Question 1

Which of the following statements regarding the WatsonCrick model of DNA is not accurate?

Accepted Answer

The Watson-Crick model of DNA is a right-handed helix, not a left-handed helix.

Question 2

DNA isolated from cow liver cells contains 28% A; what percent will be C?

Accepted Answer

According to Chargaff's rule, the amount of adenine (A) equals thymine (T), and cytosine (C) equals guanine (G) in DNA. If A is 28%, then T is also 28%, making A+T = 56%. The remaining 44% must be C and G, so C is 22%.

Question 3

Restriction enzymes typically recognize

Accepted Answer

Restriction enzymes typically recognize specific palindromic sequences, which are nucleotide sequences that read the same forward and backward on complementary DNA strands. These sequences are typically four to eight base pairs long and often contain a symmetrically placed restriction site where the enzyme can cut the DNA. Restriction enzymes do not recognize sequences in threefold symmetry, single-stranded DNA only, or several nucleotide sequences simultaneously.

Question 4

Following reports that stained chromosomes "disappeared" while observing cell division,scientists in the early 1900s determined the molecule of heredity to be

Accepted Answer

In the early 1900s, proteins were initially thought to be the molecule of heredity because they are complex and varied, unlike DNA, which was considered too simple at the time.

Question 5

The scientist credited with the discovery of DNA,which he called "nuclein," from salmon sperm in 1869 is

Accepted Answer

The scientist credited with the discovery of DNA from salmon sperm in 1869 is Johann Friedrich Miescher.

Question 6

Which of the following are components of Chargaff's rules of bases?

Accepted Answer

All of the statements listed are components of Chargaff's rules of bases. These rules indicate that in DNA, the amount of purines (A and G) is equal to the amount of pyrimidines (T and C) and that within the purines and pyrimidines, the amount of A is equal to T and the amount of G is equal to C.

Question 7

DNA isolated from Aspergillis has an adenine content of 25%.Based upon this information,what is the %G + C within the Aspergillis DNA?

Accepted Answer

The answer of DNA isolated from Aspergillis has an adenine...

Question 8

Avery,MacLeod,and McCarty (1944)demonstrated that DNA was the molecule of heredity by treating heat-killed Streptococcus pneumoniae S (smooth)strain with DNase,thereby preventing transfer of the "transforming substance" from the killed S strain to the live R (rough)strain when the two were mixed together and injected into mice.Another way that one could demonstrate transformation in bacteria would be to extract DNA from

Accepted Answer

Extracting DNA from an S strain and mixing it with cells of an R strain would demonstrate transformation, as the R strain could take up the DNA from the S strain and acquire new traits, such as virulence.

Question 9

Which of the following shows Chargaff's equivalence?

Accepted Answer

Chargaff's equivalence states that the amount of adenine (A) in DNA is equal to the amount of thymine (T), and the amount of cytosine (C) is equal to the amount of guanine (G). Synthetic DNA with one strand all A and the other all T satisfies this criteria. The other choices, mRNA and tRNA, are single-stranded RNA molecules and do not have the same base pairing rules as DNA. Single-stranded DNA could potentially have any combination of bases and therefore may not show Chargaff's equivalence.

Question 10

DNA is different from RNA in that

Accepted Answer

RNA contains a hydroxyl (-OH) group on the 2' carbon of the ribose sugar, which DNA lacks.

Question 11

In 1928,Frederick Griffith's experiments with Streptococcus pneumoniae suggested that

Accepted Answer

Frederick Griffith's experiments with Streptococcus pneumoniae suggested that heat-killed bacteria could somehow "transform" live bacteria. This was the first evidence of DNA being the molecule of heredity, but it was not conclusively proven at the time. Griffith also observed that attenuated R (rough) bacteria could be transformed into the wild type (virulent) by DNA from dead virulent S (smooth) bacteria, providing evidence that bacteria could incorporate DNA from other bacteria.

Question 12

When examining a five-carbon sugar to determine if it is ribose or deoxyribose,one looks to see if there are two H on the _____ carbon in the structure.

Accepted Answer

The 2' carbon is the only carbon that has two H in ribose, while in deoxyribose the 2' carbon has only one H.

Question 13

Circular DNA molecules found in nature (such as bacterial,viral,or mitochondrial DNA)are

Accepted Answer

Circular DNA molecules found in nature are typically negatively supercoiled. This occurs because the circular molecule must twist upon itself to form a compact structure, resulting in regions of overwinding and underwinding. The negative supercoiling in these molecules can help facilitate DNA replication and gene expression.

Question 14

The normal gene for hemoglobin was isolated,cloned,and subjected to restriction enzyme digestion with BamHI.Following gel electrophoresis,three bands are routinely obtained.However,following the same procedure with the hemoglobin gene from an individual with sickle-cell anemia,four bands are routinely obtained.These data suggest that

Accepted Answer

The fact that the sickle-cell anemia sample has four bands instead of three suggests that the mutation has resulted in the addition of another BamHI restriction enzyme cut site. This could be due to a deletion or insertion of nucleotides in the gene sequence, leading to a change in the location of the cut site.

Question 15

In experiments designed as those of Hershey and Chase (1952),³⁵S was added to a virus replicating within its bacterial host.The new virions were carefully isolated and used to infect fresh bacterial cells in the absence of any radioisotopes.Where would you expect to find the ³⁵S radioisotope?

