DNA and RNA Flashcards
What are the essential roles of DNA
- Contains genetic material for development and function of organisms
- Has hereditary material - used to pass on genetic material to offspring
Describe the structure of DNA
It is a polymer made up of nucleotide polymers
What is a mono nucleotide
A molecule that is composed of a pentose sugar, a phosphate group and an nitrogen containing organic base. Monomer unit of nucleic acids
What is a nucleotide made up of
- pentose sugar (5 carbons)
- Phosphate group (Contains phosphate ion)
- Nitrogenous base
What is the pentose sugar in DNA
Deoxyribose
What are the 4 organic bases in DNA
Guanine, Adenine, Cytosine, Thymine
What are the 2 types of organic bases found in nucleotides
- Purine bases (guanine and adenine)
- Pyrimidine bases (cytosine and thymine)
What are purine bases
Bases with 2 carbon rings (guanine and adenine)
What are pyrimidine bases
Bases with only 1 carbon ring (cytosine and thymine)
How are 2 mono nucleotides joined
Condensation reaction
Where does the condensation reaction occur between 2 nucleotides
At the hydroxyl groups on the phosphate group and pentose sugar
What bond forms between 2 mono nucleotides
Phosphodiester bond which forms and molecule of water
What is a polynucleotide
A polymer made up of many nucleotide monomers joined by a series of condensation reactions
What part of mono nucleotide is negative
Phosphate
What part of mono nucleotide is positive
Nitrogenous base
How is a dinucleotide broken into 2 mono nucleotides
Hydrolyses which requires water
How are the 2 polynucleotide strands held together in DNA
Hydrogen bonds between the 2 bases
How do the correct bases always pair up (A to T and G to C)
- A and T can form 2 hydrogen bonds, where as G and C can form 3 hydrogen bonds
- Purine bases (big) (A and G) try and can only pair with a pyrimidine base (small) (T and C) due to their sizes
In what direction do the 2 polynucleotide strands in DNA run
In opposite directions to each other (antiparallel) 5 prime to 3 prime and 3 prime to 5 prime
What are the roles of RNA
- Acts as a messenger molecule so helps transfer info from DNA to proteins
- ## Helps regulation and synthesis of proteins
How is RNA similar to DNA
It is also a polynucleotide
How is RNA different to DNA
- RNA is single stranded but DNA is double stranded
- RNA polynucleotide chains are shorter than DNA chains
- Pentose sugar in RNA is ribose and is deoxyribose in DNA
- Nitrogenous bases are GCAU (uracil)
