* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download DNA Questions – mahon – (26)
Survey
Document related concepts
Zinc finger nuclease wikipedia , lookup
DNA sequencing wikipedia , lookup
Eukaryotic DNA replication wikipedia , lookup
DNA repair protein XRCC4 wikipedia , lookup
Homologous recombination wikipedia , lookup
DNA profiling wikipedia , lookup
Microsatellite wikipedia , lookup
DNA replication wikipedia , lookup
DNA polymerase wikipedia , lookup
DNA nanotechnology wikipedia , lookup
United Kingdom National DNA Database wikipedia , lookup
Transcript
Version 001 – DNA Questions – mahon – (26) This print-out should have 34 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. DNA 01 001 10.0 points What was the basis of the belief of biologists for over two decades that proteins instead of DNA were the genetic material? I) Proteins are made of 20 amino acids while DNA is made of four nucleotides; II) Proteins have two different levels of structural organization while DNA has four; III) Proteins have a greater variety of threedimensional forms than does DNA. 1. III only 2. II only 3. I and III only correct 4. I only 5. I, II and III Explanation: Proteins have a greater variety of threedimensional forms than does DNA and they are made of 20 amino acids while DNA is made of four nucleotides. DNA 08 002 10.0 points To prove that there is a clear correlation between DNA and genetic information some students in a science fair wanted to repeat Hershey and Chase’ experiment using labeled nitrogen instead of labeled phosphate on the assumption that there are more nitrogen atoms in a nucleotide than phosphate. Why will this experiment not work? 1. Meselson and Stahl already did this experiment. 2. There is no radioactive isotope of nitrogen. 1 3. Amino acids and thus proteins also have nitrogen atoms; thus the radioactivity would not distinguish between DNA and proteins. correct 4. Radioactive nitrogen has a half-life of 100,000 years and the material would be too dangerous for too long. 5. Compared to phosphate there are more nitrogens in a nucleotide, so the latter are more radioactive. Explanation: If nitrogen is labeled, the radioactivity between DNA and proteins cannot be distinguished and as such the experiment as proposed by the students would not succeed. DNA 11 003 10.0 points What would be the percentage of thymine in a DNA sample if the percentage of cytosine were 38%? 1. 38% 2. 24% 3. It cannot be determined from the information provided 4. 31% 5. 12% correct Explanation: The total of A, T, C and G is 100%. Since cytosine is 38%, its complementary N-base G will also be 38%. The remaining 24% will consist of A and T so half of this number; namely the percentage of thymine in the sample, will be 12. DNA 13 004 10.0 points Describe the kind of chemical bonds between paired bases of the DNA double helix. Version 001 – DNA Questions – mahon – (26) 1. sulfhydryl 2 by the live R, converting the latter to S and killing the mouse. correct 2. hydrogen correct 3. there was no result. 3. covalent 4. phosphate 4. DNA from the live R was taken up by the heat-killed S, converting the latter to R and killing the mouse. 5. ionic Explanation: Two hydrogen bonds are found between adenine and thymine, and three between cytosine and guanine. DNA 22 005 10.0 points What statement would be true if the strands that make up DNA are antiparallel? 1. One strand is positively charged while the other is negatively charged. 2. The 5′ to 3′ direction of one strand runs counter to the 5′ to 3′ direction of the other strand. correct 3. Base pairings create unequal spacing between the two DNA strands. 5. RNA from the heat-killed S was translated into proteins that killed the mouse. Explanation: DNA and Heredity 02 007 10.0 points In order to show that DNA is the “transforming principle,” Avery, MacLeod, and McCarty showed that DNA could transform nonvirulent strains of pneumococcus. Their hypothesis was strengthened by their demonstration that 1. enzymes that destroy nucleic acids also destroy transforming activity. correct 2. other strains of bacteria also can be transformed successfully. 4. The chromosomes are circular in shape. 3. enzymes that destroy complex carbohydrates also destroy transforming activity. 5. The twisting nature of DNA creates nonparallel strands. 4. the transforming activity is destroyed by boiling. Explanation: The 5′ to 3′ direction of one strand runs antiparallel to the 5′ to 3′ direction of the other strand. 5. enzymes that destroy proteins also destroy transforming activity. DNA and Heredity 006 10.0 points In Griffith’s experiments, when heat-killed S strain pneumococci were injected into a mouse along with live R strain pneumococci, DNA and Heredity 14 008 10.0 points The base composition of DNA isolated from a newly discovered virus is found to be 32 percent A, 17 percent C, 32 percent G, and 19 percent T. What would be a reasonable explanation for this observation? 1. proteins released from the heat-killed S killed the mouse. Explanation: 1. The virus must be extraterrestrial. 2. DNA from the heat-killed S was taken up Version 001 – DNA Questions – mahon – (26) 2. The genome of the phage must be circular, not linear. 