Cytokinesis in Plant and Animal Cells

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Questions and Answers

What are the two main components of a spindle fiber?

Aster and centromeres

Centromeres and chromosomes

Microtubules and centrioles

Kinetochore and nonkinetochore microtubules (correct)

What is the function of the kinetochore?

To attach to the centromere

To facilitate the separation of the sister chromatids (correct)

To form the spindle equator

To overlap with the aster

During which phase of mitosis do the chromosomes become visible?

Anaphase

Metaphase

Prophase (correct)

Telophase

What is the purpose of the spindle fibers?

To separate the sister chromatids Signup and view all the answers

What happens to the nuclear envelope during prophase?

It starts to fragment Signup and view all the answers

During which phase of mitosis do the sister chromatids separate?

Anaphase Signup and view all the answers

What is the function of the aster?

To organize the microtubules Signup and view all the answers

What happens after mitosis?

Cytokinesis, the separation of the cytoplasm and its contents Signup and view all the answers

What is the result of the replication process in a coli cell?

Two daughter cells result. Signup and view all the answers

What is the term for the development of cancerous cells with specific characteristics?

Carcinogenesis Signup and view all the answers

What is the main characteristic of benign tumors?

They are encapsulated and do not invade neighboring tissue. Signup and view all the answers

What is the purpose of the contractile ring in cytokinesis?

To separate the cytoplasm between the two daughter cells Signup and view all the answers

What is the purpose of angiogenesis in cancer cells?

To form new blood vessels to feed nutrients and oxygen to a cancerous tumor Signup and view all the answers

What is the result of metastasis in cancer cells?

The cancer cells invade neighboring tissues and spread through the body Signup and view all the answers

What is the role of the Golgi apparatus in plant cell cytokinesis?

To produce vesicles that fuse to form the cell plate Signup and view all the answers

What is the function of the G1 checkpoint?

To commit the cell to division Signup and view all the answers

What is the purpose of cancer treatment?

To remove cancer cells or interfere with their ability to divide Signup and view all the answers

What is the term for cancer of the blood?

Leukemia Signup and view all the answers

What is the role of p53 protein?

To stop the cell cycle at the G1 checkpoint if DNA is damaged Signup and view all the answers

What is the function of the RB protein?

To prevent excessive cell growth by inhibiting cell cycle progression Signup and view all the answers

What is the characteristic of cancer cells in terms of their nuclei?

They have abnormally large nuclei and/or nuclei with an abnormal number of chromosomes Signup and view all the answers

What is the purpose of the G2 checkpoint?

To ensure DNA replication is completed Signup and view all the answers

What is the role of the M checkpoint?

To ensure chromosomes are distributed accurately to the daughter cells Signup and view all the answers

What happens if DNA damage is not corrected during the G1 checkpoint?

The cell cycle is stopped, and apoptosis is initiated Signup and view all the answers

What is the cell cycle?

The period of time from the production of a daughter cell to the cellular reproduction of that cell to produce two new daughter cells Signup and view all the answers

What is the longest stage of the cell cycle?

Interphase Signup and view all the answers

What happens during the G1 phase?

The cell grows and doubles the number of organelles Signup and view all the answers

What is the purpose of the S phase?

To create a duplicate DNA strand Signup and view all the answers

What happens during the G2 phase?

The cell synthesizes proteins needed for cell division Signup and view all the answers

What is the result of mitosis?

The production of genetically identical daughter cells Signup and view all the answers

What is the role of spindle fibers in mitosis?

To separate sister chromatids Signup and view all the answers

What is the result of cytokinesis?

The division of the cytoplasm and its contents Signup and view all the answers

What is the purpose of radiation therapy in cancer treatment?

To kill cancerous cells by damaging their DNA Signup and view all the answers

Which of the following is NOT a protective behavior against cancer?

Cigarette smoking Signup and view all the answers

What is the purpose of hormonal therapy in cancer treatment?

To interrupt the signals that contribute to cancer cell division Signup and view all the answers

What is the effect of excessive alcohol consumption on cancer risk?

It increases the risk of certain types of cancer Signup and view all the answers

What is the purpose of chemotherapy in cancer treatment?

To kill cancer cells that have metastasized Signup and view all the answers

What is a recommended dietary guideline for reducing cancer risk?

Increased consumption of vegetables from the cabbage family Signup and view all the answers

Study Notes

The Cell Cycle

The cell cycle spans the period of time from the production of a daughter cell to the cellular reproduction of that cell to produce two new daughter cells.
The cell cycle consists of two main stages: Mitotic (M) phase and Interphase.

Interphase

A cell spends most of its existence in Interphase, where it performs normal activities and functions.
Interphase has three stages: G1, S, and G2.
During G1, the cell grows and doubles its organelles and resources in preparation for DNA replication.
During S, DNA replication begins to create a duplicate DNA strand, resulting in sister chromatids.
During G2, the cell synthesizes proteins needed for cell division.

Mitotic (M) Phase

The M phase consists of Mitosis and Cytokinesis.
Mitosis is the division of nuclear material (DNA), producing two genetically identical daughter chromosomes.
Cytokinesis is the division of the cytoplasm and its contents, resulting in two daughter cells with the same number of chromosomes as the original cell.

Mitosis and Cytokinesis

The separation of sister chromatids during mitosis occurs in four phases: Prophase, Metaphase, Anaphase, and Telophase.
The spindle fibers, organized by the centrosome, attach to each duplicated chromosome at the kinetochore, facilitating the separation of sister chromatids.
In animal cells, centrosomes consist of two centrioles and an array of microtubules called an aster.
Cytokinesis in plant cells occurs by forming a new cell wall between the daughter cells, with the Golgi apparatus producing vesicles that fuse to form the cell plate.

The Cell Cycle Control System

The cell cycle is tightly regulated to ensure it is completed correctly.
The control system has checkpoints that control the progression of the cell cycle, ensuring that the stages of interphase occur sequentially in the correct order.
The G1 checkpoint is important, as passing this point commits the cell to division.
Proteins like p53 and RB protein regulate the cell cycle, stopping it at the G1 checkpoint if DNA is damaged and initiating DNA repair.

Cancer and the Cell Cycle

Cancer is a disease of the cell cycle, characterized by uncontrolled cell division.
Cancer cells lack differentiation, have abnormally large nuclei, and/or nuclei with an abnormal number of chromosomes.
Cancer cells form a mass of dividing cells called a tumor, which can undergo metastasis.
Cancer treatments include surgery, radiation therapy, chemotherapy, and hormonal therapy.

Prevention of Cancer

Evidence suggests that certain lifestyle changes can reduce the risk of certain types of cancer.
Adopting protective behaviors, such as avoiding potentially harmful activities, and following a protective diet can help reduce the risk of cancer.

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Description

Learn about the process of cytokinesis in plant and animal cells, including the formation of contractile rings and cell plates.