What each part of a cell does

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Use this

   Comparison chart, not to scale: a rounded cell with letters A, B and C. B sits on a large round body near the middle. C sits on a small bean-shaped part with a folded inside.

2. 1.

   Ari's class says: the nucleus is like a school's main office, which keeps the plans and gives directions. Is this a good comparison?

   • Agree: the nucleus holds the DNA and directs the cell, like an office with plans
   • Disagree: a cell has no principal, so it cannot be like a school
   • Agree: the nucleus really is a small office room inside the cell
   • Agree: the nucleus makes the cell's food, as an office makes lunch

3. Use this

   Comparison chart, not to scale: a boxy plant cell with letters A and B. A sits on a thick outer layer around the whole cell. B sits on the thin boundary line just inside it.

4. 2.

   Bo's class says: the cell wall is like a school's front doors, which decide who comes in and out. Is this a good comparison?

   • Disagree: the membrane controls what goes in and out; the wall supports the cell
   • Agree: a cell wall really has doors that open and close
   • Agree: the cell wall controls what goes in and out, like the doors
   • Disagree: a cell and a school are too different to compare

5. Comparison chart, not to scale

   a rounded cell with letters A, B and C. A sits on a small bean-shaped part with a folded inside. B sits on a large round body near the middle. C sits on the thin boundary line around the cell. Job column: B | holds the DNA and directs the cell's activities; C | controls what goes in and out of the cell.

6. 3.

   Jun says: mitochondria are like a factory's power station, which gets energy out of fuel for the machines. Is this a good comparison?

   • Agree: mitochondria make energy from nothing, like a power station
   • Disagree: a cell has no machines, so nothing in it is like a power station
   • Agree: mitochondria release energy from food, like a power station from fuel
   • Disagree: the nucleus is the power station, since it makes the cell's energy
7. 4.

   “Comparison chart, not to scale:” Kira says: ribosomes are like the workers on a factory assembly line, who build the products. Is this a good comparison?

   • Disagree: ribosomes are tiny dots, but assembly workers are people, so it fails
   • Disagree: ribosomes are really the factory's power station
   • Agree: ribosomes build proteins, as assembly workers build products
   • Agree: ribosomes are tiny workers who build things by hand
8. 5.

   Radish root cell drawing, not to scale. No green parts are drawn. No job column. A radish root cell grows underground and has no chloroplasts. Luz finds it still releases energy from food. Why does that happen?

   • Its nucleus makes the energy for the cell
   • Its mitochondria make the energy from nothing, so the cell needs no food
   • It has tiny chloroplasts that are too small to see
   • It has mitochondria, which release energy from food in plant cells too
9. 6.

   A lab removes the cell wall from a radish root cell that Milo studies. The cell still keeps most things out and lets water in. Why?

   • The nucleus now controls what goes in and out
   • The cell membrane still controls what goes in and out
   • The wall's job moved to the cytoplasm, which keeps things out
   • Pieces of the wall stay behind and still control what goes in

10. Use this

    Radish root cell drawing, not to scale: a boxy cell with letters A, B and C. No green parts are drawn. Job column: A | supports and protects the cell and gives it shape; B | holds the DNA and directs the cell's activities; C | releases energy from food for the cell to use.

11. 7.

    Noah finds a radish root cell with a cell wall, a nucleus and mitochondria, but no chloroplasts. Which jobs can this cell still do?

    • Support itself, direct its activities, release energy and make sugar from light
    • Support itself, direct its activities and release energy from food
    • Support itself and release energy, but not direct its activities
    • Direct its activities and make its own energy in the nucleus

12. Use this

    Radish leaf cell drawing, not to scale: a boxy cell with letters A to D. A sits on a thick outer layer around the whole cell. B sits on a green oval part with stacks inside. C sits on a small bean-shaped part with a folded inside. D sits on a large round body near the middle. No job column.

13. 8.

    Pia studies a radish leaf cell in bright light. It makes sugar, then uses that sugar to get energy. Which parts, in order, do these two jobs?

    • Mitochondria first, then chloroplasts
    • Nucleus first, then mitochondria
    • Chloroplasts first, then mitochondria
    • Chloroplasts first, then cell wall
14. 9.

    “not to scale” Tala keeps a potato plant's leaves in a dark closet for a day. Their cells still have green chloroplasts but make no sugar. Why?

    • Its mitochondria use up the sugar in the dark
    • Chloroplasts need light energy to make sugar
    • Its nucleus makes the sugar, and the nucleus needs light
    • The cell wall blocks the light from reaching the nucleus
15. 10.

    “Wilted potato leaf cell drawing, not to scale:” Zee sees a wilted potato leaf cell that lost water from its large central vacuole. Its cell wall is not damaged. Why is the cell limp?

    • The cell wall controls water, so it let the water drain out of the cell
    • The mitochondria ran out of water to release energy
    • The vacuole's water kept the cell firm, so the wall alone could not
    • The nucleus keeps the cell firm, and it dried out