Ch 10

Question 1

What is the purpose of cell division in multicellular eukaryotes?

Answer 1

To develop from a single cell and renew, repair, or replace cells as needed

Cell division is essential for growth and maintenance of multicellular organisms.

Question 2

Cell division is an integral part of the cell cycle. What does it involve?

Answer 2

An ordered series of events involving cell growth and cell division that produces two new daughter cells

The cell cycle includes phases of growth (interphase) and division (mitosis).

Question 3

Most cell division results in the distribution of identical genetic material to two daughter cells. What is this genetic material?

Answer 3

DNA

DNA is packaged into chromosomes during cell division.

Question 4

Every eukaryotic species has a characteristic number of chromosomes in each cell nucleus. What are somatic cells?

Answer 4

Cells that are not reproductive cells (sperm or eggs)

Somatic cells contain two sets of chromosomes.

Question 5

How many sets of chromosomes do gametes (reproductive cells) have?

Answer 5

One set of chromosomes

Gametes include sperm and eggs.

Question 6

In preparation for cell division, DNA is replicated and the chromosomes _______.

Answer 6

condense

Chromosomes become more tightly packed to facilitate separation during division.

Question 7

During cell division, what happens to the two sister chromatids of each duplicated chromosome?

Answer 7

They separate and move into two nuclei

This ensures that each daughter cell receives an identical set of chromosomes.

Question 8

Once separate, the chromatids are called _______.

Answer 8

chromosomes

This transition occurs during the later stages of cell division.

Question 9

What is the mitotic spindle made of?

Answer 9

• Microtubules
• Associated proteins

The mitotic spindle controls chromosome movement during mitosis.

Question 10

In animal cells, the assembly of spindle microtubules begins in the _______.

Answer 10

centrosome

The centrosome is the microtubule organizing center.

Question 11

The centrosome replicates during _______.

Answer 11

interphase

This replication forms two centrosomes that migrate to opposite ends of the cell.

Question 12

During which phases do the two centrosomes migrate to opposite ends of the cell?

Answer 12

• Prophase
• Prometaphase

This migration is essential for proper spindle formation.

Question 13

What is an aster in the context of cell division?

Answer 13

A radial array of short microtubules extending from each centrosome

Asters play a role in the organization of the mitotic spindle.

Question 14

The spindle includes which components?

Answer 14

• Centrosomes
• Spindle microtubules
• Asters

These components work together to facilitate chromosome movement.

Question 15

The cell cycle consists of which main phases?

Answer 15

• Interphase
• Mitotic phase including mitosis and cytokinesis

Interphase is further divided into subphases.

Question 16

What are the subphases of Interphase?

Answer 16

• G1 phase (first gap) - growth
• S phase (synthesis) - growth & DNA duplication
• G2 phase (second gap) - growth

Each phase has specific roles in preparing the cell for division.

Question 17

What are the two main processes involved in cell division?

Answer 17

• Mitosis (Karyokinesis)
• Cytokinesis

Mitosis is the division of genetic material in the nucleus, while cytokinesis is the division of the cytoplasm.

Question 18

What is the first phase of mitosis?

Answer 18

Prophase

In prophase, chromosomes condense, spindle fibers emerge, and the nuclear envelope breaks down.

Question 19

During which phase of mitosis do kinetochores appear at the centromeres?

Answer 19

Prometaphase

In this phase, spindle fibers connect to the kinetochores of the chromosomes.

Question 20

What happens during the metaphase of mitosis?

Answer 20

• Chromosomes are moved to the metaphase plate
• Centrosomes finish moving to opposite sides of the cell

This phase ensures that chromosomes are properly aligned for separation.

Question 21

What occurs during anaphase?

Answer 21

• Sister chromatids are separated
• Spindle fibers pull chromosomes toward opposite poles of the cell

Each sister chromatid is now considered a separate chromosome.

Question 22

What is the final phase of mitosis?

Answer 22

Telophase

In telophase, chromosomes reach each side of the cell and the nuclear envelope redevelops.

Question 23

When does cytokinesis begin during the cell division process?

Answer 23

During anaphase

Cytokinesis is the process of dividing the cytoplasm and begins while mitosis is still occurring.

Question 24

In animal cells, cytokinesis occurs by a process known as _______.

Answer 24

cleavage furrow formation

This process involves the contraction of actin filaments to pinch the cell into two.

Question 25

What directs the **sequential events** of the cell cycle?

Answer 25

A distinct cell cycle control system ## Footnote This system ensures that the cell cycle progresses in an orderly manner.

Question 26

What are the **specific checkpoints** in the cell cycle?

Answer 26

* G1 checkpoint * G2 checkpoint * M checkpoint ## Footnote These checkpoints are critical for assessing whether the cell can proceed to the next phase.

Question 27

What does the **G1 checkpoint** check for?

Answer 27

* Favorable conditions for cell division * Genomic damage * Cell size ## Footnote If conditions are not favorable, the cell will exit the cycle into a non-dividing state called the Go phase.

Question 28

What happens if the cell does not receive the **go-ahead signal** at the G1 checkpoint?

Answer 28

It exits the cycle into the **Go phase** ## Footnote The Go phase is a non-dividing state.

Question 29

What does the **M checkpoint** check for?

Answer 29

That all sister chromatids are attached to spindle microtubules ## Footnote This ensures proper chromosome segregation during cell division.

Question 30

What is **density-dependent inhibition**?

Answer 30

Crowded cells stop dividing ## Footnote This is a regulatory mechanism that prevents over-proliferation of cells.

Question 31

What is **anchorage dependence**?

Answer 31

Cells must be attached to a substratum in order to divide ## Footnote This requirement helps regulate cell growth and prevents inappropriate cell division.

Question 32

True or false: **Cancer cells** exhibit density-dependent inhibition.

Answer 32

FALSE ## Footnote Cancer cells do not respond to normal regulatory signals that control the cell cycle.

Question 33

What do cancer cells form within otherwise normal tissue?

Answer 33

Tumors, masses of abnormal cells ## Footnote These tumors can disrupt normal tissue function and lead to various health issues.

Question 34

What does G2 checkpoint check?

Answer 34

Replication complete.

Question 35

What is a **benign tumor**?

Answer 35

A lump where abnormal cells remain only at the original site ## Footnote Benign tumors do not invade surrounding tissues.

Question 36

What characterizes a **malignant tumor**?

Answer 36

Invades surrounding tissue and can metastasize ## Footnote Malignant tumors export cancer cells to other parts of the body, potentially forming additional tumors.