Topic 6 – Cell Cycle and Mitosis

Day 1

Bell Ringer (5 minutes)*pick up worksheet by the door*Get out your homework and answer these questions on the back page:What do I need to do to pass my real EOC?How can my teacher help me succeed?

Cell Cycle and Cancer

Our plan today: -Concept map making

-Mitosis “race”-Mitosis “drama”

-Exit tickets and data check in

What are we learning today?Benchmark: Objectives:

✓ I will describe the role of chromosomes in cell division.

✓ I will name and describe the main events of the cell cycle

✓ I will explain how the cell cycle is regulated

✓ I will describe how cancer cells are different from other cells

✓ SC.912.L.16.6 – Describe the cell cycle, including the process of mitosis. Explain the role of mitosis in the formation of new cells and its importance in maintaining chromosome number during asexual reproduction.

✓ SC.912.L.14.2 – Explain the relationship between mutation, cell cycle, and uncontrolled cell growth potentially resulting in cancer.

Let’s look at MITOSIS up close● During mitosis one cell divides once to form

two identical cells.● The major purpose of mitosis is for growth

and to replace worn out cells.

What is the cell cycle?

❑ During the cell cycle, a cell grows,prepares for division, and divides to form two daughter cells.

❑ Most prokaryotic cells begin to replicate, or copy, their DNA once they have grown to a certain size.

❑ When DNA replication is complete,the cells divide through a processknown as binary fission.

❑ Binary fission is a form of asexual reproduction during which two genetically identical cells are produced.

What is the eukaryotic cell cycle?❑ The eukaryotic cell cycle consists of four phases:

❑ Gap 1 or G1

❑ Synthesis or S

❑ Gap 2 or G2

❑ Mitosis or M

❑ The period of growth that consists of the G

1, S, and G

2 is

called interphase

❑ Period between cell divisions.

❑ Much longer in time than mitosis.

TIME SPENT IN PHASES

What are the main events of the G1

phase?

❑ Cell increases in size.

❑ Cell synthesizes

new proteinsand organelles.

What are the main events of the S phase?

❑ New DNA is synthesized whenthe chromosomes are replicated.

❑ At the end of this phase

the cell contains twice

as much DNA as it did at the beginning.

What are the main events of the G2

phase?

❑ Shortest of the three phases ofinterphase.

❑ Many of the organelles and molecules required for cell division are produced.

❑ At the end of this phase the cell is ready to divide.

What are the main events of the M phase?❑ In eukaryotes, cell division

occurs in two stages: mitosisand cytokinesis.

❑ Mitosis is the division

of the cell nucleus.

❑ Cytokinesis is the division of the cytoplasm.

How do cells regulate the cell cycle?❑ Cancer is a disorder in which

some of the body’s cellslose the ability to controlgrowth.

❑ Checkpoints are biologicalstoplights telling the cell if it cansafely go or when to stop and fixa problem.❑ G

1 checkpoint makes sure the cell

is large enough to enter the S phase.❑ G

2 checkpoint makes sure the DNA is

completely replicated, that replication errors have been repaired, and the cell is large enough to replicate.

❑ M checkpoint make sure the chromosomes are aligned on the spindle ready for nuclear division.

What are some important cell structures involved in mitosis?

1. Chromosome: Package of DNA containing genetic information

2. Chromatid: Each strand of a duplicated chromosome

3. Centromere: The area where each pair of chromatids is joined

4. Centrioles: Tiny structures located in the cytoplasm of animal cells that help organize the spindle

5. Spindle: Fanlike microtubule structure that helps separate the chromatids

What are the main events of prophase?❑ First phase of mitosis.

❑ Chromatin condense intochromosomes.

What are the main events of prophase?❑ First phase of mitosis.

❑ Chromatin condense intochromosomes.

❑ Centrioles move to opposite sides of nucleus.

What are the main events of prophase?❑ First phase of mitosis.

❑ Chromatin condense intochromosomes.

❑ Centrioles move to opposite sides of nucleus.

❑ Spindle forms.

❑ DNA strands attach at a point called their centromere.

What are the main events of prophase?❑ First phase of mitosis.

❑ Chromatin condense intochromosomes.

❑ Centrioles move to opposite sides of nucleus.

❑ Spindle forms.

