Nucleic acids Flashcards
What are nucleic acids?
-long chains (polymers) of lots of nucleotide monomers joined together by phosphodiester bonds.
what 3 components make up nucleotides?
- Pentose sugar (either deoxyribose or ribose)
- Nitrogenous base (G, C, A, T or U)
- Phosphate
what are the 4 bases, and what are the complimentary to?
-Guanine, Cytosine, Adenine, Thymine or Uracil
G - C
A - T
How many hydrogen bonds hold guanine and cytosine together?
3
How many hydrogen bonds hold together Adenine and Thyme (or uracil)?
2
What bases are purine, and what does it mean?
Adenine and Guanine
- means they have a large double ring structure
What bases are pyrimidines, and what does it mean?
Cytosine and Thymine
- means they are smaller as they are composed of a single ring
Why do purines always base pair with pyrimidines?
Because it’s the only way DNA can keep a regular shape and not become too bulky or narrow
What are the differences between DNA and RNA?
- They contain different sugars- the pentose sugar in DNA is deoxyribose and in RNA is ribose
- RNA contains uracil instead of thymine
- DNA is double-stranded whereas RNA is single-stranded
- DNA has hydrogen bonds between the two complementary strands
What happens during DNA and RNA synthesis?
-Nucleotides are connected through the formation of phosphodiester bonds between the phosphate group on one nucleotide and the pentose sugar of the next nucleotide.
What type of reaction is the synthesis of DNA and RNA?
Condensation reaction
What enzymes catalyse DNA and RNA synthesis?
DNA polymerase or RNA polymerase
What reaction is involved in the breaking of phosphodiester bonds?
Hydrolysis reaction
