bio benkj;

FOLIO BIOLOGY PRACT

FORM 5Name :Afiq Danial B. Mohd

Fitri

Matrix No : 29118

Number Activity 4.3 (Experiment)Title Studying the effects of temperature on salivary amylase activityAim To study the effects of temperature on salivary amylase activityProblem Statement

What are the effects of temperature on salivary amylase activity?

Hypothesis The rate of reaction catalysed by salivary amylase is highest at 37˚C / The optimum

temperature for salivary amylase is 37˚CVariables Manipulated variable: Temperature of medium of reaction

Responding variable: The rate of reaction catalysed by salivary amylase Fixed variable: Volume of saliva, volume and concentration of starch

suspension and pH of medium

Material 1% starch suspension Saliva suspension Iodine solution Ice cubes Distilled water

Apparatus Beakers Test tubes Test tube rack Syringes Droppers Glass rods White tile with grooves Thermometer Bunsen burner Tripod stand Wire gauze Stopwatch

Technique used

Test the presence of starch using iodine test Record the time taken for the hydrolysis of starch to be completed.

Procedure 1. The mouth is rinsed with distilled water.2. The saliva suspension is prepared by spitting into a small beaker and

diluting the saliva with an amount of distilled water equal to the amount of saliva.

3. Five water baths are prepared at the following temperatures : 00C, 200C, 37oC, 50oC and 60oC.

4. Two test tubes are labelled P and Q.5. 4 ml of starch suspension are placed in the test tube P and 1 ml of saliva

suspension in test tube Q.6. Both test tubes are placed into the first water bath (at 00C) for 5 minutes.7. A drop of iodine solution is placed into each groove of a clean spotting tile.8. The starch suspension from test tube P is poured into the saliva suspension in

test tube Q. The stopwatch is started immediately.9. A drop of suspension is taken from test tube Q every minute and tested

with iodine solution on the spotting tile.10. Test tube Q is kept in the water bath throughout the experiment.11. The time taken for the complete hydrolysis of starch is recorded in the

table, that is, when the iodine solution does not turn blue anymore.12. Steps 4 to 9 are repeated for temperatures 200C, 37oC, 50oC and 60oC.

Presentation

of dataTemperature

of water bath (oC)

Time taken for complete hydrolysis of starch, t

(minutes)

Rate of reactions,

1/t(minutes)

0 >30 <0.0320 8 0.1337 0.33 350 6 0.1760 >30 <0.03

Conclusion The rate of reaction is highest at the temperature 37oC. The hypothesis is accepted.

Number Activity 4.4 (Experiment)Title Studying the effects of pH on the activity of pepsinAim To study the effects of pH on the activity of pepsinProblem Statement

What are the effects of pH on the activity of pepsin?

Hypothesis An acidic medium at pH 3 is optimum for the activity of pepsinVariables Manipulated variable: pH of medium

Responding variable: Rate of reaction catalysed by pepsin Fixed variable: Volume and concentration of albumen suspension, volume

and concentration of pepsin solution and temperature of medium

Material Egg albumen suspension 1% pepsin solution 0.1 M hydrochloric acid 0.1 M sodium hydroxide solution Distilled water

Apparatus Beakers Test tubes Test tube rack Droppers Glass rod Thermometer 5 ml syringes pH paper Bunsen burner Tripod stand Wire gauze Stopwatch

Technique used

Observe and record the conditions of mixtures before and after 20 minutes

Procedure 1. The egg albumen suspension is prepared by adding 1 g of dried egg albumen to 100 cm3 of water the mixture is then heated to 90oC.

2. Three test tubes are labelled P, Q and R.3. 5 ml of egg albumen suspension and 1 ml of pepsin solution are placed in

each test tube.4. 5 drops of distilled water are added to test tube P.5. 5 drops of dilute hydrochloric acid are added to test tube Q.6. 5 drops of dilute sodium hydroxide solution are added to test tube R.7. All the three test tubes are placed into a water bath at 37oC for 20 minutes.8. The appearance of the contents in each test tube is recorded at the beginning

and at the end of the experiment.9. The contents in each test tube are tested with pH paper.10. The results are recorded in table.

