Cell Function - Mitosis and Meiosis Lecture Notes

Comprehensive vocabulary flashcards covering the basics of genetics, cell cycle phases, the detailed steps of mitosis and meiosis, and types of cell death based on the BIOL 102 lecture.

Chromosomes

Thread-like structures or complexes of DNA organized during cell division.

Euchromatin

Loose chromatin threads that are active at interphase.

Heterochromatin

Tightly coiled, compact chromatin that is not active at interphase.

Histone Acetylation

The addition of acetyl groups resulting in loose packing of nucleosomes, allowing transcription factors to bind DNA and express genes.

Histone Methylation

The addition of methyl groups causing nucleosomes to pack tightly, making DNA inaccessible and genes inactive.

Telomeres

Caps at the outer regions of chromosome arms that protect the ends from damage and unraveling, shortening with each cell division.

Sister Chromatids

Two identical halves of a replicated chromosome joined at the centromere.

Centromere

The point of attachment for chromosomes to spindle fibers during cell division.

Kinetochores

A complex of proteins where spindle fibers connect to the centromere.

Homologous Chromosomes

Chromosomes that carry the same number of genes at the same loci.

Totipotent

The ability of early embryonic stem cells to differentiate into any cell type.

Progenitor Cells

Cells that have committed to a line of development and are pluripotent.

Pluripotent

The ability of a cell to differentiate into some cell types but not all.

Cell Cycle

The sequence of events from one cell division to the next, consisting of $G_1$, S, $G_2$, and M phases.

Interphase

The preparatory stage before cell division consisting of Gap 1 ($G_1$), Synthesis (S), and Gap 2 ($G_2$).

Gap 1 ($G_1$) Phase

The state immediately after cell division where cells produce proteins like cyclins and enzymes needed for growth and metabolism.

Synthesis (S) Phase

The specific phase of the cell cycle where DNA replication occurs and chromosomes become duplicated.

Gap 0 ($G_0$)

A non-dividing phase for cells that exit the cell cycle.

Karyokinesis

The period of nuclear division during the M phase.

Cytokinesis

The period of cytoplasmic division during the M phase.

Mitosis

A type of cell division in somatic cells that produces two genetically identical diploid ($2n$) daughter cells.

Prophase (Mitosis)

The phase where centrioles move to poles, the spindle forms, the nuclear membrane disintegrates, and microtubules attach to kinetochores.

Metaphase (Mitosis)

The phase where duplicated chromosomes line up at the center of the cell.

Anaphase (Mitosis)

The phase where spindle microtubules shorten, pulling sister chromatids apart toward opposite poles.

Telophase (Mitosis)

The phase where chromosomes arrive at poles, nuclear membranes reform, and the nucleolus reappears.

Meiosis

A type of cell division in germ cells producing four genetically unidentical haploid ($n$) daughter cells.

Leptotene

The first subdivision of Prophase I where chromosomes condense and thicken.

Zygotene

The subdivision of Prophase I where homologous chromosomes pair in a process called synapsis.

Synaptonemal Complex

A protein complex formed during zygotene that intimately holds a pair of homologous chromosomes together.

Pachytene

The subdivision of Prophase I where crossing over of genetic material occurs between non-sister chromatids.

Diplotene

The phase where synapsis ends and the synaptonemal complex disappears, but chromosomes remain attached at chiasmata.

Chiasmata

Points of attachment where homologous chromosomes remain connected after the synaptonemal complex disappears.

Bivalent (or Tetrad)

A pair of homologous chromosomes consisting of four chromatids.

Diakinesis

The final subdivision of Prophase I where chromosomes are fully condensed and the nuclear membrane disintegrates.

Apoptosis

A natural biological process of programmed cell death used to maintain cell numbers or remove abnormal cells.

Necrosis

Uncontrolled cell or tissue death due to injury, infection, or lack of blood flow, causing damage to surrounding cells.

Mutation

A sudden change in genetic information, such as a change in DNA nucleotide sequence or gene order on a chromosome.