Identify three possible components of a DNA nucleotide.
deoxyribose, phosphate group, thymine. DNA and RNA have similar structures: a pentose sugar with a nitrogenous base and a phosphate group. DNA and RNA differ in the type of pentose sugar each possesses (DNA has deoxyribose; RNA has ribose) and in one base (DNA has thymine; RNA has uracil).
In a nucleic acid polymer, the hydrogen bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers?
nitrogenous bases
DNA is composed of building blocks called _____.
nucleotides. DNA is a composed of nucleotide units.
In eukaryotic cells DNA has the appearance of a _____.
double helix. Eukaryotic DNA is organized as a double helix.
Write the complementary sequence for the following DNA sequence, in order from 3' to 5':
5' - CGATATTGAGCTAAGCTT - 3'
3' - GCTATAACTCGATTCGAA - 5'
If a segment of DNA contains 28 percent T nucleotides, then the percentage of A nucleotides in that segment will be _____.
28 percent
In a DNA double helix, the chemical bonds that form between the complementary nitrogenous bases are _____.
hydrogen bonds
Which statement concerning the DNA double helix is correct?
Base pairing allows production of identical daughter molecules.Complementary base pairing is the chemical interaction that underlies the replication of genetic information stored in DNA.
If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?
3'-TAAACG-5'
Adenine pairs with thymine and guanine pairs with cytosine.
If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?
75. 100 nucleotide pairs are a total of 200 nucleotides. Because of base pairing, if there are 25 adenine there must also be 25 thymine. This leaves 200-50 = 150 nucleotides to be divided evenly between guanine and cytosine.
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.
hydrogen bonds. Nitrogenous base pairs are joined by hydrogen bonds.