Presentation of data

Test tube

pH ContentsAppearance of contents

At the beginning of the experiment

At the end of the experiment

P 7 Albumen + pepsin + distilled water

White suspension White suspension

Q 2 Albumen + pepsin + dilute hydrochloric acid

White suspension Clear solution

R 9 Albumen + pepsin + dilute sodium hydroxide solution

White suspension White suspension

Conclusion Pepsin catalyses the hydrolysis o protein only in acidic conditions. The hypothesis is accepted.

Number Activity 4.6 (Experiment)Title Studying the effect of enzyme concentration on the activity of salivary amylaseAim To study the effect of enzyme concentration on the activity of salivary amylaseProblem Statement

What are the effects of enzyme concentration on the activity of salivary amylase?

Hypothesis The rate of enzymatic reaction increases with the increase in enzyme concentration as long as there are no other factors limiting the rate of reaction.

Variables Manipulated variable: Enzyme concentration Responding variable: Rate of reaction Fixed: Substrate concentration and temperature

Material 1% starch suspension 0.5% amylase solution / saliva suspension Iodine solution Distilled water

Apparatus 5 ml of syringe 1 ml of syringe White tiles with grooves Test tubes Glass rod Dropper Measuring cylinder Stopwatch Beaker Thermometer Water bath (Bunsen burner, tripod stand and wire gauze)

Technique used

Test for the presence of starch using iodine test Record the time taken for the hydrolysis of starch to be completed with a

stopwatch

Procedure1. The mouth is rinsed with distilled water.2. The saliva suspension is prepared by spitting into a small beaker and diluting

the saliva with an amount of distilled water equal to the amount of saliva.3. Six test tubes are labelled P, Q, R, S, T and U are filled with the following

starch suspensions using different syringes.

Test tubeType of starch suspension

P 4 ml 0.1% starch suspensionQ 4 ml 0.2% starch suspensionR 4 ml 0.3% starch suspensionS 4 ml 0.4% starch suspensionT 4 ml 0.5% starch suspensionU 4 ml 0.6% starch suspension

4. 1 ml of saliva suspension is placed in a test tube.5. A drop of iodine solution is placed into each groove of a clean spotting tile.6. Test tube P and the test tube containing the saliva suspension are placed into a

water bath at 37oC.7. After 5 minutes, the saliva suspension is poured into the starch suspension in

the test tube P. The stopwatch is started immediately.8. A drop of suspension is taken from test tube P every minute and tested with

iodine solution on the spotting tile.9. Test tube P is kept in the water bath throughout the experiment.10. The time taken for the complete hydrolysis of starch is recorded in the table,

that is, when the iodine solution does not turn blue anymore.

11. Steps 4 to 10 are repeated for test tubes Q, R, S, T and U.


Concentration of starch suspension, C(%)

Time taken for the complete hydrolysis of starch, f

Rate of reaction = C/t

(Seconds) (minutes)0.1 300 5.00 0.020.2 300 5.00 0.040.3 300 5.00 0.060.4 300 5.00 0.080.5 375 6.25 0.080.6 450 7.50 0.08

Conclusion The rate of enzymatic reaction increases with the increase in substrate concentration until it reaches a maximum rate. The hypothesis is accepted.

Number Activity 5.4 (Observation)Title Preparing a slide of onion root tip to identify the various stages of mitosisAim To prepare and observe a slide of onion root tip to identify the various stages of

mitosisMaterial Aceto-orcein stain / acetic orcein stain

1 M hydrochloric acid Onion bulb Distilled water

Apparatus Petri dish Watch glass Blade / Scalpel Mounting needles Toothpicks Beaker Bunsen burner Microscope Glass slides Cover slips Filter papers

Technique used

Prepare a slide of onion root tip by using the aceto-orcein stain / acetic orcein stains the chromosomes

Observe the slide of onion root tip to identify the various stages of mitosis by using light microscope.

