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• PERFECT SCORE BIOLOGY 2011

1

BAHAGIAN SEKOLAH BERASRAMA PENUH DAN

SEKOLAH KECEMERLANGAN

KEMENTERIAN PELAJARAN MALAYSIA

PERFECT SCORE BIOLOGY

2011 Teachers Module

PAPER 3

QUESTION 1

• PERFECT SCORE BIOLOGY 2011

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Question 1 :

No. Questions Marks Student notes

1 A group of students carried out an experiment to study the effect of the concentration of

glucose on the activity of yeast . Diagram 1.1 shows the method used by the students.

The initial height of the coloured liquid in the manometer is shown in Diagram 1.2.

The experiment was repeated using different concentrations of glucose. Table 1.1 shows the

results of the experiment after 10 minutes.

Diagram 1.1

DIAGRAM 1.2

rubber tubing

Manometer with

coloured liquid

Initial height of

coloured liquid

Boiling tube containing yeast

suspension

Glass tube

clip

Rubber stopper

Initial height of coloured liquid :

1 cm

• PERFECT SCORE BIOLOGY 2011

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Percentage concentration of glucose / %

Final height of coloured liquid in the manometer after 10 minutes /cm

10

15

20

3

5

8

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No. Questions Marks Student notes

(a) Complete Table 1.2 by recording the height of coloured liquid in the manometer after 10 minutes

(b) (i) Based on Table 1.1, state two observations . 1. At 10% concentration of glucose ,the final

height of coloured liquid after 10 min is 3 cm 2. At 20% concentration of glucose , the final

height of coloured liquid after 10 min is 8 cm

(ii) State the inference which corresponds to the observation in 1(b(i). 1. Low activity of yeast in lower concentration of

glucose, less carbon dioxide is released

2. High activity of yeast in high concentration of glucose, more carbon dioxide is released

(c) Complete Table 1.2 for the three variables based on the experiment.

Variable

Method to handle the variable

Manipulated variable: The concentration of glucose

Use different concentration of nutrients/glucose

Responding variable: Height of coloured liquid// The rate of yeast activity

Record the height of coloured liquid by using a metre rule // Calculate rate of yeast respiration using formula: = height of coloured liquid time

Controlled variable : Volume of yeast suspension /mass of yeast/volume of glucose/pH/light intensity/temperature/time taken

Fix the volume of 100cm3 of yeast suspension /the mass of 4 g of yeast /pH5 /light intensity at distance of 50cm /temperature at room temperature/time taken for 10 minutes

3

3

3

• PERFECT SCORE BIOLOGY 2011

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(d) State the hypothesis for the experiment. The higher/ lower the concentration of glucose, the higher / lower the rate of yeast activity

(e) (i) Based on Table 1.1, construct a table and record the results of the experiment which includes the following aspects:

Percentage concentration of glucose

Height of coloured liquid

The rate of the activity of yeast

Percentage concentration of glucose (%)

Height of coloured liquid

(cm)

The rate of the activity of yeast

(cm/min)

10 3

0.3

15 5

0.5

20 8

0.8

Table 1.1

(e) (ii) Draw a graph of the rate of the activity of yeast against the concentration of glucose

(iii)

Based on the graph in 1(e)(ii), state the relationship between the rate of the activity of yeast and the concentration of glucose. Explain your answer. When the concentration of glucose increases/decreases, the rate of yeast activity increases/decreases, more substrate for yeast to use for energy production, more yeast reproduced.

(f) Based on the experiment, define anaerobic respiration in yeast operationally. An anaerobic respiration is when yeast using glucose to produce gas that causes the rising of liquid in manometer tube and the process is affected by concentration of glucose

3

3

3

3

3

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(g) The experiment is repeated by using 1 ml of 0.1 mol dm-3 of sodium hydroxide solution is added into the boiling tube. Predict the manometer reading after 10 minutes. Explain your prediction.

1 cm, not increase, sodium hydroxide is alkali, the medium is not suitable for yeast.

(h) The following list is part of the apparatus and material used in this experiment. Complete Table 1.3 by matching each variable with the apparatus and material used in the experiment.

