DNA Structure and Function

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DNA Structure and Function
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DNA is an example of a(n)

1. Amino acid
2. Nucleic acid
3. Carbohydrate
4. Lipid

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DNA is made up of monomers called

1. Triglycerides
2. Amino acids
3. Nucleotides
4. ATP

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DNA contains the pentose sugar

1. Ribose
2. Glucose
3. Galactose
4. Deoxyribose

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Which of the following is NOT a nitrogen base in
DNA?

1. Adenine
2. Guanine
3. Uracil
4. Thymine
5. Cytosine

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DNA (Deoxyribonucleic Acid)

• Function
• Store, copy, transmit genetic information
• Structure
• polymer nucleic acid
• monomers nucleotides

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II. Basics of DNA Structure

• DNA - stands for deoxyribonucleic acid
• B. double-stranded
• C. 3-D model is called double helix
• Discovered by James Watson Francis Crick
  (Received Nobel Prize 1962) with the help of
  Rosalind Franklins x-ray crystallography picture

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Nucleotides

• 3 parts
• nitrogen base (C-N ring)
• pentose sugar (5C)
• ribose in RNA
• deoxyribose in DNA
• phosphate (PO4) group

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Types of nitrogen bases

• purines
• double ring N base
• adenine (A)
• guanine (G)
• pyrimidines
• single ring N base
• cytosine (C)
• thymine (T)
• T is only in DNA
• uracil (U)
• U is only in RNA

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Pairing of nucleotides

• Nucleotides bond between DNA strands
• Hydrogen bonds between complimentary base pairs
• purine pyrimidine
• A T
• 2 H bonds
• G C
• 3 H bonds

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DNA Structure

• Sugar/Phosphate Backbone
• Sides of ladder
• Phosphodiester bond
• (strong covalent bond) between
• sugar and phosphate
• Nitrogen Bases in center
• Steps of ladder
• Hydrogen bonds between
• Nitrogen bases

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DNA is Anti-Parallel

• The two strands
• of DNA run in
• opposite directions
• This allows for the
• bases to come in contact at the center of the
  molecule

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RNA

• Ribonucleic acid
• Many different types (mRNA,
• tRNA, rRNA, microRNA, etc.)
• Single Stranded
• Ribose sugar (5 carbon sugar)
• 4 nitrogen bases
• Pyrimidines Uracil and Cytosine
• Purines Adenine and Guanine
• Base Pairing Rules
• A pairs with U
• G pairs with C