Download A. Nucleic Acid = polymer of nucleotides 1. nucleotide = molecule

A.
B.
Nucleic Acid = polymer of nucleotides
1. nucleotide = molecule made up of…
a. a pentose (5 carbon) sugar called Deoxyribose
b. a phosphate group attached to the 5 ´ carbon of the pentose
c. one of four nitrogenous bases is attached to the 1´ carbon of
the pentose
- the four DNA nitrogenous bases are Adenine, Guanine,
Cytosine, and Thymine
DNA is a double helix
1. two individual polymers of nucleotides bond to one another
a. this process causes the two strands to coil into a
“double helix”
b. this bonding forces the nitrogenous bases to the inside of the
helix, while the deoxyribose and phosphate groups (referred
to as the sugar-phosphate backbone) get forced to the outside
1 ´ Carbon
pg. 87
the “prime” numbering system is used to distinguish between carbon atoms
in deoxyribose and carbon atoms in the nitrogenous bases
A. Hydrogen Bonding – Hydrogen covalently
bonded to one electronegative atom while
being attracted to another electronegative
atom.
1. this bonding is due to partial (+) and (-)
charges (polarity) within the molocules in
question
2. Occurs with F, O, and N
B. Hydrogen bonding between the two stands
of the DNA molecule creates
1. triple bonds between Guanine & Cytosine
2. double bonds between Adenine & Thymine
fig. 16.8 pg. 310
C.
Hydrogen bonding takes place between the
complementary nitrogenous bases between either
nitrogen and/or oxygen
1. forces the sugar-phosphate backbone to the
outside – aided by hydrophilic attractions of the
phosphate groups and H2 O
2. leaving the non-polar nitrogenous bases on
the inside
3. ten base pairs make up one turn in the dbl helix
fig. 16.7b pg 30
A. The two strands of the DNA
molecule are antiparallel
1. the sugar phosphate backbones
run in opposite directions
2. each terminal phosphate
group is attached to
a 5 ´ carbon, while the terminal
OH groups are attached
to 3 ´ carbons.
3. as a result the complementary
strand must run in the opposite
direction
similar to fig.
16.7a pg 309
fig. 16.12 pg. 296
A. All enzymes are proteins, made up of chains of amino acids.
B. Restriction Enzymes digest DNA by “cutting” DNA between specific
nucleotides (a disruption of the bond between a phosphate group and
the next sugar molecule), at locations identified as recognition
sequences which are approximately 6 base pairs long and enzyme
specific!
C. In a mixture of DNA and restriction enzymes, each enzyme causes the
disruption of the DNA backbone within each of the recognition
sequences that occur in that particular strand of DNA.
D. Restriction enzymes have a dual active site. One region of the active
site bonds to its recognition sequence, while another region of the
active site disrupts the DNA between two specific bases within the
recognition sequence.
Recognition
Sequence
A- T -A -C -C -G - G -T -A-A- G
T -A -T - G - G - C - C -A- T -T - C
Restriction
Enzyme
DNA Fragment Two
DNA Fragment One
A- T -A -C
-C -G - G-T -A-A- G
T -A -T - G - G - C
- C -A- T -T - C
The End