Nucleotides

Question 1

• What was originally believed to be the building blocks of DNA/chromosomes and why

Answer 1

○ It was originally thought to be protiens because they were so numerous and could make so many different combinations and had the perfect shape
- There are 20 different amino acids
that can make endlessly different protiens

Question 2

• What are the actual building blocks of DNA/chromosomes and why where they doubted

Bonus what are the 4 nucleotides found in DNA

Answer 2

○ Nucleotides are the building blocks of DNA/chromosomes
○ Nucleotides have only 4 different structural units in DNA/chromosomes so it was hard to believe they could make so much genetic variation

bonus: Adenine, guanine, cytosine, thymine
- Which were thought to occur in a repeating pattern
-This is not the case

Question 3

• What does each nucleotide base contain

Answer 3

○ Nitrogen
○ Usually 2 N per ring

Question 4

• What two nucleotides are considered purines

○ Bonus: draw their structures and tell me a structural difference

Answer 4

○ Adenine
○ Guanine

bonus: A structural difference is that Guanine has a =O where adenine has a NH2
- They both have a NH2 just in
different spots

Question 5

• What two nucleotides are considered pyrimidines

○ Bonus: draw their structures and tell me structural differences

Answer 5

○ Cytosine
○ Thymine

bonus: Thymine has a CH3 meth group

Question 6

• What pyrimidine is only found in RNA

○ Bonus: draw its structure and how is it structurally different from cytosine and thymine

Answer 6

○ Uracil

bonus: It is structurally different because it has two =O bonds

Question 7

• What nucleotides are found in DNA vs RNA

Answer 7

○ DNA contains Adenine, guanine, cytosine, thymine
○ RNA contains Adenine, guanine, cytosine, uracil

Question 8

• Why are the purines and pyrimidines considered bases

Answer 8

○ They donate protons in extremely high or low pHs

Question 9

• What is the sugar used for DNA vs RNA

○ Bonus: what is the difference

Answer 9

○ DNA uses Deoxyribose
○ RNA uses ribose

bonus: Ribose has a OH bonded to 2’ carbon
Deoxyribose only has a H bonded to its 2’ carbon

Question 10

• Where is the 5’ carbon located on the ribose and deoxyribose sugars

Answer 10

○ It is not in the ring but bonded to C4’

Question 11

• How do you number the carbons in the sugar ring that connected to the nucleotide base

Answer 11

○ You use a ‘ to indicate they are part of the sugar ring and start numbering them so that 5’ is bonded to 4’ and not part of the ring

Question 12

• What is the linkage between nucleotides called

Answer 12

○ Phosphodiester bond
§ A single phosphate group forms ester bonds to
C5’ and C3’
§ C-O-P-O-anything but C