What is the effect produced by the PRK technique designed to correct nearsightedness?
A.
The density of the cornea is increased.
B.
The radius of
... [Show More] curvature of the cornea is increased.
C.
The index of refraction of the cornea is increased.
D.
The thickness of the cornea at the apex is increased. - ANSWER B.
The radius of curvature of the cornea is increased.
in passage, it says nearsightedness flattens the cornea. Flattening the cornea would increase the radius of curvature.
The use of pulsed laser radiation in the PRK procedure, as opposed to continuous laser radiation, allows the cornea to:
A.
absorb more radiation.
B.
change its index of refraction.
C.
increase the area exposed to radiation.
D.
maintain a lower average temperature. - ANSWER D.
maintain a lower average temperature.
The pulsed laser radiation interacts with the cornea for a shorter time than a continuous laser radiation, thus less heat is transferred to the cornea. This allows the cornea to maintain a lower average temperature by cooling off between pu
Which conclusion can be drawn from the experimental results described in the passage?
A.
Compound 1 selectively sensitizes cancer cells to chemotherapeutic action by Compound 2.
B.
Compound 1 sensitizes all cells to chemotherapeutic action.
C.
Compound 2 induces apoptosis in cancer cells only in conjunction with treatment with Compound 1.
D.
Compound 2 inhibits the NF-κB signaling pathway, which leads to apoptosis. - ANSWER A.
Compound 1 selectively sensitizes cancer cells to chemotherapeutic action by Compound 2.
The results shown in Figure 1 and Table 1 show that treatment of cancerous cell lines with Compound 1 sensitizes cancer cells to chemotherapeutic action as a result of exposure to Compound 2.
What is the concentration of the acute leukemia CC95 Combination value in micromolar (μM) units?
A.
6 × 10-10 μM
B.
6 × 10-7 μM
C.
6 × 10- 4 μM
D.
6 × 10-2 μM - ANSWER The CC95 Combination value for acute leukemia cells was 0.6 nM, or 0.6 × 10-9 M. This corresponds to 0.6 × 10-9 M × (1 μM/1 × 10-6 M) = 0.6 × 10-3 μM = 6 × 10-4 μM.
Which transition produces a photon with the longest wavelength?
A.
Transition 1
B.
Transition 2
C.
Transition 3
D.
Transition 4 - ANSWER B.
Transition 2
The longest wavelength has the smallest photon energy (closest energy levels)
Which of the following functional groups is present in pyrrolizidine (Figure 1)?
A.
An amide
B.
An amine
C.
An imine
D.
A carbamate - ANSWER B.
An amine (R3N) where R=H
Compound 3 is prepared from Compound 2 (Figure 2) by:
A.
reduction of the ketone and lactonization of the gamma-hydroxyester.
B.
hydrolysis of one ester and formation of an acetal from the ketoacid.
C.
reduction of one ester and formation of an acetal from the gamma-hydroxyketone.
D.
reduction of one ester and the ketone followed by dehydration to a ketoether. - ANSWER A. [Show Less]