Procedure 1. About 5mm of the tip of an anion root is cut.2. The root tip is placed in a watch glass containing a mixture of acetic orcein

stain and HCl.3. The watch glass is warmed up for five minutes.4. The stained root tip is then placed on a clean slide.5. The root tip is cut into two. The half which is further from the tip is

discarded.6. Two drops of acetic orcein are then added to the root tip on the slide.7. By using a needle, the tissue in the root tip are spread out as thinly as

possible.8. The slide is covered with a cover slip. Any excess stain is removed by gently

pressing on the cover slip with a piece of filter paper.9. The slide is warmed again for a few seconds to intensify the stain.10. The slide is examined under a light microscope.

Conclusion Different stages of mitosis can be observed in the onion root tip.

Number 6.1 (Observation)Title Determining the energy value in food samplesAim To determine the energy value in food samplesProblem Statement

Which food sample has a higher energy value?

Hypothesis Cashew nut/ Walnut has a higher energy value that goundnutVariables Manipulated variable: Type of food sample

Responding variable: Energy value of food samples Fixed variable: Mass of water and mass of food sample

Material Fresh peanut (whole) Fresh cashew nut / Fresh walnut (whole) Plasticine Cotton wool Distilled water Matches

Apparatus Boiling tube Thermometer (0 – 100˚C) Pin (5 – 8 cm) Bunsen burner Retort stand and clamp Wind shield Electronic balance

Technique used

Measure and determine the energy value in different food samples Compare the energy value in different food samples (groundnut and cashew

nut / walnut) Measure the mass of the different food samples by using electronic balance

Procedure 1. A whole peanut is selected and its weight recorded.2. A clean and dry boiling tube is filled with 20 cm3 of distilled water.3. A boiling tube is clamped to a retort stand.4. The initial temperature of the water in the boiling tube is recorded.5. The peanut is spiked firmly at the end of the pin and mounted on some

plasticine.6. A test tube was moved over the burning peanut and it was positioned so that

the top of the flame first touches the bottom of the boiling tube.7. The water is stirred gently with the thermometer.8. The final temperature (the highest temperature reached) is recorded as soon

as the peanut has stopped burning.9. The energy value of the peanut is calculated based on the following formula:

Energy value = Mass of water (g) x increases in temperature ( o C) x 4.2 (J g -1 o C) Mass of peanut (g)

10. The procedure was repeated using a cashew nut.


Food sampleGroundnut Cashew nut

Initial temperature of water (oC)

27 27

Final temperature of water (oC)

45 90

Difference in temperature (oC)

18 63

Mass of water (g) 20 20Mass of nut (g) 0.5 1.2

Number Activity 6.3 (Experiment)Title Determining the vitamin C content in various fruit juicesAim To determine the vitamin C content in various fruit juicesProblem Statement

Do different types of fruit juices contain similar amounts of vitamin C?

Hypothesis Lime juice contains a higher concentration of vitamin C compared to pineapple juice and orange juice.

Variables Manipulated variable: Types of fruit juices Responding variable: Volume of fruit juice needed to decolourise DCPIP solution Fixed variable: Volume of DCPIP solution and standard concentration of ascorbic

acid solution

Material 1.0% dichlorophenolindophenol (DCPIP) solution 0.1% ascorbic acid solution Freshly prepared lime juice Freshly prepared pineapple juice Freshly prepared orange juice

Apparatus Specimen tubes

1 ml syringe 5 ml syringes with needles 50 ml beakers Gauze cloth Knife / Scalpel

Technique used

Measure and determine the volume of standard vitamin C solution needed to decolourise of a fixed volume of DCPIP.

Measure and determine the volume of juice needed to decolourise the same volume of DCPIP.

Calculate the vitamin C content of juice by comparing it with the standard vitamin C solution.

Procedure 1. Four specimen tubes are labelled as A, B, C and D.2. 1 ml of DCPIP is placed in each specimen tube.3. A syringe is filled with 5 ml of ascorbic acid solution.4. The needle of the syringe is immersed in the DCPIP solution as shown in the figure above.5. The ascorbic acid solution is added drop by drop to the DCPIP solution and the tube is

shaken gently.

CAUTION : The test tube should not be shaken vigorously.

