Cell Division and the Cell Cycle

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Questions and Answers

What are the two basic phases of the cell cycle?

G2 Phase and G0 Phase

Interphase and M Phase (correct)

Karyokinesis and Cytokinesis

G1 Phase and S Phase

During which phase does DNA replication occur?

G2 Phase

M Phase

S Phase (correct)

G1 Phase

What happens to the amount of DNA during the S phase if the initial amount is denoted as 2C?

It doubles to 3C

It decreases to 1C

It remains 2C

It increases to 4C (correct)

What characterizes the quiescent stage (G0) of the cell cycle?

Cells no longer proliferate unless stimulated Signup and view all the answers

How many stages are there in the karyokinesis of mitosis?

Four stages Signup and view all the answers

What occurs during the G2 phase of the cell cycle?

Cell growth continues and proteins are synthesized in preparation for mitosis Signup and view all the answers

In which type of cells is mitotic division primarily observed in animals?

Diploid somatic cells Signup and view all the answers

What feature characterizes prophase in mitosis?

Chromosomes become visible Signup and view all the answers

What is the primary purpose of meiosis?

To produce haploid cells Signup and view all the answers

Which phase of prophase I is characterized by the visibility of chromosomes under a microscope?

Leptotene Signup and view all the answers

What structure forms when homologous chromosomes synapse during prophase I?

Tetrads Signup and view all the answers

During which meiotic phase do homologous chromosomes separate?

Anaphase I Signup and view all the answers

Which event occurs during the pachytene stage of prophase I?

Crossing over begins Signup and view all the answers

What notable change occurs during the diplotene stage?

Dissolution of the synaptonemal complex Signup and view all the answers

What is formed around the chromosome clusters at each pole during telophase?

Nuclear membrane Signup and view all the answers

What characterizes the metaphase stage of mitosis?

Chromosomes are fully condensed and aligned at the metaphase plate Signup and view all the answers

What is the term for the X-shaped structures formed during crossing over?

Chiasmata Signup and view all the answers

What do spindle fibers attach to during metaphase?

Kinetochores Signup and view all the answers

What happens during interkinesis between meiosis I and meiosis II?

Cell growth and metabolic activity increase Signup and view all the answers

How do plant cells achieve cytokinesis?

Through the formation of a cell plate Signup and view all the answers

What results from karyokinesis not being followed by cytokinesis?

Multinucleate condition leading to syncytium Signup and view all the answers

Which structure are chromosomes made up of during metaphase?

Sister chromatids Signup and view all the answers

Which phase occurs after metaphase in the mitotic process?

Anaphase Signup and view all the answers

What is the primary outcome of mitosis in multicellular organisms?

Formation of diploid daughter cells with identical genetic complement Signup and view all the answers

Study Notes

Cell Division

The cell cycle is a series of events where a cell duplicates its genome, synthesizes other components, and divides into two daughter cells.
DNA synthesis happens in a specific stage of the cell cycle.
A typical eukaryotic cell divides approximately every 24 hours. Yeast divides faster, in about 90 minutes.
The cell cycle has two main phases: Interphase and M Phase (Mitosis).
Interphase takes up over 95% of the cell cycle.
The M Phase is when mitosis (cell division) happens.
Interphase is broken down into three phases: G1 phase, S phase, and G2 phase.
During G1, the cell grows and prepares for DNA replication
During S, DNA replication occurs.
If initial DNA is 2C, it becomes 4C after S phase.
In the G2 phase proteins for mitosis are synthesized.
Cells that don't divide further enter a quiescent stage (G0).
Mitosis only happens in diploid somatic cells in animals, though some exceptions exist, like male honey bees.
In plants, mitosis occurs in both haploid and diploid cells.
Mitosis is described as equational division because the chromosome number stays the same.
Mitosis stages: prophase, metaphase, anaphase, and telophase.

Prophase

The first stage of karyokinesis (nuclear division) that occurs after S and G2 phases of interphase.
Golgi complexes, endoplasmic reticulum, nucleolus and nuclear envelope are not visible in cells at the end of prophase.
The nuclear envelope disintegrates in the early stage of metaphase.
Chromosomes appear condensed during prophase.

Metaphase

Chromosomes align in the middle of the cell.
Each chromosome consists of two chromatids held together by a centromere.
Small disc-shaped structures called kinetochores are on the centromeres.
The alignment line is called the metaphase plate.

Anaphase

Sister chromatids separate and move to opposite ends of the cell.

Telophase

Chromosomes reach the poles.
Nuclear membranes begin to reform.
Chromosomes decondense.

Cytokinesis

Cytoplasm division.
Animals: Cleavage furrow forms.
Plants: Cell plate forms.

Meiosis

Cell division that reduces the chromosome number by half (haploid cells).
Two sequential cycles of nuclear and cell division: meiosis I and meiosis II.
Prophase I is divided into five stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.
Crossing over (exchange of genetic material between non-sister chromatids) happens.
Meiosis produces four haploid cells.
Meiosis is important for sexual reproduction because it creates genetic variability in organisms.

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Description

Test your knowledge on the intricacies of the cell cycle and cell division. This quiz covers phases such as Interphase and M Phase, as well as key processes like DNA replication. Explore the differences in division timelines across various organisms, from yeast to diploid somatic cells.