Osu Bio 1113 - Ch. 16

Front 1

1) In his transformation experiments, what did Griffith observe?

Back 1

B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

Front 2

2) How do we describe transformation in bacteria?

Back 2

E) assimilation of external DNA into a cell

Front 3

3) After mixing a heat-killed, phosphorescent strain of bacteria with a living nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait?

Back 3

D) Descendants of the living cells are also phosphorescent.

Front 4

4) In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

Back 4

B) DNA contains phosphorus, whereas protein does not.

Front 5

5) Which of the following investigators was/were responsible for the following discovery?

Back 5

D) Erwin Chargaff

Front 6

6) Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

Back 6

A) 8%

Front 7

7) Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

Back 7

A) the diameter of the helix

Front 8

8) It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

Back 8

A) sequence of bases

Front 9

9) In an analysis of the nucleotide composition of DNA, which of the following will be found?

Back 9

C) A + C = G + T

Front 10

10) Replication in prokaryotes differs from replication in eukaryotes for which of the following reasons?

Back 10

B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

Front 11

11) What is meant by the description "antiparallel" regarding the strands that make up DNA?

Back 11

B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

Front 12

12) Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

Back 12

E) DNA in both daughter cells would be radioactive.

Front 13

13) An Okazaki fragment has which of the following arrangements?

Back 13

C) 5' RNA nucleotides, DNA nucleotides 3'

Front 14

14) In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

Back 14

B) No replication fork will be formed.

Front 15

15) Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?

Back 15

C) DNA polymerase III

Front 16

16) Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

Back 16

C) gaps left at the 5' end of the lagging strand

Front 17

17) The enzyme telomerase solves the problem of replication at the ends of linear chromosomes by which method?

Back 17

D) adding numerous short DNA sequences such as TTAGGG, which form a hairpin turn

Front 18

18) The DNA of telomeres has been found to be highly conserved throughout the evolution of eukaryotes. What does this most probably reflect?

Back 18

E) that the critical function of telomeres must be maintained

Front 19

19) At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:
3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

Back 19

D) 5' A C G U U A G G 3'

Front 20

20) Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?

Back 20

B) replication without separation

Front 21

21) To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?

Back 21

E) endonuclease, DNA polymerase I, DNA ligase

Front 22

22) What is the function of DNA polymerase III?

Back 22

C) to add nucleotides to the 3' end of a growing DNA strand

Front 23

23) The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that

Back 23

A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.

Front 24

24) The leading and the lagging strands differ in that

Back 24

A) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

Front 25

25) A new DNA strand elongates only in the 5' to 3' direction because

Back 25

E) DNA polymerase can only add nucleotides to the free 3' end.

Front 26

26) What is the function of topoisomerase?

Back 26

A) relieving strain in the DNA ahead of the replication fork

Front 27

27) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Back 27

C) It joins Okazaki fragments together.

Front 28

28) Which of the following help(s) to hold the DNA strands apart while they are being replicated?

Back 28

D) single-strand binding proteins

Front 29

29) Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells are impaired in what way?

Back 29

D) They cannot repair thymine dimers.

Front 30

30) Which of the following would you expect of a eukaryote lacking telomerase?

Back 30

D) a reduction in chromosome length in gametes

Front 31

31) Which of the enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?

Back 31

IV. DNA polymerase I

Front 32

32) Which of the enzymes separates the DNA strands during replication?

Back 32

I. helicase

Front 33

33) Which of the enzymes covalently connects segments of DNA?

Back 33

III. ligase

Front 34

34) Which of the enzymes synthesizes short segments of RNA?

Back 34

V. primase

Front 35

35) Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication?

Back 35

A) double-stranded DNA, four kinds of dNTPs, primers, origins

Front 36

36) Studies of nucleosomes have shown that histones (except H1) exist in each nucleosome as two kinds of tetramers: one of 2 H2A molecules and 2 H2B molecules, and the other as 2 H3 and 2 H4 molecules. Which of the following is supported by this data?

Back 36

B) The two types of tetramers associate to form an octamer.

Front 37

37) In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding?

Back 37

D) the 30-nm chromatin fiber

Front 38

38) Which of the following statements describes the eukaryotic chromosome?

Back 38

D) It consists of a single linear molecule of double-stranded DNA plus proteins.

Front 39

39) If a cell were unable to produce histone proteins, which of the following would be a likely effect?

Back 39

B) The cell's DNA couldn't be packed into its nucleus.

Front 40

40) Which of the following statements is true of histones?

Back 40

B) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together.