6. The amount of ascorbic acid solution used to decolourise DCPIP solution is recorded.7. Steps 1 to 6 are repeated using lime juice, pineapple juice and orange juice.8. The percentage and concentration of vitamin C in the three types of fruit juices are

calculated using the formulae below:

Percentage of vitamin C in fruit juice = volume of 0.1% ascorbic acid solution × 0.1 % Volume of fruit juice used

Concentration of vitamin C in fruit juice = volume of 0.1% ascorbic acid solution × 1.0 mg cm-3

Volume of fruit juice used


Solution/fruit juice

Volume of solution or fruit juice needed to

decolourise 1 ml of DCPIP solution

Percentage of vitamin C in fruit (%)

Vitamin C concentration in

fruit juice (mg cm-3)

1 2 3 Average0.1% ascorbic acid

1.0 1.0 1.0 1.0

Lime juice 2.5 2.6 2.4 2.5 1.0 × 1.02.5= 0.04%

1.0 × 1.02.5= 0.40 mg cm-3

Pineapple juice 3.6 3.6 3.5 3.6 1.0 × 1.03.6= 0.03%

1.0 × 1.04.9= 0.30 mg cm-3

Orange juice 5.0 5.1 5.2 5.2 1.0 × 1.05.2= 0.01%

1.0 × 1.05.2= 0.19 mg cm-3

Conclusion Lime juice has a higher vitamin C content ( 0.40 mg cm-3) compared to pineapple juice (0.30 mg cm-3) and orange (0.19 mg cm-3).

Number Activity 6.4 (Experiment)Title Planning and conducting an experiment to study enzyme action on starchAim To study enzyme action on starchProblem Statement

How does the enzyme in saliva act on starch?

Hypothesis The enzyme is saliva digest starch into a reducing sugar / The enzyme in saliva hydrolyses starch into a reducing sugar

Variables Manipulated variable: Absence or presence of salivary amylase and starch Responding variable: Presence of reducing sugar Fixed variable: Temperature at 37˚C, starch concentration and volume of

mixture

Material 1% starch suspension Benedict’s solution Iodine solution Saliva suspension Distilled water

Apparatus 10 ml pipette 500 ml beaker Test tubes Test tube holder Test tube rack

Thermometer Droppers Glass rod White tile Bunsen burner Tripod stand Wire gauze

Technique used

Confirmation test for the presence of starch using iodine solution Confirmation test for the presence of reducing sugar using Benedict’s solution

Procedure 1. The mouth of the student is rinsed with water and 2 ml of saliva is collected in a beaker and diluted with 2 ml of distilled water.

2. 1 ml of diluted saliva is poured into a test tube. The presence of starch is tested.3. 1 ml of diluted saliva is poured into another test tube. The presence of reducing sugar

was tested.4. Step 2 and 3 are repeated using starch suspension.5. A water bath is prepared by using a Bunsen burner to heat some water in a beaker on

a tripod and gauze till its boils, then the flame is turn down to keep the water just boiling. While waiting for the water to boil, three test tube are labelled A, B and C.

6. 1 ml of saliva is put into test tubes A and C, 1ml of distilled water is put into test tubes B and C and 5ml of starch suspension is added to test tubes A and B.

7. Test tube C is heated in a beaker of boiling water for 5 minutes.8. All the test tubes are immersed in the water bath of 37oC for 30 minutes.9. After 30 minutes, an iodine test and a Benedict’s test are carried out on the contents

in test tubes A, B and C.

Test tube ContentsA 1 ml starch + 1 ml salivaB 1 ml starch + 1 ml distilled waterC 1 ml saliva + 1 ml distilled water

Presentation of data Test Content Observation

Iodine test Starch suspension Dark blueSaliva Yellowish brown

Benedict’s test Starch suspension Blue solutionSaliva Blue solution

Test Test tube ObservationIodine test A (1 ml starch + 1 ml saliva) Yellowish brown

B (1 ml starch + 1 ml distilled water) Dark blueC (1 ml saliva + 1 ml distilled water) Dark blue

Benedict’s test A (1 ml starch + 1 ml saliva) Brick-red precipitateB (1 ml starch + 1 ml distilled water) Blue solutionC (1 ml saliva + 1 ml distilled water) Blue solution

Conclusion The enzyme in saliva that is salivary amylase digest starch into a reducing sugar. Hypothesis is accepted.