3 3. DNA can also act an enzyme 4. molecules are extremely long. 3. The genome of the phage is singlestranded, not double-stranded. correct 5. is transcribed into RNA and then into proteins with specific functions. correct 4. Some of the T was converted to C during the isolation procedure. Explanation: 5. In some viruses, double-stranded DNA is made up of base pairs containing two purines or two pyrimidines. DNA and heredity 40 011 10.0 points During DNA replication Explanation: 1. the template strands must separate so that both can be copied. correct DNA and Heredity 16 009 10.0 points Which feature of the Watson-Crick model of DNA structure explains its ability to function in replication and gene expression? 1. Each strand contains all the information present in the double helix. correct 2. Bases are exposed in the major groove of the double helix. 3. There are structural and functional similarities between DNA and RNA. 4. The double helix is right-handed, not lefthanded. 5. DNA replication does not require enzyme catalysts. Explanation: DNA and Heredity 32 010 10.0 points Although DNA is made up of only four different bases, it can encode the information necessary to specify the workings of an entire organism because DNA 1. molecules are found in the nucleus. 2. is directly translated into proteins, which are made up of 20 different amino acids. 2. the template strands come back together after the passage of the replication fork. 3. origins of replication always give rise to single replication forks. 4. two replication forks diverge from each origin but one always lags behind the other. 5. one template strand must be degraded to allow the other strand to be copied. Explanation: DNA and Heredity 56 012 10.0 points The enzyme DNA ligase is required continuously during DNA replication because 1. the parental strands must be joined back together. 2. 3’-deoxynucleoside triphosphates must be converted to 5’-deoxynucleoside triphosphates. 3. fragments of the leading strand must be joined together. 4. fragments of the lagging strand must be joined together. correct 5. the complex of proteins that work together at the replication fork must be kept Version 001 – DNA Questions – mahon – (26) from falling apart. Explanation: GA SB2 02 013 10.0 points If one strand of a DNA molecule is TACCTA, what is the sequence of the complentary strand? 1. ATGGAT correct 2. GATCCA 3. TACCTA 4. GTAGGT Explanation: In DNA, A pairs with T, C pairs with G. Holt Bio 10 05 014 10.0 points Because the genetic code is the same in all organisms, it appears that 1. different life-forms have different ancestors. 4 tion 3. to degrade damaged DNA molecules 4. to add nucleotides to the end of a growing DNA strand correct 5. to rejoin the two DNA strands (one new and one old) after replication Explanation: The function of DNA polymerase is to add nucleotides to the end of a growing DNA strand. DNA 26 016 10.0 points E. coli cells grown on 15 N medium and transferred to 14 N medium are allowed to grow for two generations (two rounds of DNA replication). DNA extracted from the cells on the second medium are then centrifuged. What density distribution of DNA would you expect in this experiment? 1. one low-density band 2. thymine will soon replace uracil in RNA. 2. one high-density and one low-density band 3. the codon GUC codes for different proteins in different organisms. 3. one low-density and one intermediatedensity band correct 4. the genetic code evolved more than once. 5. all life-forms have a common ancestor. correct Explanation: Recall DNA 19 015 10.0 points Describe the function of DNA polymerase. 1. to seal together the broken ends of DNA strands 2. to unwind the DNA helix during replica- 4. one intermediate density band 5. one high-density and one intermediatedensity band Explanation: In the Meselson-Stahl experiment, E.coli was grown for two generations, the first on a medium containing a heavy isotope of nitrogen 15 N and the second on a medium containing normal nitrogen 14 N. Such an experiment should give two bands, one of intermediate density and the other of low density, if the DNA replication is semi-conservative. DNA 28 017 10.0 points Version 001 – DNA Questions – mahon – (26) Meselson and Stahl cultured a strain of bac terium first in a medium containing 15 N ; thereafter they subcultured the bacterium in a medium containing 14 N. Consider the possible results of this experiment: 14 N DNA→ 14 N−15 N→ hybrid DNA 15 5 5. unwind the parental double helix Explanation: The function of DNA ligase is to piece Okazaki fragments together. GA SB2 04 019 10.0 points A characteristic of a DNA molecule that is not a characteristic of a protein molecule is that the DNA molecule 1. is composed of subunits (or monomers). N DNA→ A B C D E Which diagram would show the expected result after one round of DNA replication in the presence of 14 N? 1. A 2. B 3. E 4. D correct 5. C Explanation: A band of hybrid DNA, one strand consisting of N15 and the other of N14 will be found in the middle of the tube; i.e., marked “D”. DNA 34 018 10.0 points What role does DNA ligase play in the elongation of the lagging strand during DNA replication? 1. join Okazaki fragments correct 2. catalyze the lengthening of telomeres 3. synthesize RNA nucleotides to make a primer 4. stabilize the unwound parental DNA 2. is found inside cells. 