DNA and Its Role in Heredity

A set of vocabulary flashcards covering key concepts from the lecture on DNA and its role in heredity.

DNA

Deoxyribonucleic acid; a double-stranded molecule that carries genetic information.

RNA

Ribonucleic acid; a single-stranded molecule involved in protein synthesis.

Nucleotide

The basic monomer unit of nucleic acids, consisting of a pentose sugar, nitrogenous base, and phosphate group.

Deoxyribose

A five-carbon sugar that forms the backbone of DNA.

Ribose

A five-carbon sugar found in RNA.

Pyrimidines

Nitrogenous bases that consist of a single ring structure; includes cytosine (C), thymine (T), and uracil (U).

Purines

Nitrogenous bases with a double-ring structure; includes adenine (A) and guanine (G).

Antiparallel strands

The orientation of the two strands of DNA that run in opposite directions.

Hydrogen bonds

Weak bonds that hold the base pairs together in the DNA double helix.

Phosphodiester bond

Covalent bond between the phosphate group of one nucleotide and the sugar of another nucleotide in DNA or RNA.

Griffith's Experiment

An experiment that demonstrated bacterial transformation by showing that dead smooth strain bacteria could convert live rough strain bacteria into virulent forms.

Avery's Experiment

An experiment that established DNA as the material responsible for transformation in bacteria.

Hershey-Chase Experiment

An experiment that confirmed DNA, not protein, is the genetic material, using radioactive isotopes.

X-ray Crystallography

A technique used to determine the three-dimensional structure of molecules, crucial in identifying the double helical structure of DNA.

Complementary base pairing

The specific hydrogen bonding between adenine and thymine (A-T) and between guanine and cytosine (G-C) in DNA.

Semiconservative replication

The method by which DNA replicates, where each new DNA molecule consists of one old strand and one newly-synthesized strand.

Okazaki fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

Leading strand

The DNA strand that is synthesized continuously in the 5' to 3' direction, following the replication fork.

Lagging strand

The DNA strand that is synthesized discontinuously in short segments away from the replication fork.

Telomeres

Repeated sequences at the ends of linear chromosomes that protect them from degradation during replication.

Polymerase Chain Reaction (PCR)

A technique used to amplify a specific DNA segment, producing millions of copies.

Introns

Non-coding regions of a gene that are removed during mRNA processing.

Exons

Coding regions of a gene that are expressed and spliced together after introns are removed.

Signal sequences

Short stretches of amino acids that direct proteins to their cellular destinations.

Operons

Gene clusters in prokaryotes that are transcribed together and regulated as a unit.

Inducible operon

An operon that is normally off but can be turned on by the presence of a specific inducer.

Repressible operon

An operon that is normally on but can be turned off by the presence of a co-repressor.

Natural selection

The process by which individuals with advantageous traits survive and reproduce more successfully.

Gene flow

The transfer of alleles between populations through migration.

Genetic drift

Random changes in allele frequencies in small populations.

Speciation

The process by which one species splits into two or more distinct species.

Allopatric speciation

Speciation that occurs when populations are geographically separated.

Sympatric speciation

Speciation that occurs without geographic separation.

Phylogenetic tree

A diagram that represents evolutionary relationships among species based on genetic data.

Homologous traits

Traits that are similar due to shared ancestry; important for constructing phylogenies.

Molecular clocks

Method used to estimate the time of divergence between species based on mutation rates.