Number Activity 6.5 (Experiment)Title Planning and conducting an experiment to study the enzyme action on a protein food

sampleAim To study the enzyme action on a protein food sampleProblem Statement

How does the enzyme acts on protein?

Hypothesis The test tube contains albumen and pepsin solution becomes clear at the end of the experiment

An acidic medium is needed for protein digestion by pepsin

Variables Manipulated variable: Absence or presence of pepsin in albumen Responding variable: Cloudy or clear (clarity of contents) albumen

suspension after 20 minutes Fixed variable: Concentration and volume of albumen, concentration and

volume of pepsin (enzyme), concentration of hydrochloric acid, surrounding temperature at 37˚C

Material Albumen (egg-white) suspension Dilute hydrochloric acid Pepsin suspension Distilled water

Apparatus 10 ml pipette 500 ml beaker

Test tubes Test tube rack Droppers Thermometer Stopwatch Water bath (Bunsen burner, tripod stand and wire gauze)

Technique used

Observe albumen digestion under the presence or the absence of pepsin and hydrochloric acid.

Procedure 1. Four test tubes are labelled A-D.2. About 5 cm3 of albumen suspension are placed into each test tube.3. Three drops of dilute hydrochloric acid are added to test tube B, C and D.4. 1 cm3 of 1% pepsin solution is placed into a clean test tube by using a graduated

pipette and it is heated over a small Bunsen flame until the liquid boils. The boiled pepsin is added to the egg-white suspension in test tube D.

5. A water bath of temperature 4ooC is prepared by using a 250 cm3 beaker and the beaker is filled with water until it is half full.

6. 1 cm3 of 1% pepsin is added to test tubes 1 and 3 only by using a graduated pipette.7. All the four test tubes are placed in the water bath.8. The four test tubes are removed from the water bath after five or six minutes and they

are placed in a test tube rack. The appearances of the contents are noted and compared.

Presentation of data Test

tubeContents Results

Start of experiment

End of experiment

A Albumen + pepsin Cloudy ClearB Albumen + HCl Cloudy CloudyC Albumen + pepsin + HCl Cloudy CloudyD Albumen +boiled pepsin +

HClCloudy Cloudy

Conclusion Digestion of protein by pepsin takes place in an acidic medium. The hypothesis is accepted.

Number Activity 6.7 (Observation)Title Studying the movement of substances through the Visking tubingAimProblem Statement

What substances can move across the Visking tubing?

Hypothesis Small molecules can move across the Visking tubingVariables Manipulated variable: Contents of the Visking tubing

Responding variable: Change in colour of water sample in iodine test and Benedict’s test

Fixed variable: Temperature of water bath (37˚C), volume of solution

Material 1% starch suspension 1% glucose solution Iodine solution Benedict’s solution Visking tubing Thread Distilled water

Apparatus Boiling tube Test tubes 10 ml syringe Pipette A pair of scissors Water bath (Bunsen burner, tripod stand and wire gauze)

Technique used

Confirmation test for the presence of starch using iodine solution Confirmation test for the presence of reducing sugar using Benedict’s solution

Procedure 1. A beaker full of water is warmed to 35oC.2. A knot is tied in one end of the visking tubing, by wetting it, spinning it and then

tying it.3. 2 ml of saliva and 8 ml of starch suspension are one Visking tubing and put into a

boiling tube of warm water labelled as A. As for the boiling tube labelled as B, 2 ml of distilled water and 8 ml of starch suspension are added to the Visking tubing.

4. The other end of the Visking tubing are then tied carefully.5. The outside of the Visking tubing are rinsed with tap water to remove all traces of

starch and saliva.6. Immediately, a dropper is used to withdraw two samples of water from boiling tube

A.7. The Iodine test and Benedict’s test are carried out on the two samples of water.8. The observation are recorded.9. Steps 6 to 7 are repeated for boiling tube B.10. After 30 minutes, two water samples are taken from each set. The iodine test and

Benedict’s test are carried out on the water samples.11. The observation are recorded.


