Cell Phys: Chapter 16

17) 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 (E. coli) DNA as a reference. Based on the information in the graph, you can determine that the DNA of the new strain has a high A) G-C content with respect to E. coli. B) pyrimidine content with respect to E. coli. C) A-T content with respect to E. coli. D) purine content, with respect to E. coli. E) histone content with respect to E. coli.

A) G-C content with respect to E. coli.

3) The scientist credited with the discovery of DNA (nuclein) from white blood cells in pus on surgical bandages is A) Johann Friedrich Meischer. B) Eduard Zacharias. C) Fredrick Griffiths. D) Martha Chase. E) Oswald Avery.

A) Johann Friedrich Meischer.

11) DNA is different from RNA in that A) RNA contains an additional oxygen atom on the ribose sugar. B) RNA is made up five bases, whereas DNA is made up of four. C) RNA cannot exist as a double helix. D) in general, RNA molecules are longer than DNA molecules. E) All of these statements are true.

A) RNA contains an additional oxygen atom on the ribose sugar.

33) You are using genetic engineering to design a protein that needs to be synthesized in the cytoplasm and then localized in the nucleus of the cell. To accomplish this, you could add A) a DNA sequence for a nuclear localization signal into the DNA that will be present in the mature protein. B) the protein during mitosis, at a time when the nuclear membrane is dispersed. C) a nucleotide or few nucleotides to the DNA sequence for the protein. D) a series of specific polysaccharides to the carboxyterminal end of the protein. E) inverted repeats to the DNA sequence for the protein.

A) a DNA sequence for a nuclear localization signal into the DNA that will be present in the mature protein.

21) Heterochromatin is highly ________, thus constitutive heterochromatin plays a(n) ________ role and facultative heterochromatin functions in ________. A) compacted; structural; regulation of gene expression B) compacted; regulatory; structure C) denatured; regulatory; structure D) denatured; structural; regulation of gene expression E) modified; evolutionary; structure

A) compacted; structural; regulation of gene expression

6) In an experiment like that of the 1952 Hershey and Chase experiments, 35S was added to a phage replicating within its bacterial host. The new phage particles 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 immediately after infection? A) in the phage ghosts outside the bacterial cells B) incorporated into the bacterial matrix proteins C) incorporated into the bacterial DNA D) inside the bacterial cells, but separate from the bacterial DNA E) inside the bacterial cells, but separate from the bacterial proteins

A) in the phage ghosts outside the bacterial cells

30) Which of the following is the correct order of the levels of DNA packaging in eukaryotic chromosomes? A) nucleosome → chromatin fiber → looped domains → heterochromatin B) nucleosome → looped domains → chromatin fiber → heterochromatin C) heterochromatin → nucleosome → chromatin fiber → looped domains D) chromatin fiber → heterochromatin → nucleosome → looped domains E) chromatin fiber → nucleosome → looped domains → heterochromatin

A) nucleosome → chromatin fiber → looped domains → heterochromatin

10) 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. A) 1' B) 2' C) 3' D) 4' E) 5'

B) 2'

31) Unusual eukaryotic-like (possessing a defined nucleus) cells were obtained from a sample of water from a subglacial antarctic lake. To investigate the properties of the new organism's genome, the nucleus was carefully isolated and the chromatin obtained. The fibers had a "beads on a string" appearance, suggesting some type of "histones." Following digestion with micrococcal nuclease, protein removal, and gel electrophoresis, DNA fragments were obtained that are multiples of 280 base pairs in length. Longer incubation with micrococcal nuclease prior to protein removal results in fragments 200 base pairs in length. The amount of DNA that is wrapped around the "core histones" is therefore A) 80 base pairs in length. B) 200 base pairs in length. C) 360 base pairs in length. D) 480 base pairs in length. E) Not enough information is given to determine the answer.

B) 200 base pairs in length.

13) The base composition in DNA isolated from cow liver cells is 28% adenine; what percent of the bases are cytosine? A) 14% B) 22% C) 28% D) 36% E) 56%

B) 22%

16) Which of the following statements regarding the Watson-Crick model of DNA is false? A) It is the most common biological form of DNA. B) The two DNA strands form a left-handed helix. C) The two DNA strands are antiparallel. D) The bases are "stacked" in the center of the molecule. E) The backbone consists of alternating sugars and phosphates.

