Chapter 14 Quiz
If the DNA of a particular species was analyzed and it was found that it contains 23% A, what would be the percentage of T? a) 23% b) 27% c) 46% d) 54%
a) 23%
If the DNA of a particular species was analyzed and it was found that it contains 27% A, what would be the percentage of C? a) 23% b) 27% c) 46% d) 54%
a) 23%
In which direction does DNA replication take place? a) 5' to 3' b) 3' to 5' c) 5' d) 3'
a) 5' to 3'
What do RNA and DNA have in common? a) Both contain four different nucleotides. b) Both are usually double-stranded molecules. c) Both contain adenine and uracil. d) Both contain ribose.
a) Both contain four different nucleotides.
Explain how the components of DNA fit together. a) DNA is composed of nucleotides, consisting of a 5 carbon sugar, a phosphate, and a nitrogenous base. DNA is a double helical structure in which complementary base pairing occurs. Adenine pairs with thymine and guanine pairs with cytosine. Adenine and thymine form two hydrogen bonds and cytosine and guanine form three hydrogen bonds. The two individual strands of DNA are held together by covalent bonds between the phosphate of one nucleotide and sugar of the next. The two strands run antiparallel to each other. b) DNA is composed of nucleotides, consisting of a 5 carbon sugar, a phosphate, and a nitrogenous base. DNA is a double helical structure in which complementary base pairing occurs. Adenine pairs with cytosine and guanine pairs with thymine. Adenine and cytosine form two hydrogen bonds and guanine and thymine form three hydrogen bonds. The two individual strands of DNA are held together by covalent bonds between the phosphate of one nucleotide and sugar of the next. The two strands run antiparallel to each other. c) DNA is composed of nucleotides, consisting of a 5 carbon sugar, a phosphate, and a nitrogenous base. DNA is a double helical structure in which complementary base pairing occurs. Adenine pairs with cytosine and guanine pairs with thymine. Adenine and cytosine form three hydrogen bonds and guanine and thymine form two hydrogen bonds. The two individual strands of DNA are held together by covalent bonds between the phosphate of one nucleotide and sugar of the next. The two strands run antiparallel to each other. d) DNA is composed of nucleotides, consisting of a 5 carbon sugar, a phosphate, and a nitrogenous base. DNA is a double helical structure in which complementary base pairing occurs. Adenine pairs with cytosine and guanine pairs with thymine. Adenine and cytosine form three hydrogen bonds and guanine and thymine form two hydrogen bonds. The two individual strands of DNA are held together by covalent bonds between the phosphate of one nucleotide and sugar of the next. The two strands run parallel to each other.
a) DNA is composed of nucleotides, consisting of a 5 carbon sugar, a phosphate, and a nitrogenous base. DNA is a double helical structure in which complementary base pairing occurs. Adenine pairs with thymine and guanine pairs with cytosine. Adenine and thymine form two hydrogen bonds and cytosine and guanine form three hydrogen bonds. The two individual strands of DNA are held together by covalent bonds between the phosphate of one nucleotide and sugar of the next. The two strands run antiparallel to each other.
Describe the structure and complementary base pairing of DNA. a) DNA is made up of two strands that are twisted around each other to form a helix. Adenine pairs up with thymine and cytosine pairs with guanine. The two strands are anti-parallel in nature; that is, the 3' end of one strand faces the 5' end of other strand. Sugar, phosphate and nitrogenous bases contribute to the DNA structure. b) DNA is made up of two strands that are twisted around each other to form a helix. Adenine pairs up with cytosine and thymine pairs with guanine. The two strands are anti-parallel in nature; that is, the 3' end of one strand faces the 5' end of other strand. Sugar, phosphate and nitrogenous bases contribute to the DNA structure. c) DNA is made up of two strands that are twisted around each other to form a helix. Adenine pairs up with thymine and cytosine pairs with guanine. The two strands are parallel in nature; that is, the 3' end of one strand faces the 3' end of other strand. Sugar, phosphate and nitrogenous bases contribute to the DNA structure. d) DNA is made up of two strands that are twisted around each other to form a helix. Adenine pairs up with thymine and cytosine pairs with guanine. The two strands are anti-parallel in nature; that is, the 3' end of one strand faces the 5' end of other strand. Only sugar contributes to the DNA structure.
a) DNA is made up of two strands that are twisted around each other to form a helix. Adenine pairs up with thymine and cytosine pairs with guanine. The two strands are anti-parallel in nature; that is, the 3' end of one strand faces the 5' end of other strand. Sugar, phosphate and nitrogenous bases contribute to the DNA structure.