❑ DNA strands attach at a point called their centromere.

❑ Nucleolus disappears

❑ Nuclear envelope breaks down.

What are the main events of metaphase?❑ Second phase of mitosis.

❑ Centromeres of the duplicatedchromosomes line up across the center of the cell.

What are the main events of metaphase?❑ Second phase of mitosis.

❑ Centromeres of the duplicatedchromosomes line up across the center of the cell.

❑ Each chromosome is connectedto spindle fiber at its centromere.

What are the main events of anaphase?❑ Third phase of mitosis.

❑ Sister chromatids separate intoindividual chromosomes.

What are the main events of anaphase?❑ Third phase of mitosis.

❑ Sister chromatids separate intoindividual chromosomes.

❑ Chromosomes separateinto two groups near the polesof the spindle.

What are the main events of telophase?❑ Fourth and final phase of mitosis.

❑ Chromosomes spread out into a tangle of chromatin.

What are the main events of telophase?❑ Fourth and final phase of mitosis.

❑ Chromosomes spread out into a tangle of chromatin.

❑ A nuclear envelope re-forms around each cluster of chromosomes.

What are the main events of telophase?❑ Fourth and final phase of mitosis.

❑ Chromosomes spread out into a tangle of chromatin.

❑ A nuclear envelope re-forms around each cluster of chromosomes.

❑ The spindle breaks apart.

❑ A nucleolus becomes visible in each daughter nucleus.

What is cytokinesis?❑ Cytokinesis is the

division of the cytoplasm.

❑ Cytokinesis completes the process of cell division by splitting one cell into two.

❑ The process of cytokinesis is different in animal and plant cells.

What is cytokinesis?

Animal Cells

❑ The cell membrane is drawn in until the cytoplasm is pinched into two equal parts.

❑ Each part contains its own nucleus and organelles.

Plant Cells

❑ In plants, the cell membrane is not flexible enough to draw inward because of the rigid cell wall.

❑ Instead, a cell plate forms between the divided nuclei that develops into cell membranes.

❑ A cell wall then forms in between the two new membranes.

What are some important facts about mitosis?

1. Nucleus of a cell dividesinto two nuclei.

2. Takes place in somatic, or bodycells.

3. Maintains the numberof chromosomes.

4. Results in two diploid, genetically identical daughter cells.

5. Does not increase genetic diversity6. Used by many prokaryotes and protists as a form of

reproduction (binary fission or asexual reproduction).

Race car Event

Get into 4 even teams:

Pick a color: Orange/ Green/ Black/ Purple.

Let’s see what team will win the race.

The Mitosis Drama 1. Select 16 students to pair up as “sister chromatids.” Each pair

should hold a book between them as a centromere.2. Choose three more pair of students, and give each pair a

20-foot piece of string.3. Have the students act out mitosis by calling out “prophase.”

Students should move around.4. Have the students act out mitosis by calling out “metaphase.”

The eight pairs should line up across the room5. Have the students act out mitosis by calling out “anaphase.”

Pairs set the book on the floors, move two opposite ends of the room, and then move about.

6. Have the students act out mitosis by calling out “telophase.” Two pairs of students with string should surround each group of eight with their “nuclear membrane string.”

7. Have the students act out mitosis by calling out “cytokinesis.” The final pair of students with string should stretch their string between two “cells” to show cytoplasmic division.

Independent Practice

Mitosis Concept MapDIRECTIONS:

Match the picture of the phase to the name: when you are finished call the teacher so she can make sure you are correct.

Then draw it on the concept map provided in the order found in mitosis. Then, in the box provided, describe what is happening at each stage. Your explanations must include the words: nuclear membrane, chromosomes, sister chromatids, spindles, centrioles, centromeres in every box.Underline your answers.

Homework: Mitosis RAFT

Directions: You will be completing the following writing assignment on Mitosis (Cell

Division). Start by choosing the role in which you will write from. Then follow the table

across to discover the rest of the assignment. You may choose any of the 3

combinations.

Role Audience Format Topic

Parent Cell Daughter Cell Will “What I leave you when I die”

Skin Cell Skin Cell Letter to Editor “Why are you copying me?!?”

Chromosome Nucleus Text Message “Why I am important!”

Rubric

Even day Data Chat...

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