Cell Cycle Overview

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Questions and Answers

During which phase of meiosis do homologous pairs of chromosomes line up on the equatorial plate?

Anaphase I

Prophase I

Telophase I

Metaphase I (correct)

What is the state of each chromosome at the end of telophase I?

Three chromatids

A single chromatid

Two chromatids (correct)

Four chromatids

Which of the following is NOT a characteristic of Meiosis II?

It is similar to mitosis.

It is preceded by S phase for DNA synthesis. (correct)

It involves a total of four cells from the original diploid germ cell.

Chromatids migrate to opposing poles during anaphase II.

What is the chromosome number in each of the daughter cells after telophase I?

Haploid (D) Signup and view all the answers

During anaphase in both mitosis and meiosis, what happens to the genetic content of the cell?

The genetic content is distributed to either poles (A) Signup and view all the answers

What is the primary purpose of mitosis?

To generate daughter cells with identical genetic material as the parent cell. (A) Signup and view all the answers

Which phase of the cell cycle is characterized by DNA replication?

S phase (A) Signup and view all the answers

What occurs during the G1 phase of interphase?

Synthesis of macromolecules for DNA replication and cell volume restoration. (D) Signup and view all the answers

Which of the following describes the state of DNA content in a cell before and after the S phase?

From diploid (2n) to tetraploid (4n). (C) Signup and view all the answers

What is the term for the division of the cytoplasm that occurs at the end of mitosis?

Cytokinesis (D) Signup and view all the answers

What is the main difference between mitosis and meiosis?

Mitosis produces genetically identical cells, while meiosis produces genetically diverse cells. (D) Signup and view all the answers

During which phase of the cell cycle is Tubulin synthesized for microtubule assembly?

G2 Phase (D) Signup and view all the answers

What is the primary function the cell performs during the G2 phase?

Cell growth and synthesis of RNA and proteins for cell division. (C) Signup and view all the answers

What is the correct sequence of the four stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase (B) Signup and view all the answers

During which phase of mitosis do the chromosomes line up at the equator of the mitotic spindle?

Metaphase (C) Signup and view all the answers

Which event characterizes the beginning of anaphase?

Separation of sister chromatids. (D) Signup and view all the answers

During which stage of mitosis does cytokinesis start and what does it entail?

Late Anaphase, formation of a cleavage furrow (D) Signup and view all the answers

What is the final result of mitosis in terms of chromosome number?

Diploid (2n) number of chromosomes in two daughter cells (D) Signup and view all the answers

What is the term for the structure formed when homologous chromosomes pair up during prophase I of meiosis?

Tetrad (D) Signup and view all the answers

What process during Prophase I of meiosis contributes to genetic variability?

Crossing over between homologous chromosomes (D) Signup and view all the answers

Study Notes

Cell Cycle

The cell cycle is a series of events where a cell prepares for division into two daughter cells.
Cell division of existing cells is essential for embryonic development and occurs after birth for growth and replacement of dead cells.
Daughter cells must have the same number and genetic content as the parent cell.

Major Events of Cell Cycle

Interphase: A long period of time where the cell increases in size and duplicates its genetic material.
- G1 phase: Synthesis of macromolecules essential for DNA duplication. Cell volume is restored to normal, nucleoli are reestablished, and centrioles begin to duplicate.
- S phase: DNA is duplicated. Autosomal cells double their DNA amount from diploid (2n) to 4n in preparation for division. All the required nucleoproteins (e.g., histones) are made and incorporated into DNA, forming chromatin. Cell DNA is now double the normal amount.
- G2 phase: The cell undergoes preparation for mitosis, including DNA synthesis completion, RNA and protein synthesis for cell division, and storage of energy for mitosis. Tubulin is synthesized into microtubules.
Mitosis: A shorter period where the cell's nucleus divides first, followed by cytoplasm division, creating two daughter cells.
- Process: Mitosis occurs at the conclusion of the G2 phase. It includes karyokinesis (nucleus division) and cytokinesis (cytoplasm division). These events are divided into four phases: prophase, metaphase, anaphase, and telophase.

Mitosis Stages

Prophase: Chromosomes condense and become visible under a microscope; the centrosome divides, with the two resulting centrioles migrating to opposite poles of the cell. The nuclear envelope and nucleolus disappear.
Metaphase: Chromosomes are maximally condensed and lined up at the equator of the mitotic spindle.
Anaphase: Sister chromatids separate and migrate towards opposite poles. A cleavage furrow forms.
Telophase: Chromosomes reach the opposite poles, the nuclear envelope and nucleolus reform, and the chromosomes un-condense. Cytokinesis is complete, producing two identical daughter cells.

Meiosis

Meiosis is a special type of cell division that results in the formation of gametes (e.g., sperm and ova).
It reduces the chromosome number from diploid (2n) to haploid (1n).
Meiosis I (Reductional Division):
- Homologous chromosome pairs are separated, reducing the chromosome number from diploid to haploid.
- Prophase I involves homologous chromosome pairing, crossing over, and chiasmata formation.
- Metaphase I involves homologous chromosome pairs lining up at the equator.
- Anaphase I involves separation of homologous chromosome pairs, moving to opposite poles of the cell.
- Telophase I is similar to telophase of mitosis, resulting in two daughter cells with haploid chromosome number.
Meiosis II (Equational Division): Prophase II, Metaphase II, Anaphase II, and Telophase II, similar to mitosis. The end result is four haploid daughter cells, each with unique genetic content.

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Description

This quiz covers the essential stages of the cell cycle, including interphase and its phases: G1, S, and G2. Students will learn about cell growth, DNA duplication, and the processes that prepare a cell for division into two genetically identical daughter cells.