Chromosomes and Cellular Reproduction - Vocabulary Flashcards

60 vocabulary flashcards covering key terms and concepts from Chromosomes and Cellular Reproduction.

Prokaryotes

Unicellular organisms lacking a nucleus and membrane-bound organelles; include bacteria and archaea.

Eukaryotes

Organisms whose cells contain a nucleus and other membrane-bound organelles; includes animals, plants, fungi, and protists.

Nucleus

Membrane-bound organelle that houses the cell’s genetic material.

DNA

Deoxyribonucleic acid; the molecule that stores genetic information.

Chromosome

A DNA-protein complex that condenses during cell division to carry genes.

Chromatid

One of two identical copies of a replicated chromosome.

Centromere

Constricted region where sister chromatids are held together and where kinetochores attach during cell division.

Telomere

Protective ends of a linear chromosome.

Origin of replication

Site where DNA replication begins.

Kinetochore

Protein structure at the centromere that attaches spindle fibers to chromosomes during cell division.

Histones

Proteins around which DNA winds to form nucleosomes in eukaryotes.

Metacentric

Chromosome with the centromere near the middle, producing roughly equal-length arms.

Submetacentric

Chromosome with a off-center centromere, producing one arm longer than the other.

Acrocentric

Chromosome with the centromere near one end, resulting in a very short p arm.

Telocentric

Chromosome with the centromere at the very end.

Prokaryotic cell reproduction

Simple division; separation of replicated circular chromosome; high replication rate.

Eukaryotic cell reproduction

Mitosis and cytokinesis; includes multiple processes and regulatory checkpoints.

Homologous chromosomes

Pairs of chromosomes that carry the same genes in the same order; one from each parent.

Diploid (2n)

Having two complete sets of chromosomes.

Haploid (n)

Having one complete set of chromosomes.

Allele

Variant form of a gene.

Gene

A unit of heredity located on a chromosome that influences a trait.

DNA replication

The process of copying the cell’s DNA.

S phase

Phase of the cell cycle in which DNA is replicated.

Interphase

Period of the cell cycle between divisions, including G1, S, and G2.

G1 checkpoint

Regulated decision point before DNA synthesis.

Synthesis (S) phase

Phase where DNA is replicated.

G2 checkpoint

Checkpoint ensuring DNA replication is complete and undamaged before mitosis.

Mitosis

Nuclear division producing two genetically identical nuclei.

Cytokinesis

Division of the cytoplasm resulting in two daughter cells.

Prophase

Chromosomes condense; spindle forms; nucleolus disappears.

Prometaphase

Nuclear envelope breaks down; spindle fibers attach to kinetochores.

Metaphase

Chromosomes align on the metaphase plate.

Anaphase

Sister chromatids separate and move toward opposite poles.

Telophase

Chromosomes arrive at poles; nuclear envelope re-forms; chromosomes relax.

G0 phase

Stable, nondividing state for cells not currently dividing.

Meiosis

Production of haploid gametes through two successive divisions.

Meiosis I

Reduction division; homologous chromosomes separate, halving the chromosome number.

Meiosis II

Equational division; sister chromatids separate.

Prophase I

Chromosomes condense; homologous chromosomes synapse; crossing over occurs; nuclear envelope breaks down.

Metaphase I

Homologous chromosome pairs align on the metaphase plate.

Anaphase I

Homologous chromosomes separate and move to opposite poles; sister chromatids stay together.

Telophase I

Chromosomes arrive at poles; cytokinesis may divide the cell.

Prophase II

Chromosomes condense; spindle forms; nuclear envelope breaks down (in meiosis II).

Metaphase II

Individual chromosomes line up on the metaphase plate.

Anaphase II

Sister chromatids separate and move toward opposite poles.

Telophase II

Chromosomes arrive at poles; nuclear envelopes reform; cytoplasm divides; four haploid cells produced.

Crossing over

Exchange of chromosome segments between non-sister chromatids of homologous chromosomes during prophase I.

Tetrad

Four-sister chromatid structure formed by paired homologous chromosomes during prophase I.

Synapsis

Pairing of homologous chromosomes during prophase I.

Independent assortment

Random orientation of homologous chromosome pairs during metaphase I.

Interkinesis

Brief interval between meiosis I and II; no DNA replication in some cells.

Chiasmata

Sites where crossing over occurs between chromatids.

Shugoshin

Protein protecting centromeric cohesin during meiosis I; later degraded to allow separation in meiosis II.

Cohesin

Protein complex holding sister chromatids together until they are separated.

Gamete

A haploid reproductive cell (sperm or egg) that fuses during fertilization.

Spermatogenesis

Production of sperm in the male gonads.

Oogenesis

Production of eggs (oocytes) in the female gonads.

Zygote

Diploid cell formed when a sperm fertilizes an egg.

Fertilization

Fusion of two haploid gametes to form a diploid zygote.