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69 terms

bio

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the genes of this phage were made of DNA
In an important experiment, radioactively labeled bacteriophages were allowed to infect bacteria. In the first trial, the phages contained radioactive DNA, and radioactivity was detected in the bacteria. Next, other phages containing radioactive protein were allowed to infect bacteria, and radioactivity was not detected in the bacteria. These experiments led to the conclusion that _____. (10.1)
the protein and DNA of T4
Scientists have discovered how to put together a bacteriophage with the protein coat of phage T2 and the DNA of phage T4. If this composite phage were allowed to infect a bacterium, the phages produced in the host cell would have _____. (10.1)
adenine, guanine, cytosine, thymine
Which one of the following lists the four bases contained in DNA? (10.2)
nitrogen base, a sugar, and a phosphate group
Which one of the following describes a nucleotide most completely? (10.2)
X-ray crystallography
What technique was most helpful to Watson and Crick? (10.3)
the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1
Chargaff found that for DNA _____. (10.3)
TATCCA
One strand of a DNA molecule has the base sequence ATAGGT. The complementary base sequence on the other strand of DNA will be _____. (10.3)
hydrogen bonds between nucleotide bases
The two sugar-phosphate strands of a DNA molecule are joined to each other through _____. (10.3)
Watson and Crick
Who is generally credited with discovering that the DNA molecule is constructed as a double helix? (10.3)
guanine-cytosine
Which one of the following accurately reflects complementary base pairing in the DNA molecule? (10.3)
Adenine and uracil are present in equal amounts.
Which one of the following is NOT true about double-stranded DNA? (10.3)
the sequence of nucleotides along the length of one strand of the DNA molecule
The information in DNA is contained in _____. (10.3)
The two strands of the helix are held together by covalent bonds.
Which one of the following statements does NOT apply to the Watson-Crick model for DNA? (10.3)
a model of DNA replication
The statement that each new molecule of DNA contains one parental and one newly synthesized strand of DNA refers to _____. (10.4)
both strands of a molecule act as templates
During the replication of DNA molecules _____. (10.5)
DNA polymerase
Two new strands of DNA molecules grow as bases are added by the enzyme _____. (10.5)
attach free nucleotides to the new strand
The role of DNA polymerases in DNA replication is to _____. (10.5)
DNA ligase
What enzyme joins DNA fragments? (10.5)
nucleotides
Monomers for the synthesis of DNA are called _____. (10.5)
5'-TAAGCGATA-3'
One strand of DNA has the following sequence of nucleotides: 3'-ATTCGCTAT-5' The base sequence on the other strand of DNA would be _____. (10.5)
A polymerase constructs a new strand alongside each old one by pairing complementary nucleotides.
Which description of DNA replication is correct? (10.5)
the information for making a polypeptide
A gene is usually _____. (10.6)
Beadle and Tatum
Who of the following formulated the one gene-one enzyme hypothesis? (10.6)
thymine
Which one of the following is NOT associated with RNA? (10.7)
U ... A
When messenger RNA (mRNA) is being made, the RNA base ____ always pairs with the base _____ in DNA. (10.7)
GCA
The DNA code is CGT. What messenger RNA is made from this? (10.7)
nucleic acids
Information is transferred from the nucleus to the cytoplasm of eukaryotic cells in the form of _____. (10.7)
gene and mRNA ... a ribosome and tRNA
A particular ____ carry the information for making a specific polypeptide, but ____ can be used to make any polypeptide. (10.7)
3... codon
The number of nucleotide bases "read" together on the mRNA to designate each amino acid is __________; this unit is called a __________. (10.7)
Each amino acid in a protein is coded for by three bases in the DNA.
Which one of the following statements is true? (10.7)
redundant
Which one of the following statements is true? (10.7)
mRNA is synthesized on only one of the chains
During the transcription of a given portion of a DNA molecule _____. (10.9)
promoter
One strand of a DNA molecule has the following sequence: 3'-AGTACAAACTATCCACCGTC-5'. In order for transcription to occur in that strand, there would have to be a specific recognition sequence, called a(n) __________, to the left of the DNA sequence indicated. (10.9)
during transcription
At one point as a cell carried out its day-to-day activities, the nucleotides GAT were paired with the nucleotides CUA. This pairing occurred _____. (10.9)
a specific nucleotide sequence in DNA that signals a stop
A terminator in mRNA synthesis is _____. (10.9)
RNA polymerase
Which one of the following catalyzes the linkage between nucleotides to form RNA? (10.9)
all of the above
In transcription, _____. (10.9)
3, 2, 1
What is the proper order of the following events in the expression of a eukaryotic gene?