3. can be very large. 4. can replicate itself. correct Explanation: DNA can replicate itself, whie proteins are built from the DNA code. GA SB2 44 020 10.0 points After replication, each DNA molecule has 1. one strand – half old and half new. 2. two strands – both completely new. 3. two strands – one old and one new. correct 4. two strands – each strand is half old and half new. Explanation: DNA is a double stranded molecule. When DNA replicates, the DNA double strand untwists and unzips, so both old strands are separated from each other. When nucleotides pair up to form new DNA molecules, each DNA molecule is made of one old strand and one new strand. GA SB2 01 021 10.0 points During protein synthesis, the amino acid se- Version 001 – DNA Questions – mahon – (26) 6 quence is determined by the 1. genetic code in the DNA molecule. correct 2. ATP produced by mitochondria. 3. signals sent by the plasma membrane. 4. speed at which translation occurs. 5. number of mitochondria in the cell. Explanation: The DNA code (or order of nucleotide ”letters” A, T, C, and G) codes for the order of amino acids to make proteins for the cell. GA SB2 34 022 10.0 points The complementary mRNA sequence for the DNA sequence GAACCT is 1. GAACCU. 2. GAACCT. 3. CUUGGA. correct 4. CTTGGA. Explanation: mRNA will have complementary base pairs to DNA: A with T, U with A, C with G, and G with C. Remember that RNA has uracil (U) instead of thymine (T). GA SB2 45 023 10.0 points The mRNA receives information from DNA by 1. accepting proteins through the nuclear membrane pores. 2. making an exact copy of both strands of the DNA molecule. 3. joining with its complementary bases on a single DNA strand. correct 4. joining with the two DNA strands and forming a triple helix. Explanation: mRNA pairs up nucleotides with only one of the strands of DNA, called the template strand. Holt Bio 10 06 024 10.0 points During transcription, the genetic information for making a protein is encoded as a molecule of 1. transfer RNA. 2. messenger RNA. correct 3. ribosomal RNA. 4. translation RNA. Explanation: Raven15 54 025 10.0 points Transcription is the first stage in the Central Dogma and is initiated by 1. mRNA polymerase binding to a site known as the promoter. 2. RNA polymerase binding to a site known as the initiator. 3. RNA polymerase binding to a site known as the promoter. correct 4. DNA polymerase binding to a site known as the promoter. 5. tRNA polymerase binding to a site known as the promoter. Explanation: Recall Raven15 64 026 10.0 points RNA splicing in eukaryotic cell protein syn- Version 001 – DNA Questions – mahon – (26) thesis means that the product of translation called the 7 3. None of these 4. rRNA 1. secondary transcript does not sufficiently explain RNA splicing. 2. primary transcript is cut and put back together to produce the mature mRNA transcript. correct 3. secondary transcript is cut and put back together to produce the mature tRNA transcript. 4. primary transcript is cut and put back together to produce the mature tRNA transcript. Explanation: Recall Starr 14 06 027 10.0 points A mature messenger RNA 1. leaves the nucleus and carries out its function in the cytoplasm. 2. contains a sequence of triplet codons that specify amino acids. 3. All of these correct 4. has no introns. 5. occurs in very small amounts compared to the total RNA. Explanation: Recall Starr 14 18 028 10.0 points What class of RNA binds free amino acids and carries them to ribosomes? 1. tRNA correct 2. All of these 5. mRNA Explanation: Recall StarrW 13 05 029 10.0 points Each codon calls for a specific 1. polypeptide. 2. amino acid. correct 3. lipid. 4. protein. 5. carbohydrate. Explanation: Recall GA SB2 15 030 10.0 points The function of messenger RNA (mRNA) is to 1. prevent DNA mutations during replication. 2. translate the base sequence at the ribosomes. 3. make a copy of the DNA instructions and bring it to the ribosome. correct 4. carry amino acids to the ribosome. Explanation: mRNA travels from the nucleus to the ribosome with the DNA instructions for building proteins. GA SB2 08 031 10.0 points The information that controls the production of proteins in a cell must pass from the nucleus Version 001 – DNA Questions – mahon – (26) to the 8 Explanation: Recall 1. cell membrane. 2. mitochondria. 3. chloroplasts. 4. ribosomes. correct Explanation: Ribosomes take information from mRNA (which came from DNA in the nucleus) to construct the protein. Raven15 24 032 10.0 points The majority of amino acids have a specific tRNA molecule that transports it to the site of protein synthesis. Therefore, in humans the number of different tRNA molecules would be at least 1. thousands. 2. 40. 3. 3. 4. 80. 5. 20. correct Explanation: Raven15 39 033 10.0 points The bond that forms between the newly added amino acid and the previous amino acid on the chain is called a 1. hydrogen bond. 2. hydrophobic bond. 3. hydrophilic bond. 4. phosphodiester bond. 5. peptide bond. correct Raven15 50 034 10.0 points If the DNA triplet code were ATG-CGT, the tRNA anticodons would be 1. UACGCA 2. UAGCGU 3. ATGCGT 4. TGCGTA 5. AUGCGU correct Explanation: The DNA is transcribed into mRNA which reads UACGCA. The anticodon needed to pair with this would be AUGCGU.