POTCHEFSTROOM HIGH SCHOOL FOR BOYS PRATICAL 1 LIFE SCIENCE

GRADE 10

Name: _____________________________

Date: _____________________________

Total: 35

Duration: 60 Minutes

Learners mark out of 35

Learner’s percentage

Weighting of SBA task

SKILL ASSESSED

Skills for practical work Description Question numberFollow Instructions Give Instructions

Adhere to safety rules

Handle Apparatus Knowledge of apparatus

Improvising apparatus

Handling chemicals/apparatus correctly

Work safely and take precautions

Make observations Make drawings

Measuring (proportions/ratios, scale)

Describing objects/processes

Grouping/Classifying materials

Observing results/features

Comparisons

Record Data Tables

Graphs

Drawings

Descriptions

Measure Reading scales

Scaling

Measuring out quantities

Estimations

Making valid measurements

Supply correct Units

Interpret Converting information

Apply knowledge

Analyse data

Make deductions

Design/plan investigation

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KNOWLEDGE AREA

Tissues, Cells and Molecular Studies

Structure, Control and Processes

Environmental Studies Diversity change and continuity

SPECIFIC OUTCOMES

Knowledge Practical skills Society and Science

Required percentage : 20 % 60 % 20 %

Actual percentage: 23 % 54 % 23 %

TOPIC: ORGANIC MOLECULES: ENZYMES

INSTRUCTIONS

1. Use black/blue ink or black ball-point pen. No pencil answers except for drawings.

2. Answer ALL the questions.

3. Write neatly and legibly

4. All drawings should be done in pencil and labelled in blue or black ink.

5. Draw diagrams or flow charts only when requested to do so.

6. The diagrams in this question paper may not necessarily be drawn to scale.

7. Non-programmable calculators, protractors and compasses may be used.

LEARNER DECLARATION

I confirm that this work was conducted under supervision in class by myself. I confirm that this work is my own.

Signature of learner: Date:

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QUESTION 1.1:

Study the following experiment and answer the questions that follow:

Learners conducted an investigation to determine the effect of an enzyme called pectinase on apple juice production. Pectinases hydrolyses pectin, which is a component of the cell wall. It is useful because pectin is the jelly-like matrix which helps

cement plant cells together and in which other cell wall components, such as cellulose fibrils, are embedded. Therefore, pectinase enzymes are commonly used in processes involving the degradation of plant materials, such as speeding up the

extraction of fruit juice from fruit, including apples.

Experimental set –up:

The learners weighed out 50g of apple pulp in a 100 cm3 beaker and added 2 cm3 pectinase to this pulp. They mixed the pulp for 10 seconds using a glass rod and left it standing then for 5 minutes. The learners then used a filter funnel as shown in the diagram to pour the mixture into a measuring cylinder. They used a timer to track the total volume of apple juice in the measuring cylinder every 5 minutes for the next 30 minutes. The results were recorded in the table below.

Time (minutes) Volume of apple juice (cm3)

0 2.5

5 6

10 12

15 17.5

20 18

25 18

30 18

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1.3.1 Formulate a hypothesis for this investigation.

_____________________________________________________________________________ (2)

1.3.2 What is the dependent variable for this investigation?

_____________________________________________________________________________ (1)

1.3.3 Name THREE fixed/controlled variables for this investigation

___________________________

___________________________

___________________________ (3)

1.3.4 Use the information in the table to draw a line graph of the results on the next page (6)

1.3.5 Describe the results of the investigation

_____________________________________________________________________________ (2)

1.3.6 Explain how you can make this investigation more reliable and accurate

______________________________________________________________________________________

______________________________________________________________________________________

_____________________________________________________________________________________(3)

[17]

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QUESTION 1.2:

Read the information on fruit juice production and answer the questions that follow:

1.2.1 What is biotechnology? _____________________________________________________________________________ (2)

1.2.2 What is the substrate that pectinases work on?

_____________________________________________________________________________ (1)

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The presence of enzymes in food is very common. The use of enzymes in food processing is of the greatest impacts of biotechnology. Enzymes are involved in product development and in the development and enhancing of organoleptic characteristics (aroma, flavour and colour).

There are mainly two groups of enzymes which are used in fruit juice industries namely pectinases and amylases.

Pectinases were of the first enzymes to be used and commercially applied in the processing of juices and wines. Currently these enzymes account for approximately 20% of the worldwide enzyme market and are naturally produced by plants, fungi, yeast and bacteria. Apple juice clarification is affected by pH, temperature, enzyme contact time with the pulp and enzyme concentration. Overall the time required to obtain clarification is inversely proportional to the concentration of the enzymes used at a constant temperature in the range of 5 – 50°C, with treatment time of 2 – 16h. ,

1.2.3 What type of organic molecule is the substrate mentioned in 1.2.2?

_____________________________________________________________________________ (1)

1.2.4 Name TWO industries where pectinases is used.

_____________________________________________________________________________ (2)

1.2.5 What is meant by ‘clarification’ in the juice making industry?

_____________________________________________________________________________ (2)

[8]

QUESTION 1.3:

The line graph below shows the effect of pH on pectinase. Study the graph and answer the questions that follow:

The effect of pH on pectinase activity

1.3.1 What is the optimum pH for pectinase? ___________________________________________ (1)

1.3.2 What is the relative activity of the pectinase at pH 8? ________________________________ (1)

1.3.3 Explain why the enzyme is not working optimally at a pH of 3.

______________________________________________________________________________________

______________________________________________________________________________________

_____________________________________________________________________________________(2)

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The pie chart below shows the industries where enzymes plays a role.

21%

12%

6%3%

21%

15%

9%

6%7%

Chart Title

Pharmaceutical Biotechnology R&DDiagnostic Biocatalyst Food & Beveridge Fabric & householdBiofuelAnimal feedOther industries

1.3.4 What percentage of the industries is dedicated to Food and Beverage? ___________________ (1)

1.3.5 How can enzymes be used in the Food and Beverage industry?

_____________________________________________________________________________ (2)

1.3.6 If the total market value of the industry is R5.8 Billion, how much is the Food and Beverage industry worth?

Show all calculations. (3)

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Biotechnological industries that uses enzymes

Question Analysis GridLife Sciences Gr 10

Task Type : Practical 1 Date: 14 March 2016Educator: Mrs T De Vos

QuestionCognitive Levels

SA1

SA2

SA3

Knowledge Area

Total

A B C D

Enzy

mes

1.1.1 2 2 2 21.1.2 1 1 1 11.1.3 3 3 3 31.1.4 6 6 6 61.1.5 2 2 2 21.1.6 3 3 3 3

01.2.1 2 2 2 21.2.2 1 1 1 11.2.3 1 1 1 11.2.4 2 2 2 21.2.5 2 2 2 2

01.3.1 1 1 1 11.3.2 1 1 1 11.3.3 2 2 2 21.3.4 1 1 1 11.3.5 2 2 2 21.3.6 3 3 3 3

0 0 0

Total Section A: 19 9 7 0 8 19 8 35 35Grand Totals: Actual Marks 19 9 7 0 8 19 8 35 35Actual Percentage 54 26 20 0 23 54 23 100 300Recommended Weighting:

Percentage40%

25%

20%

5%

20%

60%

20% 100%

100%

Marks 14 9 7 2 7 21 7 35 35

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