190 likes | 431 Views
Genetic Mutations. Unit 2-2 Notes Mr. Hefti – Pulaski Biology. Examples of mutations. 1. Genetic Mutations. “a change in the DNA of a gene” Mutations in gametes can be passed on to offspring Mutations in body cells affect only the individual in which they occur. 2. Categories.
E N D
Genetic Mutations Unit 2-2 Notes Mr. Hefti – Pulaski Biology
1. Genetic Mutations “a change in the DNA of a gene” • Mutations in gametes can be passed on to offspring • Mutations in body cells affect only the individual in which they occur
2. Categories • Point Mutations • Change in one or just a few bases in a gene • Frameshift Mutations • Cause genes to be read in the wrong three-nucleotide sequence
Three nucleotide sequences are called “codons” New rule:when referring to the amino acids that DNA codes for, T still goes with A, but now A goes to U (which stands for Uracil). See if you can find the amino acid that these DNA sequences code for using the Universal Codon Chart… C A T T T A G U A = valine A A U = asparagine
Read from the top second. Read from this side first! Then read from this side third.
2A. Point Mutations • Substitution • One nitrogenous base is replaced with a different one • C T A G G A • G A U C A U • GAU = ? / CAU = ? / CCU = ? • Aspartate / Histidine / Proline
2B. Frameshift Mutations • Insertion • One or more bases are added to a gene • T A G C C T • A G U C G G A • AGU = ? / AUC = ? / CGG = ? • Serine / Isoleucine / Arginine
2B. Frameshift Mutations • Deletion • One or more bases are deleted from a gene • C G A T A G • __C U A U C • GCU = ? / AUC = ? • Alanine / Isoleucine • CUA = ? / UC = ? • Leucine / “Nothing”
3. Sources of Mutations • X-rays • UV rays • Radiation • Asbestos • Alcohol • LSD • Marijuana • Benzene • Formaldehyde
4. Genetic Diseases • Some genetic diseases are caused by inherited mutations • Sickle cell anemia • Tay-Sach’s disease • Cystic fibrosis • Hemophilia • Huntington’s disease
Sickle cell anemia • Recessive • Causes for the abnormal development of rbc’s • Sickle shape causes cells to break apart or get jammed in blood vessels
Tay-Sach’s disease • Recessive • Causes infants’ nervous systems to break down • Death in early childhood
Cystic Fibrosis • Recessive • Causes for the overproduction of mucus • Mucus clogs organs, especially lungs making breathing difficult
Hemophilia • Sex-linked recessive • Blood clotting disorder
Huntington’s disease • Dominant • Causes brain to gradually deteriorate • Usually goes unnoticed until adulthood