bio quiz unit 1

Cell cycle

The regular sequence of growth and reproduction in eukaryotic cells, consisting of interphase, mitosis, and cytokinesis.

Interphase

The primary life stage where a cell grows and replicates its DNA, occupying about $90\%$ of the total cycle time.

$G_1$ phase

The first growth phase of interphase in which the cell performs normal functions, increases in size, and prepares for DNA replication.

$S$ phase

The synthesis phase of interphase during which chromosomal DNA is completely duplicated.

$G_2$ phase

The growth phase of interphase where proteins that form spindle microtubules are synthesized in preparation for nuclear division.

Chromosome

The tightly packaged, condensed structural form of genetic material (DNA and proteins) that typically exhibits an $X$-shape after replication.

Sister chromatids

The two identical halves of a duplicated chromosome produced during DNA replication.

Centromere

The constricted attachment region located at the center of a duplicated chromosome that binds sister chromatids together.

Mitosis

The process of eukaryotic nuclear division that separates replicated genetic material into two nuclei through four sequential stages.

Prophase

The first phase of mitosis where chromatin condenses into distinct, visible chromosomes.

Metaphase

The mitotic stage in which spindle fibers attach to centromeres and align chromosomes along the cellular equator.

Metaphase plate

The imaginary midline plane across the center of a dividing cell along which chromosomes align.

Anaphase

The mitotic phase where spindle fibers shorten, pulling sister chromatids apart to opposite cell poles.

Telophase

The final stage of nuclear division where separated chromosomes reach opposite poles, relax, and the spindle apparatus breaks down.

Cytokinesis

The physical process that divides the cytoplasm of a parental cell into two separate daughter cells.

Cleavage furrow

The shallow groove formed on the cell surface that pinches an animal cell into two distinct units during division.

Products of mitosis

Two daughter cells that are genetically identical to each other and clones of the parent cell.

Asexual reproduction

A form of reproduction requiring only one parent that rapidly produces offspring with no genetic variation.

Sexual reproduction

A reproductive process requiring two partner organisms that results in offspring with complete genetic variation.