bio ch 12
DNA synthesis proceeds from _______ direction.
5'-3'
match: demonstrated that genetic traits can be transferred from one bacterium to another
griffith
. The bacteriophages used in Alfred Hershey's and Martha Chase's experiments showed that:
DNA was injected into bacteria.
Antiparallel=
Said of a double-stranded nucleic acid in which the 5' to 3' direction of the sugar- phosphate backbone of one strand is reversed in the other strand.
DNA replication=
Sequence of nucleotides in DNA are precisely copied and the process
Leading strand =
Strand of DNA that is synthesized continuously
____, the ends of eukaryotic chromosomes, shorten with every cell division.
Telomeres
How is a bacterial chromosome replicated?
The circular DNA molecule is replicated from one origin of replication bidirectionally.
Because a newly synthesized DNA molecule contains ____, the replication process is said to be semiconservative.
one parental strand and one new strand
Match: prevents the hydrolysis of single DNA strands by nucleases
single- strand binding protein
Match: prevents formation of hydrogen bonds between complementary base pairs
single-strand binding protein
Mismatch repair=
special enzyme recognizes the incorrectly paired nucleotides and remove them, DNA polymerase then fill in the missing nucleotides
The ends of eukaryotic chromosomes can be lengthened by:
telomerase.
In replication of DNA is considered semiconservative because each old strand serves as a __________ for the formation of a new strand.
template
From the DNA X-ray crystallography data, Franklin and Wilkins inferred that ____ while Watson and Crick determined that ____.
the flat nucleotide bases are stacked upon each other; DNA is helical.
Chargaff's rules=
the ratio of adenine to thymine and guanine to cytosine was always the same
Errors in DNA replication can come from:
the sun's UV radiation.
Match: produces breaks in the DNA molecules and then rejoins the strands to prevent supercoiling
topoisomerase
True or False: Adenine and thymine are held together by "two" hydrogen bonds in a double-stranded DNA molecule.
true
In the experiments of Griffith, the conversion of nonlethal R-strain bacteria to lethal S-strain bacteria:
was due to transformation.
A replication fork is:
a Y-shaped structure where parental DNA strands are separated by helicase.
Which of the following nucleotide sequences represents the complement to the DNA strand5′ − AGATCCG- 3′?
3′ − TCTAGGC- 5′
What type of subunits make up a single strand of DNA? What do they contain? How are the subunits linked?
Adenine, thymine, guanine, and cytosine nucleotides make up a single strand of DNA. They are linked together through their 5′ phosphate groups that are covalently bonded to the 3′ carbon of the deoxyribose subunit of the next base in the polynucleotide chain
_____ bonds link the sugar and phosphate groups in the backbones of DNA molecules.
Covalent phosphodiester
Match: joins successive nucleotides to a growing polynucleotide strand, complementary to the template strand
DNA polymerase
When a mutation occurs during DNA replication, ____ replaces the incorrect nucleotide with the correct one after the mismatched nucleotide has been removed.
DNA polymerase
true or false: One of the "pyrimidine" bases in a DNA molecule is adenine.
False- Purine
Match: grew bacteria in the presence of heavy nitrogen (15N), followed by growth 14N medium for one or two generations, then measured the density of the DNA
Messelson and Stahl
Give names of three enzymes involved in nucleotide excision repair.
Nuclease, DNA polymerase, and DNA ligase
How are eukaryotic chromosomes replicated?
The linear DNA molecules are replicated from multiple origins of replication bidirectionally.
14. Which of the following statements is FALSE with regard to DNA replication?
The strand being copied is read in the 5'->3' direction.
Which of the following statements concerning DNA is FALSE?
The sugar present in DNA is ribose.
Telomeres=
chromosomes have protective end caps
What allows each strand of DNA to serve as a template for a new DNA strand during replication?
complementary base pairing between purines and pyrimidines on opposite strands
Semiconservative replication=
explains the perpetuation of mutation. Each daughter double helix consists of, 1 original strand from parent molecule and 1 new complementary strand.
