Cellular respiration: the equation and its three stages
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
“model, not to scale” Ari reads a diagram of one stage of breaking down glucose. In box A, 1 glucose is split into 2 pyruvate. Where in the cell does stage A happen?
- In the nucleus
- In the mitochondrial matrix
- On the inner mitochondrial membrane
- In the cytoplasm
Flow diagram (model, not to scale), drawn across a cell with one mitochondrion. No wavy arrow label is drawn. Bo reads a diagram of the citric acid cycle. In box B, an acetyl group joins a four-carbon molecule and CO2 is released. Where does stage B happen?
- On the inner mitochondrial membrane
- In the mitochondrial matrix
- On a ribosome next to the nucleus
- In the cytoplasm outside the mitochondrion
Read this first
Use this
Flow diagram (model, not to scale), drawn across a cell with one mitochondrion. Inputs in boxes on the left: electrons from NADH; oxygen. Outputs in boxes on the right: water. Box C is the chain of proteins. A wavy arrow points out: energy used to make ATP.
Esme reads that oxygen is used at box C, a chain of proteins that passes electrons along. Where is this electron transport chain found?
- In the cytoplasm outside the mitochondrion
- On the inner mitochondrial membrane
- In a vacuole near the cell membrane
- In the matrix inside the mitochondrion
Equation card, from OpenStax Biology 2e
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy. Inputs in boxes on the left: glucose, C6H12O6; oxygen, 6O2. Outputs in boxes on the right: carbon dioxide, 6CO2; water, 6H2O. A wavy arrow points out: energy.
Kira reads the respiration equation. How many oxygen molecules, O2, does the equation use for each glucose?
- 12, the count of oxygen atoms instead
- 2, the small number after the O
- 6, the large number in front of the O2
- 1, the same count as the glucose
Flow diagram (model, not to scale), drawn on the inner membrane of a mitochondrion. Luz follows oxygen to the last stage. Oxygen picks up electrons and hydrogen ions at the end of the chain. What product forms in box D?
- Carbon dioxide, CO2
- Pyruvate, from glycolysis
- Water, H2O
- Glucose, C6H12O6
Glycolysis ATP count (real data, from OpenStax Biology 2e)
measure ATP per glucose ATP spent 2 ATP made 4 Noah reads that glycolysis spends 2 ATP and makes 4 ATP from one glucose. Which phrase describes the ATP glycolysis adds for the cell?
- ATP made by the electron transport chain
- A small net gain of 2 ATP per glucose
- A net gain of 4 ATP, with nothing spent
- Most of the ATP made from one glucose
Use this
Flow diagram (model, not to scale), drawn inside a pea plant cell. No wavy arrow label is drawn. The cell has chloroplasts and mitochondria.
Pia looks at a pea plant cell that has chloroplasts and mitochondria. What do the mitochondria do?
- They take in air through the leaf for the plant
- They make glucose from light
- They stay idle, since chloroplasts handle the plant's energy
- They use sugars to make ATP
Ren reads a chart of where the ATP from glucose is made. Blank box D makes about 90 percent of the ATP. Which label fits D?
- Pyruvate oxidation in the matrix
- The citric acid cycle in the matrix
- Chemiosmosis on the inner membrane
- Glycolysis in the cytoplasm
Use this
Flow diagram (model, not to scale), drawn across a cell. Inputs in boxes on the left: glucose; oxygen. Outputs in boxes on the right: carbon dioxide; water. A wavy arrow F points out of the reaction; its label is blank.
Tala sees glucose and oxygen go into a cell, with a wavy arrow F pointing out. Which label fits the wavy arrow F?
- Air breathed out by the lungs
- Light energy from the Sun
- New energy made by the cell
- Energy moved into ATP and heat
No wavy arrow label is drawn. Zee sees pyruvate broken down in the mitochondrial matrix, with a gas leaving at box G. The gas is made from pyruvate's carbon. Which label fits G?
- Water vapor, formed from the pyruvate
- Oxygen, the same gas the cell took in
- Carbon dioxide, with carbon from pyruvate
- Glucose, rebuilt from the pyruvate