DNA + RNA

• Heredity is the passing on of features from parents to offspring by means of genes.
• A gene is a length of DNA that codes for a specific protein
• Genes are found on chromosomes.
• Characteristics are controlled by genes.
• Chromosomes are made up of 60% protein and 40% DNA.
• Acquired variation is not inhereted or genetically controlled.
• Inherited variation is controlled by genes.
• Humans have 46 chromosomes, or 23 pairs.
• Point mutations are changes in just one base pair of a gene. e.g. sickle cell anaemia.
• DNA stands for deoxyribonucleic acid.
• The four bases used in DNA are adenine, thymine, guanine and cytosine.
• The base adenine joins with thymine, and the base guanine joins with cytosine.
• DNA strands have a double helix shape.
• There are 20 different amino acids that are used in the production of proteins.
• DNA codes for each amino acid by having triplet code.
• DNA replication takes place during the interphase of a cell. The double helix unwinds and an enzyme breaks the bond between the two strands. The incoming bases attach to the exposed bases.
• In DNA profiling, DNA is released, cut into fragments, the fragments are seperated and the patterns are compared.
• Ribonucleic acid (RNA) contains of the base uracil instead of thymine.
• RNA is a single-stranded molecule and its bases are complimentary to those of DNA.
• DNA is made up of units called nucleotides.
• Adenine and guanine are purine bases while thymine and cytosine are pyrimidine bases.
• A nucleotide is made up of a phosphate, a sugar, and a nitrogen base.
• In protein synthesis, genes are used to produce different proteins.
• The three types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
• The major steps involved in protein synthesis are transcription and translation.