Nucleic Acids Flashcards
Why do we crush the strawberries when purifying DNA?
To damage the cell wall, so we can access the components of the cell within
Why do we mix the sample with detergent?
To break the phospholipid bilayer in the cell membrane
Why do we add protease enzyme when purifying DNA?
To break down the histone proteins that are associated with DNA
Why do we add ethanol to the mixture when purifying DNA?
Ethanol is what actually causes the DNA to precipitate out of the solution
Why should the ethanol be cold?
Why should it be added AFTER the protease enzyme is added?
- so it doesn’t damage the DNA molecules
- so it doesn’t slow down the enzymes action
Why do we add salt when purifying DNA?
Salt acidifies the sugar phosphate backbone and breaks the hydrogen bonds holding the structure together
What are nucleotides?
the monomers of DNA
what are the four nucleotides?
adenine, thymine, cytosine, guanine
what base is different in RNA?
URACIL instead of thymine
differences between purines and pyrimidines?
purines bigger, double carbon ring structure.
pyrimidines smaller, single carbon ring structure.
name the purine bases
adenine and guanine
name the pyrimidine bases
cytosine and thymine
name the complementary bases and how many bonds and which bonds they make
adenine and thymine- 2 hydrogen bonds
cytosine and guanine- 3 hydrogen bonds
why is DNA described as anti parallel?
the strands run in opposite directions to each other
which is the 3 prime end (3’)
one that ends with a hydroxyl group
which one is the 5 prime end (5’)
one that ends with a phosphate group
how many strands in a DNA molecule?
2
the distance between the strands is always ___________ because there is an ____________ of complementary bases.
equidistant, equal number
differences between RNA and DNA
- RNA has 1 strand , DNA has 2
- DNA has A,T,C,G and RNA has A,U,C,G
- RNA is much smaller
- RNA has ribose as pentose sugar, DNA has deoxyribose.
similarity between RNA and DNA
RNA uracil still forms 2 hydrogen bonds with adenine.
how are DNA polynucleotides formed? and where?
condensation reaction to form phosphodiester bonds between the hydroxyl group on the 3 carbon on one nucleotide and phosphate group on carbon 5 on the next nucleotide.
what does DNA nucleotide consist of?
- pentose sugar deoxyribose
- phosphate group PO4-2
- nitrogenous base (A,T,C,G)
what happens to RNA after protein synthesis?
they are degraded in the cytoplasm and the phosphodiester bonds are hydrolysed, and nucleotides are released and recycled.
what is DNA replication?
the process where one DNA molecule is replicated to produce two identical DNA molecules