Boiling tube

Beginning of the experiment After 30 minutesIodine test Benedict’s test Iodine test Benedict’s test

A Yellowish brown

Blue solution Yellowish brown

Brick-red precipitate

B Yellowish brown

Blue solution Yellowish brown

Blue solution

Conclusion Starch needs to be broken down into smaller molecules of reducing sugars to enable them to move across the Visking tubing. The hypothesis is accepted.

Number Activity 6.8 (Experiment)Title Studying the effects of macronutrient deficiency in plantsAim To study the effects of macronutrient deficiency in plantsProblem Statement

What are the effects of macronutrient deficiency in plants? / Do macronutrient deficiency have any effects on plant growth and development?

Hypothesis Plant grows healthily in a complete Knop’s solution Macronutrient deficiencies affect plant growth and development.

Variables Manipulated variable: Components of minerals in culture solution Responding variable: Growth of the seedling / Condition of the plants Fixed variable: Volume and concentration of solution, size and type of maize

seedlings, amount of air that is pumped into the jar, amount of sunlight, surrounding temperature

Material Maize seedlings Potassium nitrate (KNO3) Potassium dihydrogen phosphate (KH2PO4) Magnesium sulphate (MgSO4) Calcium nitrate (Ca(NO3)2) Ferum(III) phosphate (FePO4) Cotton wool Black paper Distilled water

Apparatus Glass jars Rubber bungs with holes Straight glass tubes to fit into the holes of the rubber bungs L-shaped delivery tubes to the connected to a vacuum pump

Knife

Technique used

Observe the effects of different deficiencies on young maize seedling. Maize seedling are under identical conditions of light, temperature and

moisture.

Procedure 1. Eight glass jars labelled and filled and filled with culture solution of the following composition.

2. Eight seedlings of the same size are selected. One maize seedling is placed in each rubber bung of a gas jar, with its roots in the culture solution.

3. A right-angled glass tube is placed in another hole in the rubber bung. Air must be blown through the right-angled tubes daily to provide oxygen to the roots for respiration.

4. All the glass are wrapped with black papaer and they are placed in a condition where all the seedlings received an equal amount of sunlight.

5. Distilled water is used to top up the solution from time to time.6. Air is pumped into the solution using in air pump.7. The culture solution is changed once a week.8. The growth of each seedling is observed at the end of one month.9. The colour, number, size and shapes of leaves, height of seedling, length of roots, the

growth of branches and the strength of the stems are observed and recorded in a table.


Jar

Deficient in Observation

A All elements (distilled water) No growth Death of seedling

B None macronutrients (knop’s solution)

Normal and healthy growth

C Nitrogen Stunted growth Yellowing of leaving

D Phosphorus Stunted growth Roots not well-developed Leaves dark green in colour with red

spots Premature leaf fall-off

E Sulphur Roots not well-developed Leaves pale in colour

Glass far Components of each jar

Calcium nitrate (0.8 g)

Potassium nitrate (0.2 g)

Potassium dehydration phosphate

(o.2 g)

Magnesium sulphate

(0.2 g)

Ferum(II) phosphate (0.2 g)

Distilled water (1000 cm3)

A (distilled water)

No No No No No Yes

B (complete Knop’s solution)

Yes Yes Yes Yes Yes Yes

D (Deficient in phosphate)

Replaced with calcium chloride

Replaced with potassium chloride

Yes Yes Yes Yes

E (Deficient in sulphur)

Yes Yes Replaced with potassium chloride

Yes Replaced with ferum (II) oxide

Yes

F (Deficient in potassium)

Yes Replaced with sodium nitrate

Replaced with calcium phosphate

Yes Yes Yes

G (Deficient in calcium)

Replaced with sodium nitrate

Yes Yes Yes Yes Yes

H (Deficient in magnesium)

Yes Yes Yes Replaced with potassium phosphate

Yes Yes

F Potassium Yellowing of leaving Soft and tender stem Withering of leaf edges and tips

G Calcium Stunted growth Leaves with irregular shapes Death of apical buds Yellowish leaf edges

H magnesium Stunted growth Leaves pale and yellow Yellow spots

Conclusion Plants need various macronutrients for a healthy growth. The hypothesis is accepted.

