How many questions are in this quiz?

This quiz has 123 questions focused on cellular respiration and photosynthesis in AP Biology.

No. Every question has 4 options and there is no timer, so you can work at your own pace.

Can I choose the number of questions I answer in one session?

Yes. You can set your preferred question count before starting to fit a quick review or a longer practice run.

What difficulty should I pick for AP Bio prep?

Use easier for pathway order and definitions, and harder for regulation, inhibitors, and data-based questions. Mixed is great for realistic exam-style practice.

What topics are covered within the 123 questions?

You’ll see glycolysis, pyruvate oxidation, the Krebs cycle, the ETC/chemiosmosis, light reactions, the Calvin cycle, and comparisons between the pathways.

AP Biology: cellular respiration and photosynthesis

About this quiz

What you’ll practice

This quiz targets the “energy transformation” backbone of AP Biology, from harvesting light energy to producing ATP through oxidative phosphorylation. Expect questions that test both vocabulary and cause-and-effect reasoning across organelles, enzymes, and gradients.

Each question has 4 options and there’s no timer, so you can slow down to interpret graphs, predict outcomes of inhibitors, and check stoichiometry without rushing.

Difficulty and question settings

Set your preferred question count before you start, then choose a difficulty that fits your goal: easier for recall and pathway order, harder for regulation, experimental design, and data interpretation. The overall mix is balanced so you’ll see a steady rotation of straightforward checks and deeper application items.

Common pitfalls to avoid

Many mistakes come from mixing up where steps occur (cytosol vs mitochondrion; thylakoid vs stroma) or confusing electron carriers and their roles. Another frequent trap is assuming “more oxygen” always means “more ATP,” without considering limiting steps and membrane integrity.

Tips for higher scores

Track locations: matrix, intermembrane space, thylakoid lumen, stroma
Separate inputs/outputs for each stage (ATP, NADH, FADH2, CO2, O2, sugars)
Remember what builds the proton gradient and what spends it (ATP synthase)
Watch for wording about oxidation vs reduction and electron acceptors/donors
Use process-of-elimination on distractors that swap organelles or carriers
For experiment questions, identify the independent variable and the readout first