Cellular respiration: the equation and its three stages
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Use this
Flow diagram (model, not to scale), drawn across a cell. Inputs in boxes on the left: 1 glucose (6 carbons). Outputs in boxes on the right: 2 acetyl groups (2 carbons each); CO2 released. Stage 1, in the cytoplasm: glucose becomes 2 pyruvate (3 carbons each). Stage 2, in the mitochondrial matrix: each pyruvate loses 1 carbon as CO2 and becomes an acetyl group.
Pia tracks the carbons of 1 glucose through glycolysis and then pyruvate oxidation. How many CO2 have left, and how many carbons are in the acetyl groups?
- 2 CO2 left in the cytoplasm during glycolysis, and 4 carbons are in the acetyl groups
- 2 CO2 have left in the matrix, and 6 carbons are in the acetyl groups
- 4 CO2 have left in the matrix, and 2 carbons are in the acetyl groups
- 2 CO2 have left in the matrix, and 4 carbons are in the acetyl groups
Use this
Flow diagram (model, not to scale), drawn inside a cell. Inputs in boxes on the left: glucose, amount not shown; oxygen, amount not shown. Outputs in boxes on the right: 18 CO2 released (model data); water.
A model cell releases 18 CO2 as it breaks down glucose by cellular respiration. Zee uses the equation. How many glucose were broken down, and how many O2 were used?
- 18 glucose and 18 O2
- 3 glucose and 3 O2
- 6 glucose and 36 O2
- 3 glucose and 18 O2
Read about only: the teacher handles the equipment. Ari's class adds tube C with 10 g of the same germinating bean seeds, kept in the same conditions. Which prediction fits the card?
- About 12.0 mL of oxygen and 24.0 mL of CO2, since respiration creates extra energy and gas
- About 12.0 mL of oxygen and 0 mL of CO2, since plant cells use up carbon dioxide
- About 6.0 mL of each gas, because the same kind of seeds respire at the same rate
- About 12.0 mL of oxygen and 12.0 mL of CO2, since twice as many cells respire
Use the table
Breathing rate card (model data). Each breath moves the same amount of air.
moment breaths per minute resting 15 during a 3-minute run 36 after 5 minutes of rest 18 Bo reads the breathing card (each breath moves the same amount of air). How many times more air is breathed per minute in the run, and where is the extra oxygen used?
- 2.4 times as much, used in the lungs for cellular respiration
- 2.4 times as much, used at the electron transport chain
- 0.4 times as much, used at the electron transport chain
- 21 times as much, used in glycolysis in the cytoplasm
Notebook lines (model data)
line notebook says 1 Glycolysis happens in the cytoplasm 2 Pyruvate is oxidized to an acetyl group in the mitochondrial matrix 3 The citric acid cycle happens in the cytoplasm 4 The electron transport chain sits in the inner mitochondrial membrane Jun's notebook lists four lines about cellular respiration. One line has a flaw. Which line has the flaw?
- Line 4: the chain sits in the matrix, not the inner membrane
- Line 3: the citric acid cycle happens in the matrix, not the cytoplasm
- Line 1: glycolysis happens in the mitochondrial matrix, not the cytoplasm
- Line 2: pyruvate is oxidized in the cytoplasm, not the matrix
Use this
Notebook line (model data), 1 row. Columns: line, notebook says. 1, Glycolysis nets 4 ATP per glucose, which is most of the ATP a cell makes.
Kira's notebook says glycolysis nets 4 ATP per glucose, which is most of the ATP a cell makes. What is the flaw?
- Glycolysis nets 4 ATP, and the later stages add a few more
- Glycolysis nets 6 ATP, and chemiosmosis makes the rest
- Glycolysis nets 2 ATP, and chemiosmosis makes about 90 percent of the ATP
- Glycolysis nets 2 ATP, and the lungs make about 90 percent of the ATP
Breathing and muscle card (model data)
moment breaths per minute oxygen used by leg muscle cells (relative units) resting 13 1 after 3 minutes of fast walking 22 3 after 2 minutes of rest 15 1 Luz says the card proves breathing is cellular respiration, because both numbers rise together. What is the flaw?
- Breathing moves air in and out; cellular respiration is the reaction in cells
- Nothing is wrong, since breathing is how cells make ATP
- The card shows muscle cells created extra energy, not respiration
- Cellular respiration happens in the lungs, which speed up with breathing
“Flow diagram (model, not to scale)” Milo says leaf cells make their own glucose, so they do not need cellular respiration. Which reply is correct?
- Disagree: leaves breathe through tiny openings, and that breathing is their cellular respiration
- Disagree: plant mitochondria break sugars down with oxygen to make ATP
- Agree: plant cells make food, so they skip the breakdown of glucose
- Agree: plants use light for their ATP, so mitochondria are not needed
Flow diagram (model, not to scale), drawn across a cell. Noah says cellular respiration creates the energy a cell uses. Which reply is correct?
- Disagree: glycolysis moves the energy into ATP, and the later stages add little
- Disagree: it moves energy that glucose already stored into ATP and heat
- Agree: the cell creates the energy, which is why glucose gets used up
- Disagree: the energy comes from the oxygen turning into CO2
Use this
Notebook page with a flow diagram (model, not to scale), drawn across a cell. Inputs in boxes on the left: 6 O2, which holds 12 oxygen atoms. Outputs in boxes on the right: 6 CO2, which holds 12 oxygen atoms. Last stage, on the inner mitochondrial membrane: oxygen accepts electrons and forms water.
Tala counts 12 oxygen atoms in 6 O2 and 12 in 6 CO2, and says the oxygen a cell takes in becomes its CO2. Which reply is correct?
- Disagree: oxygen forms water at the last stage, and the CO2 carbon comes from glucose
- Disagree: the CO2 is released by glycolysis in the cytoplasm
- Disagree: the oxygen is used in the lungs, so cells make CO2 without it
- Agree: the counts match, so the O2 oxygen moves into the CO2