Fundamental Molecular Biology Exam Questions and Answers

Fundamental Molecular Biology Exam Questions and Answers Define mutation - Answer-mutations are changes in the genetic material of a cell (or virus) Define gene - Answer-A gene is a genomic sequence (DNA or RNA) directly encoding functional product molecules, either RNA or protein What is a spontaneous mutation? - Answer-a naturally occurring mutation in the absence of a mutagen How often to spontaneous mutations occur? - Answer-3 new mutations per 10^8 base pairs per generation. 200 new mutations in each human child. What is net mutation? - Answer-DNA damage minus DNA repair = net mutation DNA repair is working to lower net mutation rate How is net mutation rate increased? - Answer-Increasing rate of DNA damage e.g. sunbathing, exposure to radiation like chernobyl Reducing repair efficiency e.g. In bright sunlights, each skin cell suffers 50-100 T-T dimers (a pair of abnormally chemically bonded adjacent thymine bases in DNA, caused by UV radiation) every seconds. Xeroderma pigmentosum patients are unable to repair T-T dimers, therefore they all become mutations. What are germline cells? - Answer-Reproductive cells, can differentiate into anything. 1 cell. Passed onto next generation What are somatic cells? - Answer-Any cell of a living organism other than the reproductive cells. Genetic dead end. Is the mutation rate higher in germ line cells or somatic cells? - Answer-Higher in somatic cells. GERMLINE CELLS- low mutation rate (-200/generation) SOMATIC CELLS- higher mutation rate (10X, 100X, 1000X) Most random mutations affect unimportant regions and therefore do not change the phenotype. What are these unimp