Ch 13-2 Flashcards
What were the two rival theories for replication until the late 1950s?
Conservative and dispersive replication
Whose experiment proved the semi-conservative form of replication?
Matthew Meselson and Franklin Stahl
What is the name for the sites where DNA replication begins?
Origins of replication
What enzyme unwinds the DNA strands at the replication fork?
Helicase
What is the function of single-strand binding proteins
To keep the single strands of DNA from rebinding to one another
What enzyme creates a short RNA primer to initiate DNA synthesis?
Primase
In what direction is DNA synthesized?
5’ – 3’ direction
On which strand of DNA does synthesis occur continuously?
Leading strand
What are the short fragments of DNA synthesized on the lagging strand called?
Okazaki fragments
What enzyme joins together the Okazaki fragments?
DNA ligase
Meselson and Stahl grew E.coli in media with nucleotide precursors using ________ (heavier)
15 N
If conservative replication was correct, DNA of _________ densities would have been found after the first replication
Two
Eukaryotic cells can have ________ of origins of replication
Thousand
__________ enzymes help to relieve strain ahead of the replication fork.
Topoisomerase
The enzymes which synthesize DNA are not able to __________ the synthesis reaction
Initiate
DNA nucleotides are indicated as ___________ to indicate the presence of deoxyribose rather than ribose.
dNTP
The two strands of DNA run ___________ to one another
Antiparallel
Synthesis on the lagging strand cannot occur ___________.
Continuously
Okazaki fragments are 100-200 dNTP long in ___________.
Eukaryotes
What type of macromolecule did most scientists originally believe was the inherited material?
○
A. Lipids
○
B. Proteins
○
C. Carbohydrates
○
D. Nucleic Acids
B
Bacterial transformation involves what type of genetic transfer?
○
A. Horizontal
○
B. Vertical
○
C. Diagonal
○
D. None of the above
A
Who determined that even proportions of matching bases were found across numerous species?
○
A. Rosalind Franklin
○
B. James Watson
○
C. Francis Crick
○
D. Erwin Chargaff
D
What technique did Rosalind Franklin use to capture the first images of DNA?
○
A. Microscopy
○
B. Chromatography
○
C. X-ray diffraction
○
D. Electrophoresis
C
What form of chromatin is easily accessibly and available for transcription?
○
A. Heterochromatin
○
B. Euchromatin
○
C. Chromatin
○
D. None of the above
B
The Meselson-Stahl experiment proved which model of replication?
○
A. Conservative
○
B. Semiconservative
○
C. Dispersive
○
D. None of the above
B
How many origins of replication do prokaryotes have?
○
A. One
○
B. Two
○
C. Thousands
○
D. It varies depending on the species
A
What is the function of DNA polymerase?
○
A. To unwind the DNA double helix
○
B. To create a short RNA primer
○
C. To synthesize new DNA strands
○
D. To join together Okazaki fragments
C
In which direction does DNA polymerase add nucleotides to the growing DNA strand?
○
A. 3’ to 5’
○
B. 5’ to 3’
○
C. Both directions
○
D. It varies depending on the strand
B
What is the function of DNA ligase?
○
A. To unwind the DNA double helix
○
B. To create a short RNA primer
○
C. To synthesize new DNA strands
○
D. To join together Okazaki fragments
D
T/f
DNA replication is a conservative process.
F
DNA replication is a semi-conservative process.
T/ f
Meselson and Stahl used isotopes of nitrogen to distinguish between old and new DNA strands.
T
T/f
Prokaryotes have multiple origins of replication.
F
Prokaryotes have a single origin of replication.
T/f
Helicase unwinds the DNA double helix at the replication fork.
T
T/f
Topoisomerase prevents the DNA strands from rebinding.
F
Single-strand binding proteins prevent the DNA strands from rebinding.
T/f
Primase synthesizes a short RNA primer to provide a starting point for DNA polymerase
T
T/f
DNA polymerase can initiate the synthesis of a new DNA strand without a primer.
F
DNA polymerase cannot initiate the synthesis of a new DNA strand without a primer.
T/f
The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously.
T
T/f
Okazaki fragments are found on the leading strand.
Okazaki fragments are found on the lagging strand.
T/f
DNA ligase seals the gaps between Okazaki fragments.
T
