Topic 9
In DNA replication, the matching up of free nucleotides with complementary nucleotides is drive by the enzyme
DNA polymerase
What enzyme is responsible for adding new nucleotides to a growing DNA chain during replication?
DNA polymerase
The two strands of DNA run into the opposite directions, this is called .....
Antiparallel
Cytosine (C) binds with ____________ through ___ hydrogen bonds.
guanine (G), 3
The unwinding of the DNA strand to begin replication is driven by what enzyme?
helicase
What kind of bonding between complementary nitrogen bases hold the two strands of the DNA molecule together?
hydrogen
What are the three steps in DNA replication? i. Ribosomes are attached to the DNA molecule at the start sequence. ii. The enzyme, helicase, unwinds the DNA molecule. iii. Free nucleotides match with complementary bases in the DNA strands. iv. Amino acids are used to hold nucleotides in place. v. The phosphate of the new nucleotide is attached to the deoxyribose sugar of the adjacent nucleotide on the same strand
ii, iii, v
The three parts of a nucleotide include
nitrogenous base , deoxyribose sugar, phosphate
Adenine (A) binds with ___________ through ____ hydrogen bonds.
thymine (T), 2
he supercoiling of bacterial DNA is relaxed by enzyme known as
topisomerase/gyrase.
The product of DNA replication is
two identical molecules of DNA each having one new and one old strand
Where in the eukaryotic cell does DNA replication occur?
In the nucleus
What does 'semi-conservative' mean when discussing DNA replication?
It means that at the end of the replication process, there is an exact copy of the original DNA, but with one newly synthesized strand and one pre-existing strand
True/False: In both prokaryotes and eukaryotes, the replication is semi-conservative.
True
A random change in the sequence of the DNA that becomes permanent is called
a mutation
Of the four nitrogenous bases, which are the purines?
adenine and guanine
The two purines bases in DNA are:
adenine and guanine
The four different nitrogenous bases are
adenine, thymine, cytosine, and guanine.
The two strands of DNA run in ___________ directions.
anti-parallel
Of the four nitrogenous bases, which are the pyrimidines?
cytosine and thymine
What does DNA stand for?
deoxyribonucleic acid
What components make up the backbone (the outside of the strands) of the DNA molecule?
deoxyribose and phosphate groups
The monomers that make up DNA (which is a nucleic acid) are
nucleotides
What two parts of the nucleotide form the backbone of the DNA?
deoxyribose sugars & phosphate.
What are the three molecular components of a nucleotide?
deoxyribose, nitrogen bases and phosphate groups
Are purines double or single ringed?
double
Synthesis of the DNA strand runs from the ___ to ___ direction.
5', 3'
If the sequence of bases in one strand of DNA is 5' TAGCCT3', the sequence of bases in the complementary strand will be
5'AGGCTA3'
What is the difference between a purine and a pyrimidine?
Purines are nitrogen bases composed of two rings; pyrimidines are nitrogen bases composed of one ring
In DNA base pairing, A pairs with ______ and G pairs with ______.
T,C