1. translation
2. RNA processing
3. transcription (10.10)
Exons from the same gene could be spliced in different ways to make different mRNAs.
A cell biologist found that two different proteins with largely different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same gene in the cell nucleus. Which mechanism below could best account for this? (10.10)
both introns and exons are transcribed, but the RNA transcribed from introns does not leave the nucleus
Usually, in eukaryotic genes _____. (10.10)
Introns are cut out and the resulting exons are spliced together.
Which one of the following statements correctly describes mRNA processing in eukaryotes? (10.10)
occurs in an intron
A base-substitution mutation in a germ cell line is likely to have NO effect on phenotype if the substitution _____. (10.10)
in the nucleus
In a eukaryotic cell, transcription takes place _____. (10.10)
deliver amino acids to their proper site during protein synthesis
The function of tRNA during protein synthesis is to _____. (10.11)
GUA
The nucleotide sequence of a DNA codon is GTA. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a transfer RNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodon? (10.11)
hydrogen bonds
The bonds that hold tRNA molecules in the correct three-dimensional shape are _____. (10.11)
polypeptides are synthesized at ribosomes, according to instructions carried by mRNA
The bonds that hold tRNA molecules in the correct three-dimensional shape are _____. (10.11)
It holds the growing polypeptide chain.
The P site of a ribosome does which one of the following? (10.12)
translation
Which one of the following processes does NOT take place in the nucleus? (10.12)
methionine
The first amino acid inserted into a new polypeptide chain in eukaryotic cells is always _____. (10.13)
the ribosome encounters "stop" codons
During translation, amino acid chain elongation occurs until _____. (10.14)
manufactured proteins to be short and defective
A virus infects a cell and randomly inserts many short segments of DNA containing a stop codon throughout the organism's chromosomes. This will probably cause _____. (10.14)
transfer RNA
During the process of translation, ____ matches an mRNA codon with the proper amino acid. (10.14)
The polypeptide chain moves over and bonds to the single amino acid.
A sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show? (10.14)
Messenger RNA is made on a DNA template, and then amino-acid-bearing transfer RNAs line up on it in through codon-anticodon pairing.
Which brief outline of protein synthesis is correct? (10.15)
all of the above
Mutations are _________. (10.16)
substitution of one nucleotide
A geneticist found that a particular mutation had no effect on the polypeptide encoded by a gene. This mutation probably involved _____. (10.16)
One of its kinds of proteins might contain an incorrect amino acid.
Imagine an error occurring during DNA replication in a cell, so that where there is supposed to be a T in one of the genes, there is instead a G. What effect will this probably have on the cell? (10.16)
causes mutations in the DNA
Ultraviolet (UV) radiation is damaging because it ____________. (10.16)
can occur naturally
Genetic mutations _____. (10.16)
only nucleic acid
When a bacteriophage infects an E. coli cell, what part of the phage enters the bacterial cytoplasm? (10.17)
lytic
The phage reproductive cycle that kills the bacterial host cell is a _____ cycle. (10.17)
viral genetic material that has been incorporated into a bacterial cell's chromosome
A prophage is a(n) _____. (10.17)
the nucleic acid of the phage is all that enters the host cell
In the lytic life cycle of phages _____. (10.17)
all of the above
In the lysogenic cycle of phages _____. (10.17)
The virus gets an envelope when it leaves the host cell.
A microbiologist analyzed chemicals obtained from an enveloped RNA virus—similar to a mumps virus—that infects monkeys. He found that the viral envelope contained a protein characteristic of monkey cells. Which of the following is the most likely explanation? (10.18)
Ebola
Which of these is classified as an emerging virus that can have a direct impact on human health? (10.20)
They contain the enzyme reverse transcriptase.
How do retroviruses such as HIV differ from other viruses? (10.21)
RNA information is copied into DNA
Reverse transcription, carried out by retroviruses, is the process by which _____. (10.21)