KA3

• A gene is a section of DNA that codes for a protein
• each chromosome, inside the nucleus is made up of hundreds of genes
• DNA is a double stranded helix
• each strand of a DNA molecule is held together by complementary bace parings
• there is 4 base parings called adenine, thymine, guanine and cytosine
• A always joins to T
• G always joins to C
• the sequence of the brace parings determines the order of the amino acids
• the amino acids sequence determines the structure (shape) and function of the protein
• DNA is found in the nucleus
• messenger RNA (mRNA)is a molecule which carries a complimentary copy of the genetic code from the nucleus to the ribosome in the cytoplasm. This is where protein synthesis occurs.
• Individual units of DNA are nucleotides which have sections called bases
• Proteins are made up of amino acids
• All occurs within the ribosomes in the cytoplasm
• mRNA copies a sequence of genetic code from the DNA sequence, carries it to the nucleus and into the ribosomes. This is where the base sequence copied by mRNA codes for a specific amino-acids which are bound together in the ribosome to make proteins.