Click on a lesson name to select.

Ch.5 Cell Growth and Division

5.1 The Cell Cycle5.2 Mitosis and Cytokinesis5.3 Regulation of the Cell Cycle5.4 Asexual Reproduction5.5 Multicellular life

Cellular Growth

Ratio of Surface Area to Volume

Section 5.1

The Cell Cycle

As the cell grows, its volume increases much more rapidly than the surface area.

The cell might have difficulty supplying nutrients and expelling enough waste products.

Cellular Growth

Transport of Substances

Substances move by diffusion or by motor proteins.

Diffusion over large distances is slow and inefficient.

Small cells maintain more efficient transport systems.

Cellular Growth

Cellular Communications

The need for signaling proteins to move throughout the cell also limits cell size.

Cell size affects the ability of the cell to communicate instructions for cellular functions.

Cellular Growth

The Cell Cycle

Cell division prevents the cell from becoming too large.

It also is the way the cell reproduces so that you grow and heal certain injuries.

Cells reproduce by a cycle of growing and dividing called the cell cycle.

Interphase is the stage during which the cell grows, carries out cellular functions, and replicates.

Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide.

The Cell Cycle

Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.

The Stages of Interphase

The first stage of interphase, G1

The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.

The Second Stage of Interphase, S

The cell copies its DNA in preparation for cell division.

The Third Stage of Interphase, G2

The cell prepares for the division of its nucleus.

Mitosis and Cytokinesis

The Stages of Mitosis

Prophase

The cell’s chromatin tightens.

Sister chromatids are attached at the centromere.

Spindle fibers form in the cytoplasm.

Section 5.2

The nuclear envelope seems to disappear.

Spindle fibers attach to the sister chromatids.

Mitosis and Cytokinesis

Metaphase

Sister chromatids are pulled along the spindle apparatus toward the center of the cell.

They line up in the middle of the cell.

Mitosis and Cytokinesis

Anaphase

The microtubules of the spindle apparatus begin to shorten.

The sister chromatids separate.

The chromosomes move toward the poles of the cell.

Mitosis and Cytokinesis

Telophase

The chromosomes arrive at the poles and begin to relax.

Two new nuclear membranes begin to form and the nucleoli reappear.

The spindle apparatus disassembles.

Mitosis and Cytokinesis

Cytokinesis

In animal cells, microfilaments constrict, or pinch, the cytoplasm.

In plant cells, a new structure, called a cell plate, forms.

Mitosis and Cytokinesis

Cell Cycle Regulation

Normal Cell Cycle

Different cyclin/CDK combinations signal other activities, including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.

Section 5.3

Quality Control Checkpoints

The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong.

Spindle checkpoints also have been identified in mitosis.

Cell Cycle Regulation

Abnormal Cell Cycle: Cancer

Cancer is the uncontrolled growth and division of cells.

Cancer cells can kill an organism by crowding out normalcells, resulting in the loss of tissue function.

Cell Cycle Regulation

Causes of Cancer

The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations.

Various environmental factors can affect the occurrence of cancer cells.

Cell Cycle Regulation

Apoptosis

Programmed cell death

Cells going through apoptosis actually shrink and shrivel in a controlled process.

Cell Cycle Regulation

Stem Cells

Unspecialized cells that can develop into specialized cells when under the right conditions

Cell Cycle Regulation

Embryonic Stem Cells

After fertilization, the resulting mass of cells divides repeatedly until there are about 100–150 cells. These cells have not become specialized.

Cell Cycle Regulation

Adult Stem Cells

Found in various tissues in the body and might be used to maintain and repair the same kind of tissue

Less controversial because the adult stem cells can be obtained with the consent of their donor

Cell Cycle Regulation

1. A2. B3. C4. D

CDQ 1

A. interphase

B. prophase

C. metaphase

D. telophase

Which is the first phase of mitosis?

Chapter Diagnostic Questions

Chapter

1. A2. B3. C4. D

CDQ 2

Chapter Diagnostic Questions

Chapter

A. interphase

B. metaphase

C. anaphase

D. telophase

During what phase do the sister chromatids line up in the middle of the cell?

