Cell Cycle, Mitosis, and Meiosis - Vocabulary Flashcards

Vocabulary flashcards covering the cell cycle, mitosis, and meiosis concepts from the General Biology 1 notes.

Cell cycle

An orderly sequence of events that describes the stages of a cell’s life from the division of a parent cell to the production of new daughter cells.

Interphase

The cell cycle phase in which the cell grows and DNA is replicated; consists of G1, S, and G2.

G1 phase

The first gap phase where the cell grows and carries out normal metabolism.

S phase

DNA synthesis phase where DNA is replicated and sister chromatids form; centrosome duplicates.

G2 phase

The second gap phase where organelles are duplicated and energy is replenished; cytoskeleton dismantled.

G0 phase

A non-dividing state; mature cardiac muscle and nerve cells may permanently remain in G0.

Mitosis

Division of a cell’s nucleus producing two genetically identical diploid daughter nuclei.

Cytokinesis

Division of the cell’s cytoplasm; completes cell division; cleavage furrow in animal cells; cell plate in plant cells.

Prophase

Chromatin condenses into discrete chromosomes; nucleolus disappears; spindle forms; nuclear envelope breaks down.

Prometaphase

Nuclear envelope fragments; spindle attaches to kinetochores; chromosomes move toward the center.

Metaphase

Chromosomes align along the metaphase plate at the center of the cell.

Anaphase

Sister chromatids separate and move toward opposite poles; kinetochore microtubules shorten; cell elongates.

Telophase

Daughter chromosomes arrive at poles; nuclear envelope reforms; chromosomes de-condense; nucleolus reappears.

Cleavage furrow

In animal cells, a contractile ring of actin-myosin causes the cell membrane to pinch in during cytokinesis.

Cell plate

In plant cells, vesicles coalesce at the center to form a cell plate that becomes separating cell walls.

Centrosome

Microtubule-organizing center; duplicates during S phase and forms the spindle.

Spindle

Structure of microtubules that separates chromosomes during mitosis.

Centromere

Region of a chromosome where sister chromatids are held together and where the kinetochore forms.

Kinetochore

Protein structure at the centromere where microtubules attach during mitosis.

Chromatid

One of the two identical copies of a replicated chromosome.

Chromosome

Condensed DNA-protein structure that carries genes; consists of two sister chromatids in replicated form.

Sister chromatids

Two identical copies of a replicated chromosome held together at the centromere.

Nucleosome

The basic unit of chromatin: DNA wrapped around a core of histone proteins.

Histone

Proteins around which DNA winds to form nucleosomes.

Chromatin

The unraveled form of DNA-protein complex that condenses into chromosomes during cell division.

Telomere

Protective end regions of chromosomes that shorten with each division.

Nuclear pore

Protein channels in the nuclear envelope regulating traffic between nucleus and cytoplasm.

Chromatin fiber

Higher-order packaging of chromatin beyond nucleosomes.

Diploid

Cells with two sets of chromosomes (2n); typical of somatic cells.

Haploid

Cells with one set of chromosomes (n); produced by meiosis.

Meiosis

Reduction division producing haploid gametes; two divisions with crossing over, increasing genetic variation.

Meiosis I

Homologous chromosomes separate; crossing over occurs during Prophase I; results in two haploid daughter cells.

Meiosis II

Sister chromatids separate; results in four haploid daughter cells.

Crossing over

Exchange of genetic material between nonsister chromatids of homologous chromosomes during Prophase I.

Gamete

A haploid reproductive cell (sperm or egg).

Spermatogenesis

Male gamete formation; typically yields four sperm per meiosis.

Oogenesis

Female gamete formation; typically one egg per meiosis with polar bodies.

Regulation of the cell cycle

Molecular control system with checkpoints that govern progression through the cycle.

G1 checkpoint

Checkpoint assessing cell size, nutrients, growth factors, DNA damage, and resting state (GO).

G2 checkpoint

Checkpoint ensuring proper cell size and DNA integrity before mitosis.

Spindle assembly checkpoint

Checkpoint ensuring chromosomes are properly attached to the spindle before anaphase.

Cancer

Uncontrolled cell division caused by breakdown of mechanisms regulating the cell cycle.