The pH scale is a very common and important concept. Before moving on into more complex work in science or health care you should now the effect of acids and bases on pH values. Know what neutral pH is, and whether acids increase or decrease pH . To test your knowledge answer the next few questions. Blood pH must stay within a tight range near neutral of 7.1 to 7.4 for proper body system function. A dangerous condition in patients is acidosis. It can induce mental confusion, rapid breathing, and increased heart rate. In acidosis has the blood pH increased or decreased from the normal, neutral range? A. Blood pH has dropped. B Blood pH did not change. (C) Blood pH increased.

21 When conducting the bioluminescence assay, a false positive result is detected if the sample (A) contains a lot of fat. (B) comprises of artificial dye. (C) has high initial microbial load. (D) is contaminated with chemicals. The function of cell wall in bacteria is to (A) store nutrients. (B) protect them against drying. (C) control the reproduction rate. (D) maintain the characteristic shape.

(A) State ONE example of selective media that can be used to isolate [3 marks] EACH of the following microorganisms. (i) Gram positive bacteria. (ii) Staphylococci spp. (iii) Gram negative bacteria.

(B) (i) Explain THREE precaution steps during decontamination of biohazard wastes in bag using an autoclave. (ii) Describe TWO materials that will remain undamaged after autoclaving.

34 (A) (i) Explain ONE purpose of air monitoring. (ii) Describe TWO factors that will affect air quality.

What one of the following are the CORRECT operating conditions when autoclaving biohazard wastes? (A) \( 10 \mathrm{psi} 121^{\circ} \mathrm{C} \) for 15 minutes. (B) \( 10 \mathrm{psi}, 121^{\circ} \mathrm{C} \) for 30 minutes. (C) \( 15 \mathrm{psi}, 121^{\circ} \mathrm{C} \) for 15 minutes. (D) \( 15 \mathrm{psi}, 121^{\circ} \mathrm{C} \) for 30 minutes. After conducting microbiology experiment, a laboratory technician is required to dispose the remaining culture broths. Which one of the following is the CORRECT disposal method? (A) Incineration. (B) Discard as normal waste. (C) Collection by licensed waste collectors. (D) Autoclave before discarding into the drain.