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.

Calculate the cfu/cm \( \mathrm{cm}^{2} \) for a tested surface of 4 cm in length and 3 cm in width if the number of colonies on the agar plate is 96 cfu. (A) \( 8 \mathrm{cfu} / \mathrm{cm}^{2} \) (B) \( 12 \mathrm{cmu} / \mathrm{cm}^{2} \). (C) \( 72 \mathrm{cmu} / \mathrm{cm}^{2} \) (D) \( 128 \mathrm{cmu} / \mathrm{cm}^{2} \)

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

8 Which of the following is a type of universal media? (A) MacConkey Agar. (B) Baird-Parker Agar. (C) \( \quad \) Mannitol Salt Agar. (D) Trypticase Soy Agar. 9

(B) State TWO ways in which flagellum helps a microorganism survive in an open environment. (2 ma All rights reserved. No part of this publication may be reproduced, stored in a retrieval sys transmitted in any form or by any means, electronic, mechanical, photocopying, reco otherwise, without the prior written permission of the Institute of Technical Education, Singapo Institute of Technical Education has made every effort to trace copyright holders, but if inadvertently overlooked any, we will be pleased to make the necessary arrangements a

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