Nucleic acids Flashcards
What are the components of a nucleotide?
Pentose sugar, phosphate plus organic base which contains nitrogen.
What are the components of ATP?
Ribose sugar, adenine and three phosphate groups joined together
Why is ATP formation endergonic?
Because energy is stored in the bond between the second and third phosphate.
Why is ATP hydrolysis exergonic?
Energy is released when the bond is broken between the second and third phosphate
Why is ATP known as the universal energy currency?
It is used by all living organisms to provide energy for nearly all reactions
Name three cellular processes that require ATP
Active transport, muscle contraction, protein synthesis, cell division, bulk transport.
Which bases are pyramidines and how many rings to they have?
Cytosine, Thymine, Uracil, they have one ring
Which bases are purines and how many rings to they have?
Guanine and Adenine, they have two rings
What are the base pairs and how do they join together?
Adenine and Thymine, Cytosine and Guanine. Joined by H bonds
How do you describe the different directions in which the two DNA strands run?
One runs from the 5 prime end to the 3 prime end, the other from the 3 prime end to 5 the prime end.
What are the two functions of DNA?
replication in dividing cells and coding for the order of amino acids in protein synthesis
Which enzymes are involved in DNA replication and what do they do?
DNA helicase breaks the H bonds to separate the strands, DNA polymerase catalyses the condenstation reaction to join the sugar phosphate backbone
Which isotopes were used in Meselson and Stahl’s experiment?
Nitrogen 14 and 15
If bacteria were given only N15 with which to form DNA bases, then DNA was extracted and centrifuged, where would the band be in the tube?
At the bottom
If bacteria grown in N15 were allowed to divide once in N14, then DNA was extracted and centrifuged, where would the band be in the tube?
In the middle
