Podcast
Questions and Answers
What type of activity helps reduce replication errors during DNA replication?
What type of activity helps reduce replication errors during DNA replication?
What type of interactions can lead to DNA breaks?
What type of interactions can lead to DNA breaks?
What is the direction of DNA synthesis on the leading strand during replication?
What is the direction of DNA synthesis on the leading strand during replication?
What is a mutation defined as?
What is a mutation defined as?
Signup and view all the answers
What is the function of DNA polymerase I in prokaryotes?
What is the function of DNA polymerase I in prokaryotes?
Signup and view all the answers
What type of mutation involves the substitution of one base pair with another?
What type of mutation involves the substitution of one base pair with another?
Signup and view all the answers
What are the short, discontinuous DNA fragments synthesized on the lagging strand called?
What are the short, discontinuous DNA fragments synthesized on the lagging strand called?
Signup and view all the answers
What is the purpose of ligase in DNA replication?
What is the purpose of ligase in DNA replication?
Signup and view all the answers
What is an example of a macro-lesion?
What is an example of a macro-lesion?
Signup and view all the answers
Where does DNA replication occur in eukaryotic cells?
Where does DNA replication occur in eukaryotic cells?
Signup and view all the answers
What type of mutation occurs when a purine base is replaced with another purine base?
What type of mutation occurs when a purine base is replaced with another purine base?
Signup and view all the answers
What is a key difference between prokaryotic and eukaryotic DNA replication?
What is a key difference between prokaryotic and eukaryotic DNA replication?
Signup and view all the answers
What can cause DNA mutations?
What can cause DNA mutations?
Signup and view all the answers
How many different DNA polymerases are found in eukaryotic cells?
How many different DNA polymerases are found in eukaryotic cells?
Signup and view all the answers
What is the result of stable interactions between DNA strands?
What is the result of stable interactions between DNA strands?
Signup and view all the answers
What is the purpose of RNA primers in DNA replication?
What is the purpose of RNA primers in DNA replication?
Signup and view all the answers
What is the direction of DNA polymerase activity?
What is the direction of DNA polymerase activity?
Signup and view all the answers
Which DNA polymerase is involved in the replication of the mitochondrial DNA?
Which DNA polymerase is involved in the replication of the mitochondrial DNA?
Signup and view all the answers
What is the function of telomerase in eukaryotic cells?
What is the function of telomerase in eukaryotic cells?
Signup and view all the answers
Why do eukaryotic chromosomes have multiple origins of replication?
Why do eukaryotic chromosomes have multiple origins of replication?
Signup and view all the answers
What is the shape of DNA in prokaryotic cells?
What is the shape of DNA in prokaryotic cells?
Signup and view all the answers
Which DNA polymerase is involved in the repair of DNA?
Which DNA polymerase is involved in the repair of DNA?
Signup and view all the answers
Where does a germline mutation occur?
Where does a germline mutation occur?
Signup and view all the answers
What is the effect of a point mutation on protein synthesis?
What is the effect of a point mutation on protein synthesis?
Signup and view all the answers
What is a transition mutation?
What is a transition mutation?
Signup and view all the answers
What is the result of a deletion or insertion mutation?
What is the result of a deletion or insertion mutation?
Signup and view all the answers
What is the characteristic of a germline mutation?
What is the characteristic of a germline mutation?
Signup and view all the answers
What is a transversion mutation?
What is a transversion mutation?
Signup and view all the answers
What is the effect of a substitution mutation on the DNA sequence?
What is the effect of a substitution mutation on the DNA sequence?
Signup and view all the answers
What is the result of a point mutation on a codon?
What is the result of a point mutation on a codon?
Signup and view all the answers
What is the result of a nonsense mutation?
What is the result of a nonsense mutation?
Signup and view all the answers
What is a characteristic of dynamic mutations?
What is a characteristic of dynamic mutations?
Signup and view all the answers
What is the primary function of electrophoresis in molecular biology?
What is the primary function of electrophoresis in molecular biology?
Signup and view all the answers
What is the term for a point mutation that affects a single nucleotide?
What is the term for a point mutation that affects a single nucleotide?
Signup and view all the answers
What is the method of Southern (1975) used for?
What is the method of Southern (1975) used for?
Signup and view all the answers
What is the result of a point mutation that causes a nonsense mutation?
What is the result of a point mutation that causes a nonsense mutation?
Signup and view all the answers
What is the purpose of PCR in molecular biology?
What is the purpose of PCR in molecular biology?
Signup and view all the answers
What is the term for the repetition of some triplets of the DNA that progresses from one generation to the next?
What is the term for the repetition of some triplets of the DNA that progresses from one generation to the next?
Signup and view all the answers
Study Notes
Modifications of a Database
- Replication errors: Poly DNAs with 3'-5' nuclease activity can check if the last base is added correctly, reducing possible errors.
- Formation of bridges: Stable interactions can occur between DNA strands or between proteins and DNA, leading to stable interactions.
- DNA breaks: Ionizing radiation can cause cleavage of DNA strands or breaks in both strands.
Types of DNA Mutations
- Definition of a mutation: A transmissible change in genetic material, concerning germ cells or somatic cells, which can be spontaneous or caused by alterations during replication or DNA repair.
- Classification of mutations: Macro-lesions (deletions, duplications, amplifications, fusions, inversions, and insertions) and micro-lesions (point mutations, base pair substitutions).
DNA Replication
- Elongation of replication:
- At the leading strand, synthesis occurs in the 5' → 3' direction.
- At the lagging strand, synthesis is more complicated, occurring in the 5' → 3' direction, but opposite the direction of the fork.
- Okazaki fragments are formed, and RNA primers are eliminated and replaced with DNA.
- Finally, DNA fragments are welded by a ligase.
Replication in Prokaryotes and Eukaryotes
- Prokaryotes:
- Replication occurs in the cytoplasm prior to binary fission.
- Two DNA polymerases (I and III) are involved.
- Eukaryotes:
- Replication occurs in the nucleus during S phase.
- At least five DNA polymerases (α, β, δ, λ, and ε) are involved.
- Telomeres are replicated by telomerase, and multiple origins are needed.
Germline Mutation and Classification of Gene Mutations
- Germline mutation: A mutation that occurs in cells that will differentiate into gametes, becoming hereditary.
- Classification of gene mutations:
- Substitution of bases (point mutations):
- Transition: Replacement of a base by another of the same chemical category.
- Transversion: Replacement of a base by another of a different chemical category.
- Mutations by deletion or insertion:
- Deletion or insertion of one or several nucleotides, causing a change in the reading of the DNA sequence.
- Nonsense mutations:
- Produce a stop codon, leading to non-functional proteins.
- Substitution of bases (point mutations):
Effects of Mutations on the Phenotype
- Dynamic mutations (triplet repeat expansion mutations):
- Progress from one generation to another, consisting of important repetitions of some triplets of the DNA.
- Example: Huntington's chorea.
Detection of Gene Mutations
- Methods:
- PCR (Polymerase Chain Reaction)
- Molecular hybridization
- Electrophoresis
- Southern blotting (for detecting large alterations)
- Oligonucleotide probes (for detecting point mutations)
- Direct spotting on a nitrocellulose sheet (dot-blot)
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the errors that can occur during DNA replication, including replication errors and the formation of bridges between DNA strands or between proteins and DNA.