1. A2. B3. C4. D

CDQ 3

Chapter Diagnostic Questions

Chapter

A. cytokinesis

B. interphase

C. apoptosis

D. mitosis

Which is not a phase of the cell cycle?

1. A2. B3. C4. D

FQ 1

Chapter

Which can more efficiently supply nutrients and expel waste products?

A. larger cells

B. smaller cells

C. cells with lower surface area to volume ratio

D. cells shaped like a cube

1. A2. B3. C4. D

FQ 2

Chapter

At what stage does a cell spend most of its life?

A. cytokinesis

B. interphase

C. mitosis

D. synthesis

1. A2. B3. C4. D

FQ 3

Chapter

What happens in the cell during cytokinesis?

A. The cell grows and carries out normal functions.

B. The cell copies its DNA and forms chromosomes.

C. The cell’s nucleus and nuclear material divide.

D. The cell’s cytoplasm divides.

1. A2. B3. C4. D

FQ 4

Chapter

In what stage of the cell cycle does the cell’s replicated genetic material separate?

A. cytokinesis

B. interphase

C. mitosis

D. prophase

1. A2. B3. C4. D

FQ 5

Chapter

Which diagram shows anaphase?

A. B.

C. D.

1. A

2. B

FQ 6

Chapter

At the end of mitosis the nuclear material is divided and two new cells have formed.

A. true

B. false

1. A2. B3. C4. D

FQ 7

Chapter

What are the “key and ignition” that start the various activities in the cell cycle?

A. chromatin and chromosomes

B. cyclin and CDKs

C. microtubules and spindle fibers

D. protein and ribosomes

1. A2. B3. C4. D

FQ 8

Chapter

Which of these cancer-causing substances or agents is impossible to avoid completely?

A. chemicals such as asbestos

B. food and drinks that the FDA warns may contain carcinogens

C. tobacco and second-hand smoke

D. ultraviolet radiation from the Sun

1. A2. B3. C4. D

FQ 9

Chapter

What is the term for the programmed death of cells that are damaged beyond repair or have harmful changes in their DNA?

A. apoptosis

B. carcinogens

C. cytokinesis

D. mitosis

1. A2. B3. C4. D

FQ 10

Chapter

Which cells are not locked into becoming one particular kind of cell and are capable of developing into specialized tissues?

A. apoptotic cells

B. cancer cells

C. prokaryotic cells

D. stem cells

1. A2. B3. C4. D

CAQ 1

Chapter

This cell has completed what stage of mitosis?

A. anaphase

B. interphase

C. metaphase

D. telophase

1. A2. B3. C4. D

CAQ 2

Chapter

What term is used to describe programmed cell death?

A. apoptosis

B. anaphase

C. necrosis

D. cyclins

1. A2. B3. C4. D

CAQ 3

Chapter

What is the role of cyclins in a cell?

A. to control the movement of microtubules B. to signal for the cell to divide C. to stimulate the breakdown of the nuclear

membraneD. to cause the nucleolus to disappear

1. A

2. B

3. C

STP 1

Chapter

Which cell has the lowest ratio of surface area to volume?

AB

C

1. A2. B3. C4. D

STP 2

Chapter

At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus?

A. G1

B. S

C. G2

D. M

1. A2. B3. C4. D

STP 3

Chapter

Which occurs in plant cells but not animal cells during the cell cycle?

A. formation of a cell plate

B. formation of microtubules

C. formation of a cleavage furrow at the equator of the cell

D. movement of chromosomes to the poles of the cell

1. A

2. B

STP 4

Chapter

Standardized Test Practice

Multiple changes in DNA are required to change an abnormal cell into a cancer cell.

A. true

B. false

1. A2. B3. C4. D

STP 5

Chapter

Standardized Test Practice

Which is not a condition that can result in cancer?A. a failure in the control mechanisms that regulate

the cell cycleB. a failure in the repair systems that fix changes

or damage to DNAC. a failure of the spindle fibers to move chromosomes

during mitosis

D. mutations or changes in segments of DNA that control protein production