Cell Division: Mitosis and Binary Fission

This set of vocabulary flashcards covers the fundamental concepts of cell division, including bacterial binary fission, the eukaryotic cell cycle, and the structural levels of DNA and chromosomes based on the lecture notes.

Mitosis

A type of cell division focused on making identical copies of cells, technically referring to the division of the nucleus.

Binary fission

A simple method of cell division in bacteria, meaning 'split in two', where the single chromosome is replicated and distributed into two daughter cells.

Daughter cells

The two new cells produced at the end of a cell division process.

Exponential growth

A pattern of rapid division seen in bacteria where one cell becomes two, two become four, and so on, potentially dividing every $20\text{ minutes}$.

Genome

The full collection of all DNA and the information it holds, known as genes, for a given species.

Human genome count

The diploid state for humans consisting of $46$ total chromosomes.

Chromatin

The state of genetic material when it is stretched out and genes are actively being accessed for their information.

Double helix

The structure of a DNA molecule, existing as a double-stranded twisted polymer of nucleotides.

Histone

The specific proteins that DNA is wrapped around to help package and coil the genetic material inside the nucleus.

Nucleosome

The unit of DNA wrapped around a histone protein, involving approximately $2.5$ winds.

Condensed chromatin

Tightly coiled and packaged genetic material that transitions into the visible structure of a chromosome during cell division.

Chromosome

A highly condensed structure of DNA and protein, appearing in a replicated form as an 'X' shape during cell division.

Diploid ($2n$)

The native state of having two copies of every chromosome, one from the maternal side and one from the paternal side.

Haploid ($n$)

The state of having only one copy of every chromosome, found in sex cells (eggs and sperm), which in humans is $23$.

Karyotype

A photograph of chromosomes extracted from a cell, stained and numbered from longest to shortest in pairs to visualize the genome.

Somatic cells

Typical body cells that contain $23$ pairs of homologous chromosomes.

Homologous pairs (Homologs)

Pairs of chromosomes that are the same length and contain the same set of matching genes.

Centromere

The region of a replicated chromosome that holds two identical sister chromatids together.

Sister chromatids

Two identical molecules of DNA that make up a single replicated chromosome.

Autosomes

The chromosomes numbered $1$ through $22$ in humans, excluding the sex chromosomes.

Sex chromosomes

The $23rd$ pair of chromosomes, designated as XX for genetically female or XY for genetically male.

Cell Cycle

A sequence of events and phases a cell goes through, including growth and DNA replication, before it divides.

Interphase

The primary phase of the cell cycle where the cell is not actively dividing and the DNA exists as chromatin.

$G_1$ phase

A sub-phase of interphase characterized by cell growth and the performance of typical cellular functions.

$S$ phase (Synthesis)

The sub-phase of interphase where DNA synthesis occurs, resulting in the replication of chromosomes.

$G_2$ phase

The final sub-phase of interphase where the cell builds materials and duplicates organelles in preparation for division.

Cytokinesis

The division of the cytoplasm that typically follows mitosis to complete the creation of two separate daughter cells.

Multinucleate cells

Cells that result when mitotic nuclear division is not followed by cytokinesis, such as in human muscle cells.