Structure Of A Nucleotide
-A phosphate group.
-A pentose sugar.
-Organic base (contains N); Pyrimidine - T and C, Purine - A and G.
Structure Of DNA
-Double stranded polymer.
-Each polynucleotide may contains millions of units.
-Double helix held together by hydrogen bonds.
-The pentose sugar is deoxyribose.
-Four bases: Thymine, Cytosine, Guanine, Adenine.
-Linked by compementory base: A-T, C-G.
Functions Of DNA
-Very stable so can pass from generation to generation without change.
-Very large and can carry large amounts of genetic information.
-Two strands are held by H bonds, easy to break for transcription.
-Sugar-phosphate backbone protects information.
Structure Of RNA
-Pentose sugar is ribose.
-The bases are the same but Thymine is replaced by Uracil.
-mRNA: A long molecule in a single helix, made in the nucleus, for carrying code into cytoplasm.
-rRNA: Large, complex molecule, with both single and double helices; ribosomes are made up of rRNA and protein, and is the site of translation.
-tRNA: Single stranded in a clover shape, with one end where the amino acid is carried and the other end is called the anticodon; transporting amino acids to ribosomes.
-Sugar = Deoxyribose
-Bases = CGAT
-Helix = Double
-Sugar = Ribose
-Bases = CGAU
-Helix = Single