Science: Section C - Essay questions

Question 10 (Compulsory)

Study the following statement:
Kaji pernyataan berikut:

You are given a sterile nutrient broth and Bacillus subtilis culture (bacteria culture).

''Anda diberikan bubur nutrient steril dan kultur Bacillus subtilis (kultur bakteria).

(a) Suggest one hypothesisto investigate the above statement. [ 1 mark]
     Cadangkan satu hipotesis untuk menyiasat pernyataan di atas [1 markah]

Notes: You can use...

1. 
   
   the "The higher..............(MV) ..................., the lower............ (RV) ..................//viseversa" statement   OR
2. 
   
   You can just COPY the statement in the box

as your answer. Both are accepted!

Answer:

"The higher the light intensity, the lower the growth of Bacillus subtilis"

Remember; use the named organism given in the question.

(b) Describe one experiment to test your hypothesis in l0(a) based on the following criteria:

      Huraikan satu eksperimen untuk mengkaji hipotesis di 10(a) berdasarkan kriteria berikut:


(i)   Aim of the experiment                                        [1 mark]
      Tujuan eksperimen                                           [1 markah]

(ii)  Identification of variables                                    [2 marks]
      Mengenalpasti pembolehubah                          [2 markah]

(iii) List of apparatus and materials                           [1 mark]
      Senarai radas dan bahan                                  [1 mark]

(iv) Procedure or method                                         [4 marks]
      Prosedur atau kaedah                                      [4 markah]

(v)  Tabulation of data                                             [1 mark]
      Penjadualan data                                            [1 mark]

Answer:

(i) Aim: "To study the effect of light intensity on the growth of Bacillus subtilis (bacteria)"

Note: The answer must begin with "To study....." then followed by MV and "on the" RV. 
In short, the answer should look like this "To study........MV...... on the..........RV.........."

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(ii) Variables:- (the CORRECT way to write the answer)
           Manipulated - Light intensity
           Responding - The growth of Bacillus subtilis
           Constant - (Temperature, humidity, nutrient, pH of  nutrient broth) ie. other factors that can affect the  growth of microorganisms, or volume of nutrient broth/bacterial culture or number of days

Notes: PLEASE write down every variable separately! Don't just list all variables in one blow.

For example... (WRONG way to answer)..
    Variables: Light intensity, growth of microorganism and volume of nutrient broth.

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(iii) Apparatus and materials: (this time, PLEASE write all apparatus & materials together - to avoid mistakes)
     Bacterial culture, sterile nutrient broth, test tubes, sterile cotton wool, syringe
 Note: list all materials & apparatus that are used in the experiment.

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(iv) Procedures: (you can answer in point form)

• Set up apparatus as shown in the diagram above (this type of answer must accompanied with a labelled diagram as above)
• Transfer 1 ml (CV) of bacterial culture in each test tube and plug them with sterile cotton wool
• Place the test tube in the following places:
•          A - under bright light       }
•          B - on the cabinet           }     MV
•          C - in a dark cupboard   }
• Keep for 2 days (CV)
• Observe the cloudiness of the nutrient broth (RV) in each test tube and record in the table

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(v) Data: (in table form - should clearly stated the MV and RV on the title)

                                       (MV)                                  (RV)

That's all! - easily 10 marks for you....

Wassalam,