Cell Biology Chapter 3 Quiz

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Questions and Answers

What are the two main stages of cell division?

Karyokinesis and cytokinesis (correct)

Nuclear division and interphase

Mitosis and S phase

Interphase and cytokinesis

Which phase follows mitosis and cytokinesis in the cell cycle?

S phase

G2 phase

Prophase

G1 phase (correct)

What significant role does the spindle apparatus play during cell division?

Facilitating apoptosis

Organizing microtubules for chromosome separation (correct)

Initiating cytokinesis

Separating homologous chromosomes

What happens during the interphase of the cell cycle?

Cells prepare for mitosis Signup and view all the answers

Which of the following best describes homologous chromosomes?

Pairs of chromosomes containing the same genes Signup and view all the answers

What occurs during the G1 phase of the cell cycle?

The cell increases in size and produces proteins. Signup and view all the answers

What is the role of centrioles in animal cells?

To produce spindle fibers. Signup and view all the answers

Why do cells have limitations on their size?

To facilitate cellular exchange. Signup and view all the answers

When is DNA replicated during the cell cycle?

During the S phase. Signup and view all the answers

What is the effect of anti-tumor drugs that stabilize microtubules?

They cause cell cycle arrest. Signup and view all the answers

What results from a high genome to volume ratio in cells?

Efficient cellular operations. Signup and view all the answers

What can be inferred about the G1 checkpoint in the cell cycle?

It ensures that the cell is ready for division. Signup and view all the answers

What is the significance of centrosomes in animal cells?

They are involved in spindle formation. Signup and view all the answers

Which statement about metaphase is correct?

Chromosomes align at the cell's equatorial plane. Signup and view all the answers

What is the correct chromosome and chromatid count at the end of anaphase?

92 chromosomes, 92 chromatids Signup and view all the answers

Which of the following describes telophase?

The nuclear envelope re-forms and chromosomes decondense. Signup and view all the answers

What is the function of the kinetochore during mitosis?

To facilitate chromosome separation by microtubules. Signup and view all the answers

Which cell types are usually found in the G0 phase?

Nerve cells and cardiac cells. Signup and view all the answers

During which phase is the chromatid count doubled?

Anaphase Signup and view all the answers

What happens to the chromosomes at the end of cytokinesis?

They decondense into chromatin and each cell has 46 chromosomes. Signup and view all the answers

What is a primary outcome of meiosis?

Four non-identical haploid daughter cells Signup and view all the answers

During which phase of meiosis do homologous chromosomes separate?

Meiosis I Signup and view all the answers

Which event increases genetic variation during meiosis?

Crossing over Signup and view all the answers

What occurs during prophase I of meiosis?

Crossing over between homologous chromosomes Signup and view all the answers

Which of the following correctly describes meiosis II?

Sister chromatids separate Signup and view all the answers

What is one source of genetic variation not associated with meiosis?

Mutations Signup and view all the answers

How many times does the nuclear division occur in meiosis?

Twice Signup and view all the answers

Which feature distinguishes meiotic daughter cells from mitotic daughter cells?

Meiotic daughter cells are non-identical haploid Signup and view all the answers

What is formed during Prophase I that is essential for crossing over?

Tetrads Signup and view all the answers

During which phase do homologous chromosomes line up at the metaphase plate?

Metaphase I Signup and view all the answers

What does independent assortment during Metaphase I ensure?

Different alleles are segregated randomly Signup and view all the answers

What structure is responsible for physically linking homologous chromosomes during synapsis?

Synaptonemal complex Signup and view all the answers

What ultimately occurs to homologous chromosomes during Anaphase I?

They separate and move to opposite poles Signup and view all the answers

What denotes the locations where crossing over occurs between homologous chromosomes?

Chiasmata Signup and view all the answers

What is the overall chromosome composition at the end of Telophase I?

46 chromosomes, 92 chromatids Signup and view all the answers

What occurs to the nuclear envelope during Prophase I?

It breaks down Signup and view all the answers

How does random joining of gametes contribute to genetic variation?

It allows for different combinations of alleles Signup and view all the answers

What is the result of crossing over during meiosis?

Exchange of genetic material between homologous chromosomes Signup and view all the answers

What is the result of cytokinesis in meiosis?

Two haploid daughter cells Signup and view all the answers

During which phase do sister chromatids separate in meiosis?

