Cell Division and Chromosomes

Flashcards covering key vocabulary and concepts from lectures on cell division and chromosomes.

Omnis cellula e cellula

Latin axiom meaning 'every cell originates from another cell,' proposed by Rudolf Virchow.

Eukaryotic cell cycle

A series of phases including G1, S, G2, and M that lead to cell division.

Binary fission

A simple method of asexual reproduction seen in bacteria.

Cytogenetics

Field of genetics involving the microscopic examination of chromosomes.

Karyotype

A photographic representation of the number and form of chromosomes in a cell.

Sister chromatids

Two identical copies of a chromosome joined at the centromere.

Diploid (2n)

Cells that contain two sets of chromosomes, one from each parent.

Haploid (1n)

Cells that contain one set of chromosomes, as seen in gametes like sperm and eggs.

Homologous chromosomes

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

Cyclin-dependent kinases (cdks)

Enzymes that, when activated by cyclins, advance the cell cycle.

Mitosis

The process of nuclear division that produces two genetically identical daughter nuclei.

Cytokinesis

Division of the cytoplasm to form two separate daughter cells.

Checkpoint proteins

Proteins that monitor the condition of the cell and DNA integrity during the cell cycle.

G1 phase

The first gap phase of the cell cycle where the cell grows and synthesizes proteins.

S phase

The phase of the cell cycle where DNA replication occurs, producing sister chromatids.

G2 phase

The second gap phase where the cell prepares for mitosis.

M phase

The phase of the cell cycle where mitosis and cytokinesis occur.

Metaphase checkpoint

A checkpoint that ensures all chromosomes are properly attached to the spindle apparatus before segregation.

Anaphase

The phase in mitosis where sister chromatids are pulled apart to opposite poles.

Telophase

The phase in mitosis where chromosomes de-condense and the nuclear envelope reforms.

Cleavage furrow

A constriction that forms in animal cells during cytokinesis to separate the daughter cells.

Cell plate

A structure that develops in plant cells during cytokinesis to separate daughter cells.

Nondisjunction

The failure of chromosomes to separate properly during cell division, leading to aneuploidy.

Aneuploidy

An abnormal number of chromosomes, such as trisomy or monosomy.

Polyploidy

The presence of more than two complete sets of chromosomes in an organism.

Cohesin proteins

Proteins that hold sister chromatids together during mitosis.

Kinetochores

Protein complexes that form at the centromeres of chromosomes, essential for mitotic spindle attachment.

S-phase

The part of interphase where DNA synthesis occurs.

Prophase

The phase of mitosis where chromosomes condense and the nuclear envelope begins to break down.

Prometaphase

The phase of mitosis where the nuclear envelope is completely broken down and spindle fibers attach to kinetochores.

G-Bands

Dark bands produced by staining chromosomes that help identify them during karyotyping.

Genetic diversity

Variation in traits among individuals that can enhance adaptability and survival.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis, increasing genetic variation.

Gamete

A haploid reproductive cell, such as sperm or egg, that unites during fertilization.

Zygote

The diploid cell formed from the fusion of two haploid gametes.

Mitosis vs. Meiosis

Mitosis results in two identical daughter cells, while meiosis produces four genetically diverse haploid cells.

Nuclear envelope

A membrane that surrounds the nucleus, disintegrates during prophase and reforms during telophase.

FtsZ

A protein in bacteria that functions similar to tubulin and is involved in cell division.

Trisomy 21

Down syndrome, caused by the presence of an extra copy of chromosome 21.

Turner syndrome

A chromosomal disorder where a female has only one X chromosome (XO).

Klinefelter syndrome

A condition where a male has an extra X chromosome (XXY).

Genetic recombination

The process by which genetic material is mixed during sexual reproduction, leading to genetic diversity.

Alleles

Different forms of the same gene that can result in variations in traits.

Centromere

The region of a chromosome where sister chromatids are joined and where kinetochores form.