LOOKING BACK

KEY CONCEPTS SUMMARY

• All organisms are made up of one or more cells.

– The cell theory states that the cell is the basic unit of life, that all organisms

are made up of one or more cells, and that all cells come from pre-existing

cells.

– Single-celled organisms, such as bacteria, consist of just one cell.

– Every plant and animal, including humans, is a multicellular organism and is

classified as a eukaryote.

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LOOKING BACK

KEY CONCEPTS SUMMARY

• Microscopes enable us to examine cells in detail.

– Plant and animal cells have most of the major cell structures in common.

– Materials for cell activity pass through the cell membrane by diffusion and

osmosis.

– Plant cells contain a cell wall, a large central vacuole, and chloroplasts.

– Cells grow and divide to replace worn-out cells, to allow for growth in

organisms, to repair damaged cells, and to reproduce.

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LOOKING BACK

KEY CONCEPTS SUMMARY

• The cell cycle occurs in distinct stages.

– The cell cycle has three stages: interphase, mitosis, and cytokinesis.

– Interphase is the stage when cells grow, perform their specific functions,

produce more organelles, and replicate their DNA.

– Mitosis is the division of the DNA in a cell’s nucleus.

– Cytokinesis is the division of the entire cell into two new identical daughter

cells.

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LOOKING BACK

KEY CONCEPTS SUMMARY

• Cell division is important for growth, repair, and reproduction.

– Mitosis and cytokinesis together make up the cell division portion of the cell

cycle.

– Mitosis results in each daughter cell receiving an exact copy of the parent

cell’s DNA.

– Cells go through four phases during mitosis: prophase, metaphase,

anaphase, and telophase (PMAT).

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LOOKING BACK

LOOKING BACKKEY CONCEPTS SUMMARY

• Cancer cells generally divide more rapidly than normal cells.

– Cancer is a broad group of diseases in which groups of cells grow and divide

uncontrollably.

– Uncontrolled cell growth and division create a mass of cells that may form a

tumour.

– A benign tumour does not seriously affect nearby cells and does not spread

through the body.

– A malignant tumour is made up of cancer cells; it may invade and damage

surrounding tissues.

– Cancer cells can metastasize to other parts of the body.

– Prevention and screening minimize the risk of cancer.

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LOOKING BACK

LOOKING BACKKEY CONCEPTS SUMMARY

• Medical imaging technologies are important in diagnosing and treating

disease.

– Screening sometimes involves imaging technologies

– Medical imaging technologies include endoscopy, X-ray, ultrasound, CT

scanning, and MRI.

– Imaging technologies are widely used diagnostic tools that aid in the

detection of cancer and other diseases.

– Microscopic examination of cells is the only way to confirm a diagnosis of

cancer.

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QUIZ

MULTIPLE CHOICE

For each question, select the best answer from the four alternatives.

1. Cells must perform certain basic activities to stay alive. Those activities are

performed by

(a) bacterium

(b) organelles

(c) eukaryotes

(d) diffusion

2. Why do cells divide?

(a) so that they can reproduce

(b) so that they can grow

(c) so that they can repair damage

(d) all of the above

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QUIZ

3. When single-cell organisms divide, only one parent is involved. What is the

name of this process?

(a) osmosis

(b) sexual reproduction

(c) diffusion

(d) asexual reproduction

4. Which one is not a phase of mitosis?

(a) prophase

(b) centrophase

(c) metaphase

(d) anaphase

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QUIZ

FILL IN THE BLANKS

Copy each of the following statements into a notebook. Fill in the blanks with a term from the box

below that correctly completes the sentence.

5. ___________ divide more rapidly than normal cells.

6. Only _____________ have chloroplasts.

7. In the cytokinesis phase, the cytoplasm divides and two

identical ______________ are produced.

8. Uncontrolled cell growth may create a mass of cells that form a

lump or tumour. Tumours may be ___________ or ____________.

9. _____________ refers to random changes in a cell’s DNA.

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benign; daughter cells; plant cells; malignant; mutation; cancer cells

A

B C

QUIZ

SHORT ANSWER

10. In your notebook, write which

of the three stages of the cell

cycle correspond to the letters

in the diagram. Then describe

what occurs during each of

the stages.

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QUIZ ANSWERS

MULTIPLE CHOICE

1. Cells must perform certain basic activities to stay alive. Those activities are

performed by

(a) bacterium

(b) organelles

(c) eukaryotes

(d) diffusion

2. Why do cells divide?

(a) so that they can reproduce

(b) so that they can grow

(c) so that they can repair damage

(d) all of the above

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2

QUIZ ANSWERS

3. When single-cell organisms divide, only one parent is involved. What is the name of

this process?

(a) osmosis

(b) sexual reproduction

(c) diffusion

(d) asexual reproduction

4. Which one is not a phase of mitosis?

(a) prophase

(b) centrophase

(c) metaphase

(d) anaphase

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QUIZ ANSWERS

FILL IN THE BLANKS

5. Cancer cells divide more rapidly than normal cells.

6. Only plant cells have chloroplasts.

7. In the cytokinesis phase, the cytoplasm divides and two identical daughter cells are

produced.

8. Uncontrolled cell growth may create a mass of cells that form a lump or tumour.

Tumours may be benign or malignant.

9. Mutation is a term that refers to random changes in a cell’s DNA.

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QUIZ ANSWERS

SHORT ANSWER

10.

(a) Interphase is the stage when the cell carries out all life activities except division.

(b) Mitosis is the stage when the contents of the nucleus divides.

(c) Cytokinesis is the stage when the remainder of the cell—the cytoplasm,

organelles, and cell membrane—divides.

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