Number Activity 6.11 (Experiment)

Title Investigating the effect of light intensity on the rate of photosynthesisAim To investigate the effect of light intensity on the rate of photosynthesisProblem Statement

How does light intensity affect the rate of photosynthesis?

Hypothesis The higher the light intensity, the higher the rate of photosynthesisVariables Manipulated variable: Distance between light source and plant

Responding variable: Number of bubbles released in five minutes (rate of photosynthesis)

Fixed variable: Type and size of plant, percentage of sodium hydrogen carbonate solution and voltage of bulb

Material A few sprigs of Hydrilla sp. 1% sodium hydrogen carbonate solution Plasticine Distilled water

Apparatus Light source (60 W bulb) 500 ml beaker Test tube Glass filter funnel Stopwatch Thermometer Meter rule Razor

Technique used

Count the number of gas bubbles released in five minute with a stopwatch

Procedure 1. A piece of well-illuminated Hydrilla sp. about 10 cm long which already has bubbles emerging from it is choosen. A clean oblique cut with a sharp razor blade is made near the lower end of the stem, under water. One may have to cut the end of the stem several times until bubbles emerge rapidly.

2. The plant is placed, bubbling end upwards, in a test tube containing the same water that the pondweed has been kept in.

3. Sodium hydrogen carbonate solution is used for supply carbon diooxode to the plant.4. The test tube is put to stand in a beaker of water to reduce temperature fluctuation

during the experiment and the temperature is checked from time to time to make sure that it is room temperature (28oC).

5. A light source is placed 50 cm away facing the test tube.6. The light source is powered on and observations were made. A one minute bubble

count is made when the rate of bubbles given is constant.7. The sodium hydrogen carbonate solution in the beaker is replaced with fresh solution.8. Steps 5 to 6 are repeated by putting the bench lamp at different distances of 40 cm, 30

cm, 20 cm and 10 cm from the test tube. The results are recorded.

Presentation of data Distance from the light

source, d (cm)Light intensity (1/d) Number of gas bubbles

released per minute10 0.1 2020 0.05 1530 0.33 1140 0.025 750 0.02 3

Conclusion The rate of photosynthesis increases with the increases in light intensity but is limited by the concentration of carbon dioxide. The hypothesis is accepted.

Number Activity 7.2 (Experiment)Title Investigate the process of anaerobic respiration in yeastAim To investigate the process of anaerobic respiration in yeastProblem Statement

What are the products of fermentation?

Hypothesis In the absence of oxygen, yeast undergoes anaerobic respiration to produce carbon dioxide, ethanol and energy

Variables Manipulated variable: Presence of yeast Responding variable: Changes on lime water and temperature Fixed variable: Anaerobic condition

Material 5% yeast suspension 5% glucose solution Paraffin oil Lime water

Apparatus Boiling tubes Test tubes Thermometers Stoppers with delivery tubes Measuring cylinders Beaker

Technique used

Record and measure the changes in temperature with thermometers. Observe the change in lime water.

Procedure 1. Water is boiled for 15 minutes to removed all the dissolved oxygen.2. Two boiling tubes are filled with the boiled water, and then they were allowed to

cool to 25oC in sealed flasks (they are sealed to prevent oxygenation).3. 5 ml of yeast suspension is poured into a boiling tube A and 15 ml of boiled glucose

solution is added.4. Boiling tube B is filled with 15 ml of boiled glucose solution only.5. A thin layer of paraffin oil is added on the surface of the water in each of the boiling

tubes (the water remains deoxygenated by preventing contact with air).6. Each boiling tube is connected via a delivery tube to a test tube containing lime

water.7. The initial temperatures of the contents of the boiling tubes A and B are recorded.8. The set-up is left for one hour.9. After one hour, the final temperatures are recorded and the change in the appearance

of the lime water is recorded.10. The stoppers are removed and the gas that comes out of the boiling tubes is smelled.11. The results are recorded in a table.


