Microorganisms

Question 4:By using the apparatus set-up in Figure 4, suggest five different ways to measure the rate of carbon dioxide production from the action of yeast in sugar solutions at different temperatures. Answer:Apparatus set-up XMethod 1: Observe and compare the volume of carbon dioxide collected in the balloon. Apparatus set-up YMethod 2: Observe and compare … Read more

Question 3:Figure 3 shows an experiment to study the effect of temperature on the growth of Bacillus sp. The condition of the nutrient broth in test tubes P, Q and R is observed after three days. The results of the experiment are recorded in Table 1. (a) State one observation of the nutrient broth that … Read more

Question 2:Figure 2 shows microorganisms P, Q, R, S and T.Figure 2 (a) Classify P, Q, R, S and T based on the following characteristics:(i) have cell wall and cell membrane(ii) have no cell wall and cell membrane.(b) Name the group of microorganisms that has no cell wall and cell membrane.(c) (i) Name microorganism P.(ii) … Read more

Question 1:Figure 1 shows the results of an experiment to study the effect of different antibiotic concentrations on the growth of bacteria. (a) State one hypothesis for this experiment.(b) State the variables in this experiment.(i) Constant variable(ii) Manipulated variable(c) What is the effect of antibiotics based on this experiment? Answer:(a) The higher the concentration of … Read more

Question 1:State five examples of aseptic techniques used to control the spread of pathogens. Answer:• Sterilisation• Boiling• Using antiseptic• Disinfecting• Radiation Question 2:How is the aseptic technique related to the phrase ‘prevention is better than cure’? Answer:The aseptic technique is applied to protect a person from infections by eliminating existing or nearby pathogens before the … Read more

Question 1:Name two examples of useful microorganisms in each of the following fields:(a) medicine(b) agriculture(c) industry Answer:(a) Recombinant DNA of E. coli, Penicillium chrysogenum (b) Bifidobacteria sp., Nitrosomonas sp., Nitrobacter sp. (c) Yeast, Lactobacillus bulgaricus, Bifidobacteria sp. Question 2:State two examples of foods that use microorganisms and name the microorganisms. Answer: Question 3:(a) What is … Read more

Question 1:What are microorganisms? Answer:Microorganisms are minute organisms which cannot be seen with the naked eye. Question 2:(a) Name five groups of microorganisms.(b) What are the characteristics used to classify microorganisms into five groups? Answer:(a) Fungi, algae, protozoa, bacteria, viruses (b) Size, shape, method of reproduction, nutrition, habitat Question 3:Name the group of microorganisms that … Read more