Question

3.1.9-12.g natasha is making a model of cellular respiration. her model shows the pathway followed when there is enough oxygen available. what does natasha’s model show?

an aerobic pathway consisting of glycolysis and fermentation

an anaerobic pathway consisting of glycolysis and fermentation

an aerobic pathway consisting of glycolysis, and the reactions in the mitochondria

Explanation:

1. Recall the definitions of aerobic and anaerobic respiration: Aerobic respiration requires oxygen and occurs in the presence of oxygen, involving glycolysis, the Krebs cycle (in mitochondria), and the electron transport chain (in mitochondria). Anaerobic respiration occurs without oxygen and involves glycolysis followed by fermentation.
2. Analyze each option:

• Option 1: Fermentation is part of anaerobic respiration, not aerobic. So this is incorrect.
• Option 2: The model is for when there is enough oxygen, so it's aerobic, not anaerobic. Also, fermentation is anaerobic, so this is incorrect.
• Option 3: Aerobic respiration (when oxygen is available) includes glycolysis (in the cytoplasm) and then reactions in the mitochondria (Krebs cycle and electron transport chain). This matches the condition of enough oxygen.

Answer:

C. an aerobic pathway consisting of glycolysis, and the reactions in the mitochondria