{{asɛmtiNe Ɔkyerɛwfo}} | Nhomakorabea | Nneɛma a ɛma wotumi yɛ ade

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Model 2 - The Cell Cycle:

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Read This:

In the model of the cell cycle, it begins at the flat part of the G₁arrow with the one cell with the asterisk (*) and ends at the tip of the M arrow with two cells, both without an asterisk.

Notice what happens to the size of the cell from the beginning of G₁ to end of G₁ (near the beginning of S).

4

Using model 1, list the four steps of mitosis in order.

1st

2nd

3rd

4th

2

Where is mitosis in the cell cycle? It occurs before, or prior to, and after .

2

Refer to the cell cycle shown at the left.

a.) How many cells are present at the begining of mitosis?

b.) How many cells are present at the end of mitosis?

1

Refer back to model 1. Look for the replicated chromosomes in the cell in prophase.

How many chromatids are present in each replicated chromosome?

2

1

Read This:

A chromosome is a structure made mainly of two components:

DNA
Proteins called histones

The DNA wraps around the histones, which helps keep it organized, similar to how folding clothes keeps them neat, and allows it to fit inside a cell (in prokaryotes) or inside the nucleus (in eukaryotes).

When a cell is preparing to divide (through mitosis or meiosis, followed by cytokinesis), the DNA wraps more tightly around the histones than usual. This tighter wrapping causes the chromosomes to condense, meaning they become more compact and take up less space. Because of this, chromosomes become visible under a light microscope at this stage. At other times, they are not easily seen and cannot be clearly distinguished from the rest of the nucleus.

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Model 2 - The Cell Cycle:

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In the model of the cell cycle, it begins at the flat part of the G1 arrow with the one cell with the asterisk (*) and ends at the tip of the M arrow with two cells, both without an asterisk.

Notice what happens to the size of the cell from the beginning of G1 to end of G1 (near the beginning of S).

1

Describe what each new cell at the end of telophase would contain, with respect to chromosome number, if replication of chromosomes (DNA) did not occur prior to mitosis.

1

If the situation in the previous question occurred, would these new cells be able to survive? Why do you think this?

1

The S phase of the cell cycle stands for synthesis, which means to make or build something more complex out of simpler parts. Scientists know that during the S phase DNA is being made in the nucleus of the cell. Why do you think the cell needs to make more DNA at this time in the cell cycle?

1

Refer to Model 1.

The chromosomes that are shaped like “X” (made of two sister chromatids) have double the amount of DNA than the chromosomes that are shaped like “I.”

During what phase of the cell cycle do you think the chromosomes are replicated (copied)?

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4

Refer to Model 1.

a. In which phase of mitosis do you see the spindle fibers forming?

b. At what phase of mitosis do the replicated chromosomes (sister chromatids) separate?

c. In which phase do you see that the spindle fibers have disappeared?

d. Look at metaphase and anaphase. Suggest the purpose of the spindle fibers during mitosis.

1

Refer to Model 1.

What happens to the nuclear membrane during and after prophase.

1

Why might it be imporant for the nuclear envelope to breakdown during mitosis?

1

At what point during mitosis has the nuclear membrane reformed?

1

What is actually dividing during cytokinesis?

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Cellular division has two parts — mitosis (the division of the nucleus) and cytokinesis (the division of the cytoplasm and the rest of the cell) — that will form two new daughter cells. Using model 1 and the cell cycle model, above, and what you have learned thus far, provide a logical reason why mitosis needs to come before cytokinesis during the cell division.

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For 17 - 21, refer to Model 1 to help you describe the basic events of each phase cell division.

In the table to the bottom-left, each blank has a number in a circle, these correspond to the numbered questions to the right of the table.

Use your note-taking sheet, but do not look things up on the internet - I can tell when you do this.

Try to restrict your comments to what the nucleus and chromosomes are doing. In other words, be brief and get to the point.

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1

Describe the primary events of prophase.

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Describe the primary events of metaphase.

1

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Ɛhia

0

After having completed this activity, provide a list of one or two things that you have learned or anything that you understand better than you did prior to this activity.

Ɛhia

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Copy of 2.) Mitosis and Cell Cycle Models (5/28/2026)

Copy of 2.) Mitosis and Cell Cycle Models (5/28/2026)

Describe what each new cell at the end of telophase would contain, with respect to chromosome number, if replication of chromosomes (DNA) did not occur prior to mitosis.

If the situation in the previous question occurred, would these new cells be able to survive? Why do you think this?

The S phase of the cell cycle stands for synthesis, which means to make or build something more complex out of simpler parts. Scientists know that during the S phase DNA is being made in the nucleus of the cell. Why do you think the cell needs to make more DNA at this time in the cell cycle?

Why might it be imporant for the nuclear envelope to breakdown during mitosis?

Describe the primary events of prophase.

Describe the primary events of metaphase.

After having completed this activity, provide a list of one or two things that you have learned or anything that you understand better than you did prior to this activity.

After having completed this activity, my confidence regarding this concept has:

Describe what each new cell at the end of telophase would contain, with respect to chromosome number, if replication of chromosomes (DNA) did not occur prior to mitosis.

If the situation in the previous question occurred, would these new cells be able to survive? Why do you think this?

The S phase of the cell cycle stands for synthesis, which means to make or build something more complex out of simpler parts. Scientists know that during the S phase DNA is being made in the nucleus of the cell. Why do you think the cell needs to make more DNA at this time in the cell cycle?

Why might it be imporant for the nuclear envelope to breakdown during mitosis?

Describe the primary events of prophase.

Describe the primary events of metaphase.

Describe the primary events of anaphase.

Describe the primary events of telophase.

Describe the primary events of cytokinesis.

After having completed this activity, provide a list of one or two things that you have learned or anything that you understand better than you did prior to this activity.

After having completed this activity, my confidence regarding this concept has:

Describe the primary events of anaphase.

Describe the primary events of telophase.

Describe the primary events of cytokinesis.