Structure of DNA Flashcards
DNA is composed of
-two polynucleotide strands wound around each other in a double helix
The pentose sugar in the nucleotides is
-deoxyribose
What are the four organic bases in DNA
-Thymine
-Guanine
-Cytosine
-Adenine
Which bases are the purines?
-adenine, guanine
Which two bases are the pyrimidines
-thymine, cytosine
Where are the deoxyribose sugars and phosphate groups located
-outside of DNA and form the backbone
The bases of two strands do what in DNA
-face each other, pointing inwards
What joins the bases?
-hydrogen bonds
How many hydrogen bonds are between adenine and thymine?
-two
How many hydrogen bonds are between guanine and cytosine?
-three
What do the hydrogen bonds do?
-maintain the shape of the double helix
A DNA molecule is
-long, thin and tightly coiled within the chromosome
What are antiparallel strands?
The nucleotides in one strand are arranged in the opposite direction from those in the complimentary strand
DNA is suited to its function because:
-stable molecule
-information content passes essentially unchanged from generation to generation
-large molecule, carries a lot of genetic information
-as base pairs are on inside of double helix, within the deoxyribose-phosphate backbones, genetic info is protected
