The Mitotic Cell Cycle and Chromosome Structure

Vocabulary flashcards covering the key terms, stages, structures, and processes of the mitotic cell cycle based on the lecture notes.

Mitotic Cell Cycle

A series of precisely timed and carefully regulated stages of growth, DNA replication, and cell division comprising Interphase, Mitosis, and Cytokinesis that produces two genetically identical clone cells.

Chromosome

A thread-like structure of tightly coiled chromatin (composed of DNA, proteins, and RNA) visible during cell division that carries genetic information in the form of genes.

Chromatid

One of two identical parts of a chromosome, held together by a centromere, formed during interphase by DNA replication.

Sister Chromatids

Two identical chromatids of one chromosome that contain identical genes and are joined together at a centromere.

Centromere

The region of a chromosome that holds two sister chromatids together and contains no genes.

Telomeres

Structures at the ends of chromosomes that permit continued DNA replication, prevent the loss of genes, protect chromosome ends from degradation, and prevent chromosome ends from attaching to each other.

Interphase

The phase of the cell cycle between nuclear divisions consisting of G1, S, and G2 stages, during which the cell grows and replicates its DNA.

G1 Phase

The stage of interphase during which the cell grows, increases its volume of cytoplasm and organelle quantity, and synthesizes RNA and proteins needed for DNA replication.

S Phase

The stage of interphase during which DNA replication occurs (doubling the chromosome number), histones are synthesized, and centrosomes are duplicated.

G2 Phase

The stage of interphase where the cell replenishes energy stores, synthesizes proteins for chromosome manipulation, duplicates organelles, and repairs errors in DNA replication.

Mitosis (Karyokinesis)

The multistep process of nuclear division consisting of prophase, metaphase, anaphase, and telophase, during which duplicated chromosomes are aligned, separated, and moved into two genetically identical daughter cells.

Prophase

The first stage of nuclear division in which chromatin condenses into visible X-shaped chromosomes, the nucleolus and nuclear envelope disappear, centrosomes migrate to opposite poles, and spindle fibers form.

Condensin Proteins

Proteins that assist sister chromatids in coiling more tightly during prophase to become visible as X-shaped structures.

Kinetochore

Protein structures that form on the centromere during prophase and serve as attachment sites for spindle fibers.

Metaphase

The phase of mitosis in which maximally condensed chromosomes align at the metaphase plate or equator attached to spindle fibers by their centromeres.

Anaphase

The phase of mitosis where centromeres split, sister chromatids separate into individual chromosomes, and contracting spindle fibers pull them toward opposite poles leading by the centromere.

Telophase

The final stage of nuclear division in which single-chromatid chromosomes uncoil, nuclear envelopes reform around each set of chromosomes, and spindle fibers dissolve.

Cytokinesis

The final stage of cell division during which the cytoplasm splits to divide the parent cell into two separate daughter cells.

Cleavage Furrow

A constriction formed at the equator of an animal cell during cytokinesis created by a contractile ring of actin and myosin proteins that pinches the cell into two.

Cell Plate

A structure formed across the equator of a plant cell during cytokinesis by fusing vesicles that deposit pectins to form the middle lamella and subsequently cell walls.

Protein p53

A protein produced in response to DNA damage that halts the cell cycle during the G1 phase before DNA replication occurs so that DNA repair can take place.

Colchicine

A chemical agent that stops sister chromatids from separating during mitosis, causing cells to reach metaphase but fail to complete it.