Click on a lesson name to select. Chapter 9 Cellular Reproduction Section 1: Cellular Growth Section 2: Mitosis and Cytokinesis Section 3: Cell Cycle

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Chapter 9 Cellular Reproduction

Section 1: Cellular Growth

Section 2: Mitosis and Cytokinesis

Section 3: Cell Cycle Regulation

9.1 Cellular Growth

Objectives:

1. Explain why cells are relatively small.

2. Summarize the primary stages of the cell cycle.

3. Describe the stages of interphase.

9.1 Cellular Growth

Main Idea – Cells grow until they reach their size limit, then they either stop growing or divide.

9.1 Cellular Growth

Ratio of Surface Area to Volume

Chapter 9 Cellular Reproduction

Cellular Reproduction

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.

Chapter 9

9.1 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.

Chapter 9

9.1 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 ReproductionChapter 9

9.1 Cellular Growth

Cell Size Limitations1. ratio of surface area to volume

a. Cells are smaller than a period (100um).b. Surface area refers to the plasma membrane ; L x W x number of sides (6)c. Volume refers to the contents of the cell; L x W x Hd. Volume increases faster than surface areae. Higher ratio of surface area to volume allows cell

to maximize diffusion and transport; more efficient

2. Transport of substances – smaller cells have more efficient transport

3. Cellular communications – smaller size is more efficient for protein synthesis

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

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


9.1 Cellular Growth

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.

Chapter 9


The Second Stage of Interphase, S

The cell copies its DNA in preparation for cell division.

Chapter 9

9.1 Cellular Growth


The Third Stage of Interphase, G2

The cell prepares for the division of its nucleus.

Chapter 9

9.1 Cellular Growth

The Cell Cycle - a cycle of growing and dividing in eukaryotic cells

1. Interphase – cell grows, develops and replicates DNA, prepares for division;

3 substages: G1 (Gap 1) – cell is growing and replicating organelles

S – synthesis – DNA replication occursChromosomes – contain genetic material

Chromatin – relaxed form of DNA in nucleus

G2 (Gap 2) cell prepares for mitosis

Chromosome Structure

Chromatin

2. Mitosis cell’s nucleus (DNA) divides (4 stages) (PMAT)

3. Cytokinesis – cytoplasm divides; result is 2 identical daughter cells

9.1 Section Assessment (pg. 247 1-6)

1. When the cell increases in size, transportation of substances across the membrane becomes difficult. The cell is not efficient.

2. The primary stages of the cell cycle are interphase, mitosis, and cytokinesis.

3. DNA is replicated during the S stage of interphase.

Diagram of cell cycle – see pg. 246

Interphase Longest phase

Cell grows

DNA replication occurs

Mitosis Nucleus divides

Occurs in 4 stages

Cytokinesis Shortest phase

Cytoplasm divides

5. The large cell would not be able to maintain itself because the plasma membrane-to-cell contents ratio would be too large and diffusion and transport would be inefficient.

6. surface area = 5 um x 5 um x 6 = 150 um2

volume = 5 um x 5 um x 5 um = 125 um3

Ratio is 6:5

Result inefficient transport

9.2 Mitosis and Cytokinesis

Objectives:

1. Describe the events of each stage of mitosis.

2. Explain the process of cytokinesis.

Main Idea

Eukaryotic cells reproduce by mitosis, the process of nuclear division, and cytokinesis, the process of cytoplasm division.



The Stages of Mitosis

Prophase

The cell’s chromatin tightens.

Sister chromatids are attached at the centromere.

Spindle fibers form in the cytoplasm.

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The nuclear envelope seems to disappear.

Spindle fibers attach to the sister chromatids.

Chapter 9


Prometaphase


Metaphase

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

They line up in the middle of the cell.

Chapter 9



Anaphase

The microtubules of the spindle apparatus begin to shorten.

The sister chromatids separate.

The chromosomes move toward the poles of the cell.

Chapter 9



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.