Variables

Apparatus

Material

Manipulated

Measuring cylinder

Glucose

Responding

Coloured liquid

Metre ruler

Controlled

electronic balance

Yeast

Yeast, metre rule, coloured liquid, electronic balance, glucose solution, measuring cylinder

3

3

• PERFECT SCORE BIOLOGY 2011

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Question 2 :

No. Questions Marks Student notes

2 Lemna minor is a species of free-floating aquatic plants from the duckweed family Lemnaceae. The plants grow mainly by vegetative reproduction: two daughter plants bud off from the adult plant. An experiment is carried out to investigate the effect of abiotic factor such as pH on Lemna sp. growth. Experiment is done under controlled conditions: 12 hours a day light exposure and using the same Knops solution. Petri dish is filled with 20 ml Knops solution with different pH value and 5 Lemna sp. each. The Knops solution is treated by adding acid or alkali to achieve the pH value needed. ** Knops solution is a solution which contains essential nutrient for plants growth.

Figure 1 After 7 days, the observation is made and the result shown in Table 1.1 .

pH value

Petri dish

Number of Lemna sp.

3

4

Lemna minor

Petri dish

Knops solution

• PERFECT SCORE BIOLOGY 2011

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5

5

7

8

9

11

11

5

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13

1

Table 1.1

No. Questions Marks Student notes

(a) State the number of Lemna sp. in the spaces provided in Table 1.1

(b) (i) Based on Table 1, state two different observations .

Able to state any two observations correctly according to 2 criteria:

pH ( Manipulated Variable)

Number of Lemna sp (Responding Variable) Sample answers: 1. At pH 2 (Knop solution), the number of Lemna sp is 4 2. At pH 8 (Knop solution), the number of Lemna sp is 11 3. At pH 12 ( Knop solution), the number of Lemna sp is

1 4. At pH 12 (Knop solution), the number of Lemna sp

grow is less than at pH 2/4/6/8/10 5. At pH 8 (Knop solution), the number of Lemna sp is

more than at pH2/4/6/10/12 *1,2 &3 is a horizontal observation

*4 & 5 is a vertical observation

(ii) State the inferences which corresponds to the observations in 1(b)(i). Able to make one logical inference for each observation based on the criteria

suitable abiotic factor

Favourable for Lemna sp growth Sample answers:

3

3

3

• PERFECT SCORE BIOLOGY 2011

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1. Strong acidic condition is not favorable for Lemna growth.

2. Weak/slight alkaline // neutral condition is most favorable for Lemna growth.

3. Strong alkaline is not favorable for Lemna growth. 4. Strong alkaline condition is the least favorable for

Lemna growth compare with other conditions. 5. Neutral/Slight alkaline condition is the best/moss

favorable condition for Lemna growth. *1,2 &3 is a horizontal inference *4 & 5 is a vertical inference

(c) Complete Table 1.4 to show the variables involved in the experiment and how the variables are operated.

Variables How the variables are operated

Manipulated:

pH

Add/Use acid or alkali to the Knop solution to get different pH condition// Use pH solution: pH2, pH4, pH6, pH8, pH10,pH12 // change/alter the medium condition

Responding:

Number of Lemna sp

Count and record the number of Lemna sp. plants after 7 days.

Fixed:

Light exposure /

Volume of Knop solution

Fix 12 hours light exposure every day /

Maintain the volume at 20ml

(d) State the hypothesis for this experiment.

Able to state a hypothesis to show a relationship between the manipulated variable and responding variable and the hypothesis can be validated, based on 3 criteria:

manipulated variable

responding variable

1. In low pH, number of Lemna sp is less than in a higher pH.

2. The higher pH the higher number of Lemna sp. 3. In a neutral condition the number of Lemna sp.

3

3

• PERFECT SCORE BIOLOGY 2011

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plants is the highest /the most. 4. The more alkali the medium is the less number of

Lemna sp.

(e) (i) Construct a table and record the results of the experiment. Your table should contain the following title.

pH of water

Number of Lemna sp.

Able to draw and fill a table with all columns and rows