Mutations and Viruses
n Any change to the ______(“letters”) in DNA are called mutations!
u change the DNA, changes the mRNA, may change protein, may change trait
Types of Mutations
______mutation: change in a single base pair in DNA (substitution)
Point Mutations typically only affect ______in the protein…
Causes no change in the function of the protein or Partial function of the protein. Example: Sickle Cell Anemia
• ______mutation causes a change in a purine (A, G) with a pryimidine. (C, T)
Creates a ______mutation, that changes the amino acid
• ______mutation causes a change in a purine with a purine and a prymidine with a prymidine!
Creates a ______mutation, that changes the amino acid
• ______mutation causes a change in the bases, but no change in the amino acid.
This is due to the “______” in the DNA code!
• ______mutation causes a change with a new stop codon in the wrong place.
Creates a ______mutation, that changes the amino acid to STOP!
______mutation: a single base pair is added or deleted and shifts the reading of the codons.
– Adding a base is called an insertion. - Removing a base is called a deletion.
Frameshift Mutations affect ______in the protein…
Causes a non-functional protein. (Example: Phenylketenuria PKU.)
______mutations: any change in the structure or number of chromosomes.
– deletion: part of a chromosome is removed
– duplication: part of a chromosome is repeated
– inversion: part of a chromosome breaks off and is reinserted backwards
– insertion and translocation: part of a chromosome breaks off and attaches to another chromosome
What Causes DNA to Mutate?
• There are various ways to create a change in the genetic code.
– Some can mutate certain bases or genes. Some can turn on the wrong expression of certain genes.
• Keep in Mind, there are 3 possible outcomes for a mutation in a(n) individual / gene pool:
– ______ (good)
• The natural environment can favor certain changes in allelic frequencies. natural selection!
– ______ (bad)
– ______ (neither good or bad)
• ______alters genes through mutation and can turn on oncogenes (genes promoting cancer)
– UV Radiation from repeated, overexposure to the sun. X-Ray Radiation from repeated, overexposure to radioactive materials & machines. Electromagnetic Radiation from repeated, overexposure to high frequency machines. Mutagens from toxic substances (carcinogens) such as smog, pollution and other man-made substances.
– Why is Lead Poisoning a Harmful Mutation? ______
Viruses
• Viruses can live in the body for long periods of time up to an organism’s entire lifetime.
• Some viruses have been linked to changes in the DNA causing diseases and disorders:
– Example: Epstein Barr virus has been linked to certain types of cancer.
• Viruses are non-living particles of ______that cause influenza.
• Named after their disease or discoverer. (Bacteriophages – attack Bacteria)
• Likely evolved later since they are dependent on ______. What is Living?
Viral Reproduction
______cycle : Virus attaches to host cell, Inserts viral nucleic acid and inserts it into the host cell’s chromosome (prophage), Gets replicated as host cell divides (through mitosis). Can remain inactive for a long period of time.
• ______cycle: Starts as the lysogenic cycle until triggered. Takes over cell machinery to make virus only! (Chops up cell’s DNA to shut down all defenses.) Viruses are assembled in the host cell. Burst out of the host cell releasing new virus!
What are 3 reasons viruses are considered Not Living? ______