Video Notes: The Genome and DNA Replication — Vocab 9/9/25 genetics

Vocabulary flashcards covering the genome, chromosomes, haploid/diploid concepts, DNA replication mechanics, key enzymes, and the cell cycle as discussed in the notes.

Genome

The complete set of genetic material in an organism, including all genes and noncoding sequences.

Chromosome

A DNA molecule carrying genetic information; prokaryotes have circular chromosomes, while eukaryotes have linear chromosomes.

Haploid

Having one complete set of chromosomes (n); typical of gametes.

Diploid

Having two complete sets of chromosomes (2n); typical of somatic cells.

Nucleic acids

Polymers of nucleotides (DNA and RNA) that store and transmit genetic information.

Nucleotide

The monomer of nucleic acids composed of a sugar, a phosphate group, and a nitrogenous base.

DNA replication

The process by which a cell copies its genome to produce two identical DNA molecules.

Semi-conservative replication

Each daughter DNA molecule contains one original strand and one newly synthesized strand.

Origin of replication (ORI)

A specific DNA sequence where replication begins and initiator proteins bind to start the process.

Replication bubble

The opening created at the origin as strands separate, enabling replication to proceed.

Replication fork

The Y-shaped region where the DNA is unwound and new DNA is synthesized; two forks form at each origin.

Initiation

Early stage of DNA replication where the origin is recognized and the replication machinery is assembled.

Helicase

Enzyme that unwinds the DNA double helix at the replication fork.

Single-strand binding proteins (SSBPs)

Proteins that bind to separated DNA strands to keep them from reannealing.

DNA gyrase

Topoisomerase II enzyme that relieves supercoiling tension ahead of the replication fork.

Primase

RNA polymerase that synthesizes short RNA primers to provide a 3′ end for DNA synthesis.

DNA polymerase III

Primary elongation enzyme in bacteria; adds nucleotides to the growing DNA strand in the 5′→3′ direction.

DNA polymerase I

Enzyme that removes RNA primers and fills in with DNA; slower than Pol III and has 5′→3′ exonuclease activity.

DNA ligase

Enzyme that seals nicks in the sugar-phosphate backbone, joining Okazaki fragments on the lagging strand.

Okazaki fragments

Short, discontinuous DNA fragments synthesized on the lagging strand and later joined together.

Leading strand

The DNA strand synthesized continuously in the same direction as the replication fork movement.

Lagging strand

The DNA strand synthesized discontinuously in short fragments (Okazaki fragments) opposite the fork direction.

5′→3′ polymerization direction

DNA polymerases synthesize new DNA in the 5′ to 3′ direction, requiring a 3′-OH end to extend.

Anti-parallel

Orientation of the two DNA strands running in opposite directions (one 5′→3′, the other 3′→5′).

Replicon

A DNA segment that is replicated from a single origin of replication.