Which elements do nucleotides contain? - answer-Carbon, hydrogen, nitrogen, oxygen and phosphorous
What are the two types of nucleic acid? - answer-DNA and RNA
What is a nucleic acid? - answer-A large monomer made up of many nucleotide monomers linked in a chain
What are the 3 components o...
OCR A Level Biology- Nucleic Acids
Which elements do nucleotides contain? - answer-Carbon, hydrogen, nitrogen,
oxygen and phosphorous
What are the two types of nucleic acid? - answer-DNA and RNA
What is a nucleic acid? - answer-A large monomer made up of many nucleotide
monomers linked in a chain
What are the 3 components of DNA and RNA? - answer-1. Phosphoryl group
2. Pentose monosaccharide (Deoxyribose in DNA, Ribose in RNA)
3. An organic, nitrogenous base (ATGC in DNA, AUGC in RNA)
How are the components in a nucleic acid monomer joined? - answer-By strong
covalent bonds formed via condensation reaction
What is the difference between ribose and deoxyribose? - answer-Deoxyribose has 1
less oxygen (4, not 5)
What part of a nucleic acid is acidic? - answer-The phosphoryl group, which is also
negatively charged (PO4²⁻)
How is a polynucleotide formed? - answer-When the phosphoryl group (5th carbon
of sugar, aka 5') of one nucleotide and OH group of the 3rd carbon of the adjacent
nucleotide's pentose monosaccharide attach via a condensation reaction
What is the bond between 2 nucleotides called? - answer-Phosphopdiester bond
What is the part of a nucleic acid other than the bases called? - answer-Sugar-
phosphate backbone
What way does each strand of DNA run? - answer-From 3' to 5'
What does it mean that the strands in DNA are antiparallel? - answer-The sugar-
phosphate backbone of each strand run in opposite directions
What bonds attract the base pairs of DNA to each other? - answer-Hydrogen bonds
How many hydrogen bonds are there between A and T/U bases? - answer-2
How many hydrogen bonds are there between G and C bases? - answer-3
Which bases are purine? - answer-Adenine and Guanine
What are the full names of A,T,G,C and U? - answer-Adenine, thymine, guanine,
cytosine, uracil
, What is the difference between pyrimidine and purine molecules? - answer-Purines
have double carbon ring structures, pyrimidines have single carbon ring structures
Which bases are pyrimidine? - answer-Thymine, Cytosine and Uracil
What is the difference between the bases of DNA and RNA? - answer-DNA has
Thymine, RNA has Uracil
How do purine and pyrimidine molecules fit together? - answer-In a complementary
fashion
What does complementary base pairing in DNA ensure about the relative amounts
of ATGC? - answer-There is exactly the same amount of Adenine and Thymine, and
likewise for Guanine and Cytosine
Which enzyme catalyses the unwinding and separation of DNA's two strands? -
answer-DNA Helicase
How does the DNA molecule unwind? - answer-DNA Helicase travels along the DNA
backbone, catalysing reactions which break the hydrogen bonds between
complementary base pairs as it reaches them.
What happens after the DNA strand has been 'unzipped' in DNA replication? -
answer-Free deoxyribose nucleotides present in the nucleus form hydrogen bonds
with their complementary bases.
What does DNA Polymerase do? - answer-Causes a phosphodiester bond to form
between unjoined deoxyribose nucleotides which have been attracted to the
unzipped strand of DNA
What direction is the only one DNA polymerase works in? - answer-From the 3' end
to the 5' end of the DNA strand
Why does DNA have to replicate each template strand in opposite directions? -
answer-Because DNA polymerase only runs along a strand in one direction, but DNA
only unwinds and unzips in one direction
Which strand of DNA is the leading strand, and can therefore undergo continuous
replication? - answer-The strand which is unzipped from the 3' end, as DNA
polymerase can replicate it continuously as the strands unzip
What happens to the strand unzipped from the 5' end in DNA replication? - answer-
DNA has to wait until a section has been unzipped, then work back along the strand.
This results in DNA being produced in segments called Okizaki Fragements.
What joins Okizaki Fragments together? - answer-DNA Ligase
What is the name of the strand unzipped from the 5' end, and what type of
replication does it undergo? - answer-Called the lagging strand and undergoes
discontinuous replication
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