Biology Chapter 8: DNA Replication, Binary Fission, and Mitosis

Vocabulary-style flashcards covering DNA replication enzymes, the eukaryotic cell cycle, mitosis phases, prokaryotic binary fission, and the characteristics and treatment of cancer.

Zygote

A fertilized egg that divides by mitosis to develop into a mature adult.

Meiosis

A form of cell division that occurs only during reproduction, producing sex cells with half the DNA of body cells.

Apoptosis

Programmed cell death that carves out distinctive structures during development and weeds out aging or defective cells.

Genome

All of a cell’s genetic material.

Helicases

Enzymes that unwind the DNA helix during replication.

Primase

The enzyme that adds a short strand of RNA to each DNA template strand to start replication.

DNA polymerase

The enzyme that synthesizes new DNA strands by adding nucleotides to the 3-prime end, starting at RNA primers.

Leading strand

The DNA strand where synthesis is continuous as DNA polymerase follows the helicase as it unzips the DNA.

Lagging strand

The DNA strand where synthesis is discontinuous because DNA polymerase moves in the opposite direction from helicase.

Ligases

Enzymes that form covalent bonds between DNA segments to fill in gaps after RNA primers are replaced.

Origins of replication

Multiple spots along the chromosomes where DNA replication begins simultaneously.

Binary fission

An asexual process in prokaryotes that replicates a single circular chromosome and distributes it to two identical daughter cells.

Nucleosomes

Bead-like structures formed when naked DNA wraps around histone proteins.

Chromatin

A substance formed by clusters of nucleosomes held together by scaffold proteins to keep DNA tightly packed.

Interphase

The multi-phase stage of the cell cycle where the cell is not dividing, but replicates its DNA and carries out normal functions.

G1 phase

The part of interphase where the cell grows, functions normally, and performs protein synthesis.

G0 phase

A state where the cell continues to function but does not replicate its DNA or divide.

S phase

The portion of interphase where the cell replicates its entire genome.

G2 phase

The portion of interphase where the cell produces proteins necessary for mitosis.

Mitosis

The division of the nucleus in eukaryotic cells, divided into five phases.

Prophase

The first phase of mitosis where chromosomes condense and become visible while the spindle forms.

Prometaphase

The mitotic phase where the nuclear envelope breaks up and spindle fibers attach to kinetochores.

Metaphase

The mitotic stage where chromosomes line up along the equator of the cell.

Anaphase

The mitotic stage where sister chromatids separate and move toward opposite poles.

Telophase

The final stage of mitosis where two new nuclei form.

Cytokinesis

The division of the cell's cytoplasm; characterized by a cleavage furrow in animal cells and a cell plate in plant cells.

Benign tumor

An abnormal mass of tissue contained within a capsule of connective tissue that prevents it from spreading.

Malignant tumor

A mass of cancerous cells that lack a capsule and can seed new tumors throughout the body via metastasis.

Proto-oncogenes

Normal genes that produce proteins stimulating cell division; they can become oncogenes that accelerate the cell cycle when mutated.

Tumor suppressor genes

Genes that produce proteins to block cancer development; their function is lost or silenced in many cancer cells.

BRCA1

An inherited gene mutation that increases the risk of breast cancer.

Adaptive therapy

An experimental cancer treatment that uses declining or intermittent drug doses to maintain competition between drug-resistant and drug-susceptible cells.