DNA replication is bidirectional and discontinuous; explain your understanding of those concepts. a) DNA polymerase reads the template strand in the 3' to 5' direction and adds nucleotides only in the 5' to 3' direction. The leading strand is synthesized in the direction of the replication fork. Replication on the lagging strand occurs in the direction away from the replication fork in short stretches of DNA called Okazaki fragments. b) DNA polymerase reads the template strand in the 5' to 3' direction and adds nucleotides only in the 5' to 3' direction. The leading strand is synthesized in the direction of the replication fork. Replication on the lagging strand occurs in the direction away from the replication fork in short stretches of DNA called Okazaki fragments. c) DNA polymerase reads the template strand in the 3' to 5' direction and adds nucleotides only in the 5' to 3' direction. The leading strand is synthesized in the direction away from the replication fork. Replication on the lagging strand occurs in the direction of the replication fork in short stretches of DNA called Okazaki fragments. d) DNA polymerase reads the template strand in the 5' to 3' direction and adds nucleotides only in the 3' to 5' direction. The leading strand is synthesized in the direction of the replication fork. Replication on the lagging strand occurs in the direction away from the replication fork in long stretches of DNA called Okazaki fragments.
a) DNA polymerase reads the template strand in the 3' to 5' direction and adds nucleotides only in the 5' to 3' direction. The leading strand is synthesized in the direction of the replication fork. Replication on the lagging strand occurs in the direction away from the replication fork in short stretches of DNA called Okazaki fragments.
What is the function of histones in eukaryotic organisms? a) DNA wraps around the protein. b) They moderate the effects of DNA polymerase. c) They prevent excessive coiling of the DNA. d) They assist the rRNA in protein synthesis.
a) DNA wraps around the protein.
Why is it important that base pairing occurs during replication? a) It is important that base pairing occurs during replication so matching the genetic information upon replication ensures the inheritance of traits. b) It is important that base pairing occurs during replication so the daughter cells of the parents do not have to have matching genetic information. c) It is important that base pairing occurs during replication so when the daughter cells receive matching genetic information, they do not have a good chance of survival. d) It is important that base pairing occurs during replication so daughter cells never receive the same genetic information as the parent cell.
a) It is important that base pairing occurs during replication so matching the genetic information upon replication ensures the inheritance of traits.
Explain how we know base pairing takes place between a purine and pyrimidine. a) Only the pairing between a purine and pyrimidine can explain the uniform diameter of the DNA double helix. Adenine and thymine form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds. b) Only the pairing between a purine and pyrimidine can explain the non-uniform diameter of the DNA double helix. Adenine and thymine form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds. c) Only the pairing between a purine and pyrimidine can explain the uniform diameter of the DNA double helix. Adenine and thymine form three hydrogen bonds, whereas cytosine and guanine form two hydrogen bonds. d) Only the pairing between a purine and pyrimidine can explain the uniform diameter of the DNA double helix. Adenine and thymine form two disulfide bonds, whereas cytosine and guanine form three hydrogen bonds.
a) Only the pairing between a purine and pyrimidine can explain the uniform diameter of the DNA double helix. Adenine and thymine form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds.
