Cell Cycle and Cell Division (Mitosis, Meiosis, Gametogenesis)

A comprehensive set of practice flashcards covering the cell cycle, mitosis, meiosis, gametogenesis (spermatogenesis and oogenesis), and key structures/processes involved in cell division.

What is the basic function of the cell cycle?

To duplicate DNA and segregate copies into two genetically identical daughter cells.

What phases comprise Interphase?

G1, S, and G2 (the cell grows and duplicates DNA before mitosis).

What happens during S phase?

DNA synthesis; replication of the entire genome.

What happens during G1 phase?

Growth and metabolic activity; production of proteins and organelles; cell increases in size.

What happens during G2 phase?

Protein production; checking that copies of DNA are correct and intact before mitosis.

What occurs during Mitosis?

The nucleus divides so that two daughter cells receive a complete set of chromosomes.

What is G0 phase?

A metabolic state to maintain the cell, not preparing for division.

Where are cell cycle checkpoints located?

End of G1, the G2/M transition, and during metaphase.

What are the main types of cell division?

Prokaryotic Binary Fission; Eukaryotic Mitosis; Eukaryotic Meiosis.

What happens during Prokaryotic Binary Fission?

DNA duplicates, the cell elongates, and the cell divides into two identical cells (cytokinesis).

List the stages of mitosis.

Prophase, Prometaphase, Metaphase, Anaphase, Telophase.

What happens in Prophase (mitosis)?

Chromosomes condense and become visible; spindle fibers form; nuclear envelope breaks down; centrosomes move to poles.

What happens in Prometaphase (mitosis)?

Nuclear envelope fragments; kinetochores appear; spindle microtubules attach to kinetochores; chromosomes condense further.

What happens in Metaphase (mitosis)?

Chromosomes line up at the metaphase plate; kinetochores are attached to opposite poles.

What happens in Anaphase (mitosis)?

Centromeres split; sister chromatids separate and are pulled toward opposite poles; spindle fibers shorten.

What happens in Telophase (mitosis)?

Chromosomes arrive at poles and decondense; nuclear envelope reforms; spindle breaks down; cytokinesis follows.

What is the role of the centrosome in mitosis?

Organizes the mitotic spindle and moves to opposite poles.

What is Meiosis?

A two-stage division producing four haploid cells with half the original chromosome number.

What are the two stages of Meiosis?

Meiosis I and Meiosis II.

What happens in Meiosis I?

Homologous chromosomes separate; crossing over occurs during Prophase I; chromosome number is reduced by half.

What happens in Prophase I of meiosis?

Chromosomes condense and pair with their homologues; synapsis and crossing over occur; nuclear envelope breaks down; spindle forms.

What happens in Metaphase I?

Bivalents (paired homologues) align on the metaphase plate; orientation is random.

What happens in Anaphase I?

Homologous chromosomes separate to opposite poles; sister chromatids remain attached.

What happens in Telophase I and Cytokinesis?

Two haploid cells form; nuclear membranes form around each set; cytoplasm divides.

What stages comprise Meiosis II?

Prophase II, Metaphase II, Anaphase II, Telophase II.

What happens in Prophase II?

Nucleoli and nuclear membranes disperse; chromatids condense; centrioles move to poles; spindle fibers attach to centromeres.

What happens in Metaphase II?

Single chromosomes align on the metaphase plate; kinetochores attach to microtubules from opposite poles.

What happens in Anaphase II?

Centromeres split; sister chromatids separate and move to opposite poles; chromatids become separate chromosomes.

What happens in Telophase II?

Nuclear envelopes form around each set of chromosomes; cytokinesis yields four haploid gametes.

What is Gametogenesis?

The process of meiosis to form gametes (spermatogenesis and oogenesis).

Where does Spermatogenesis occur?

In the walls of the seminiferous tubules of the testes.

What are spermatogonia?

Stem cells at the periphery that divide by mitosis; one daughter becomes a primary spermatocyte, the other remains as stem cell.

What is the outcome of spermatogenesis in terms of gametes and chromosome number?

Four sperm, each haploid (n).

What is the outcome of oogenesis regarding mature gametes and polar bodies?

One functional ovum and polar bodies (usually discarded) with haploid sets.

What is a tetrad in meiosis?

A pair of homologous chromosomes, each with two sister chromatids (four chromatids total).

What is crossing over and when does it occur?

Exchange of genetic material between homologous chromosomes during Prophase I, creating recombined chromosomes.

What is the difference between mitosis and meiosis in the end products?

Mitosis yields two genetically identical diploid cells; Meiosis yields four genetically diverse haploid gametes.

What is the function of the contractile ring in cytokinesis?

Forms a cleavage furrow to divide the cytoplasm and complete cell division.

What is the role of kinetochores?

Protein structures at centromeres where spindle fibers attach to chromatids during cell division.