Theme 1B Flashcards
What molecules are found in nucleic acids?
Pentose sugar: ribose (RNA) or deoxyribose (DNA)
Nitrogenous base: purines or pyrimidine
Phosphate group
The pentose sugar of RNA has a _______ group on its carbon 2
OH
The pentose sugar of DNA (deoxyribose) has a _____ on its carbon 2
H atom
Not OH
What are the nitrogenous bases used in DNA? In RNA?
DNA : ACGT
RNA: ACGU
Look at each nitrogenous base and identify which is which
LOOK ON GOOGLE DOC
What is a nucleoside.
Molecule of a sugar and a nitrogenous base
What carbon does the base bind to in a nucleoside.
Carbon 1
What is a nucleotide.
And nucleoside molecule but also with a phosphate group attached to carbon 5 of the sugar
What parts are DNA composed of
A bunch of deoxyribonucleotides.
Which carbons on the sugars in DNA are attached to the phosphate
C5 and C3
What causes DNA (polynucleotide) to be polar.
The 5 carbon end with phosphate group
The three carbon end with OH group
What charge is a dna molecule, why?
Negative because of the negatively charged phosphates in the pentose phosphate backbone
Ended on Slide 8
What is x ray diffraction
They have x ray source and it shoots beam of x rays to the DNA sample. The beam diffracts (splits) then shows pic of dna on photographic plate
What did x ray diffraction show us of dna
Showed that DNA was cylindrical and around
2mm in diameter
Showed 0.34nm periodicy (that base were stacked on top of one another)
Show x shaped pattern which indicated helical structure
What is a purine on one strand of dna always paired with?
A pyrimidine on the others strand (this fits chargaffs rule
The backbone of DNA is ___
, and the bases
(interior) are ___
Polar hydrophilic
Nonpolar hydrophobic
Why are the two strands of dna antiparallel?
Allows bases to properly line up with each other