Accepted Answer

³⁵S labels sulfur, which is found in proteins but not in DNA. In the Hershey and Chase experiment, ³⁵S was used to label the protein coat of the phage. After infection, the protein coat (phage ghosts) remains outside the bacterial cell, so the ³⁵S would be found in the phage ghosts.

Question 16

Base sequence variations between individuals that result from point mutations are called

Accepted Answer

Point mutations are changes in a single nucleotide base pair, resulting in single nucleotide polymorphisms (SNPs), which are a common type of genetic variation between individuals. SNPs occur at a frequency of at least 1% in a population and can lead to differences in traits and susceptibility to disease.

Question 17

The 5' end of a DNA molecule can be chemically distinguished from the 3' end because there is a(n)__________ group at the 5' end and a(n)__________ group at the 3' end.

Accepted Answer

The phosphate group (PO₄) is present at both the 5' and 3' ends of a DNA molecule, but it is only covalently bonded to a deoxyribose sugar at the 5' end. Therefore, the 5' end is distinguished by the presence of a free phosphate group (PO₄), while the 3' end is distinguished by the presence of a hydroxyl group (-OH) attached to the 3' carbon of the deoxyribose sugar. Choice D is the only option that includes both of these groups as distinguishing features.

Question 18

A recently isolated bacterial strain has been given to you for general characterization of the genome.You begin by isolating the DNA and subjecting it to thermal denaturation.You use Escherichia coli DNA as a reference (A + T = G +C).
 Figure 18.1
Based on the information in the graph, you can determine that the DNA has a high

Accepted Answer

The answer of A recently isolated bacterial strain has been...

Question 19

The specific field of study that examines the gene products of a genome is known as

Accepted Answer

The specific field of study that examines the gene products of a genome is known as proteomics. Genomics refers to the study of the entire genome, including its organization, function, and evolution. Bioinformatics is the use of computational tools and techniques to analyze biological data. Annotation is the process of identifying and labeling different aspects of a genome, such as genes and regulatory sequences. Therefore, only choice D, proteomics, is the best answer to this question.

Question 20

An example of a purine is

Accepted Answer

Purines are a family of nitrogenous bases that have a double-ring structure. Adenine and guanine are both purines, while thymine, cytosine, and uracil are pyrimidines, which have a single-ring structure. Acridine is not a nitrogenous base at all, but rather a polycyclic aromatic hydrocarbon. Therefore, the best choice for an example of a purine is guanine (choice B).

Quiz 18: The Structural Basis of Cellular Information: DNA, chromosomes, and the Nucleus

Which of the following statements regarding the WatsonCrick model of DNA is not accurate?

DNA isolated from cow liver cells contains 28% A; what percent will be C?

Restriction enzymes typically recognize

Following reports that stained chromosomes "disappeared" while observing cell division,scientists in the early 1900s determined the molecule of heredity to be

The scientist credited with the discovery of DNA,which he called "nuclein," from salmon sperm in 1869 is

Which of the following are components of Chargaff's rules of bases?

DNA isolated from Aspergillis has an adenine content of 25%.Based upon this information,what is the %G + C within the Aspergillis DNA?

Which of the following shows Chargaff's equivalence?

DNA is different from RNA in that

In 1928,Frederick Griffith's experiments with Streptococcus pneumoniae suggested that

When examining a five-carbon sugar to determine if it is ribose or deoxyribose,one looks to see if there are two H on the _____ carbon in the structure.

Circular DNA molecules found in nature (such as bacterial,viral,or mitochondrial DNA) are

In experiments designed as those of Hershey and Chase (1952) ,³⁵S was added to a virus replicating within its bacterial host.The new virions were carefully isolated and used to infect fresh bacterial cells in the absence of any radioisotopes.Where would you expect to find the ³⁵S radioisotope?

Base sequence variations between individuals that result from point mutations are called

The 5' end of a DNA molecule can be chemically distinguished from the 3' end because there is a(n) group at the 5' end and a(n) group at the 3' end.

The specific field of study that examines the gene products of a genome is known as

An example of a purine is

Quiz 18: The Structural Basis of Cellular Information: DNA, chromosomes, and the Nucleus

Which of the following statements regarding the WatsonCrick model of DNA is not accurate?

DNA isolated from cow liver cells contains 28% A; what percent will be C?

Restriction enzymes typically recognize

Following reports that stained chromosomes "disappeared" while observing cell division,scientists in the early 1900s determined the molecule of heredity to be

The scientist credited with the discovery of DNA,which he called "nuclein," from salmon sperm in 1869 is

Which of the following are components of Chargaff's rules of bases?

DNA isolated from Aspergillis has an adenine content of 25%.Based upon this information,what is the %G + C within the Aspergillis DNA?

Which of the following shows Chargaff's equivalence?

DNA is different from RNA in that

In 1928,Frederick Griffith's experiments with Streptococcus pneumoniae suggested that

When examining a five-carbon sugar to determine if it is ribose or deoxyribose,one looks to see if there are two H on the _____ carbon in the structure.

Circular DNA molecules found in nature (such as bacterial,viral,or mitochondrial DNA) are

Base sequence variations between individuals that result from point mutations are called

The 5' end of a DNA molecule can be chemically distinguished from the 3' end because there is a(n) __________ group at the 5' end and a(n) __________ group at the 3' end.

The specific field of study that examines the gene products of a genome is known as

An example of a purine is

The 5' end of a DNA molecule can be chemically distinguished from the 3' end because there is a(n) group at the 5' end and a(n) group at the 3' end.