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https://www.cliffsnotes.com//study-notes/31577725
, ○
Coupled transcription and translation in bacteria (no
nucleus).
○ Eukaryotic mRNAs have 5' caps and 3' poly-
A tails; bacterial mRNAs do not. ○ More
initiation factors are used in eukaryotes.
3. Antibiotics that target translation
○ Some antibiotics target bacterial ribosomes without
affecting human ones.
○ Example: Tetracycline blocks tRNA binding,
Chloramphenicol blocks peptide bond formation.
Chapter 15: Mutation, DNA
Repair, and Cancer 15.1
Consequences of Mutations
1. Mutations and polypeptide sequence
○ Silent mutation: codon changes but same amino acid.
○ Missense mutation: codon changes and so does amino
acid.
○ Nonsense mutation: codon becomes a
stop codon → truncated protein. ○
Frameshift mutation: insertion/deletion
shifts the reading frame.
2. Human disease examples
○ Sickle Cell Anemia: Missense mutation in
β-globin gene (Glu → Val). ○ Tay-Sachs:
Frameshift mutation in HEXA gene.
3. Mutations outside coding regions ○ Can occur in:
■ Promoters → reduced transcription.
This study source was downloaded by 1205308 from cliffsnotes.com on 02-04-2026 09:00:10 GMT -06:00
https://www.cliffsnotes.com//study-notes/31577725
https://www.cliffsnotes.com//study-notes/31577725
, ○
Coupled transcription and translation in bacteria (no
nucleus).
○ Eukaryotic mRNAs have 5' caps and 3' poly-
A tails; bacterial mRNAs do not. ○ More
initiation factors are used in eukaryotes.
3. Antibiotics that target translation
○ Some antibiotics target bacterial ribosomes without
affecting human ones.
○ Example: Tetracycline blocks tRNA binding,
Chloramphenicol blocks peptide bond formation.
Chapter 15: Mutation, DNA
Repair, and Cancer 15.1
Consequences of Mutations
1. Mutations and polypeptide sequence
○ Silent mutation: codon changes but same amino acid.
○ Missense mutation: codon changes and so does amino
acid.
○ Nonsense mutation: codon becomes a
stop codon → truncated protein. ○
Frameshift mutation: insertion/deletion
shifts the reading frame.
2. Human disease examples
○ Sickle Cell Anemia: Missense mutation in
β-globin gene (Glu → Val). ○ Tay-Sachs:
Frameshift mutation in HEXA gene.
3. Mutations outside coding regions ○ Can occur in:
■ Promoters → reduced transcription.
This study source was downloaded by 1205308 from cliffsnotes.com on 02-04-2026 09:00:10 GMT -06:00
https://www.cliffsnotes.com//study-notes/31577725
