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Zorluk: OrtaExplicit Detail Retrieval

In 1928, British bacteriologist Frederick Griffith conducted a landmark experiment investigating Streptococcus pneumoniae, the bacterium responsible for pneumonia. Griffith utilized two distinct strains: the virulent 'S' (smooth) strain, enclosed in a protective polysaccharide capsule that shielded it from the host's immune system, and the non-virulent 'R' (rough) strain, which lacked this capsule. When Griffith injected mice with heat-killed S-strain bacteria, the mice survived, confirming that dead bacteria alone were harmless. However, when heat-killed S-strain bacteria were combined with living R-strain bacteria and injected into mice, the animals succumbed to pneumonia, and living S-strain bacteria were subsequently isolated from their blood. Griffith concluded that a non-living 'transforming principle' had passed from the dead S-strain bacteria to the living R-strain bacteria, permanently endowing them with the ability to synthesize the protective capsule. Although Griffith did not identify the chemical identity of this transforming principle, his findings established that genetic traits could be horizontally transferred between bacterial strains.

According to the passage, which of the following statements regarding Griffith's 1928 experiment are explicitly supported by the text?

  1. Mice injected exclusively with heat-killed S-strain bacteria survived the procedure.Cevap
  2. B
    The protective polysaccharide capsule of the R-strain bacterium was chemically destroyed by heat prior to injection.
  3. Griffith succeeded in isolating living S-strain bacteria from mice exposed to a mixture of live R-strain and heat-killed S-strain bacteria.Cevap

Cevap

The statements confirming that mice injected exclusively with heat-killed S-strain bacteria survived and that living S-strain bacteria were isolated from mice injected with the mixture of live R-strain and heat-killed S-strain bacteria are both explicitly supported.
The passage provides direct factual support for two statements. First, it explicitly confirms that mice injected with heat-killed S-strain bacteria survived. Second, it explicitly states that after injecting the mixture of live R-strain and heat-killed S-strain bacteria, living S-strain bacteria were isolated from the blood of the affected mice.

Adım Adım Çözüm

1
Locate explicit passage facts regarding the heat-killed S-strain injection in isolation.
The text explicitly states: 'When Griffith injected mice with heat-killed S-strain bacteria, the mice survived.' This directly validates the statement about mice surviving exclusive injection with heat-killed S-strain bacteria.
Explicit detail retrieval requires matching statement claims directly against textual evidence.
2
Evaluate the statement concerning the capsule of the R-strain bacterium.
The text states that the R-strain 'lacked this capsule.' It does not claim that the R-strain possessed a capsule that was destroyed by heat.
Recognize misread details where traits of one strain are misattributed to another.
3
Locate explicit passage evidence regarding bacterial isolation following the combination injection.
The text states that when heat-killed S-strain and living R-strain were combined, 'living S-strain bacteria were subsequently isolated from their blood.' This confirms the statement regarding the recovery of live S-strain bacteria.
Direct paraphrase matching confirms explicit support.

Anahtar Kavram

Explicit detail verification requires confirming that each chosen statement reflects explicitly stated facts without misattributing modifiers or characteristics.
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Explicit Detail Retrieval

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