebs cycle).

• Like NADH, it helps generate ATP, but it contributes a bit less energy compared to NADH.

ELECTRON TRANSPORT CHAIN

1. Where does it occur?

Cristae 

2. What are the 2 roles of the ETC?

electron transport

Proton pump 

3. How is ATP made in the ETC - be specific?

4. What are the products of the ETC

12 H2O 32 ATP 

5. What is the final electron acceptor?

Oxygen

6. What will disrupt the ETC?

Cyanide

7. Know the ETC pathway

FERMENTATION

1. What type of cells utilizes each pathway?

Glycolysis- all cells

CAC- eukaryotic

ETC- eukaryotic

lactic- muscle

ethanol- yeast bacteria

2. Know the lactic acid pathway

3. Know the ethanol pathway

in yeast cells

4. What is the purpose of fermentation?

• No O2 

• A different molecule becomes the electron acceptor

• Purpose → regenerate NAD+ to keep glycolysis going 

5. What are the products of each?

Fermentation- ethanol NAD+ 

Lactic acid -lactate NAD+