Light reactions and the Calvin cycle

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Chloroplast cutaway (model, not to scale).

2. 1.

   Ari studies a chloroplast drawing. Part A is a stack of flat, disc-shaped thylakoids. What is A called?

   • The stroma
   • The granum
   • The outer membrane
   • The thylakoid lumen
3. 2.

   Bo studies a chloroplast drawing. Part D is the liquid-filled space around the stacks of thylakoids. What is D?

   • The stroma
   • The granum
   • The stoma
   • The thylakoid membrane
4. 3.

   Esme wants to find the chlorophyll that absorbs light in a chloroplast. Which part holds it?

   • The thylakoid membranes
   • The outer membrane
   • The stroma
   • The fluid inside each thylakoid
5. 4.

   “model, not to scale” Jun reads that chlorophyll absorbs light and its energy is stored in ATP and NADPH. Which stage is this?

   • Fermentation
   • The light reactions
   • The Calvin cycle
   • Glycolysis

6. Use this

   Flow diagram (model, not to scale), drawn inside a chloroplast. The name of the stage in box B is not shown.

7. 5.

   Kira reads that carbon dioxide is built into sugar (G3P) using ATP and NADPH. Which stage is this?

   • Cellular respiration
   • The light reactions
   • The Calvin cycle
   • The citric acid cycle
8. 6.

   Luz reads that water is split and oxygen is released. Which stage does this?

   • Cellular respiration
   • The Calvin cycle
   • The light reactions
   • Electron transport in a mitochondrion
9. 7.

   What it carries is not shown. Milo reads a chloroplast diagram. Arrow A runs from the thylakoid membranes to the stroma. What does A carry?

   • Oxygen and water
   • ATP and NADPH
   • ADP, Pi and NADP+
   • Nothing, since the Calvin cycle needs no help

10. Use this

    Flow diagram (model, not to scale), drawn inside a chloroplast. In the thylakoid membranes: water and a wavy arrow of light energy go in; oxygen comes out. In the stroma: carbon dioxide goes in; G3P comes out. Arrow B runs from the stroma back to the thylakoid membranes. What it carries is not shown.

11. 8.

    Noah reads a chloroplast diagram. Arrow B runs from the stroma back to the thylakoid membranes. What does B carry?

    • Nothing, since ATP and NADPH are used up for good
    • ATP and NADPH
    • G3P, made by the light reactions
    • ADP, Pi and NADP+
12. 9.

    The name of the sugar and the zone that builds it are not shown. Ren fills in box D, the sugar that leaves the chloroplast. What goes in D, and where is it built?

    • ATP, built in the stroma
    • G3P, built in the thylakoid membranes
    • G3P, built in the stroma
    • ATP, built in the thylakoid membranes

13. Use this

    Flow diagram (model, not to scale), drawn inside a chloroplast. In the stroma: NADPH goes in and is spent. Box E is an output box in the stroma. An arrow carries box E back to the thylakoid membranes. The name in box E is not shown.

14. 10.

    Zee fills in box E, made when the Calvin cycle spends NADPH. What goes in E?

    • Nothing: the spent NADPH just disappears
    • NADPH
    • Carbon dioxide
    • NADP+