Topic gudie vocabulary

Centromeres

The center of the chromosome where the sister chromatids are held together.

Centrosomes

An organelle located near the nucleus in the cytoplasm that divides and migrates to opposite poles of the cell during mitosis and is involved in the formation of the mitotic spindle, assembly of microtubules, and regulation of cell cycle progression.

Centrioles

Organelles involved in the development of spindle fibers in cell division.

Spindle fibers

Fibers produced by centrioles that attach to a chromosome.

Histone proteins

Proteins that provide structural support for a chromosome by wrapping around the DNA, giving the chromosome a more compact shape.

G1 phase

The stage of interphase where the cell is preparing to divide.

S phase

The period of DNA synthesis during which the cell replicates its genetic content.

G2 phase

A period of rapid cell growth and protein synthesis during which the cell prepares itself for mitosis.

Prophase

The first stage of mitosis where chromosomes become visible, centrioles and centrosomes separate, and mitotic spindles and asters form.

Metaphase

The second stage of mitosis where chromosomes line up across the center of the cell and spindle fibers attach to the sister chromatids.

Anaphase

The third stage of mitosis where sister chromatids separate and move towards the centrioles/centrosomes.

Telophase

The fourth stage of mitosis where the nuclear membrane reforms, spindle fibers break apart, and the nucleolus becomes visible.

Cytokinesis

The final stage of the cell cycle where the cell's cytoplasm divides, distributing the organelles into each of the two new identical daughter cells.

Benign tumor

A cluster of cells that are less harmful and remain localized.

Malignant tumor

A tumor that is capable of metastasis, invasive, and dangerous.

Metastasis

The process where cancer cells break loose and spread to other parts of the body.

Binary fission

The process by which most prokaryotes reproduce.

Homologous chromosomes

Two chromosomes in a pair, normally one inherited from the mother and one from the father.

Sister chromatids

Two identical chromatids that make up a chromosome.

Autosomes

One of the numbered chromosomes, as opposed to the sex chromosomes.

Sex chromosomes

Chromosomes involved in determining the sex of an organism, typically one of two kinds (X or Y).

Gametes

Mature haploid male or female germ cells that are able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Prophase I

The first phase of meiosis where chromatids thicken, the nuclear membrane breaks down, and homologous chromosomes pair up to form tetrads.

Metaphase I

The second phase of meiosis where homologous chromosomes line up in the middle of the cell.

Anaphase I

The third phase of meiosis where spindle fibers pull homologous chromosomes apart, making sister chromatids move towards the centriole.

Telophase I

The fourth phase of meiosis where two daughter cells are formed, which are haploid but still contain replicated genetic information.

Prophase II

The first phase of meiosis II where the nuclear membrane breaks down, centrioles move to opposite sides, and spindle fibers assemble.

Metaphase II

The second phase of meiosis II where sister chromatids line up in the middle of the cell.

Anaphase II

The third phase of meiosis II where spindle fibers pull sister chromatids apart towards the centriole.

Telophase II

The fourth phase of meiosis II where four identical haploid daughter cells are formed, which are gametes (egg or sperm) with half the amount of original chromosomes.

Crossing over

The exchange of chromosome segments between homologous chromosomes during prophase I of meiosis.

Mitosis

A type of cell division that results in two identical daughter cells.

Meiosis

A type of cell division that results in four genetically different cells, used for the production of gametes.

DNA replication

The process of copying a DNA sequence to produce a complementary strand of DNA.

DNA helicase

Enzyme that unzips the DNA strands by breaking the hydrogen bonds.

DNA polymerase

Enzyme that joins nucleotides according to base pairing rules and "proofreads" for mistakes.

DNA ligase

Enzyme that connects the segments of DNA to complete the new DNA strand.