Bio Quarter
Mitosis: The process of cell division that results in two genetically identical daughter cells. It consists of sever
l stages: prophase, metaphase, anaphase, and telophase.
Interphase: The phase of the cell cycle when the cell is not dividing but preparing for mitosis. It consists of G1, S, and G2 phases.
S Phase (Synthesis Phase): The part of interphase where DNA replication occurs, ensuring that the cell’s genetic material is duplicated before cell division.
M Phase (Mitosis Phase): The phase where the cell actually divides, including both mitosis and cytokinesis.
Cytokinesis: The final stage of cell division, where the cytoplasm divides, resulting in two distinct daughter cells.
Checkpoints (G1, S, G2, and M): Regulatory points in the cell cycle that ensure proper progression. They check for DNA damage, cell size, and proper chromosome alignment:
G1 checkpoint: Ensures the cell is ready for DNA synthesis.
S checkpoint: Ensures DNA is replicated correctly.
G2 checkpoint: Checks for DNA damage after replication.
M checkpoint: Ensures chromosomes are properly aligned before cell division.
DNA Replication: The process of copying the DNA molecule to produce two identical DNA molecules, one for each daughter cell.
Meiosis: A type of cell division that reduces the chromosome number by half, producing four non-identical haploid cells (gametes).
Prophase: The first stage of mitosis, where the chromatin condenses into visible chromosomes, and the nuclear envelope begins to break down.
Metaphase: The second stage of mitosis, where chromosomes align at the metaphase plate (the center of the cell).
Anaphase: The third stage of mitosis, where sister chromatids are pulled apart toward opposite poles of the cell.
Telophase: The final stage of mitosis, where the nuclear envelope re-forms around the separated chromatids, now considered individual chromosomes.
Microtubules: Tubular structures that make up part of the cytoskeleton and are involved in various cell functions, including mitosis, where they form the mitotic spindle.
Mitotic Spindle: The structure made of microtubules that helps separate the chromosomes during mitosis.
Kinetochore: A protein structure on the centromere of a chromosome where spindle fibers attach during mitosis.
Sister Chromatids: Two identical copies of a chromosome, connected by a centromere, formed during DNA replication.
Centromere: The region of a chromosome where the sister chromatids are joined and where the spindle fibers attach.
Centrosome: A structure in animal cells that organizes microtubules and helps form the mitotic spindle.
Crossing Over: The process during meiosis where homologous chromosomes exchange genetic material, increasing genetic diversity.
Non-sister Chromatids: Chromatids from different homologous chromosomes, which can undergo crossing over during meiosis.
Homologous Chromosomes: A pair of chromosomes, one from each parent, that have the same structure and carry genes for the same traits.
Gametes: Reproductive cells (sperm and egg) that are haploid and combine during fertilization.
Haploid: A cell with one set of chromosomes (n), typical of gametes.
Diploid: A cell with two sets of chromosomes (2n), typical of somatic cells.
Chromatin: A complex of DNA and proteins found in the nucleus of a cell. It condenses to form chromosomes during cell division.
Chromosomes: Structures made of DNA and proteins that carry genetic information. They are visible during mitosis and meiosis.
G0: A resting phase where cells are not actively dividing or preparing to divide. Some cells, like neurons, remain in this phase permanently.
Antiparallel: Refers to the opposite orientation of the two strands of DNA, with one strand running 5' to 3' and the other 3' to 5'.
Tumor: An abnormal growth of cells that can be benign (non-cancerous) or malignant (cancerous).
Recombinant Chromosomes: Chromosomes that have been formed by recombination during meiosis, where genetic material is exchanged between homologous chromosomes.
Cleavage Furrow: The indentation that forms during cytokinesis in animal cells, leading to the division of the cell into two daughter cells.
Cell Plate: The structure that forms during cytokinesis in plant cells, where the cell wall will eventually develop to divide the cell into two.
Metaphase Plate: The imaginary plane where chromosomes align during metaphase.
Helicase: An enzyme that unwinds the double helix of DNA during DNA replication.
DNA Polymerase: An enzyme that synthesizes a new DNA strand by adding nucleotides to a pre-existing strand during DNA replication.
5’ and 3’ End: The orientation of a DNA strand. The 5' end has a phosphate group, and the 3' end has a hydroxyl group. DNA is synthesized in the 5' to 3' direction.
Apoptosis: Programmed cell death, a natural process for eliminating damaged or unnecessary cells.
Tumor Suppressor: Proteins that help regulate the cell cycle and prevent tumor formation. They inhibit cell division or induce apoptosis if necessary.
Oncogene: A gene that has the potential to cause cancer when mutated or overexpressed. It promotes uncontrolled cell growth.
Overexpression: When a gene is expressed at higher levels than normal, which can contribute to cancer if the gene is an oncogene.
Benign: A non-cancerous tumor that does not spread to other parts of the body.
Malignant: A cancerous tumor that can invade nearby tissues and spread to other parts of the body.
Transformation: The process by which normal cells are converted into cancerous cells, often due to mutations.
Capsule: A protective outer layer found on some tumor cells, particularly malignant tumors, that helps them evade the immune system.
Chemotherapy: A treatment for cancer that uses drugs to kill or slow the growth of cancer cells.
Radiation: A cancer treatment that uses high-energy radiation to damage or kill cancer cells.
Surgery: A treatment for cancer that involves physically removing the tumor from the body.
T Cell Replacement Therapy: A treatment that involves replacing or augmenting T cells (immune cells) to help fight cancer. This includes therapies like CAR-T cell therapy.