A1.2 Nucleic Acids

DNA

deoxyribonucleic acid

RNA

ribonucleic acid

nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

dehydration synthesis

Condensation reaction where molecules are connected by loss of a water molecule.

phosphodiester bond

the type of bond that links the nucleotides in DNA or RNA. joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide

Purines

Adenine and Guanine

Pyrimidines

Cytosine and Thymine

Nucleosome

Bead-like structure in eukaryotic chromatin, composed of a short length of DNA wrapped around a core of histone proteins

Bacteriophage

A virus that infects bacteria

Radioisotopes

isotopes with nuclear instability

Hershey-Chase Experiment

confirmed that DNA is the genetic material because only radiolabeled DNA could be found in bacteriophage-infected bacteria

Chargaff's Rule

[A]=[T] and [G]=[C], they pair up across from one another forming two strands also called base pairing.

falsification principle

The reasoning principle that to test a rule, it is necessary to look for situations that would falsify the rule.

genetic code

the order of bases in DNA that determines the sequence of amino acids in proteins.

Cytosine

A pyrimidine base found in dna and rna that pairs with guanine.

Guanine

a purine (nitrogenous base) component of nucleotides and nucleic acids; links with cytosine in DNA

Adenine

a purine nitrogenous base, found in coenzymes ATP and NADP and in nucleic acids that pairs with thymine

Thymine

a pyrimidine nitrogen base in DNA that pairs with adenine

pentose

5 carbon monsaccharide sugar

Condensation

formation of larger molecules involving the removal of water from smaller component molecules.

polynucleotide

a long, unbranched chain of nucleotides, as found in DNA and RNA

Codon

three consecutive bases in DNA or RNA which specify an amino acid

Polymer

large organic molecules made up of repeating subunits (monomers)

uracil

a pyrimidine found in RNA (but not DNA); pairs with DNA adenine

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

Gene

sequence of DNA that codes for a protein and thus determines a trait

chromosome

length of DNA that carries specific genes in a linear sequence

locus

Location of a gene on a chromosome

Allele

Different forms of a gene

homologous chromosomes

Pair of chromosomes that are the same size, same appearance and same genes.

Genome

all of an organism's genetic material

Mutation

A change in a gene or chromosome.

Histone

protein molecule around which DNA is tightly coiled in chromatin

Bacteriophage

A virus that infects bacteria