Podcast
Questions and Answers
A new daughter strand of DNA is synthesized by what enzyme?
A new daughter strand of DNA is synthesized by what enzyme?
DNA polymerase
Free nucleotides are added to a growing daughter DNA strand by?
Free nucleotides are added to a growing daughter DNA strand by?
a reaction between the 3' hydroxyl of the growing strand and the 5' phosphate of the free nucleotides
Why is a primer necessary for DNA synthesis?
Why is a primer necessary for DNA synthesis?
DNA polymerase requires an existing 3' hydroxyl to which it can add nucleotides.
What does DNA polymerization by DNA polymerase require?
What does DNA polymerization by DNA polymerase require?
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In which direction is a new strand of DNA synthesized?
In which direction is a new strand of DNA synthesized?
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How many replication forks are there in each replication bubble?
How many replication forks are there in each replication bubble?
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New strands of DNA grow from the 5' to 3' direction regardless of whether they are the leading or lagging strand.
New strands of DNA grow from the 5' to 3' direction regardless of whether they are the leading or lagging strand.
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Lagging strand DNA synthesis is the replication fork, and the overall direction of lagging strand growth is the replication fork.
Lagging strand DNA synthesis is the replication fork, and the overall direction of lagging strand growth is the replication fork.
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The leading strand is synthesized in the direction and the lagging strand is synthesized in the direction.
The leading strand is synthesized in the direction and the lagging strand is synthesized in the direction.
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DNA polymerase III always adds nucleotides to which end of the growing strand?
DNA polymerase III always adds nucleotides to which end of the growing strand?
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Which statement is true of DNA replication?
Which statement is true of DNA replication?
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An individual unit of replication is referred to as?
An individual unit of replication is referred to as?
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Which description about prokaryotic versus eukaryotic DNA replication is not correct?
Which description about prokaryotic versus eukaryotic DNA replication is not correct?
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Study Notes
DNA Synthesis
- DNA polymerase synthesizes new daughter strands of DNA.
- Free nucleotides are added to a growing DNA strand via a reaction between the 3' hydroxyl of the strand and the 5' phosphate of nucleotides.
- A primer is crucial for DNA synthesis as DNA polymerase needs an existing 3' hydroxyl to add nucleotides.
- DNA replication occurs in the 5' to 3' direction, with nucleotides added at the 3' end.
Leading and Lagging Strands
- Each replication fork has a leading and lagging strand; the leading strand is synthesized continuously from a single RNA primer.
- The leading strand grows in the same direction as the replication fork.
- The lagging strand consists of short Okazaki fragments, each requiring its own primer, and is synthesized discontinuously in the opposite direction of the replication fork.
- After replication, Okazaki fragments of the lagging strand are joined together.
Replication Bubble and Forks
- DNA replication is bidirectional, forming replication bubbles with two forks moving away from the origin of replication.
- When a bubble forms, one fork opens and moves left while the other moves right.
Direction of DNA Synthesis
- Both leading and lagging strands grow from the 5' to 3' direction.
- Newly synthesized strands require nucleotides to always be added to a free 3' hydroxyl end.
Okazaki Fragments and Lagging Strand Growth
- Lagging strand growth occurs in 5' to 3' direction, but overall growth is toward the replication fork.
- Upon completion, lagging strand fragments (Okazaki fragments) are linked together.
Role of DNA Polymerase III
- DNA polymerase III adds nucleotides specifically to the 3' end of the growing strand.
Characteristics of DNA Replication
- The lagging strand is characterized by being composed of Okazaki fragments.
- DNA replication is not continuous for the lagging strand but is continuous for the leading strand.
- Each individual unit of replication is referred to as a replicon.
Prokaryotic vs. Eukaryotic DNA Replication
- Recognize that certain statements about prokaryotic and eukaryotic DNA replication may vary, yet specifics are not detailed in the text provided.
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Description
Test your knowledge of key concepts in genetics with these flashcards focusing on DNA synthesis. Each card presents a critical question related to enzymes, nucleotides, and the role of primers in DNA replication. Challenge yourself and reinforce your understanding of genetic processes.
