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DNA. Mutations – any change in the nucleotides of a DNA sequence. Genetic Changes Chapter 11.3. Effects of mutations:. Mutations in body cells cause problems for individual effects all new cells after cell division Mutations in reproductive cells: - PowerPoint PPT Presentation
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DNAGenetic Changes
Chapter 11.3
Mutations – any change in the nucleotides of a DNA sequence
Effects of mutations: • Mutations in
body cells – cause problems
for individual – effects all new
cells after cell division
• Mutations in reproductive cells: – become a part of
the genetic makeup of the offspring
– Passed on to children
Types of Mutations
• Point Mutation-change in a single base-Could change an amino acid-May then change structure and/or function of entire protein
Point Mutation
DNA template strand
Point Mutation example: Sickle
Cell Anemia
Frameshift MutationA single base is added or deleted from a DNA strand
- Causes a one base shift in the reading of codons
- Changes all the amino acids after the mutation
Frameshift mutation
Frameshift Mutation - HIV resistance
• Deletion of single nucleotide in CCR5 gene• Problem with the immune cell receptor that
HIV recognizes- HIV can’t recognize cell and infect it
• However, the mutation also affects the normal function of the immune cells
Therefore it is both beneficial and detrimental.
Sentence Analogies
• Point mutation: single change in a nucleotide
THE SUN WAS HOT
THE SON WAS HOT
• Frameshift mutation: addition or deletion of nucleotide that affects all the amino acids after.
THE SUN WAS HOT
THE ESU NWA SHO T - added letter E
THS UNW ASH OT - deleted letter E
Chromosomal Mutations
• Parts of chromosomes break or are lost during mitosis or meiosis
• Parts rejoin wrong (backwards or on different chromosomes)
• Common in plants
Example: Cri du Chat (Cat Cry Syndrome)
–Missing part of Chromosome 5
Causes of Mutations
• Spontaneous: Natural
• Environmental Factors:
Mutagen – any agent that can cause a change in DNA – Radiation (X rays, ultraviolet
rays, nuclear)– Chemicals (dioxins, asbestos)– Viruses
Protection: some enzymes that can repair DNA have evolved
Stopping Point
Protein Synthesis animation