BOOKLET 3: DNA

Nucleic acids

Polymers of nucleotides, DNA or RNA.

Polymers

Large molecules made of repeating sub-units.

Monomers

Single sub-units that form polymers.

Nucleotides

Monomers of nucleic acids, consisting of three parts.

Nucleoside

Nucleotide without the phosphate group.

Nitrogenous bases

Components of nucleotides: A, T, C, G, U.

Adenine

Nitrogenous base, pairs with thymine or uracil.

Thymine

Nitrogenous base, pairs with adenine in DNA.

Cytosine

Nitrogenous base, pairs with guanine.

Guanine

Nitrogenous base, pairs with cytosine.

Uracil

Nitrogenous base, replaces thymine in RNA.

Chargaff's rule

Equal amounts of A&T and C&G in DNA.

Pyrimidines

Single-ringed bases: C, U, T.

Purines

Double-ringed bases: A, G.

Antiparallel

Strands run in opposite directions.

5' and 3' ends

Refers to carbon positions in nucleotides.

RNA

Single-stranded nucleic acid with ribose sugar.

DNA

Double-stranded nucleic acid with deoxyribose sugar.

tRNA

Transfers amino acids to ribosomes.

mRNA

Carries genetic information from DNA to ribosomes.

rRNA

Structural component of ribosomes.

Central dogma

DNA -> RNA -> Protein synthesis process.

Anticodon

tRNA sequence complementary to mRNA codon.

DNA replication

Process of copying DNA before cell division.

Phosphodiester bond

Link between nucleotides in DNA/RNA.

Condensation reaction

Reaction releasing water when forming bonds.

DNA helicase

Enzyme that unwinds DNA strands.

RNA primers

Short RNA sequences initiating DNA synthesis.

DNA polymerase

Enzyme synthesizing new DNA strands.

DNA ligase

Enzyme joining Okazaki fragments together.

Unzipping

First stage of DNA replication, breaking bonds.

DNA synthesis

Third stage, adding nucleotides to form new strands.

Hydrogen bonds

Weak bonds between nitrogenous bases in DNA.

Base pairing rules

A pairs with T, C pairs with G.