DNA Flashcards
Two types of nucleic acid
Deoxyribonucleic acid
Ribonucleic acid
What does DNA do
Carries genetic code and codes for protein
Name of monomer and polymer of nucleic acid
Nucleotide
Polynucleotide
How do they form, what bond and what do they lose
Condensation reaction
Phosphodiester bond
Water
What does a nucleotide contain
A phosphate group
Pentose sugar (depending on DNA or RNA)
Nitrogenous base
Types of pentose sugar
DNA = deoxyribose sugar
RNA = ribose sugar
types of bases
A, C, T, G and U
Base A
- Adenine
Purine
In both DNA and RNA
Base T
Thymine
Pyrimidine
Only in DNA
Base G
Guanine
Purine
Both DNA and RNA
Base C
Cytosine
Pyrimidine
Both DNA and RNA
Base U
Uracil
Pyrimidine
Only RNA
Difference between Pyrimidine and purine
Purine has 2 nitrogenous bases and is larger
Pyrimidine has 1 nitrogenous base and is shorter
How does double helix form
1 complementary bases pair up between nitrogenous bases on 2 polynucleotide chains
Held by hydrogen bonds
Strands are anti parallel forms contestant distance
DNA twists to form very stable double helix
Amount of hydrogen bonds in complementary bases
A-T have 2 hydrogen bonds
C-G have 3 hydrogen bonds
Features of a genetic code
- Triple code
- Non overlapping
- Degenerate
- Universal
Universal
Almost all living organisms have the same 5 bases and triplet of DNA base codes and same amino acids
Triple code
3 nucleotides code for 1 amino acid (3 bases)
Non overlapping
Code is read so each base is only 1 triplet code
Degenerate
More triplet codes than amino acids so many amino acids can be coded for by several amino acids
What is needed in transcription
Gene, RNA polymerase, free RNA nucleotides that are activated