In DNA replication, the lagging strand:
is synthesized as a series of Okazaki fragments.
The DNA strand that is replicated smoothly and continuously is called the:
leading strand.
The chemical group in box 5 of the accompanying figure is a:
phosphate
Telomeres shorten slightly with each cell cycle but can be extended by the enzyme ____________.
telomerase
According to Chargaff's rules:
the adenine content in any DNA molecule is always equal to the thymine content.
The bases of nucleotides include 2 purines__________ and 2 pyrimidines ____________.
(adenine (A) or guanine (G)), (thymine (T) or cytosine (C))
Why is DNA able to store large amounts of information?
Its nucleotides can be arranged in a large number of possible sequences.
Match: demonstrated that DNA is replicated semiconservatively
Meselson and Stahl
________ hydrogen bonds form between adenine and thymine, and _______ hydrogen bonds form between guanine and cytosine.
2, 3
Which of the following causes the unwinding of the DNA double helix?
DNA helicase
true or false: The two strands of a DNA double helix can be described as running "parallel" to each other.
False - antiparallel
True or false: The process of DNA replication is "conservative."
False -semiconservative
True or false: An RNA primer is synthesized by "RNA primase"
False- DNA primase
Name 4 nitrogenous bases. (2 purines and 2pyrimidines)
Purines- adenine (A), guanine (G) Pyrimidines- thymine (T), cytosine (C)
Before the 1940s, scientists believed that proteins, rather than DNA, were the carriers of genetic material in the cell. Why?
Twenty different amino acids could produce a large number of unique combinations.
Watson and Crick model suggested that DNA is made up of ___________ to form double helix.
2 nucleotide chains
Origin of replication=
A specific site on the DNA where replication begins
Lagging strand=
A strand of DNA that is synthesized as a series of short segments
Which base connects to which, and how many hydrogen bonds are between them?
A-T, 2 hydrogen bonds C-G, 3 hydrogen bonds
Match: discovered that DNA was responsible for bacterial transformation
Avery
Match: demonstrated the ratio of nucleotide bases in DNA
Chargaff
Match: catalyzes the synthesis of an RNA primer at both leading and lagging strand
DNA helicase
_________ are the enzymes which break hydrogen bond during replication.
DNA helicase
Match: catalyzes a reaction that occurs in the lagging strand but not in the leading strand
DNA ligase
Match: catalyzes formation of sugar-phosphate bonds in adjacent Okazaki fragments
DNA ligase
Okazaki fragments are joined together by:
DNA ligase.
Match: adds nucleotides only to the 3' end of an existing polynucleotide strand
DNA polymerase
Which of the following adds new nucleotides to a growing DNA chain?
DNA polymerase
____________ catalyzes the linking together of nucleotide subunits.
DNA polymerase
True or False: Okazaki fragments are found in the "leading" strand of DNA.
False- Lagging
X-ray diffraction images produced by ____ were used by Watson and Crick to infer the structure of DNA.
Franklin
Match: discovered that the genetic material in bacteriophages is DNA
Hershey and Chase
Match: used proteins labeled with 35S and DNA labeled with 32P to demonstrate that viral DNA entered bacterial cells, but viral proteins did not
Hershey and Chase
Okazaki fragment=
One of many short segments of DNA, each 100 to 1000 nucleotides long, that must be joined by DNA ligase to form the lagging strand in DNA replication.
Double helix=
The structure of DNA, which consists of two antiparallel polynucleotide chains twisted around each other.
Replication fork=
Y-shaped structure produced during the semiconservative replication of DNA.
Mutations=
any change in DNA
Hydrogen bonds can form between guanine and ____, and between adenine and ____.
cytosine; thymine
DNA molecule consists of two polynucleotide chains that associate as a __________.
double helix
Match: binds DNA at the origin of replication and breaks the hydrogen bonds between the paired bases
helicase
Match: opens the double helix like a zipper
helicase
DNA is a nucleic acid which carries the molecular basis of_________
inheritance
