Mitosis and Meiosis

Cell Division Regulation

The process of controlling cell division to prevent errors in DNA replication and to regulate cell quantity.

Mutation

A change in the DNA sequence that can lead to altered genes or proteins.

Tumor

An abnormal mass of tissue resulting from excessive cell division.

DNA

The molecule that stores genetic information in all living organisms.

Polymer

A large molecule composed of many repeated subunits.

Nucleotides

The monomers that compose DNA, each consisting of a sugar, a phosphate group, and a nitrogenous base.

Double Helix

The structure of DNA, consisting of two intertwined strands.

Hydrogen Bonds

Weak bonds that hold the two strands of DNA together.

Complementary Base Pairing

The pairing of specific nitrogenous bases in DNA: A with T and C with G.

Histones

Proteins that help package and manage DNA in the nucleus.

Chromatin

The structure formed by DNA and histone proteins in non-dividing cells.

Somatic Cells

Any cell of the body except sperm and egg cells.

Homologous Chromosomes

Chromosome pairs, one from each parent, that are similar in shape and size.

Light Microscope

An optical instrument used to view small specimens or cells.

Telomere

Protective caps at the end of chromosomes that prevent chromosome deterioration.

Cellular Aging

The process by which cells lose their ability to divide; related to telomere shortening.

Typical Human Cell Division Limit

A typical human cell undergoes 50 to 70 divisions before aging.

Prokaryotic Cells

Cells without a nucleus; they have circular chromosomes located in the nucleoid region.

Eukaryotic Cells

Cells with a nucleus; they possess linear chromosomes associated with histones.

Interphase

The phase of the cell cycle when the cell grows and duplicates its DNA.

M Phase

The phase of mitosis where cell division occurs, including prophase, metaphase, anaphase, and telophase.

Prophase

The first stage of mitosis where chromosomes condense and the nuclear membrane begins to break down.

Metaphase

The stage of mitosis where chromosomes align at the cell's equator.

Anaphase

The stage in which sister chromatids are pulled apart to opposite sides of the cell.

Telophase

The final stage of mitosis where the nuclear membranes reform, and cytoplasm divides.

Cytokinesis

The process in which the cytoplasm of a parental cell divides into two daughter cells.

Daughter Cells

The two cells that result from the division of a single parent cell.

Genetic Identity in Mitosis

Daughter cells produced by mitosis are genetically identical to each other and to the original cell.

Chromosome Duplication

The process during the S phase of interphase where each chromosome is duplicated.

Chromosome Alignment

The arrangement of chromosomes in a line during metaphase.

Spindle Fibers

Microtubules that help separate the chromosomes during cell division.

Nuclear Membrane

The double membrane that encloses the nucleus and separates it from the cytoplasm.

Cell Cycle

The series of events that take place in a cell leading to its division and replication.

Chromosome Number in Humans

Humans have 46 chromosomes, arranged in 23 pairs.