You and a classmate are discussing early experiments in genetics, and you state that Avery, MacLeod, and McCarty provided the first evidence that DNA carries genetic information. Your classmate argues that Griffith was the first to demonstrate this. Which statement best defends your argument?
A. Because Avery, MacLeod, and McCarty did their experiments after those done by Griffith, they had much more information regarding the structure and function of DNA.
B. Although Griffith first demonstrated transformation, Avery, MacLeod, and McCarty provided evidence that DNA rather than protein or RNA was the transforming agent.
C. DNA used by Avery, MacLeod and McCarty was extracted solely from transformed strains of pneumococci, while Griffith used native pneunococcal strains.
D. Enzymes were used in the experiments carried out by Avery, MacLeod, and McCarty while Griffith transformed cells chemically or by using heat.
E. Avery, MacLeod, and McCarty worked with purified DNA extracts while Griffith worked with bacterial strains.
Answer: B
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Assume that production of hairs on a plant’s leaves is controlled by a single gene with two alleles, H (dominant) and h (recessive). Hairy leaves are dominant to smooth (nonhairy) leaves.
a. Name the genotype(s) of a smooth-leaved plant. b. Name the genotype(s) of a hairy-leaved plant. c. What are the possible genotypes of gametes produced by the smooth-leaved plant? d. What are the possible genotypes of gametes produced by the hairy-leaved plant? Homozygous:
DNA is recognized as a left-handed molecule
Indicate whether the statement is true or false
A zebroid is the sterile hybrid offspring of a horse and a zebra. This is an example of ____
a. hybrid inviability b. hybrid sterility c. allopatric speciation d. prezygotic reproductive isolation e. hybrid breakdown
Population size levels off at the ________ of an environment.
A. biotic potential B. population growth C. carrying capacity D. environmental resistance