Podcast
Questions and Answers
Which of the following is a key structural difference between DNA and RNA?
Which of the following is a key structural difference between DNA and RNA?
- DNA contains phosphate groups, while RNA does not.
- DNA is single-stranded, while RNA is double-stranded.
- DNA contains the base uracil, while RNA contains thymine.
- DNA contains deoxyribose sugar, while RNA contains ribose sugar. (correct)
DNA replication results in two new DNA molecules, each containing two newly synthesized strands.
DNA replication results in two new DNA molecules, each containing two newly synthesized strands.
False (B)
What is the term for the process where a double-stranded DNA molecule unwinds into two single strands due to heating?
What is the term for the process where a double-stranded DNA molecule unwinds into two single strands due to heating?
DNA denaturation
During re-annealing, if a strand of DNA has the sequence 5'-GCAATCTA-3', it will bind to a complementary strand with the sequence 5'-______-3'.
During re-annealing, if a strand of DNA has the sequence 5'-GCAATCTA-3', it will bind to a complementary strand with the sequence 5'-______-3'.
In what directions does DNA synthesis proceed?
In what directions does DNA synthesis proceed?
DNA helicase introduces twisting tension ahead of the replication fork.
DNA helicase introduces twisting tension ahead of the replication fork.
What enzyme synthesizes short RNA sequences to provide a 3' OH end for DNA polymerase to initiate replication?
What enzyme synthesizes short RNA sequences to provide a 3' OH end for DNA polymerase to initiate replication?
DNA polymerase adds a ______ nucleotide to the new strand when it encounters an 'A' on the template strand.
DNA polymerase adds a ______ nucleotide to the new strand when it encounters an 'A' on the template strand.
What is the primary function of the 3' to 5' exonuclease activity of DNA polymerase?
What is the primary function of the 3' to 5' exonuclease activity of DNA polymerase?
The leading strand is synthesized discontinuously, while the lagging strand is synthesized continuously.
The leading strand is synthesized discontinuously, while the lagging strand is synthesized continuously.
What term describes the short DNA fragments synthesized on the lagging strand during DNA replication?
What term describes the short DNA fragments synthesized on the lagging strand during DNA replication?
The enzyme that connects Okazaki fragments by forming phosphodiester bonds is called DNA ______.
The enzyme that connects Okazaki fragments by forming phosphodiester bonds is called DNA ______.
Match the following enzymes with their functions in DNA replication:
Match the following enzymes with their functions in DNA replication:
Which of the following prevents the re-annealing of DNA strands during DNA replication?
Which of the following prevents the re-annealing of DNA strands during DNA replication?
What is the role of DNA PolIII in prokaryotic DNA replication?
What is the role of DNA PolIII in prokaryotic DNA replication?
DNA replication always starts at multiple, random locations on the parental DNA.
DNA replication always starts at multiple, random locations on the parental DNA.
What is the term for the location on the DNA where replication is actively taking place?
What is the term for the location on the DNA where replication is actively taking place?
The proofreading activity of PolIII relies on the ______ subunit which must be bound to the alpha subunit for full proofreading activity.
The proofreading activity of PolIII relies on the ______ subunit which must be bound to the alpha subunit for full proofreading activity.
Concerning the lagging strand, synthesis is said to be:
Concerning the lagging strand, synthesis is said to be:
DNA Pol requires a free 5'OH end template.
DNA Pol requires a free 5'OH end template.
Flashcards
DNA vs RNA
DNA vs RNA
DNA is a double-stranded molecule containing the genetic code. RNA is single-stranded and involved in protein synthesis.
DNA Replication Result
DNA Replication Result
DNA replication results in two identical DNA molecules, each with one original and one new strand.
Semi-conservative Replication
Semi-conservative Replication
DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand.
