5.6

Introduction Mutation: error made in DNA sequence that is inherited. (Must be in the __________ cells). Could have deleterious side effects, no effects, or positive effects. Deleterius: cystic fibrosis Positive effect: natural selection. No effect: mostly in eukaryotes (two copies of each gene).

Types of Mutations Silent Mutation: no effect on operation of cell 1) occur in noncoding regions, ______. 2) Redundancy of genetic code: UUU and UUC both code for phenylalanine. Mistake in 3 rd base during transcription would not change PP translated. Missense mutation Change in base sequence alters a codon  different AA. Ex// sickle cell anemia Nonsense mutation Change in DNA causes stop codon to replace codon specifying for an AA. Often lethal to the cell

Point mutations – specific to one base pair Substitution One base pair substituted for another. Frameshift Mutation When mutation causes change in the reading frame Deletion One or more nucleotides removed. Very drastic shift in reading frame! (all AA beyond the mutation may be altered!) Insertion One or more nucleotides inserted. Similar consequence to deletion.

Question Will an insertion or deletion of 3 sequential nucleotides cause a frameshift mutation? Is this as serious as a frameshift mutation as one or two nucleotides?

Translocation Apparent at the chromosomal level Relocation of groups of base pairs from one part of the genome to another. Two segments of chromosomes break and exchange places. leukemia

Transposable elements “jumping genes” Move from one location to another in the genome: if fall on coding region, could disrupt the correct transcription of the gene.

Inversion Chromosomal segment that has reversed its orientation in the chromosome.

Causes of Genetic Mutations Spontaneous mutation Simple errors of genetic machinery. (Poly I and III usually act as spell-checkers, but can miss errors sometimes). Induced mutations Due to exposure from mutagenic agents UV radiation, X rays, certain chemicals.

Mutagens UV light Ozone layer usually acts as a protective translucent shield against high-energy (UV) light. Depletion in ozone  increased high-energy (UV)  increase in point mutations. X-ray Can break SP backbone  automatically annealed by DNA-repairing enzymes (which can make mistakes)  base pairs can be lost

Cancer Considered a genetic disease Mutations result in oncogenes: mutant versions of genes that control cell growth and division.

Cystic Fibrosis Caused by one of at least 60 different types of mutation in the CFTR gene (cystic fibrosis transmembrane regulator)  severity depends on location of the mutation. Causes thick, sticky mucus in the lungs along with other symptoms.

Pesticides Linked to deleterious mutations: many banned in Canada. yaSbw&feature=related

DNA-resembling mutagens Some chemicals resemble DNA and can cause mutations AIDS therapy: some AIDS drugs resemble nitrogenous bases in DNA and insert themselves into the virus`s DNA. When viral DNA is to be duplicated, DNA polymerase stops  does not recognize chemical as a base  progression of disease is slowed.

Seatwork/Homework Page 263, #1-8

Independent Reading/Study Read section 5.7. Make short notes in your notebook. PPs 1-3 Read section 5.8. Make short notes in your notebook. PP 1 & 2

Biotechnology Assignment Each student will be assigned one of the following biotechnological processes/ideas: Restriction Endonucleases (answer PP 1-5) Gel Electrophoresis (answer PP 11-15) Plasmids (answer PP 16-18) Transformation (answer PP 19-22) In a PP presentation, summarize your assigned process. (in minutes)You must present this to the class, and supply the class with handouts of the information.