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.
Answer: D
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Antigens on red blood cells are hereditary traits that allow blood to be typed in different ways. One system is based on a gene with two alleles, M and N. If the frequency of the M allele in a population is 0.4, then according to the Hardy-Weinberg rule, the expected frequency of the heterozygous MN genotype is ___.
A. 0.16 B. 0.24 C. 0.36 D. 0.48 E. 0.6 Clarify Question · What is the key concept addressed by the question? · What type of thinking is required? · What key words does the question contain and what do they mean? Gather Content · What do you already know about the Hardy-Weinberg principle? How does it relate to the question? Consider Possibilities · What other information is related to the question? Which information is most useful? Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer? Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
A cell in G0 state ____
a. is actively growing before cell division begins b. has a cleavage furrow and the cytoplasm is beginning to divide c. is actively replicating chromosomes d. is in cytokinesis e. has entered a resting stage and is not actively dividing
Which molecule is responsible for separating double-stranded DNA into single strands?
A. DNA primase. B. DNA helicase. C. topoisomerase. D. DNA ligase. E. single-stranded binding proteins.
Which statement is true?
a. Charophytes belong to the polyphyletic group Streptophta. b. Plasmodesmata persist in mature forms of chlorophytes. c. Charophytes divide along cell plates called phragmoplasts. d. Both chlorophytes and land plants show apical growth.