CH 8 & 9 Cell Cycle, Mitosis, Cancer DNA replication and sexual reproduction, Meiosis, Chromosomal Abberatiions.

Vocabulary-style flashcards covering key terms and concepts from the video notes on cell division, including mitosis, meiosis, DNA replication, and related cellular processes.

Interphase

The cell cycle phase when the cell grows and copies its DNA; includes G1, S, and G2; chromatin is uncondensed and the cell is not yet dividing.

Prophase

Chromosomes condense, the mitotic spindle forms, the nucleolus disappears, and centrosomes move to opposite poles.

Prometaphase

The nuclear envelope breaks down and kinetochores attach to spindle microtubules; chromosomes begin moving toward the cell center.

Metaphase

Chromosomes align along the cell’s equator with sister chromatids attached to spindle fibers to ensure equal separation.

Anaphase

Sister chromatids separate and are pulled toward opposite poles as microtubules shorten.

Telophase

Chromosomes arrive at the poles, the nuclear envelope and nucleolus re-form, chromosomes decondense, and the spindle disassembles.

Cytokinesis

Division of the cytoplasm to form two separate daughter cells; often overlaps with late mitosis; not technically part of mitosis.

Mitosis

Nuclear division that produces two genetically identical nuclei; followed by cytokinesis to form two daughter cells.

Kinetochore

Protein structure at the centromere where microtubules attach during mitosis.

Centromere

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

Chromatids

Two identical copies of a duplicated chromosome held together at the centromere until separation in anaphase.

Origin of replication

Sites on chromosomes where DNA replication begins; replication proceeds bidirectionally from each origin.

Semiconservative replication

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Mitotic spindle

Microtubule structure that organizes and drives chromosome movement during mitosis.

Chromosome

A long DNA molecule with associated proteins that carries genetic information; becomes visible when condensed during mitosis.

Diploid

Organisms or cells with two complete sets of chromosomes (2n); humans have 46 in somatic cells.

Haploid

Cells with a single set of chromosomes (n); gametes are haploid.

Homologous chromosomes

Chromosome pairs that are the same size and shape and carry the same genes, one from each parent; not identical sequences.

Crossing over

Exchange of genetic material between homologous chromosomes during meiosis I, creating new allele combinations.

Independent assortment

Random orientation of chromosome pairs during meiosis I, producing many possible gamete combinations.

Meiosis

Cell division that reduces chromosome number by half to produce haploid gametes; involves two divisions (I and II) with crossing over and independent assortment.

Nondisjunction

Failure of homologous chromosomes or sister chromatids to separate properly, causing abnormal chromosome numbers in gametes.

Down syndrome

A trisomy of chromosome 21 caused by nondisjunction; individuals have three copies of chromosome 21.

P53

A master tumor suppressor gene; promotes apoptosis in damaged cells; inactivation is common in many solid tumors.

Apoptosis

Programmed cell death that removes damaged or unnecessary cells to protect the organism.

Cancer treatments

Strategies to treat cancer include surgical removal of tumors, anticancer drugs, and radiation therapy.

Zygote

Fertilized egg formed by the fusion of a sperm and an egg, containing 46 chromosomes in humans.

Gamete

A haploid reproductive cell (sperm or egg) that fuses during fertilization to form a zygote.

Autosomes

Non-sex chromosomes; humans have 22 pairs (chromosomes 1–22) that are not involved in sex determination.

Sex chromosomes

Chromosomes that determine sex (XX in females, XY in males); 23rd pair in humans.

G1 phase

First gap phase of the cell cycle where cell growth occurs before DNA synthesis.

S phase

Synthesis phase of the cell cycle during which DNA replication occurs.

G2 phase

Second gap phase; cell prepares for mitosis and ensures DNA is fully replicated and undamaged.