wunder beta

🧬 How Do Cells Copy DNA?

Follow the replication fork as helicase opens DNA, polymerase builds new strands, Okazaki fragments are joined, and proofreading protects the copied sequence.

lessons

~20 min

to learn

🔬 Science

subject

Adults

level

Start the course →

What you’ll learn

A copy begins with a splitExplain semiconservative copying, complementary pairing, and the replication fork.The parental helix separates, and each original strand becomes a template for a complementary new strand.
Polymerase has a directionUse 5-prime and 3-prime direction to predict leading and lagging synthesis.Polymerase extends only 5-prime to 3-prime, so antiparallel templates require different construction patterns.
Lagging strands are assembledDescribe primers, Okazaki fragments, primer replacement, and ligase.Repeated short starts solve the direction problem, and finishing enzymes turn fragments into a continuous strand.
Proofreading protects the sequenceDistinguish polymerase proofreading from later mismatch repair.Layered quality-control mechanisms correct many wrong bases while allowing rare errors to persist as mutations.
From one fork to a whole genomeConnect local fork mechanics to copying an entire chromosome.Origins and multiple bidirectional forks scale the same unwinding, synthesis, assembly, and checking mechanism to a genome.

Questions this course answers

What does semiconservative replication mean?

Each original strand stays paired with one newly synthesized complementary strand.

Put the core events at a replication fork in order.

Opening must come before priming, extension, and finishing.

Match each replication protein to its main job.

The fork works because these proteins divide opening, starting, building, and joining jobs.

Why is one daughter strand made discontinuously?

Antiparallel templates force one polymerase to build away from the advancing fork in fragments.

Put lagging-strand fragment maturation in order.

Each fragment must be started, extended, converted to DNA, and joined to its neighbor.

Explain in your own words how proofreading lowers replication errors.

Proofreading is an active correction step coupled to synthesis, not just the ability to choose a likely base.

Grounded in trusted sources

National Human Genome Research Institute, DNA Replication, https://www.genome.gov/genetics-glossary/DNA-Replication
Alberts et al., DNA Replication Mechanisms, Molecular Biology of the Cell, NCBI Bookshelf, https://www.ncbi.nlm.nih.gov/books/NBK26850/
OpenStax, Biology 2e, 14.4 DNA Replication in Prokaryotes, https://openstax.org/books/biology-2e/pages/14-4-dna-replication-in-prokaryotes
OpenStax, Biology 2e, 14.6 DNA Repair, https://openstax.org/books/biology-2e/pages/14-6-dna-repair
NCBI Bookshelf, The Cell: DNA Replication, https://www.ncbi.nlm.nih.gov/books/NBK9940/

Every Wunder lesson is built from real, reputable sources — never invented.

Related Science courses

🧬How DNA Replication Works 🌦️How does the weather system of the planet work?🪸How Does a Coral Polyp Build a Reef?🐋How Whales Hold Their Breath 🐟How does a salmon find its home river?🦋How does a monarch butterfly navigate to Mexico?🧠How does the brain build a mind?🪴How does a Venus flytrap count?

Wunder is a personalized learn-anything platform — tell it any topic and it builds a beautiful, fact-checked course in minutes, with narration, a knowledge check, and a college-style University track.

Browse more Science courses · All topics · Home