Cell Cycle & Division, Mitosis, & Nondisjunction Quiz 3

Vocabulary flashcards covering 64 key terms related to the cell cycle, mitosis, meiosis, and associated genetic concepts.

Cell Cycle

Ordered sequence of events from a cell’s formation to its own division.

Cell Division

Process by which a cell divides to form two daughter cells.

Binary Fission

Cell division in prokaryotes that produces two identical cells.

Mitosis

Nuclear division for growth, replacement, or repair that yields genetically identical cells.

Meiosis

Two-division process that produces haploid gametes from a diploid cell.

DNA Overload

Information crisis that occurs when a cell grows too large for its DNA to meet cellular demands.

Exchange of Materials

Need for efficient movement of nutrients, gases, and wastes across the membrane; limited by cell size.

Cytokinesis

Division of cytoplasm into separate cells; differs in plants and animals.

Cleavage Furrow (Animal Cells)

Indentation of plasma membrane during animal cytokinesis created by a contractile ring.

Cell Plate Formation (Plant Cells)

Fusion of vesicles that forms new membranes and a cell wall during plant cytokinesis.

Chromatin

Thin, fibrous complex of DNA and proteins.

Sister Chromatids

Identical copies of a chromosome produced during S phase.

Homologous Pair

Matching pair of chromosomes, one maternal and one paternal.

Centromere

Region where sister chromatids are joined.

P-arm

Short, upward arm of a chromosome.

Q-arm

Long, downward arm of a chromosome.

Telomere

Protective end region of a chromosome.

Interphase

Period of cell growth and DNA replication between divisions.

G1 Phase

Interphase stage in which the cell increases in size.

S Phase

Interphase stage when DNA is replicated, forming sister chromatids.

G2 Phase

Interphase stage in which enzymes and structures needed for mitosis are produced.

Mitosis (M Phase)

Stage of nuclear division followed by cytokinesis.

Cell Cycle Control System

Cyclically operating set of molecules that coordinates cell-cycle events.

Checkpoints

Control points that can halt or allow progression in the cell cycle.

Cyclins

Regulatory proteins synthesized during the cell cycle.

Cyclin-Dependent Kinases (Cdk)

Enzymes activated by cyclins that phosphorylate target proteins.

Prophase

Chromosomes condense, spindle forms, nuclear envelope disintegrates.

Metaphase

Chromosomes align on the cell equator with spindle fibers attached; longest mitotic stage.

Anaphase

Sister chromatids separate and move to opposite poles; shortest mitotic stage.

Telophase

Chromosomes decondense; nuclear envelopes reform; spindle disappears.

Cytokinesis (End of Mitosis)

Division of cytoplasm producing two genetically identical daughter cells.

Somatic Cells

Diploid body cells such as skin or brain cells.

Gametes

Haploid sex cells—sperm or ova.

Diploid (2n)

Condition of having two homologous chromosomes per set.

Haploid (n)

Condition of having one chromosome per set.

Polyploid

Having more than two chromosomes per set (e.g., 3n).

Fertilization

Fusion of sperm and egg to form a zygote.

Zygote

Fertilized egg cell.

Homologous Chromosomes

Chromosome pair similar in size and gene content; one maternal, one paternal.

Tetrad

Structure of a homologous pair containing four chromatids.

Locus

Specific position of a gene on a chromosome.

Autosomes

Non-sex chromosomes (pairs 1–22) coding most traits.

Sex Chromosomes

Chromosomes that determine sex: XX for female, XY for male.

Spermatogenesis

Meiosis in males that produces sperm.

Oogenesis

Meiosis in females that produces ova.

Polar Bodies

Small cells produced during oogenesis that degenerate.

Interphase I

Pre-meiotic phase in which chromosomes replicate, forming sister chromatids.

Prophase I

Chromosomes condense, homologs pair (synapsis) to form tetrads, and crossing over occurs.

Crossing Over

Exchange of segments between nonsister chromatids at chiasmata, creating genetic variation.

Metaphase I

Tetrads align at the metaphase plate; independent assortment occurs.

Anaphase I

Homologous chromosomes separate; sister chromatids remain attached.

Telophase I

Haploid sets reach poles followed by cytokinesis.

Meiosis II

Second meiotic division analogous to mitosis without prior DNA replication.

Prophase II / Metaphase II / Anaphase II / Telophase II

Sequential stages of meiosis II culminating in four haploid cells.

Non-disjunction

Failure of chromosomes or chromatids to separate during anaphase, causing abnormal numbers.

Monosomy

Condition with only one chromosome of a pair (e.g., Turner’s 45,X).

Trisomy

Condition with three chromosomes of a pair (e.g., Down’s 47,+21).

Down’s Syndrome

Trisomy 21; extra chromosome 21 leading to characteristic developmental traits.

Turner’s Syndrome

Monosomy X; infertile female with distinctive features.

Klinefelter’s Syndrome

XXY trisomy; infertile male with some female characteristics.

Edward’s Syndrome

Trisomy 18; causes small size and heart defects.

Amniocentesis

Prenatal procedure sampling amniotic fluid to detect genetic disorders.

Karyotype

Photograph of an individual’s chromosomes used to identify abnormalities.