Single-Celled Organisms · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

One Cell, Every Job

Science · Organisms & Life Processes · ages 11-12
Name ______________________   Date ____________

  1. What does the 'N' stand for in MRS NERG?

    • Number
    • Nutrition
    • Nucleus

  2. Which of these is an example of a single-celled organism?

    • Bacterium
    • Dog
    • Oak tree

  3. An Amoeba's body is made of many cells working together.

    Circle one:   True   False

  4. A bacterium is one single cell. Your body is made of trillions of cells, each with its own job. Which statement is true?

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    • One cell does every job, but your cells share the work
    • The bacterium has no jobs to do at all
    • Your body only has one job to do, just like the bacterium

  5. An Amoeba stretches out part of itself and creeps toward a food particle. Which life process is this?

    • Excretion
    • Reproduction
    • Movement

  6. A bacterium splits into two identical bacteria. Which life process just happened?

    • Respiration
    • Reproduction
    • Sensitivity

  7. A tapeworm's body has thousands of cells, each doing a different job like sensing or moving. A Paramecium's body is just one cell. Which one must carry out every single life process inside that one cell?

    • The Paramecium
    • The tapeworm
    • Both organisms need only one cell each

  8. Ali says a bacterium can't grow because it doesn't have a stomach or muscles like an animal. What is wrong with Ali's idea?

    • Bacteria never grow at all, so Ali is right
    • Only animals with stomachs are able to grow
    • Cells can grow with no stomach or muscles
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Answer key

For grown-ups. Fold this page away before handing over the rest.

One Cell, Every Job W1-mt_g9RcQOhU5d-s1

  1. Nutrition · N stands for Nutrition, taking in or making food. It is easy to mix up with 'nucleus', a cell part you already know.
  2. Bacterium · A bacterium is made of just one cell that carries out every job of life by itself.
  3. False · An Amoeba is unicellular. Its whole body is just one cell.
  4. One cell does every job, but your cells share the work · A multicellular body splits life's jobs among many specialized cells, but a single cell has no one else to share the work with.
  5. Movement · Moving from place to place is Movement, the first letter in MRS NERG.
  6. Reproduction · Splitting into two new cells is Reproduction, one of the seven jobs in MRS NERG.
  7. The Paramecium · The tapeworm's cells share different jobs between them, but the single-celled Paramecium's one cell must handle every process itself.
  8. Cells can grow with no stomach or muscles · Growth doesn't need separate organs. A single cell can grow while still handling every one of the seven life processes on its own.
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