Which of the following is the best definition for "replication fork". a) Y-shaped structure formed during initiation of replication b) ring-shaped protein that holds the DNA pol on the DNA strand c) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides d) DNA at the end of linear chromosomes
a) Y-shaped structure formed during initiation of replication
What is a purine? a) a double ring structure with a six-membered ring fused to a five-membered ring b) a single six-membered ring c) a double six-membered ring d) three phosphates covalently bonded by phosphodiester bonds
a) a double ring structure with a six-membered ring fused to a five-membered ring
Which of the following is the best definition for "helicase". a) during replication, this enzyme helps to open up the DNA helix by breaking the hydrogen bonds b) enzyme that causes underwinding or overwinding of DNA when DNA replication is taking place c) enzyme that catalyzes the formation of a phosphodiester linkage between the 3' OH and 5' phosphate ends of the DNA d) enzyme that synthesizes the RNA primer; the primer is needed for DNA pol to start synthesis of a new DNA strand
a) during replication, this enzyme helps to open up the DNA helix by breaking the hydrogen bonds
Which of the following is the best definition for "silent mutation". a) mutation that does not affect the gene product b) mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent c) mutation that results from exposure to chemicals or environmental agents d) mutation that affects a single base
a) mutation that does not affect the gene product
Which of the following is the best definition for "nucleotide excision repair". a) type of DNA repair mechanism in which the wrong base, along with a few nucleotides upstream or downstream, are removed b) type of repair mechanism in which mismatched bases are removed after replication c) function of DNA pol in which it reads the newly added base before adding the next one
a) type of DNA repair mechanism in which the wrong base, along with a few nucleotides upstream or downstream, are removed
If DNA replicates in a semi-conservative manner, what is the outcome? a) Both copies of DNA have double- stranded segments of parental DNA and newly synthesized DNA interspersed. b) Each double-stranded DNA includes one parental or "old" strand and one "new" strand. c) The parental DNA remains together, and the newly formed daughter strands are together. d) The two "arms" of the chromosomes exchange with each other. The resulting copies have the upper half old and the lower half new material.
b) Each double-stranded DNA includes one parental or "old" strand and one "new" strand.
What effect does a frameshift mutation have on a strand of DNA? a) The amino acid translated at the point of the frameshift changes. b) Nucleotides and codons are read in a different order beyond where the frameshift occurred. c) It changes one codon to a redundant codon that codes for the same amino acid. d) It adds a new codon at the point of the frame shift.
b) Nucleotides and codons are read in a different order beyond where the frameshift occurred.
What is a pyrimidine? a) a double ring structure with a six-membered ring fused to a five-membered ring b) a single six-membered ring c) a double six-membered ring d) three phosphates covalently bonded by phosphodiester bonds
b) a single six-membered ring
Which enzyme initiates the splitting of the double DNA strand during replication? a) DNA gyrase b) helicase c) ligase d) telomerase
b) helicase
Which of the following statements about components of DNA replication is/are false? 1. Primase is an enzyme that synthesizes the RNA primer, which is required for DNA polymerase to start synthesis of a new DNA strand. 2. Helicase is an enzyme that helps to open up the DNA helix by breaking the hydrogen bonds during replication. 3. Helicase is an enzyme that catalyzes the formation of a phosphodiester linkage between the 3' OH and 5' phosphate ends of the DNA. 4. Topoisomerase is an enzyme that causes underwinding or overwinding of DNA when DNA replication is taking place. a) 1 b) 2 c) 3 d) 4
c) 3
The DNA double helix has been said to look like a twisted ladder. If you were to untwist the ladder, what makes up each rung of the ladder? What holds the rungs together at the sides? a) Each 'rung' of the ladder is formed by sugar-phosphate molecules being held together at the sides by phosphates. b) Each 'rung' of the latter is formed from the attachment of base pairs with nothing holding them together at the sides. c) Each 'rung' of the ladder is formed between the pairing of nitrogenous bases. The 'rungs' are held together at the sides by sugar-phosphate molecules. d) The DNA strand does not look like a twisted ladder at all.
c) Each 'rung' of the ladder is formed between the pairing of nitrogenous bases. The 'rungs' are held together at the sides by sugar-phosphate molecules.