B) The two DNA strands form a left-handed helix.

29) Which of the following statements is true regarding mitochondrial and chloroplast genomes? A) They contain mostly interspersed and tandemly repeated DNA. B) They are able to replicate independently of the nuclear DNA. C) They contain all the genes necessary for aerobic respiration. D) They are degenerate bacterial genomes that don't contain important protein-coding genes. E) They only encode for ribosomal and transfer RNAs.

B) They are able to replicate independently of the nuclear DNA.

9) An example of a purine is A) thymine. B) guanine. C) deoxyribose. D) cytosine. E) ribose 5-phosphate.

B) guanine.

18) Circular DNA molecules found in nature are A) positively supercoiled. B) negatively supercoiled. C) not supercoiled, due to their small size. D) always oriented in a triple helix to conserve space. E) always in the Z-DNA formation.

B) negatively supercoiled.

22) Alteration of histones by addition of methyl and acetyl groups to particular amino acids A) changes B-DNA to Z-DNA. B) results in the remodeling of chromatin that can activate or inhibit gene expression. C) creates G bands seen after Giemsa staining of chromosomes. D) helps preserve telomeres during DNA replication. E) alters the denaturation and renaturation of DNA.

B) results in the remodeling of chromatin that can activate or inhibit gene expression.

14) DNA isolated from Aspergillis has an adenine content of 25%. Based upon this information, what is the %G + %C within the Aspergillis DNA? A) 0% B) 25% C) 50% D) 75% E) The answer cannot be determined from this information.

C) 50%

19) What characteristic is shared between most prokaryotic and mitochondrial genomes? A) <5 % protein-coding genes B) >20% interspersed repeats C) circular chromosomes D) linear chromosomes E) circular chromosomes with <5 % protein-coding genes

C) circular chromosomes

35) The nucleolus A) is surrounded by a thin nucleolar membrane. B) is found in prokaryotes. C) contains tRNA. D) synthesizes ribosomal RNA. E) is found in prokaryotes and contains tRNA and rRNA.

C) contains tRNA.

27) Which type of DNA makes up the smallest portion of the human genome? A) introns B) unique noncoding DNA C) exons D) tandemly repeated DNA E) interspersed repeated DNA

C) exons

38) Each of the following structures is found within the nucleus of a eukaryotic cell except A) transfer RNA. B) histones. C) plasmids. D) the nucleolus. E) All of these are found in the nucleus.

C) plasmids.

5) Following reports that the amount of DNA varied over time within cells, scientists in the early 1900s concluded that the genetic material had to be A) DNA. B) RNA. C) protein. D) lipids. E) carbohydrates.

C) protein.

37) Mitochondrial DNA can be used to identify a species based upon A) NADH dehydrogenase sequences. B) variation in the mitochondrial rRNA genes. C) the 648 bp DNA bar code region. D) the proportion of GC base pairs. E) the size of the mitochondrial genome.

C) the 648 bp DNA bar code region.

23) Fluorescent in situ hybridization (FISH) would be helpful in determining A) the location of B-DNA and Z-DNA. B) the position and structure of nucleosomes. C) the position of particular chromosomes or sequences inside the nucleus. D) the base composition of a DNA sample. E) the number of nuclear pores on the nuclear envelope

C) the position of particular chromosomes or sequences inside the nucleus.

7) Avery, MacLeod, and McCarty (1944) demonstrated that DNA was the genetic material 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 A) an R strain and mix it with cells of an S strain. B) both S and R strains and mix it to allow recombination to take place. C) an ampicillin-sensitive strain and mix it with cells of an ampicillin-resistant strain. D) an S strain and mix it with cells of an R strain. E) None of the above are correct.

D) an S strain and mix it with cells of an R strain.

15) Which of the following shows Chargaff's equivalence? A) RNA B) single-stranded DNA C) histones D) double-stranded DNA E) deoxyribose

D) double-stranded DNA

4) In 1928, Frederick Griffith's experiments with Streptococcus pneumoniae suggested that A) bacteria do not incorporate the DNA of other bacteria. B) attenuated R (rough) bacteria easily revert to the wild type (virulent). C) RNA was the genetic material. D) heat-killed bacteria could somehow "transform" live bacteria. E) protein was the genetic material.

