Chapter 14 – How Eukaryotic Cells Sort and Transmit Chromosomes: Mitosis and Meiosis

Flashcards summarizing key terms and definitions related to the eukaryotic cell cycle, mitosis, meiosis, and chromosome structure.

Chromosome

A structure made of DNA and protein that contains genetic information.

Karyotype

A photographic representation of the chromosomes of a cell, revealing the number, size, and form of the chromosomes.

Diploid

A cell that contains two complete sets of chromosomes, one from each parent (2n).

Haploid

A cell that contains one complete set of chromosomes (1n).

Sister Chromatids

Identical copies of a chromosome, joined together at the centromere after DNA replication.

Homologous Chromosomes

Chromosome pairs, one from each parent, that are similar in shape, size, and genetic content.

Cyclins

Proteins that regulate the cell cycle by activating cyclin-dependent kinases (CDKs).

Cyclin-Dependent Kinases (Cdks)

Enzymes that, when activated by cyclins, regulate different stages of the cell cycle.

Checkpoints

Regulatory points in the cell cycle that assess whether the cell is ready to proceed to the next phase.

Mitosis

A process of cell division that results in two genetically identical diploid daughter cells.

Meiosis

A specialized form of cell division that results in four haploid cells, contributing to genetic diversity.

Cytokinesis

The process that divides the cytoplasm of a parental cell into two daughter cells after mitosis.

Bivalent (Tetrad)

A pair of homologous chromosomes, each consisting of two sister chromatids, formed during meiosis.

Crossing Over

The process during meiosis where homologous chromosomes exchange genetic material, increasing genetic diversity.

Sexual Reproduction

A reproductive process that involves the fusion of two haploid gametes to form a diploid zygote.

Aneuploidy

An abnormal number of chromosomes in a cell, such as in conditions like trisomy or monosomy.

Polyploidy

A condition in which a cell has three or more complete sets of chromosomes.

G1 Phase

The first phase of the cell cycle where the cell grows and responds to environmental signals.

S Phase

The phase of the cell cycle where DNA replication occurs.

G2 Phase

The phase of the cell cycle that prepares the cell for division by synthesizing proteins necessary for sorting chromosomes.

M Phase

The phase of the cell cycle that includes mitosis and cytokinesis.

G1 Checkpoint

A checkpoint that regulates progression and ensures cell readiness for DNA synthesis.

G2 Checkpoint

A checkpoint that ensures the cell is ready to enter mitosis.

Metaphase Checkpoint

A checkpoint that prevents the cell from progressing into anaphase until all chromosomes are properly aligned.

Astral Microtubules

Position the spindle apparatus.

Polar Microtubules

Push the poles of the spindle apart.

Kinetochore Microtubules

Attach to kinetochores of sister chromatids for chromosome sorting.

Prophase

Chromosomes condense and become visible; the nuclear envelope breaks down.

Prometaphase

Kinetochores form; spindle attaches.

Metaphase

Chromosomes align at the cell's equatorial plane.

Anaphase

Sister chromatids are pulled apart to opposite poles of the cell.

Telophase

Chromosomes decondense; nuclear envelopes reform around each set of chromosomes.

Cytokinesis

The division of cytoplasm following mitosis, differing in plants (cell plate formation) and animals (cleavage furrow formation).

Cytokinesis

Division of the cytoplasm after mitosis; differs in plants (cell plate formation) and animals (cleavage furrow formation).

Prophase I

Chromosomes condense, crossing over occurs; bivalents (pairs of homologous chromosomes) form.

Prometaphase I

Complete nuclear envelope dissociation, spindle formation occurs.

Metaphase I

Bivalents align at the metaphase plate.

Anaphase I

Homologous chromosomes separate and are pulled to opposite poles of the cell.

Telophase I

Two haploid cells are formed; nuclear envelopes reform around each set of chromosomes