Anatomy and Physiology 12 - DNA, RNA, and Replication

This flashcard set covers the fundamental concepts of DNA and RNA structure, the experiments defining genetic material, and the molecular mechanisms of DNA replication as presented in Unit 3 of Anatomy and Physiology 12.

DNA (Deoxyribonucleic acid)

The genetic material and control molecule of life that carries encoded instructions for cellular activities and reproduction.

Frederick Griffith

Scientist who through late 1920s studies identified a transforming substance that could change nonlethal bacteria to lethal bacteria.

Hershey and Chase

Scientists who firmly established DNA as the genetic material in the early 1950s using T phage viruses and radioactive markers.

Replication

The process by which DNA makes exact copies of itself to pass onto other cells.

Mutation

Changes in the structure and number of DNA molecules that serve as the source of diversity and evolution in life.

Nucleotide

The basic building block of DNA consisting of a phosphate group, a deoxyribose sugar, and a nitrogen-containing base.

Purines

A class of nitrogen-containing bases that includes adenine (A) and guanine (G).

Pyrimidines

A class of nitrogen-containing bases that includes cytosine (C) and thymine (T).

Double helix

The structure formed by two DNA strands twisting about each other, with a backbone of alternating phosphate and sugar molecules.

Complementary base pairing

The specific bonding between purines and pyrimidines on opposite strands via hydrogen bonds (A-T and G-C).

Genes

Units of inheritance located on chromosomes consisting of DNA segments (typically about 1000 base-pairs) that control characteristics or capabilities.

Semi-conservative

A description of DNA replication where each new double helix consists of one original strand and one newly synthesized strand.

DNA helicase

The enzyme that separates DNA strands by breaking the hydrogen bonds between bases.

DNA polymerase

The enzyme that catalyzes the incorporation of new nucleotides by complementary base pairing; it can only add nucleotides to one end of the growing chain.

Leading strand

The strand of DNA that is synthesized continuously, following the path of the helicase enzyme.

Lagging strand

The strand of DNA synthesized in the opposite direction of the helicase, resulting in the formation of Okazaki fragments.

Okazaki fragments

Short segments of DNA produced during the synthesis of the lagging strand.

DNA ligase

The enzyme that connects Okazaki fragments and seals any breaks in the sugar-phosphate backbone.

RNA (Ribonucleic acid)

A single-stranded nucleic acid necessary for protein synthesis that communicates the message of DNA.

Ribose

The five-carbon sugar found in RNA, as opposed to the deoxyribose sugar found in DNA.

Uracil (U)

The nitrogenous base that replaces thymine in RNA and pairs with adenine.

Transcription

The process by which RNA is produced from a DNA template.