What are key symptoms of attention deficit/hyperactivity disorder (ADHD)? Persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development. Consistent feelings of sadness and withdrawal from social interaction. Gradual development of repetitive patterns of behavior and interests. Intense episodes of euphoria followed by periods of deep depression.

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.

(C) State TWO ways in which fermentation process helps to improve [2 marks] quality of food products.

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.

(A) (i) Describe TWO disadvantages of using Replicate Organism Detection And Counting (RODAC) plate during a surface swab. (ii) Explain TWO purposes of conducting a hand swab test. 12 m

23 Which one of the following microorganisms moves using flagellum? (A) Amoeba. (B) Euglena. (C) Paramecium. (D) Plasmodium. Which one of the following is NOT a heterotrophic microorganism? \( \begin{array}{ll}\text { (A) } \quad \text { Diatoms. } \\ \text { (B) } \quad \text { Sarcodines. } \\ \text { (C) } \quad \text { Sporozoans. } \\ \text { (D) }\end{array} \)