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Questions and Answers
What did the Lederbergs' experiment demonstrate about mutations?
What did the Lederbergs' experiment demonstrate about mutations?
Spontaneous mutations are caused solely by external agents.
Spontaneous mutations are caused solely by external agents.
False
What are the two main types of mutations discussed?
What are the two main types of mutations discussed?
Spontaneous and induced mutations.
The process used by the Lederbergs to show that mutations are random events is called ______.
The process used by the Lederbergs to show that mutations are random events is called ______.
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What role do Mismatch Repair proteins play in DNA mutation?
What role do Mismatch Repair proteins play in DNA mutation?
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Which type of mutation involves a change where one base is replaced by another?
Which type of mutation involves a change where one base is replaced by another?
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Mutations can be locked into the genome if DNA replication continues without repair.
Mutations can be locked into the genome if DNA replication continues without repair.
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Mutations in somatic cells can be transmitted to offspring.
Mutations in somatic cells can be transmitted to offspring.
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What is one example of an induced mutation?
What is one example of an induced mutation?
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What is the most common DNA repair system found in all living organisms?
What is the most common DNA repair system found in all living organisms?
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Match the type of mutation to its description:
Match the type of mutation to its description:
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A mutation that does not affect the amino acid sequence of a protein is known as a _____ mutation.
A mutation that does not affect the amino acid sequence of a protein is known as a _____ mutation.
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Match the type of mutation with its description:
Match the type of mutation with its description:
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What condition is required for mutations to become permanent in the genome?
What condition is required for mutations to become permanent in the genome?
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The virus that infects bacteria and was used in the Lederbergs' experiment is called ______.
The virus that infects bacteria and was used in the Lederbergs' experiment is called ______.
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What is one effect of mutations in noncoding sequences?
What is one effect of mutations in noncoding sequences?
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Point mutations can only involve the addition or deletion of base pairs.
Point mutations can only involve the addition or deletion of base pairs.
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At what stage do mutations occur that can be transmitted to offspring?
At what stage do mutations occur that can be transmitted to offspring?
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Nucleotide excision repair (NER) involves the removal of a damaged ______ before resynthesis.
Nucleotide excision repair (NER) involves the removal of a damaged ______ before resynthesis.
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What happens to the intact strand during nucleotide excision repair?
What happens to the intact strand during nucleotide excision repair?
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What is the original error rate of DNA polymerase before proofreading?
What is the original error rate of DNA polymerase before proofreading?
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Proofreading by DNA polymerase reduces the error rate to 1 error per billion basepairs.
Proofreading by DNA polymerase reduces the error rate to 1 error per billion basepairs.
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What are transposons commonly referred to as?
What are transposons commonly referred to as?
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The repair DNA polymerase can insert wrong __________.
The repair DNA polymerase can insert wrong __________.
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Which of the following statements is true regarding mutations?
Which of the following statements is true regarding mutations?
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Mutations always create a new protein with a different function.
Mutations always create a new protein with a different function.
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How many ways does Section 13.1 outline how mutations can affect the sequence of a gene?
How many ways does Section 13.1 outline how mutations can affect the sequence of a gene?
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A __________ can occur when a chromosome is broken.
A __________ can occur when a chromosome is broken.
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What is one potential consequence of mutations on proteins?
What is one potential consequence of mutations on proteins?
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Study Notes
Chapter 13: Altering the Genetic Material: Mutation and DNA Repair
- This chapter covers mutations and DNA repair mechanisms.
- The Lederbergs' experiments demonstrated that mutations are random events.
13.2 Causes of Mutations: The Lederbergs Showed That Mutations Are Random Events
- Joshua and Esther Lederberg's experiments investigated the cause of mutations in E. coli cells resistant to T1 bacteriophage.
- Their experiments supported the random theory of mutation.
- The studies involved replica plating, which showed that mutations occurred before exposure to the virus.
13.2 Causes of Mutations: The Lederbergs Used Replica Plating to Show That Mutations Are Random Events
- Replica plating was a technique used by Lederbergs.
- In replica plating, a velvet cloth was used to create a replica of bacterial colonies on a master plate.
- The replicas were then placed onto secondary plates with T1 bacteriophage to identify resistant colonies.
- The results showed that resistant colonies were already present on the master plate before contact with the bacteriophage. This confirmed mutations occurred randomly.
How do mutations occur?
- Usually, DNA damage precedes mutations.
- DNA damage can be repaired through various repair mechanisms.
- Mutations can be fixed or become permanent.
- Spontaneous mutations include errors during DNA replication, toxic metabolic products, and changes in nucleotide structure.
- Induced mutations come from chemical agents (e.g., benzo(a)pyrene) and physical agents (e.g., UV light, X-rays).
13.3 DNA Repair
- All living organisms have DNA repair mechanisms.
- Cells contain various systems to detect and repair DNA damage.
- Common types of DNA repair include direct repair, base excision repair, nucleotide excision repair, and mismatch repair. Examples of DNA repair pathways are nucleotide excision repair (NER).
13.1 Consequences of Mutations: Gene Mutations Alter the DNA Sequence of a Gene
- Point mutations affect a single base pair.
- Base substitutions replace one base with another.
- Single-base insertions or deletions cause frameshift mutations.
13.1 Consequences of Mutations: Gene Mutations May Affect the Amino Acid Sequence of a Polypeptide
- Silent mutations do not change the amino acid sequence.
- Missense mutations change one amino acid.
- Nonsense mutations introduce a premature stop codon.
- Frameshift mutations alter the reading frame, causing significant changes in the amino acid sequence.
13.1 Consequences of Mutations: Gene Mutations That Occur Outside of Coding Sequences Can Influence Gene Expression
- Mutations in non-coding regions can affect gene expression.
- Promoter, transcriptional regulatory elements, splice sites, and translational regulatory elements are examples of non-coding DNA sequences that can be affected by mutations.
- Changes in these regions can alter transcription, mRNA splicing, translation, or other aspects of gene expression.
13.1 When do mutations occur?
- Mutations during meiosis (gamete formation) affect offspring but not the individual.
- Mutations in somatic cells during mitosis affect the individual but not their offspring.
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Description
Explore the intricate processes of mutations and DNA repair in this detailed quiz based on Chapter 13. Learn about the groundbreaking experiments by Lederberg that unveiled the randomness of mutations in E. coli cells. Test your knowledge on techniques such as replica plating and their implications in genetics.