D) heat-killed bacteria could somehow "transform" live bacteria.

28) Packaging of prokaryotic chromosomes A) doesn't involve histone or histone-like proteins. B) involves large regions of positively supercoiled DNA but lacks histones or histone-like proteins. C) is very simple and lacks higher-level structure, such as looped domains. D) involves structural RNA molecules that contribute to the formation of looped domains. is essentially the same as eukaryotic DNA packaging.

D) involves structural RNA molecules that contribute to the formation of looped domains. is essentially the same as eukaryotic DNA packaging.

12) 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. A) amine; carboxyl B) phosphate; sulfate C) hydroxyl; hydrogen D) phosphate; hydroxyl E) amine; hydroxyl

D) phosphate; hydroxyl

34) Numerous Xenopus cells were exposed to varying amounts of ultraviolet light. Some of the resulting cells were observed to lack nucleoli. As a result, one would expect that the cell could not A) perform cellular respiration. B) replicate its DNA. C) perform photosynthesis. D) synthesize ribosomal RNA. E) perform cellular respiration or replicate its DNA.

D) synthesize ribosomal RNA.v

1) The information encoded in DNA is used within a cell in a two-stage process. The two stages of this process are called A) denaturation and renaturation. B) base-pairing and denaturation. C) replication and division. D) transcription and translation. E) replication and transcription.

D) transcription and translation.

8) Which of the following are components of Chargaff's rules of bases? A) % purines = % pyrimidines B) %C + %T = %A + %G C) %A = %T D) %G = %C E) All of these are true.

E) All of these are true.

24) Long interspersed nuclear elements (LINEs) found in eukaryotic genomes A) are mobile pieces of DNA called transposons that can copy themselves and move around the genome. B) are thought to create genomic variability important to evolutionary adaptation. C) are repeated 10-1000 times in clusters near centromeres and telomeres. D) are part of constitutive heterochromatin. E) are mobile pieces of DNA called transposons that can copy themselves and move around the genome, and they are thought to create genomic variability important to evolutionary adaptation.

E) are mobile pieces of DNA called transposons that can copy themselves and move around the genome, and they are thought to create genomic variability important to evolutionary adaptation.

2) Which of the following model organisms were used in experiments demonstrating that DNA was the genetic material? A) mice B) amoeba C) humans D) tobacco plants E) bacteria and bacteriophages

E) bacteria and bacteriophages

26) Interspersed repeated DNA A) constitutes 25%-40% of most mammalian genomes. B) is located in one region of most mammalian genomes. C) is approximately 105-107 bp in length for each repeat. D) can be classified into gene families, such as the Alu family. E) constitutes 20%-40% of most mammalian genomes and can be classified into gene families, such as the Alu family.

E) constitutes 20%-40% of most mammalian genomes and can be classified into gene families, such as the Alu family.

20) Mitochondrial and chloroplast genomes typically A) are composed of primarily noncoding DNA. B) encode all of the proteins needed for aerobic respiration and photosynthesis, respectively. C) encode for ribosomal and transfer RNAs. D) encode some of the proteins needed for aerobic respiration and photosynthesis, respectively. E) encode some of the proteins needed for aerobic respiration and photosynthesis, respectively, as well as ribosomal and transfer RNA.

E) encode some of the proteins needed for aerobic respiration and photosynthesis, respectively, as well as ribosomal and transfer RNA.

25) Which type of DNA makes up the largest portion of the human genome? A) introns B) unique noncoding DNA C) exons D) tandemly repeated DNA E) interspersed repeated DNA

E) interspersed repeated DNA

36) Which of the following structures contains the receptor protein importin? A) mitochondrion B) nucleolus C) chloroplast D) plastid E) nucleus

E) nucleus

32) The nuclear envelope functions as a A) means of separating nuclear and cytoplasmic constituents. B) means of localization of the chromosomes within the cell. C) selective barrier, allowing certain substances in or out. D) means of sequestering many of the mRNA processing activities from the cytosol. E) selective barrier that separates nuclear and cytoplasmic constituents, localizes chromosomes within the cell, and sequesters many of the mRNA processing activities from the cytosol.

E) selective barrier that separates nuclear and cytoplasmic constituents, localizes chromosomes within the cell, and sequesters many of the mRNA processing activities from the cytosol.