Key Concepts Quiz
This activity contains 27 questions.
Hershey and Chase were able to differentiate between proteins and nucleic acids using radioactive atoms of elements found only in those macromolecules. Which of the following would be found only in proteins?
In DNA, one nucleotide monomer is linked to the next through _____.
hydrogen bonds between the nitrogenous bases
covalent bonds between the sugar molecules of each nucleotide
hydrogen bonds between a purine base and a pyrimidine base
covalent bonds between the sugar of one nucleotide and the phosphate of the next
Which of the following is found in RNA but not in DNA?
four different nucleotides
a covalently bonded backbone
an additional hydroxyl group
two purines and two pyrimidines
What amount of thymine would be found in a strand of DNA composed of 15% cytosine?
Which of the following is true about double-stranded DNA?
It is shaped like a triple helix.
Its width is about 2 nm.
The two strands are identical.
Adenine and uracil are present in equal amounts.
During replication, the original "parent" DNA _____.
is broken down as a new DNA strand forms
serves as the template for the creation of two complete sets of DNA
is incorporated into the new DNA strand
is converted to RNA
Prokaryotic organisms have a single origin of replication, whereas eukaryotic organisms have many origins where replication occurs simultaneously. Which of the following is the most probable reason for this observation?
Prokaryotic DNA is single-stranded.
Prokaryotes do not replicate their DNA.
Prokaryotic DNA is much smaller than eukaryotic DNA.
Prokaryotic DNA is replicated more slowly than eukaryotic DNA.
Which of the following occurs during DNA replication?
DNA polymerase elongates the daughter strand, adding new nucleotides to the 3′ end of the molecule. The molecule grows 5′ to 3′ but is therefore read 3′ to 5′.
DNA polymerase forms daughter molecules. Ligase then links these molecules together at their 5′ ends, forming the new daughter strand.
DNA ligase replicates the new strand. DNA polymerase then proofreads the strand and makes any necessary corrections.
DNA polymerase replicates the molecule 3′ to 5′ using the original strand as a template to form the new daughter molecule.
In eukaryotes, translation is initiated only after transcription is completed. However, prokaryotes can initiate translation before a gene is completely transcribed. Which choice is the best explanation for this observation?
Translation cannot occur until the RNA leaves the nucleus in eukaryotes.
Ribosomes, which translate the proteins, are found only outside the nucleus in prokaryotes.
Prokaryotic mRNA needs to be extensively processed before it can be translated.
Eukaryotic mRNA can be processed before ribosomes are moved into the nucleus to translate the protein.
A new organism is discovered that has six different nucleotides that encode 30 different amino acids. Which of the following nucleotide combinations would encode the minimum number of amino acids needed in this organism?
Consider the following sequence and explain what effect the mutation has on the protein that is translated.
single amino acid change
complete change in amino acid sequence after the mutation
prematurely stops the translation of the protein
In transcription, _____.
the promoter region acts as an initial binding site for mRNA
both DNA strands are used as the templates
RNA polymerase links nucleotides to form mRNA.
a polypeptide is formed
In eukaryotic cells, a terminator in mRNA synthesis is _____.
an enzyme whose specific function is to stop transcription
a stop codon
a specific nucleotide sequence in DNA that signals the RNA polymerase to stop
a specific nucleotide sequence in mRNA that signals the RNA polymerase to stop
In eukaryotic cells, the RNA is processed before it leaves the nucleus. This processing _____.
includes the addition of a cap and tail, which help in exporting the mRNA molecule from the nucleus, and the removal of exons
includes the addition of a cap and tail, which protect the mRNA molecule from enzymatic attack, and the removal of introns
includes the removal of exons before the addition of a cap and tail, which assist in binding of the ribosome
includes the removal of introns before a cap and tail are added to the RNA molecule, forming the start site for translation once attached to the ribosome
What would be the anticodon for the DNA sequence CTC?
If protein production were an assembly line, a ribosome would be _____.
a loose piece that needs to be put together
the foreman who barks out instructions
the machines that move pieces to their appropriate locations
the worker who puts all of the pieces together
At the start of translation, where does the initiator tRNA bind?
start codon on the mRNA molecule
promoter on the rRNA molecule
The translation process in eukaryotes requires all of the following: _____.
ribosomes, RNA polymerase, peptide bonding
RNA polymerase, AUG codons, transfer RNA
peptide bonding, ribosomes, RNA polymerase
transfer RNA, ribosomes, AUG codons
In eukaryotes, the process of transcription is controlled by _____.
The type of mutation is represented below is a(n) _____.
The big red fly had one eye (wild type)
The fbi gre dfl yha don eey (mutant)
shift in reading frame
single base substitution
addition of a codon
During the lytic cycle, but not the lysogenic cycle, _____.
a prophage is replicated during binary fission
a phage uses the host cell's "machinery" to produce its proteins
whole viruses leave the host cell to infect other cells
a phage injects DNA into the host cell
HIV enters a white blood cell and then uses _____ to make copies of its genetic material. Once HIV proteins have been translated, the virus can be released by _____.
a virally encoded RNA polymerase … a process known as budding where the virus coats itself in the host cell's plasma membrane
the host cell's RNA polymerase … a process known as cell lysis, where the virus coats itself in host plasma membrane
a virally encoded reverse transcriptase … a process known as budding where the virus coats itself in the host cell's plasma membrane
a specific enzyme found in the host cell known as reverse transcriptase … a process known as cell lysis, where the virus coats itself in host plasma membrane
Emerging viruses can originate from _____.
mutations of viruses to prophages
a virus spreading from one host species to another
a rapidly mutating lytic phage
lambda viruses that were previously confined to bacterial populations that can now spread due to technological changes
The drug AZT was one of the first drugs used to treat HIV. Which of the following drug actions would prevent the spread of HIV without harming the host cell?
prevention of the formation of glycoproteins
inhibition of reverse transcriptase
inhibition of DNA polymerase
destruction of amino acids that are vital to viral protein synthesis
Radiation is a frequent method of sterilization. It is effective because it causes damage to DNA. However, prions, the agents that cause diseases such as mad cow disease, are unaffected by these treatments. Why?
Prions are proteins folded into the correct configuration.
Prions are proteins that are folded incorrectly.
Prions are small RNA molecules that do not encode proteins.
Prions are small carbohydrate molecules that do not encode DNA.
A microbiologist found that a colony of bacterial clones infected by a phage had developed the ability to make a particular amino acid that the bacteria could not make before the infection. This new ability was probably a result of _____.
Conjugation is a very effective process for spreading antibiotic resistance. Which statement best explains this observation?
Two different strains of bacteria can transfer DNA during conjugation.
Plasmids cause a bacterial cell to reproduce more quickly.
Plasmids can be transferred to a bacteriophage.
Conjugation is the only source of genetic variation in bacterial cells.
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