Midterm #2 Flashcards
(163 cards)
what is DNAs function
- it carries the genetic instructions required for the expression of traits in all known living organisms
- it serves as the hereditary unit of life
what is a double helix
two spiral backbones
describe what it means for DNA to be in a double helix
DNA is a twisted ladder with the rungs being the nitrogenous bases (A, C, T, G) aka the sugar phosphate backbone
what are the individual units of DNA (nucleotide)
individual units of DNA are made up of nucleotides
1 phosphate
1 sugar
1 nitrogenous base
what holds the double helix together
hydrogen bonds (IMFs) hold the two strands together
what are the complimentary base pairs
nucleotides follow complimentary base pairing rules:
- adenine pairs with thymine
- guanine pairs with cytosine
nucleic acid
large biomolecule composed of many nucleotides (DNA and RNA)
what is a nucleotide
can refer either to deoxyribonucleotide –> monomer of DNA
ribonucleotide –> monomer of RNA
draw a nucleotide
see first page of notes
draw cytosine
see first page of notes
draw thymine
see first page of notes
draw uracil
see first page of notes
draw adenine
see first page of notes
draw guanine
see first page of notes
which nitrogenous bases are purines
adenine and guanine
what nitrogenous bases are pyrimidines
cytosine, thymine, and uracil
what are the bonds in a nucleotide
- phosphodiester bonds
- glycosidic bond
how do the nucleosides differ from ribonucleoside and deoxyribonucleoside
ribonucleoside
- found in RNA
- name (ex. cytosine)
- possess two OHs on the bottom of the ring (pg. 2)
deoxyribonucleoside
- found in DNA
- name (ex. deoxycytosine)
- possess one OH on the bottom of the ring
when a new strand of DNA or RNA is being synthesized, which side is it added to?
synthesized from 5’ to 3’
5’ has the phosphate 3’ has the sugar
(see pg. 2)
function of DNA polymerase
hydrolyzes dNTPs between alpha and beta phosphate
DNA polymerases are enzymes that create DNA molecules by assembling nucleotides
how do two nucleotides link
the hydrolysis of a high energy bond provides the energy necessary to link the two nucleotides together
what does ATP break down to
ATP often breaks down to ADP and an inorganic phosphate
during DNA synthesis, what is released as a result of hydrolysis
pyrophosphate is released
when one phosphodiester bond is created, what happens
another phosphodiester bond is created (pg. 3)