DNA Structure and Function Flashcards
What does DNA stand for?
Deoxyribonucleic Acid
DNA is a polymer of ________, which are held together by ________ bonds.
nucleotides; phosphodiester
Label the 5’ end and the 3’ end of this single DNA strand.
The 3’ end carbon is attached to an -OH group and the 5’ end carbon is attached to a phosphate group.
Define:
the antiparallel nature of DNA.
The two strands of DNA that make up the double helix run in opposite directions, one strand with a 5’ -> 3’ orientation and the other with a 3’ -> 5’ orientation.
What are the three main parts of a nucleotide?
a phosphate group, a 5-carbon sugar, and a nitrogenous base
Name the purines and pyrimidines.
The purines are adenine and guanine. The pyrimidines are cytosine and thymine.
What is the difference in structure between purines and pyrimidines?
Purines are two ring structures while pyrimidines are single ring structures.
Which nitrogenous base forms hydrogen bonds with adenine?
thymine
Which nitrogenous base forms hydrogen bonds with guanine?
cytosine
Which type of bond forms between the nitrogenous bases of two complementary DNA strands?
hydrogen bond
How many hydrogen bonds form between adenine and thymine?
two hydrogen bonds
How many hydrogen bonds form between guanine and cytosine?
three hydrogen bonds
What is the central dogma of molecular biology?
DNA is transcribed to RNA which is translated to amino acids that make up a protein.
Define:
DNA helicase
an enzyme responsible for separating the two strands of a DNA double helix needed for initiation of DNA replication
What is the name of the enzyme responsible for adding deoxyribonucleotides to a newly created DNA strand during replication?
DNA polymerase