Download Section 4.3 – DNA

Section 4.3 – DNA DNA -­‐
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Deoxyribonucleic Acid Code contained in hereditary material Stored in cells that have a nucleus 1952 – Rosalind Franklin discovered that DNA is 2 chains in a spiral -­‐ 1953 – Watson and Crick made a DNA model o DNA is made of deoxyribose (sugar) and a phosphate group (sides of ladder) o Rungs are made of nitrogen bases Four Nitrogen Bases in DNA 1) A – Adenine 2) G – Guanine A pairs with T 3) C – Cytosine C pairs with G 4) T – Thymine Copying DNA 1) The 2 sides of DNA unwind and separate 2) Each side is then doubled Gene – a section of DNA on a chromosome RNA -­‐ Ribonucleic Acid -­‐ Carries the codes for making proteins from the nucleus to the ribosomes -­‐ It is made in the nucleus on a DNA pattern RNA Bases 1) A – Adenine 2) C – Cytosine 3) G – Guanine 4) U – Uracil **** Instead of deoxyribose on the sides of the ladder, it has the sugar ribose. 3 Main Types of RNA made from DNA 1) mRNA – Messenger RNA – begins protein production when it moves to the cytoplasm – Ribosomes attach to it. 2) rRNA – Ribosomal RNA – Ribosomes are made of these 3) tRNA -­‐ Transfer RNA – Brings amino acids to ribosomes **** mRNA and tRNA match their nitrogen bases. This forms a pattern. Mutation – Any permanent change in a DNA sequence of a gene or chromosome