Cell Growth and Cancer Quiz

Cell Growth and Division Controls

• Cell growth and division are regulated by proteins and checkpoints in the cell cycle.
• Internal regulators respond to events inside the cell. Examples include p53, which prevents cell division with damaged DNA.
• External regulators respond to events outside the cell. Growth factors stimulate cell division.
• Neighboring cells can affect cell division via contact inhibition.
• Cancer is uncontrolled cell division, characterized by uncontrolled growth, lack of response to regulatory signals, and invasion of tissues.
• Tumors are masses of cancerous cells. Benign tumors are non-cancerous; malignant ones are cancerous and spread.
• Defects in cell cycle genes can be caused by mutations, environmental factors, or carcinogens.

Cancer and its Treatment

• The p53 gene regulates the cell cycle and triggers apoptosis with DNA damage; mutations can cause cancer.
• Localized cancer can be treated through surgery, radiation therapy, or targeted therapies.
• Cancer cells are more susceptible to radiation due to their rapid division and reduced DNA repair capacity.

Cell Differentiation

• Differentiation is the specialization of cells for specific functions, crucial for complex organisms.
• A zygote is a fertilized egg, totipotent (capable of developing into any cell type).
• Induced pluripotent stem cells (iPS cells) are created by converting adult cells into stem cell-like cells. Ethical concerns surround the use of embryonic stem cells, often involving embryo destruction.
• Differentiation in multicellular organisms occurs through gene expression changes in precursor cells, leading to specialized cells. Examples include neurons, muscle cells, and red blood cells.
• C. elegans (a microscopic worm) is studied for differentiation due to its simple structure and well-documented cell lineage.

Cell Cycle and Mitosis

• Diploid cells have two sets of chromosomes (2n). Haploid cells have one set (1n). Gametes (sperm and egg) are haploid.
• Meiosis is the process reducing chromosomes from diploid to haploid (2n to 1n), forming four haploid cells from one diploid cell.
• Meiosis involves two divisions (Meiosis I and Meiosis II), with crossing over during prophase I of meiosis I.
• Crossing over during meiosis increases genetic variation.
• Genetic variation is crucial for adaptation and disease resistance in sexually reproducing organisms.

Gene Linkage

• Gene linkage describes genes located close together on the same chromosome and inheriting together, impacting inheritance patterns.
• Meiosis contributes to genetic diversity via processes such as crossing-over and independent assortment.