Chapter 9


The 4 Stages of Mitosis http://www.johnkyrk.com/mitosis.html

Prophase – “poles form” (centrioles) “poof”chromosomes condense; spindle forms

Metaphase – “meet in the middle”chromosomes line up at the equator

Anaphase – “pull apart”chromosomes move to opposite poles

Telophase – “pinch together” “two new”nuclear envelope forms; chromosomes decondense

http://www.johnkyrk.com/mitosis.html

Mitosis


Cytokinesis

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

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

Chapter 9


Visualizing the Cell Cycle

http://biologygmh.com/


Plant Cell Division

Remember the Stages of Cell Division

I Interphase

Probably Prophase

Make Metaphase

A Anaphase

Teacher Telophase

Crazy Cytokinesishttp://www.johnkyrk.com/mitosis.html

http://www.johnkyrk.com/mitosis.html

Prokaryotic cells undergo binary fission- cell divides into 2 genetically identical cells

WHY?

Prokaryotic cells do not have a nucleus.

Mitosis is division of the nucleus.

Binary Fission - lhs.lps.org

Bacterial Cell: Binary Fissionstudent.nu.ac.th

9.2 Section Assessment (pg. 252 1-7)

1. To complete the cell cycle, a cell must undergo cytokinesis to produce two daughter cells.

2. Mitosis

Prophase Nuclear membrane disintegrates;

chromosomes condense

Metaphase Chromosomes attach to spindle and line up at the equator of cell

Anaphase Chromosomes move apart to opposite poles

Telophase Cell pinches together;

Chromosomes relax

3. chromosome in prophase sister chromatid

centromere

4. A cell spends the most time in prophase of mitosis.

5. Cytokinesis in plant cells involves forming a cell plate between the two cells.

6. 7. In a week, 128 cells would be produced. (2, 4, 8, 16, 32, 64, 128 = 7 days)

9.3 Cell Cycle Regulation

Objectives:

1. Summarize the role of cyclin proteins in controlling the cell cycle.

2. Explain how cancer relates to the cell cycle.

3. Describe the role of apoptosis.

4. Summarize the two types of stem cells and their potential uses.

• Main Idea - The normal cell cycle is regulated by cyclin proteins.



Normal Cell Cycle

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

Chapter 9


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.

Chapter 9


Normal Cell Cycle http://cellsalive.com/cell_cycle.htm

1. cell division rate varies with type of cell

2. substances that signal cell reproduction

cyclins – proteins that regulate (start and stop) cell cycle

cyclin-dependent kinases – enzyme that binds with

cyclins during interphase and mitosis to start stages

or cell cycle, DNA replication

3. quality control checkpoints monitor cell cycle;

can stop it if error occurs

http://cellsalive.com/cell_cycle.htm


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.

Chapter 9



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.

Chapter 9


Abnormal Cell Cycle: Cancer

1. cancer – uncontrolled growth and division of cells – cell cycle fails

2. cancer cells crowd out normal cells

3. cancer cells spend less time in interphase, so

they divide fast

4. caused by mutations in DNA and environmental factors

5. carcinogens – substances that cause cancer (asbestos, tobacco, secondhand smoke, UV radiation, X rays)

6. cancer genetics – requires many changes in DNA; risk increases with age, can run in families

Comparison of Normal and Cancerous Stomach Cells

Normal Stomach Cells– Interphase 120 min.– Prophase 60 min.– Metaphase 10 min.– Anaphase 3 min.– Telophase 12 min.

Cancerous Stomach Cells– Interphase 16 min.– Prophase 15 min.– Metaphase 2 min.– Anaphase 1 min.– Telophase 3 min.


Apoptosis

Programmed cell death

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

Chapter 9


7. apoptosis - programmed cell death; can help protect against cancerous growths


Stem Cells

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

Chapter 9



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.