DNA Denaturation
DNA Denaturation
Signup and view all the flashcards
Helicase
Helicase
Signup and view all the flashcards
Topoisomerase/DNA gyrase
Topoisomerase/DNA gyrase
Signup and view all the flashcards
Single-stranded Binding Proteins (ssBP)
Single-stranded Binding Proteins (ssBP)
Signup and view all the flashcards
DNA Polymerase
DNA Polymerase
Signup and view all the flashcards
Primase
Primase
Signup and view all the flashcards
DNA PolIII
DNA PolIII
Signup and view all the flashcards
DNA Polδ
DNA Polδ
Signup and view all the flashcards
Proofreading
Proofreading
Signup and view all the flashcards
Leading Strand
Leading Strand
Signup and view all the flashcards
Lagging Strand
Lagging Strand
Signup and view all the flashcards
Okazaki Fragments
Okazaki Fragments
Signup and view all the flashcards
DNA Ligase
DNA Ligase
Signup and view all the flashcards
Study Notes
Summary of DNA and RNA
- DNA is double stranded, while RNA is single stranded
- DNA's four bases are adenine (A), thymine (T), guanine (G), and cytosine (C)
- RNA has adenine (A), uracil (U), guanine (G), and cytosine (C)
- DNA contains deoxyribose, while RNA contains ribose
- DNA serves as genetic material and remains in the nucleus
DNA Replication
- DNA separates into two individual strands during replication
- Each strand acts as a template for synthesizing a new complementary strand of DNA
- DNA polymerase synthesizes the new strand by adding nucleotides to the template strand
- The net result is two identical daughter DNA molecules, each consisting of one original and one new strand
DNA Replication as Semiconservative
- Each strand of the double helix acts as a template for the synthesis of a new strand
- Original DNA strands are conserved
- New DNA molecules are synthesized
DNA Denaturation
- DNA is double stranded
- DNA unwinds, or denatures, into two single strands when heated
- DNA will re-anneal if cooled and find its match in solution
- Different strands of DNA will anneal to their correct partner when mixed
DNA Synthesis Direction
- DNA synthesis proceeds in two directions
- Bacterial chromosomes have one single point of origin
- Eukaryotic chromosomes have multiple points of origin
DNA Unwinding
- Helicase splits DNA at the hydrogen bonds
- Topoisomerase/DNA gyrase cuts and rejoins DNA ahead of the replication fork, releasing twisting tension
- Single-stranded binding proteins (ssBP) prevent re-annealing of strands by attaching to the separate strands
DNA Polymerase
- DNA Pol is an enzyme that catalyzes the formation of the phosphodiester bonds between nucleotides
- DNA Pol uses single strand of DNA as a template to create a second strand
- DNA Pol adds a 'T' to the new strand when it encounters 'A' on the template
- DNA Pol adds a 'G' to the new strand when it encounters 'C' on the template
Primers for DNA Polymerase
- Primase adds 10-11 RNA nucleotides to the single-stranded DNA template to form a primer
- DNA Polymerase can bind to it and move along the strand
DNA Polymerase Speed and Types
- DNA replication proceeds at approximately 1000 nucleotides per second
- In prokaryotes, DNA PolIII is the main enzyme for DNA replication
- In eukaryotes, DNA Polδ is the main enzyme for DNA replication
- DNA Pol also has 3' to 5' exonuclease activity for proofreading
DNA Polymerase Proofreading
- The proofreading activity of PolIII resides in the Epsilon (ε) subunit
- Epsilon subunit must be bound to the Alpha (α) subunit for full proofreading activity
- Strains lacking the epsilon subunit have higher mutation rates
DNA Strands - Leading & Lagging
- The leading strand enables continuous DNA synthesis
- The lagging Strand enables discontinuous DNA synthesis, where Okazaki fragments are formed
Leading Strand Synthesis
- DNA Polymerase III (PolIII) synthesizes in the 5' -> 3' direction
- Leading strand synthesis requires a free 3'OH end and single-stranded DNA as a template
Lagging Strand Synthesis
- The DNA double helix is anti-parallel
- Elongation is continuous on the leading strand and discontinuous on the lagging strand where Okazaki Fragments are formed
Connecting Okazaki Fragments
- DNA Ligase catalyzes the formation of phosphodiester bonds between Okazaki fragments
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
