A1.2 Nucleic acids

DNA

Deoxyribonucleic acid; a nucleic acid that stores genetic information.

RNA

Ribonucleic acid; a nucleic acid involved in using genetic information, especially in protein synthesis.

Mutations

Permanent changes in the DNA nucleotide sequence.

Nucleic acids

Large biological molecules that store and transmit genetic information; DNA and RNA are the two main types.

Nucleotide

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

Nucleosome

A section of DNA wrapped around a core of histone proteins; the basic unit of DNA packaging.

Ribose

The five-carbon sugar found in RNA nucleotides.

Phosphate

A chemical group containing phosphorus and oxygen; one of the three components of a nucleotide.

What are the three essential components of a DNA molecule?

A phosphate group, a deoxyribose sugar, and a nitrogenous base.

Cytosine

A pyrimidine nitrogenous base found in both DNA and RNA; pairs with guanine.

Thymine

A pyrimidine nitrogenous base found in DNA; pairs with adenine.

Uracil

A pyrimidine nitrogenous base found in RNA; replaces thymine and pairs with adenine.

Adenine

A purine nitrogenous base found in both DNA and RNA; pairs with thymine in DNA and uracil in RNA.

Guanine

A purine nitrogenous base found in both DNA and RNA; pairs with cytosine.

What are the four nucleotide bases found in RNA?

Adenine, uracil, cytosine, and guanine.

Amino acids

Organic molecules that are the monomers of proteins; they are joined together during protein synthesis.

Complementary base pairing

The specific pairing of nitrogenous bases: adenine pairs with thymine in DNA or uracil in RNA, while guanine pairs with cytosine.

Multicellular organism

An organism made up of many cells that are specialized for different functions.

What is the shape of a DNA strand?

A double helix.

Polymer

A large molecule made by joining many repeating monomers together.

Polymer chain

A long chain of repeating monomers joined by chemical bonds.

Covalent bond

A strong chemical bond formed when atoms share electrons.

Condensation reaction

A reaction in which two molecules join together and water is produced as a byproduct.

Monosaccharide

The simplest type of carbohydrate; a single sugar molecule.

Reactivity

The tendency of a substance to undergo a chemical reaction.

Hydroxyl group

A functional group consisting of an oxygen atom bonded to a hydrogen atom (-OH).

Hydrolysis

A reaction in which water is used to break a chemical bond.

Dehydration synthesis

Another term for a condensation reaction; joins molecules together while removing water.

Phosphodiester bond

A covalent bond that joins nucleotides together in a nucleic acid, forming the sugar-phosphate backbone.

Byproduct

A substance produced as a result of a chemical reaction but not the main desired product.

Deoxyribose

The five-carbon sugar found in DNA nucleotides.

Synthesized

Made or produced, usually through a series of chemical reactions.

Translation

The process in which the nucleotide sequence of mRNA is used to determine the amino acid sequence of a protein.

Purine

A nitrogenous base with a two-ring structure; adenine and guanine are purines.

Pyrimidine

A nitrogenous base with a single-ring structure; cytosine, thymine, and uracil are pyrimidines.

mRNA

Messenger RNA; carries genetic information from DNA to the ribosome for protein synthesis.

tRNA

Transfer RNA; carries specific amino acids to the ribosome during translation.

rRNA

Ribosomal RNA; forms part of ribosomes and plays a role in protein synthesis.

Linker DNA

DNA that connects neighboring nucleosomes.

Chromosome

A structure made of DNA and associated proteins that carries genetic information.

Bacteriophage

A virus that infects bacteria.

Bacterium Escherichia coli (E. coli)

A species of bacterium commonly used in biological research and experiments.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Metabolism

The network of chemical reactions that occur within a living organism.

Radioactivity

The spontaneous emission of radiation from unstable atomic nuclei.

Protein synthesis

The process by which cells produce proteins using genetic information; it includes transcription and translation.

Radioisotope

An unstable radioactive isotope that emits radiation as it decays.

Radioactive isotope labelling

A technique in which radioactive isotopes are used to label molecules so their movement or location can be tracked experimentally.

Tetranucleotide

A molecule or sequence containing four nucleotides; historically used in early investigations into the structure of nucleic acids.

Hydrogen bond donor

A molecule or atom that provides a hydrogen atom for a hydrogen bond, usually when hydrogen is bonded to an electronegative atom such as oxygen or nitrogen.

Hydrogen bond acceptor

An electronegative atom with a lone pair of electrons that can accept a hydrogen bond.

Octamer

A structure made of eight molecules; in nucleosomes, the histone core is an octamer made from eight histone proteins.

Chromatin

The complex of DNA and associated proteins found in the nucleus of eukaryotic cells.

Histone

A protein around which DNA wraps to form nucleosomes.

Nitrogenous base

A nitrogen-containing molecule found in nucleotides; adenine, guanine, cytosine, thymine, and uracil are the main bases in DNA and RNA.

Sugar-Phosphate backbone

The repeating chain of sugar and phosphate groups that forms the sides of a DNA or RNA strand

Antiparallel

Describes the arrangement of the two DNA strands running in opposite directions.

Hydrogen bond

A relatively weak attraction between molecules or parts of molecules; hydrogen bonds between complementary bases help hold the two DNA strands together.

Gene

A section of DNA that contains information for producing a functional product, such as a protein or functional RNA.

Genome

The complete set of genetic material in an organism.

Transcription

The process of producing an RNA molecule using a DNA template.

Ribosome

A cellular structure made of rRNA and proteins where translation and protein synthesis occur.

DNA replication

The process by which DNA is copied before cell division.

Template strand

The DNA strand used as a pattern to produce a complementary RNA strand during transcription.

Nucleotide sequence

The specific order of nucleotides in a nucleic acid; this sequence carries genetic information.

Base pairing

A hydrogen-bonded interaction between complementary nitrogenous bases.

Purine-pyrimidine pairing

The pairing of a two-ring purine with a one-ring pyrimidine, allowing DNA to maintain a consistent width; A pairs with T and G pairs with C.

Chargaff's rule

In double-stranded DNA, the amount of adenine equals thymine and the amount of guanine equals cytosine.

Genetic information

Information encoded in the nucleotide sequence of DNA that determines the production and regulation of biological molecules.

Sugar

phosphate bond

Polynucleotide

A polymer made from many nucleotide monomers joined by phosphodiester bonds.

Protein

A polymer made from amino acids folded into a specific three-dimensional structure.

Peptide bond

A covalent bond formed between amino acids when they join together to form a polypeptide.

Polypeptide

A chain of amino acids joined by peptide bonds.