Chapter 2 Nucleic Acids Flashcards
What is the structure of a nucleotide?
Pentode sugar.
Phosphate.
Nitrogen containing base (CGATU).
What reaction joins the pentose sugar, phosphate group and organic base in a nucleotide?
Condensation.
What is the bond between two mononucleotides?
Phosphodiester bond.
Complementary base pairs in DNA
G C
A T
DNA strands are arranged into a…
Double helix.
What is the structure of RNA?
- Single stranded
- Short
- Pentose sugar is ribose
- Organic bases are C G A U
What are the three types of RNA?
(1) Transfers genetic information from DNA to ribosomes.
(2) Ribosomes are made up of proteins and another type of RNA.
(3) Involved in protein synthesis.
What is the structure of DNA?
- Pentose sugar is deoxyribose.
- Two strands of nucleotides.
- Long chains.
- Strands joined by hydrogen bonds.
Why is DNA a stable molecule?
- Phosphodiester backbone protects more chemically relative organic bases inside the double helix.
- Hydrogen bonds link base pairs. As there as three hydrogen bonds C and G, the greater the C-G pairings, the more stable DNA.
How is DNA adapted to carry out its functions?
- Stable so passes from generation to generation without changing. Rarely mutates.
- Extremely large and so it carries a lot of genetic information.
- Base paring leads to DNA being able to replicate and to transfer information as mRNA.
- Hydrogen bonds allow strands to separate during DNA replication.
- Genetic material is protected by backbone.
Describe semi-conservative replication.
(1) DNA helicase breaks hydrogen bonds between strands.
(2) Double helix unwinds.
(3) Exposed nucleotides on the template strand pair with free nucleotides by specific base pairing.
(4) Nucleotides are joined by a condensation reaction by DNA polymerase.
What is the structure of ATP?
Adenine.
Ribose.
Three phosphates.
Why are the bonds between ATP easily broken?
They are unstable so have a low activation energy.
How much energy is released when bonds between ATP are broken?
A lot.
Equation for ATP + H2O ->
Enzyme
Reaction
ADP + Pi + E
Catalysed by ATP hydrolase.
Hydrolysis reaction.