DNA Replication and Molecular Genetics

A set of vocabulary flashcards covering the proteins, mechanisms, and concepts of DNA replication, chromosome maintenance, and the central dogma.

Semi-conservative method

The method of replication where each newly synthesized DNA molecule consists of one original strand paired with one completely new complementary strand.

Origin of replication

The specific AT-rich region where DNA replication begins, featuring two hydrogen bonds per base pair that make the double helix easier to pop open.

Helicase (DNA b)

The enzyme that unwinds the helical structure of DNA and separates the two strands to open up the replication fork.

Single stranded binding proteins

Proteins that bind to single strands of separated DNA to keep them apart and under tension so the helix does not close back up.

Primase

An enzyme that lays down a short RNA primer of approximately $10$ to $15$ base pairs to provide DNA polymerase with a running start.

DNA polymerase III

The primary replicating enzyme that builds new DNA strands exclusively in the $5'$ to $3'$ direction and possesses proofreading capability to correct mistakes.

Leading strand

The strand of newly replicated DNA that is synthesized continuously toward the replication fork in the $5'$ to $3'$ direction.

Lagging strand

The strand of newly replicated DNA that is synthesized discontinuously away from the replication fork, requiring repeated priming.

Okazaki fragments

Short segments of DNA synthesized discontinuously on the lagging strand that are separated by RNA primers.

DNA polymerase I

The enzyme responsible for removing the RNA primer and replacing it with DNA nucleotides on the synthesized strand.

DNA ligase

The enzyme that joins the Okazaki fragments together to create a continuous DNA strand.

Telomeres

Repetitive, non-coding heterochromatin structures located at the ends of linear chromosomes that protect them from degradation and shortening during replication.

Telomerase

An enzyme active during meiosis in gamete formation that rebuilds and restores repetitive telomere sequences onto chromosome ends.

Central dogma

The core principle in molecular genetics stating that genetic information flows from DNA to RNA and from RNA to protein.

Transcription

The process of copying genetic information from DNA into a complementary messenger RNA transcript within the nucleus.

Translation

The process carried out by ribosomes and tRNA in which the nucleic acid code of messenger RNA is converted into an amino acid sequence to build a protein.

Retrovirus

A type of virus, such as HIV, that reverses the normal flow of the central dogma by using RNA to make DNA.

Reverse transcriptase

The enzyme utilized by retroviruses to synthesize a DNA copy from an RNA viral genome.