Master the basic features of a B-form DNA as first reported by Watson and Crick.
ID: 51927 • Letter: M
Question
Master the basic features of a B-form DNA as first reported by Watson and Crick. You should be able to list its monomers, the name of linkage that connects monomers, the diameter of the double helix and the number of base pairs per turn. You may be asked to draw a DNA structure or calculate the length of a DNA molecule based on its size. You should also develop an understanding of the meanings of such features as follows.
Anti-parallel
Complementary
5’ or 3’ ends
Base pairs
Sugar phosphate backbone
Major and minor grooves
Genetic information
Double stranded
Explanation / Answer
Monomers = Four nucleotide bases (A/TG/C), Sugar (deoxyribose) and Phosphate
Diameter of the double helix = approx 2 nm
Number of base pairs per turn = 10
Anti-parallel- the strands of a DNA are not coiled in same direction. In order to make them complementary and adjust the nucleotides, they run anti parallel, i.e. in opposite directions.
Complementary- Not all four bases pair up with each other, only the complementary does.
5’ or 3’ ends- These are used to describe the direction of DNA strand. 5' end lies in phosphate part and 3' in sugar molecule.
Base pairs- these are the complementary pair of nucleotides.
Sugar phosphate backbone - Its the chain which supports the nucleotides and give the structure to DNA
Major and minor grooves- The turn of the DNA helix has some space. The greater space is refered as major groove and lesser area as minor groove.
Genetic information- its the entire genome of the organism, which codes for all proteins responsible for proper functioning of the organism.
Double stranded- DNA is present in double strand form, means two strands of nucleotides are coiled and bonded around each other.