DNA and its role in heredity

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Bacterial transformation

The process by which bacteria take up and incorporate foreign DNA.

Bacteriophages

Viruses that infect bacteria and inject their DNA into the bacterial host.

Chargaff's rule

The observation that the amount of adenine (A) in DNA is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C).

DNA structure

The double-stranded molecule with a sugar-phosphate backbone and hydrogen bonding between complementary base pairs.

X-ray images

Images obtained by Rosalind Franklin that provided insights into the structure of DNA.

Semiconservative replication

The process in which each parent strand of DNA serves as a template for the synthesis of a new strand.

DNA polymerases

Enzymes that catalyze the addition of nucleotides to the 3' end of a new DNA strand.

Primers

Short RNA strands that are necessary for DNA synthesis and serve as starting points for DNA polymerases.

Origins of replication

Specific DNA sequences where DNA replication begins on both strands.

Replication forks

The points where DNA strands separate and new strands are synthesized during DNA replication.

Leading strand

The daughter strand that is synthesized continuously in the 5'-to-3' direction during DNA replication.

Lagging strand

The daughter strand that is synthesized discontinuously in the 5'-to-3' direction during DNA replication.

Telomerase

An enzyme that extends telomeres, preventing chromosome shortening during DNA replication.

Mismatches

Errors in DNA replication where base pairs are not properly matched.

Proofreading

A mechanism during DNA replication that removes incorrectly inserted bases and replaces them with the correct bases.

Excision repair

A DNA repair mechanism that removes damaged DNA and replaces it with the appropriate nucleotides.

Polymerase chain reaction (PCR)

A technique for amplifying a specific region of DNA.

Heat-resistant DNA polymerase

An enzyme used in PCR that can withstand the high temperatures required for DNA denaturation and amplification.

Adenine

A nitrogen-containing base found in DNA, RNA, and other compounds.

Cytosine

A nitrogen-containing base found in DNA and RNA.

Guanine

A nitrogen-containing base found in DNA, RNA, and GTP.

Thymine

A nitrogen-containing base found in DNA.

Base pairs

The complementary pairing of nucleotides in DNA, with adenine (A) pairing with thymine (T) and cytosine (C) pairing with guanine (G).

Telomeres

Repeated DNA sequences at the ends of eukaryotic chromosomes.

Template

A molecule or surface on which another molecule is synthesized in a complementary fashion, such as during DNA replication.