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WorksheetsBio Segment
Total questions: 24
Worksheet time: 12mins
Griffith's experiments with S. pneumoniae were significant because they showed that traits could be transferred from one organism to another What else did he find that was significant?
Dna was the genetic material
A virus made the bacteria pathogenic
Heat kills bacteria
Protein could not be the genetic material
The transferred traits were heritable
In the Hershey and Chase experiment that helped confirm that DNA, not protein, was the hereditary material, what was the key finding?
Radioactively labeled sulfur was present inside the infected bacteria.
Radioactively labeled phosphorus was present inside the infected bacteria
Radioactively labeled carbon was present inside the infected bacteria.
Radioactively labeled sulfur was found outside of the infected bacteria.
Radioactively labeled phosphorus was found outside of the infected bacteria.
Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA?
Chargaff
Griffith
Messelson
Franklin
In his transformation experiments, what did Griffith observe?
infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.
Mutant mice were resistant to bacterial infections
Mixing a heat-killed non pathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form
How is transformation in bacteria most accurately described?
the infection of cells by a phage DNA molecule
the type of semiconservative replication shown by DNA
the creation of a strand of RNA from a DNA molecule
assimilation of external DNA into a cell
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?
DNA contains purines, whereas protein includes pyrimidines.
DNA contains phosphorus, whereas protein does not.
DNA contains nitrogen, whereas protein does not.
DNA contains sulfur where as protein does not Frederick
In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the
amount of cytosine. Which of the following investigators was (were) responsible for this discovery?
Fredrick
Matthew
Oswald
Erwin
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8
16
31
42
It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information based on which of the following characteristics?
Complementary pairing of bases
the sequence of bases
phospahte-sugar backbones
What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?
The twisting nature of DNA creates nonparallel strands
One strand contains only purines and the other contains pyramids
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
base pairings create unequal spacing between DNA strands
In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (15N) and then transferred them to a medium containing 14N. Which of the results in the figure would be expected after one round of DNA replication in the presence of 14N?
A
B
C
D
DNA replication is said to be semiconservative. What does this mean?
The old double helix is degraded, and half of its nucleotides are used in the construction of two new double helices.
Each new double helix consists of one old and one new strand.
One of the two resulting double helices is made of two old strands, and the other is made of two new strands.
Half of the old strand is degraded, and half is used as a template for the replication of a new strand.
What is the function of helicase in DNA replication?
It relieves strain from twisting of the double helix as it is unwound.
It joins together Okazaki fragments.
It adds nucleotides to the new strand in the 5' to 3' direction.
It untwists the double helix and separates the two DNA strands.
think about the different ways in which DNA can be damaged.
Transformation
Mismatch repair
Operon repair
Nucleotide excision repair
In nucleotide excision repair, damaged DNA is excised by what enzyme(s)?
Ligase
Helicase
Primase
Nuclease
What are the repetitive DNA sequences present at the ends of eukaryotic chromosomes called?
Telomeres
Chromosome
Sacomeres
Centromeres
Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?
DNA polymerase|||
Primase
Toposiomerase
Helicase
What is the function of DNA polymerase III?
to seal together the broken ends of DNA strands
to degrade damaged DNA molecules
to add nucleotides to the 3' end of a growing DNA strand
The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that
ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells.
the nucleoside triphosphates have two phosphate groups; A
triphosphate monomers are active in the nucleoside triphosphates, but not in Atp
the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.
The leading and the lagging strands of DNA formed during DNA replication differ in that
the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
the leading strand is synthesized at twice the rate of the lagging strand.
What is the function of topoisomerase?
adding methyl groups to bases of DNA
stabilizing single-stranded DNA at the replication fork
unwinding of the double helix
relieving strain in the DNA ahead of the replication fork
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It catalyzes the lengthening of telomeres.
It joins Okazaki fragments together
It unwinds the parental double helix.
It synthesizes RNA nucleotides to make a primer
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
single-strand binding proteins
ligase
DNA polymerase
During DNA replication, which of the following enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?
helicase
DNA polymerase III
ligase
DNA polymerase I
