1. What happens when things go wrong?
Mutations
What happens when things go wrong?

2. Mutations A change in the DNA sequence
It’s a mistake made during REPLICATION or TRANSCRIPTION
Can be harmful: DISEASES or DEFORMITIES
Can be useful: organism is better able to SURVIVE
Neutral: organism is UNAFFECTED

3. Mutations
If a mutation occurs in a sperm or EGG cell, that mutation is passed to OFFSPRING
If a mutation occurs in a BODY cell, that mutation affects only the organism and is NOT passed on to the offspring

4. Types of mutations POINT mutations: bases are mismatched (CHANGED)
A. Harmful when: a mistake in DNA is carried into mRNA and results in the wrong AMINO ACIDS
B. Not harmful when: a mistake in DNA is carried into mRNA but still results in the CORRECT amino acid

5. Types of mutations FRAMESHIFT Mutations: bases are ADDED or DELETED.
A. Are usually HARMFUL because a mistake in DNA is carried into mRNA and results in MANY wrong amino acids
NOTE: Extra inserted BASES shifts affect how we read the CODONS (3 bases), which changes the AMINO ACIDS

7. Types of mutations CHROMOSOMAL Mutations
Chromosomes break or are LOST during mitosis or meiosis
Broken chromosomes may rejoin INCORRECTLY
Almost always lethal (deadly) when it occurs in a ZYGOTE (BABY)

8. Causes of mutations MUTAGENS: anything that causes a CHANGE in DNA
Examples: X rays, UV LIGHT, nuclear radiation, asbestos, CIGARETTE smoke.

10. Muscular dystrophy Genetic disease causing weak muscles
Symptoms: poor balance, difficulty walking/breathing
NORMAL amino acid sequence Start Ser Val Tyr Ala Stop
Patient 1 DNA: TAC AGG CAG AUC CGC AUU
mRNA codons:
Amino Acids:
Patient 2 DNA: TAC AGG CAT ATA CGC ATT
mRNA codon:
Which patient has MD?
What type of mutation is MD?
At which amino acid did this occur?
At which nitrogen base did this occur?