Explain the events taking place at the replication fork. If the gene for helicase is mutated, what part of replication will be affected? a) Helicase separates the DNA strands at the origin of replication. Topoisomerase breaks and reforms DNA's sugar backbone ahead of the replication fork, thereby relieving the pressure. Single-stranded binding proteins prevent reforming of DNA. Primase synthesizes DNA primer which is used by RNA polymerase to form a parent strand. If helicase is mutated, the DNA strands will be separated at the beginning of replication. b) Helicase joins the DNA strands together at the origin of replication. Topoisomerase breaks and reforms DNA's phosphate backbone after the replication fork, thereby relieving the pressure. Single-stranded binding proteins prevent reforming of DNA. Primase synthesizes RNA primer which is used by DNA polymerase to form a daughter strand. If helicase is mutated, the DNA strands will not be joined together at the beginning of replication. c) Helicase separates the DNA strands at the origin of replication. Topoisomerase breaks and reforms DNA's phosphate backbone ahead of the replication fork, thereby relieving the pressure. Single-stranded binding proteins prevent reforming of DNA. Primase synthesizes RNA primer which is used by DNA polymerase to form a daughter strand. If helicase is mutated, the DNA strands will not be separated at the beginning of replication. d) Helicase separates the DNA strands at the origin of replication. Topoisomerase breaks and reforms DNA's sugar backbone ahead of the replication fork, thereby increasing the pressure. Single-stranded binding proteins prevent reforming of DNA. Primase synthesizes DNA primer which is used by DNA polymerase to form a daughter strand. If helicase is mutated, the DNA strands will be separated at the beginning of replication.
c) Helicase separates the DNA strands at the origin of replication. Topoisomerase breaks and reforms DNA's phosphate backbone ahead of the replication fork, thereby relieving the pressure. Single-stranded binding proteins prevent reforming of DNA. Primase synthesizes RNA primer which is used by DNA polymerase to form a daughter strand. If helicase is mutated, the DNA strands will not be separated at the beginning of replication.
Which of the statements gives the best explanation for the wider genetic variation in the human population in Africa than the rest of the world? a) It has been suggested that all humans most likely descended from Africa. This is supported by the research that genetic variance in Africa was also found in the rest of the world. b) The theory that humans descended from Africa was supported by the research that most of the human genomes tested outside of Africa had close ties to the genomes of people in Africa but a genetic variance in Africa was not found in the rest of the world. c) Humans have most likely descended from Africa. This research is supported by the fact that all the human genomes tested outside of Africa had close ties to the genomes of people in Africa. Also, there is a genetic variance in Africa that was not found in the rest of the world. d) The transition to modern humans occurred within Africa which was sudden. Thus, human genomes tested outside of Africa had close ties to the genomes of people in Africa.
c) Humans have most likely descended from Africa. This research is supported by the fact that all the human genomes tested outside of Africa had close ties to the genomes of people in Africa. Also, there is a genetic variance in Africa that was not found in the rest of the world.
What effect would a nonsense mutation have? a) It would shift the reading of the codons by one base. b) It would have no effect on the DNA. c) It would stop all translation of the DNA strand. d) It would add a purine where a pyrimidine was previously.
c) It would stop all translation of the DNA strand.
What are Okazaki fragments and how they are formed? a) Okazaki fragments are long stretches of DNA on the lagging strand, which is synthesized in the direction of the replication fork. b) Okazaki fragments are long stretches of DNA on the leading strand, which is synthesized in the direction away from the replication fork. c) Okazaki fragments are short stretches of DNA on the lagging strand, which is synthesized in the direction away from the replication fork. d) Okazaki fragments are short stretches of DNA on the leading strand, which is synthesized in the direction of the replication fork.
c) Okazaki fragments are short stretches of DNA on the lagging strand, which is synthesized in the direction away from the replication fork.
Explain why half of DNA is replicated in a discontinuous fashion. a) Replication of the leading strand occurs in the direction away from the replication fork in short stretches of DNA, since access to the DNA is always from the 5' end. This results in pieces of DNA being replicated in a discontinuous fashion. b) Replication of the lagging strand occurs in the direction of the replication fork in short stretches of DNA, since access to the DNA is always from the 5' end. This results in pieces of DNA being replicated in a discontinuous fashion. c) Replication of the lagging strand occurs in the direction away from the replication fork in short stretches of DNA, since access to the DNA is always from the 5' end. This results in pieces of DNA being replicated in a discontinuous fashion. d) Replication of the lagging strand occurs in the direction away from the replication fork in short stretches of DNA, since access to the DNA is always from the 3' end. This results in pieces of DNA being replicated in a discontinuous fashion.
c) Replication of the lagging strand occurs in the direction away from the replication fork in short stretches of DNA, since access to the DNA is always from the 5' end. This results in pieces of DNA being replicated in a discontinuous fashion.
