Notes

BIOLOGY CHAPTER 15 NOTES

Mutation: heritable change in the genetic material

· Point mutation: a mutation that affects only a single base pair

· Base substitution: a point mutation in which the base sequence within a gene is changed

· Silent mutations: a base substitution that changes the nucleotide sequence, yet does not alter the amino acid sequence of the polypeptide

· Missense mutation: a base substitution that changes one amino acid in a polypeptide sequence

· Sickle cell disease: a disease involving a missense mutation in the β-globin gene which causes the normally disk-shaped red blood cells to become sickle-shaped

· https://www.youtube.com/watch?v=WhKK9ld8LRk

· Nonsense mutation: a base substitution that changes a normal codon into a stop codon, causing the translation to terminate earlier than expected

· Frameshift mutation: a point mutation in which nucleotides are added or deleted from the polypeptide sequence, causing a shift in coding amino acids

· Germ line: cells that give rise to gametes, such as egg and sperm cells

· Somatic cells: all cells in the body except for the germ line

· Mosaic: an individual with somatic regions that are genetically different from one another

· Replica plating: the process of replicating and distributing bacterial colonies by pressing a sterile velvet cloth onto a master plate and transferring that replica on to two secondary plates

· Spontaneous mutations: mutations that result from abnormalities in biological processes

· Induced mutations: mutations that are caused by environmental agents that enter the cell and alter the structure of the DNA

· Mutagens: agents that cause mutations

· Chemical mutagens: a chemical agent that can cause mutations

· https://www.google.com/search?q=what+was+the+morning+sickness+drug+birth+defects&rlz=1C1CHBF_enUS988US989&oq=what+was+the+morning+sick&aqs=chrome.0.0i512j69i57j0i15i22i30j0i22i30l3j0i15i22i30j0i22i30l3.11551j0j7&sourceid=chrome&ie=UTF-8

· Physical mutagens: a physical agent that can cause mutations

· Thymine dimer: a site where two adjacent thymine bases have become covalently crosslinked to each other, which can be caused by UV light

· Ames test: a test used to evaluate the ability of a substance to cause mutations by monitoring the rate at which a secondary, corrective mutation occurs, indicating whether an agent increases the mutation rate above the spontaneous rate

· Direct repair: a DNA repair system in which an enzyme removes a modifying alkyl group to restore the structure of the original base

· Nucleotide excision repair (NER): a DNA repair system in which a region of several nucleotides in the damaged strand is removed from the DNA and the intact undamaged strand is used as a template for resynthesis of a normal complementary strand

· Carcinogens: agents that increase the likelihood of developing cancer

· Tumor: an abnormal overgrowth of cells occurring as an early stage in cancer development

· Benign tumor: a precancerous mass of cells that do not invade adjacent tissues and do not spread throughout the body

· Malignant tumor: an overgrowth of cells that invades adjacent healthy tissues. At this stage an individual has cancer

· Metastasis: the process of cancer cells spreading through the bloodstream or surrounding body fluids

· Oncogene: a cancer-promoting mutant gene which has an abnormally high level of expression, causing uncontrolled cell growth

· Tumor-suppressor gene: a gene that when normal encodes a protein that helps to prevent cancer. When a mutation eliminates its function, cancer may occur

· Proto-oncogene: a normal gene that if mutated can become an oncogene

· Sarcoma: a tumor of connective tissue such as bone or cartilage

· Checkpoint proteins: proteins encoded by tumor-suppressor genes that prevent a cell from progressing through the cell cycle if an abnormality is detected

· Apoptosis: the process of cell shrinkage and DNA degradation caused by the p53 protein if DNA damage is too severe

· Carcinomas: cancers of epithelial cells

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