• DNA=• Deoxyribonucleic Acid• The structure of DNA was not discovered until 1953 when Watson and Crick proposed the structure below.• DNA is made up of two strands of nucleotides. nucleotides• These two strands wind around each other in a double helix. helix
• Each nucleotide is made up of three different parts:• 1) Phosphate• 2) Sugar• 3) nitrogenous base• The sugar and phosphate make chains, and the bases connect the two strands of DNA together.
• Draw the structure of DNA below and circle the nucleotides.
• There are 4 different nitrogen bases called:• 1) Adenine Purine• 2) Guanine• 3) Cytosine pyrimidine• 4) Thymine• A purine always pairs with a pyrimidine• A with T• C with G• Weak hydrogen bonds hold the nitrogen bases together.
• RNA =• Ribonucleic Acid• RNA is very similar to DNA. RNA nucleotides are also made up of three parts: sugar, phosphate, and one of four nitrogen bases.• RNA DNA• ribose (sugar) instead of deoxyribose• Uracil (bases) instead of Thyamine and• Single strand instead of double strand
• now Purine pyrimidine• Adenine pairs with Uracil• Guanine pairs with Cytosine• RNA has three different functions in the cell, depending on its structure. All RNA is single stranded
• Messenger RNA (mRNA) – carries DNA code from nucleus to the cytoplasm• Transfer RNA (tRNA) – brings amino acids to the ribosome• Ribosomal RNA (rRNA) – puts amino acids together