nucleic acids

DNA

a double stranded polymer of nucleotides, make up a polynucleotide or nucleic acid

RNA

a single stranded polymer of nucleotide

deoxyribose

five carbon pentose sugar found in DNA

ribose

five carbon pentose sugar found in RNA

organic nitrogenous base

component of a nucleotide ring structure of carbon and nitrogen, may have one or two rings

nucleotide

a complex chemical made up of pentose sugar, phosphate nad organic nitrogenous base

pyrimidine

nitrogenous base containing single ring structure, thymine, cytosine, uracil

polynucleotide

many nucleotides joined together via condensation reaction

purine

nitrogenous base containing single ring structure, adenine, guanine

double helix

two strands of DNA coiled around each other. The strands are held by weak hydrogen bonds between the organic nitrogenous bases

base pairing rule

the standard arrangement of bases in nucleotides in relation to their opposite pairing

antiparallel

the position of the sugar phosphate backbone of one DNA strand is in an opposite direction to the other strand

interphase

replication of DNA, production of organelles, ATP synthesis, increase in cell size

semi conservative replication

replicated DNA is semi conservative because it possesses 50% of the original genetic material from its parent. One original strand and one new strand of DNA is the result of DNA replication

endergonic reaction

a chemical reaction which absorbs energy from the surroundings

exergonic reaction

a chemical reaction which releases energy to the surrounding

ATP

adenosine triphosphate. A molecule that acts as the universal energy currency in living organisms

DNA polymerase

the enzyme that is used to synthesise a new strand of DNA by catalysing the addition of free nucleotides to the exposed bases

DNA helicase

the enzyme that separates the two strands of DNA that make up a DNA molecule by breaking hydrogen bonds

meselson stahl experiment

an experiment by meselson and stahl in 1958 which used an isotope of nitrogen to prove that DNA replication was semiconservative

genetic code

the sequence of bases in DNA

the triplet code

each amino acid in a polypeptide is code for by three bases

exons

regions of DNA that code for proteins

introns

regions of non coding DNA found between exons

transcription

the formation of mRNA molecule, using a length of DNA as a template, complimentary base pairing is used, The enxyme RNA polymerase catalyses the reaction

translation

stage of protein synthesis in which the amino acids are assembled at ribosomes. The order in which amino acids are joined together, by peptide bonds, is determined by the sequence of codons on the mRNA which is itself determined by the sequence of nucleotide triplets on the coding strand of a length of DNA

RNA polymerase

an enzyme that catalyses the synthesis of RNA either from a strand of DNA or another strand of RNA

tRNA

a type of RNA which carries amino acids to a ribosome during protein synthesis. Each molecule of tRNA can carry a specific amino acid. It contains a triplet of bases known as an anticodon which will bind to a complementary codon of mRNA

gene

the portion of DNA which codes for a whole polypeptide