Chapter 9



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

Chapter 9




8. stem cells -unspecialized cells that can develop into specialized cells

a. embryonic stem cells – found in embryos; controversial due to source

b. adult stem cells – found in various tissues of body including newborns; less controversial because adult can give consent for removal

9.3 Section Assessment pg. 257 (1-7)

1. Certain cyclin proteins and cyclin-dependent enzymes regulate mitosis and the cell cycle.

2. The cancer cell cycle is shorter. Cancer cells divide in an uncontrolled way.

3. Three carcinogens are cigarette smoke, UV radiation, and asbestos.

4. In apoptosis a cell undergoes programmed cell death; cancer cells divide unrestrained as long as they are supplied with essential nutrients.

5. Stem cells may be used to treat medical conditions and genetic defects.

6. Embryonic stem cells, found in developing embryos, can develop into many kinds of cells. Adult stem cells are found in developed tissues and might be used to maintain and repair the same kind of tissue in which they are found.

7. If apoptosis did not occur to cells with significant DNA damage people would probably have higher rates of cancer and genetic diseases.


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Vocabulary

AnimationClick on a hyperlink to view the corresponding lesson.

Chapter 9

A. interphase

B. prophase

C. metaphase

D. telophase

1. Which is the first phase of mitosis?



Chapter 9

A. interphase

B. metaphase

C. anaphase

D. telophase

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



Chapter 9

A. cytokinesis

B. interphase

C. apoptosis

D. mitosis

3. Which is not a phase of the cell cycle?



Chapter 9

1. 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

9.1 Formative Questions

Chapter 9

2. At what stage does a cell spend most

of its life?


A. cytokinesis

B. interphase

C. mitosis

D. synthesis


Chapter 9

3. What happens in the cell during cytokinesis?



Chapter 9

A. The cell grows and carries out normalfunctions.

B. The cell copies its DNA and formschromosomes.

C. The cell’s nucleus and nuclear materialdivide.

D. The cell’s cytoplasm divides.

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


A. cytokinesis

B. interphase

C. mitosis

D. prophase


Chapter 9

5. Which diagram shows anaphase?



Chapter 9

A. B.

C. D.

6. True or False

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



Chapter 9

7. 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


Chapter 9

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


A. chemicals such as asbestos

C. tobacco and second-hand smoke

D. ultraviolet radiation from the Sun

B. food and drinks that the FDA warns may

contain carcinogens


Chapter 9

9. 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


Chapter 9

10. 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


Chapter 9

11. This cell has completed what stage of mitosis?


A. anaphase

B. interphase

C. metaphase

D. telophase


Chapter 9

12. What term is used to describe programmed cell death?


A. apoptosis

B. anaphase

C. necrosis

D. cyclins


Chapter 9

13. What is the role of cyclins in a cell?


A. to control the movement of microtubules

B. to signal for the cell to divide

D. to cause the nucleolus to disappear

C. to stimulate the breakdown of thenuclear membrane


Chapter 9


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


Chapter 9

AB C


15. 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


Chapter 9

16. 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 equatorof the cell

D. movement of chromosomes to the poles of the cell



Chapter 9


True or False

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


Chapter 9

18. Which is not a condition that can result in cancer?



Chapter 9

A. a failure in the control mechanisms thatregulate the cell cycle

B. a failure in the repair systems that fixchanges or damage to DNA

C. a failure of the spindle fibers to movechromosomes during mitosis

D. mutations or changes in segments of DNAthat control protein production


Glencoe Biology Transparencies

Chapter 9


Image Bank

Chapter 9

cell cycle

interphase

mitosis

cytokinesis

chromosome

chromatin


Vocabulary

Section 1

prophase

sister chromatid

centromere

spindle apparatus

metaphase

anaphase

telophase


Vocabulary

Section 2

cyclin

cyclin-dependent kinase

cancer

carcinogen

apoptosis

stem cell


Vocabulary

Section 3


Visualizing the Cell Cycle

Animation

Documents

Click on a lesson name to select. Chapter 9 Cellular Reproduction Section 1: Cellular Growth Section 2: Mitosis and Cytokinesis Section 3: Cell Cycle