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

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Cellular Reproduction

Section 1: Cellular Growth

Section 2: Mitosis and Cytokinesis

Section 3: Cell Cycle Regulation


Recap: What are the 3 components of the cell theory??

1. All living organisms have one or more cells.

2. Cells are the basic unit of structure and function.

3. All cells come from preexisting cells.


• Section 1: Cellular Growth– Introduction:

• Since all living organisms are made of cells, the only way an organism can grow or heal itself is by cellular reproduction.

• Cell sizes must be limited to ensure that the needs of the cells are met.– Most cells are smaller than the period on the end

of this sentence. !!! WHY ARE THEY SO SMALL???...


• Section 1: Cell Growth

• I. Cell Size Limitations:1. Surface area to volume ratio

• A. Surface Area= all of the area available for reactions to occur (covered by the plasma membrane….)

– Formula= length x width x # of sides

B. Volume= space inside (includes organelles and cytoplasm…)

– Formula= length x width x height

Cellular Growth

Ratio of Surface Area to Volume

Section 1 Cellular Reproduction

Cellular Growth

• Is bigger better??

– No!! Small cells transport substances more efficiently.

– Surface area to volume ratio decreases as the cell grows larger.


-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.

Section 1

Cellular Growth

Cellular GrowthCell Size Limitations continued…

• 2. Transport of substances- limits cellsize because small cells can transport easier.– Think Selective permeability! Once inside,

substances move by diffusion and proteins• Slow in large cells because more space to travel

3. 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 ReproductionSection 1

Cellular Growth

II. The Cell Cycle

-Eukaryotic cells

-Somatic Cells (all body cells EXCEPT sex cells)

-Cycle produces genetically identical cells (to parent cell).


Cellular Growth

Cellular Growth

• *Once a cell reaches its size limit, it must either stop growing or divide!

• Division = Reproduction

• **Reproduction allows you to grow and heal certain injuries!

• Cell cycle=each time a cell goes through a complete cycle, it becomes 2 cells. Repeats cause continuous production of new cells.

Cellular Growth

Stages of the Cell Cycle

Cellular Growth

• 3 Main Stages: (each can be subdivided)– 1. Interphase= *Majority of a cells life; cell grows,

carries out all cell functions, and replicates DNA; (3 sub stages).

– 2. Mitosis= cell nucleus and nuclear material divide (4 sub stages).

– 3. Cytokinesis= cytoplasm divides creating a new cell. *shortest time spent here

– Cell Cycle duration varies depending on the cell type; Most animal cells around 12-24hrs.


A. The Stages of Interphase The first stage of interphase, G1 (Gap 1)

*Immediately after a cell divides. Function: growing, normal cell function, prepares to

replicate DNA. Side note: muscle and nerve cells exit after this step, brain

damage is permanent!

Section 1

Cellular GrowthDigging Deeper…


The Second Stage of Interphase, S (synthesis)

Function: cell copies its DNA (prepares for division)*Chromosomes contain DNA (housed in nucleus)

Section 1

Cellular Growth


The Third Stage of Interphase, G2 (Gap 2)

*Follows S *Function: cell nucleus prepares to divide and inventory

taken to ensure mitosis can proceed.

Section 1

Cellular Growth

Cellular Growth

• B. The stages of Mitosis– Prophase, Metaphase, Anaphase, Telophase

• Differ by: appearance and chromosome location

• Follows S phase of interphase

• Function: cells nuclear material (chromosomes) divide and separate to opposite ends of the cell.

Cellular Growth

• C. Cytokinesis– *Follows mitosis

– *Function: cell splits/divides

– Product*= 2 “daughter cells” with identical nuclei!!

Cellular Growth

• Prokaryotic cells differ…– Why?? They are simple cells!

– Use binary fission-a form of asexual reproduction to reproduce (similar to cloning)

– Homework: page 247 1-4; 6

1. A2. B3. C4. D

FQ 1

Cellular ReproductionChapter

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

Section 1 Formative Questions

1. A2. B3. C4. D

FQ 2


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


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.


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 2


The nuclear envelope seems to disappear.

Spindle fibers attach to the sister chromatids.

Section 2



Metaphase

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

They line up in the middle of the cell.

Section 2



Anaphase

The microtubules of the spindle apparatus begin to shorten.

The sister chromatids separate.

The chromosomes move toward the poles of the cell.

Section 2



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.

Section 2



Cytokinesis

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

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

Section 2


1. A2. B3. C4. D

FQ 4


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


Which diagram shows anaphase?

A. B.

C. D.


1. A

2. B

FQ 6


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


A. true

B. false

Cell Cycle Regulation


I. Normal Cell Cycle

Check points in place Different cyclin/CDK

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

Section 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.

Section 3



II. Abnormal Cell Cycle: Cancer

A. 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.

Section 3



B. 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.

Section 3



III. Apoptosis

Programmed cell death

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

Section 3



IV. Stem Cells

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

Section 3



A. 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.

Section 3




B. 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

Section 3


1. A2. B3. C4. D

FQ 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


1. A2. B3. C4. D

FQ 8


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



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



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


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1. A2. B3. C4. D

CDQ 1

A. interphase

B. prophase

C. metaphase

D. telophase

Which is the first phase of mitosis?



Chapter

1. A2. B3. C4. D

CDQ 2



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

A. cytokinesis

B. interphase

C. apoptosis

D. mitosis

Which is not a phase of the cell cycle?

1. A2. B3. C4. D

CAQ 1


This cell has completed what stage of mitosis?

A. anaphase

B. interphase

C. metaphase

D. telophase


1. A2. B3. C4. D

CAQ 2


What term is used to describe programmed cell death?

A. apoptosis

B. anaphase

C. necrosis

D. cyclins


1. A2. B3. C4. D

CAQ 3


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


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

AB

C


1. A2. B3. C4. D

STP 2



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



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



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



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


Glencoe Biology Transparencies

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Chapter

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

apoptosis

stem cell


Vocabulary

Section 3


Visualizing the Cell Cycle

Animation


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