Anaphase II Signup and view all the answers

How many rounds of cell division occur in meiosis?

2 Signup and view all the answers

What is the chromosome number in the daughter cells at the end of meiosis II?

23 chromosomes, 23 chromatids Signup and view all the answers

What is the primary difference in genetic variation between meiosis and mitosis?

Meiosis involves crossing over Signup and view all the answers

What is genetic linkage?

The likelihood of genes being inherited together Signup and view all the answers

What type of cells are produced at the end of meiosis?

Haploid cells Signup and view all the answers

Which of the following occurs during metaphase II of meiosis?

Chromosomes line up at the metaphase plate Signup and view all the answers

At the end of which phase are four genetically distinct daughter cells formed?

Telophase II Signup and view all the answers

In which type of cell division does chromosome number remain the same?

Mitosis Signup and view all the answers

Study Notes

Cell Division

Cell division involves karyokinesis (nuclear division) followed by cytokinesis (cytoplasmic division).
Diploid cells have two copies of each chromosome, called homologous chromosomes.
Humans have 46 chromosomes (23 homologous pairs).
Centrosomes, containing centrioles, produce spindle fibers for chromatid separation during anaphase.
The cell cycle has interphase (G1, S, G2) and the mitotic phase (mitosis and cytokinesis).
G1: Cell growth, protein/ribosome/mitochondria production, organelle replication; G1 checkpoint ensures readiness for DNA synthesis.
S: DNA synthesis, replication of existing DNA, creation of sister chromatids.
G2: Continued cell growth, preparation of genetic material for division, some organelle replication.
GO: Inactive state, not actively growing or dividing (e.g., nerve, cardiac cells).

Mitosis

Prophase: Nucleus disassembles, nucleolus disappears, chromatin condenses into chromosomes.
Metaphase: Chromosomes line up at the metaphase plate; each chromosome consists of two sister chromatids.
Anaphase: Microtubules shorten pulling sister chromatids to opposite poles (disjunction).
Telophase and cytokinesis: Nuclear envelope re-forms, chromosomes decondense, nucleoli reappear; 2 diploid daughter cells result.

Regulation of Cell Cycles

Surface-to-volume ratio: Small ratio (large cells) leads to difficulty in nutrient exchange, triggering cell division (e.g., anti-tumor drugs acting as microtubule inhibitors).
Genome-to-volume ratio: Low ratio (large cells) results in inability of genome to produce sufficient proteins for cell regulation.
Spindle apparatus crucial in mitotic phase; microtubules attach to kinetochores (on sister chromatids), not directly to chromosomes.

Meiosis

Meiosis produces four non-identical haploid daughter cells from one diploid parent cell, repeating nuclear division twice.
Meiosis I (separation of homologous chromosomes) and Meiosis II (separation of sister chromatids).
Events that introduce genetic variation:
- Crossing over (Prophase I): Non-sister chromatids exchange genetic material.
- Independent assortment (Metaphase I): Random alignment of homologous chromosomes producing diverse gametes.
- Random joining of gametes (fertilization): Random combination of gametes.
Prophase I: Spindle formation, nuclear envelope breakdown; homologous chromosomes form tetrads linked by chiasmata (crossover points).
Metaphase I: Homologous chromosomes line up at the metaphase plate; independent assortment occurs.
Anaphase I: Homologous chromosomes separate to opposite poles.
Telophase I and cytokinesis: Homologous chromosomes separate; 2 haploid daughter cells formed.
Prophase II, Metaphase II, Anaphase II, Telophase II & Cytokinesis: Similar steps to mitosis but with haploid cells; 4 haploid cells are created.

Differences between Meiosis and Mitosis:

Feature	Meiosis	Mitosis
Chromosome number	Reduced by half (haploid)	Remains the same
Daughter cells	4 genetically distinct haploid cells	2 identical diploid cells
Cell division	2 rounds (Meiosis I & II)	1 round
Genetic info	Sister chromatids separate in Anaphase II; Homologous chromosomes separate in Anaphase I	Sister chromatids separate in anaphase.

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Description

Test your knowledge on cell division and the cell cycle with this quiz. Covering key concepts such as mitosis, cytokinesis, and the roles of various cellular structures, this quiz is perfect for students of cell biology. Prepare to challenge your understanding of essential processes that govern cellular functions.