Which type of point mutation would result in the substitution of a stop codon for an amino acid? a) frameshift b) missense c) nonsense d) silent
c) nonsense
The splitting of each chromosome in half with each half going to a new chromosome describes which mode of replication? a) conservative b) dispersive c) semi-conservative d) semi-dispersive
c) semi-conservative
Which of the following is the best definition for "leading strand". a) during replication, the strand that is replicated in short fragments b) DNA fragment that is synthesized in short stretches on the lagging strand c) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork d) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
c) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork
Which of the following is the best definition for "mutation". a) process in which external DNA is taken up by a cell b) technique used to separate DNA fragments according to size c) variation in the nucleotide sequence of a genome
c) variation in the nucleotide sequence of a genome
DNA polymerase can only extend a newly synthesized DNA strand in the _______ direction. The continuously synthesized DNA strand is known as the _______ strand. The DNA strand complementary to the 5' to 3' parental DNA is known as the _______ strand, and is synthesized in short stretches called _________. a) 3' to 5', lagging, leading, Okazaki fragments b) 5' to 3', lagging, leading, RNA primers c) 3' to 5', leading, lagging, RNA primers. d) 5' to 3', leading, lagging, Okazaki fragments
d) 5' to 3', leading, lagging, Okazaki fragments
If the sequence of the 3' to 5' strand is TATCGTCC, then the complementary sequence has the following sequence: a) 5'-AATGCTAC- 3' b) 3'- ATAGCAGG -5' c) 3'-TTACGATG-5' d) 5'-ATAGCAGG-3'
d) 5'-ATAGCAGG-3'
Which of the following is the best definition for "telomere". a) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork b) during replication, the strand that is replicated in short fragments c) DNA fragment that is synthesized in short stretches on the lagging strand d) DNA at the end of linear chromosomes
d) DNA at the end of linear chromosomes
Which of the following is the best definition for "Okazaki fragment". a) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork b) during replication, the strand that is replicated in short fragments c) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides d) DNA fragment that is synthesized in short stretches on the lagging strand
d) DNA fragment that is synthesized in short stretches on the lagging strand
What are the short segments of DNA on the lagging strand called? a) the portion that telomeres attach to b) the Griffith portion c) the Primer fragment d) Okazaki fragments
d) Okazaki fragments
Which of the following is the best definition for "lagging strand". a) DNA fragment that is synthesized in short stretches on the lagging strand b) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides c) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork d) during replication, the strand that is replicated in short fragments
d) during replication, the strand that is replicated in short fragments
Which of the following is the best definition for "ligase". a) enzyme that contains a catalytic part and an inbuilt RNA template; it functions to maintain telomeres at chromosome ends b) enzyme that causes underwinding or overwinding of DNA when DNA replication is taking place c) enzyme that synthesizes the RNA primer; the primer is needed for DNA pol to start synthesis of a new DNA strand d) enzyme that catalyzes the formation of a phosphodiester linkage between the 3' OH and 5' phosphate ends of the DNA
d) enzyme that catalyzes the formation of a phosphodiester linkage between the 3' OH and 5' phosphate ends of the DNA
Which of the following is the best definition for "point mutation". a) mutation that does not affect the gene product b) mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent c) mutation that results from exposure to chemicals or environmental agents d) mutation that affects a single base
d) mutation that affects a single base
Which of the following is the best definition for "spontaneous mutation". a) mutation that results from exposure to chemicals or environmental agents b) mutation that does not affect the gene product c) mutation that affects a single base d) mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent
d) mutation that takes place in the cells as a result of chemical reactions taking place naturally without exposure to any external agent
Which of the following is the best definition for "primer". a) during replication, the strand that is replicated in short fragments b) DNA fragment that is synthesized in short stretches on the lagging strand c) strand that is synthesized continuously in the 5'-3' direction which is synthesized in the direction of the replication fork d) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
d) short stretch of nucleotides that is required to initiate replication; in the case of replication, the primer has RNA nucleotides
What type of point mutation would have the least effect on gene expression? a) frameshift b) missense c) nonsense d) silent
d) silent
The DNA double helix does not have which of the following? a) antiparallel configuration b) complementary base pairing c) major and minor grooves d) uracil
d) uracil