Nucleotides

Question 1

Nucleotide structure

Answer 1

• Type of biological molecule that polymerise as a chain to form nucleic acid. Nucleotides contain elements H,O,N and P
  Made of:
  1) Pentose monosaccharide sugar, containing 5 carbon atoms
  2) Phosphate group, -PO4 -2, an inorganic molecule that is acidic and negatively charged.
  3) Nitrogenous base - a complex organic molecule containing 1 or 2 carbon rings in its structure as well as nitrogen.

Question 2

Nucleotide polymerisation

Answer 2

• Linked by condensation reactions to form polymer polynucleotide.
• Phosphodiester is a covalent link between the phosphate at the 5’ carbon of the pentose sugar of one nucleotide, and the hydroxyl group at the 3’ postion of another nucleotide.
• This forms long, strong sugar-phosphate ‘backbone’ w/ base attached to each sugar.
• Phosphodiester bonds are broken by hydrolysis

Question 3

DNA nucleotides

Answer 3

• Deoxyribonucleic acid contains deoxyribose sugar - sugar with FEWER oxygen that ribose.
• Has same phosphate group but 4 possible bases: Adenine, Thymine, Guanine and Cytosine.
• A molecule of DNA contains 2 polynucleotide chains.

Question 4

RNA nucleotides

Answer 4

• Ribonucleic acid contains ribose sugar.
• RNA has same phosphate groups but 4 possible bases.
• However, Uracil replaces Thymine.
• An RNA molecule is made of single polynucleotide chain.

Question 5

Purines and Pyrimidines

Answer 5

• 4 bases can be split to purines and pyrimidines.
• Purines: Adenine and Guanine
• Pyrimidines: Thymine, Cytosine and Uracil
• AanG was Pure; Tanaka K(C)yoto and Ukai lived in Pyramids*
• Pyrimidines: smaller bases with single carbon ring structure
• Purines: larger bases with double carbon ring structures