Boiling tube A BInitial

observationFinal

observationInitial

observationFinal

observationTemperature

(oC)27 30 27 27

Lime water Clear Milky Clear ClearSmell No smell Smell of ethanol No smell No smell

Conclusion Yeast produces carbon dioxide in the absence of oxygen and, therefore, yeast respires anaerobically. The hypothesis is accepted.

Title Constructing a model of the rib cage to demonstrate the actions of the intercostals muscles and ribs

Aim To construct a model of the rib cage to demonstrate the actions of the intercostals muscles and ribs

Material Plywood Nails Rubber bands

Apparatus -Technique used

Construct a model of the rib cage Study and demonstrate the actions of the intercostals muscles and ribs

Procedure 1. The model is constructed.

Rib cage model Human respiratory structuresRubber band X External intercostal musclesRubber band Y Internal intercostal musclesPlywood P Breast bone/sternumPlywood Q RibPlywood R RibPlywood S Backbone

2. When each of the rubber band is contracted, the movement of the polywood pieces is observed and recorded.


Procedure ObservationRubber band X Plywood P is pushed upwardsRubber band Y Plywood P is pulled downwards

Conclusion The activity of the intercostals muscles complements that of the diaphragm in the breathing mechanism.

Number Activity 7.8 (Experiment)Title Studying the effects of vigorous exercise on the breathing and heartbeat ratesAim To study the effects of vigorous exercise on the breathing and heartbeat ratesProblem Statement

What is the effect of vigorous exercise on the breathing and heartbeat rates?

Hypothesis Vigorous exercise increases the breathing and heartbeat ratesVariables Manipulated variable: Resting or vigorous exercise

Responding variable: Breathing rate and heartbeat rate Fixed variable: The type and duration of exercise, gender and age of the

students

Material -Apparatus Stopwatch

Technique used

Count and record the number of breaths per minute and the number of heartbeats per minute

Procedure 1. The experiment is carried out in pairs with your partner sitting on a chair for 5 minutes.

2. The rate of breathing is measured by putting your palm on your partner’s rib cage for 1 minute. The value is recorded in a table.

3. The rate of heartbeat is measured by putting your fingers on your partner’s wrist. The value is recorded in the table.

4. Steps 2 to 3 are repeated twice.5. Your partner is allowed to run around for 5 minutes.6. Steps 2 to 4 are repeated.

Presentation of data Rate

Situation

Breathing rate (breath per minute)

Heartbeat rate (beat per minute)

1 2 3 Average 1 2 3 AverageAt rest 14 13 15 14 70 68 69 69After vigorous exercise

32 31 30 31 110 108 109 109

Conclusion Vigorous exercise will increase the rate of breathing and the rate of heartbeat. The hypothesis is accepted.

Number Activity 7.9 (Experiment)Title Demonstrating the effects of cigarette smoke on lungsAim To show the effects of cigarette smoke on lungsProblem Statement

What are the effects of cigarette smoke on lungs?

Hypothesis Cigarette smoke corrodes the cotton wool to change colour and contains acidic gas.Variables -Material Cotton wool

Universal indicator Cigarettes

Apparatus U-tube Thermometer Boiling tube Retort stand and clamp Filter pump Rubber tubing

Technique used

Observe the effect of cigarette smoke on lungs and increases the temperature of the respiratory tract. Tobacco tar makes the lungs appear brownish.

Procedure 1. The apparatus is set up.2. The colour and smell of the cotton wool and the colour of universal indicator are

observed and recorded.3. The initial temperature of the air in the U-tube is measured using a thermometer and

recorded.4. The cigarette is lighted and the filter pump is switched on to draw smoke to the wet

cotton wool and through the universal indicator.5. The change in colour and smell of the cotton wool and the colour change of the

universal indicator are observed as the cigarette burns until the end.

Presentation of data Effects Before After

Colour and smell of cotton wool

Clear, white and no smell Brown, very strong nicotine smell

Colour of universal indicator

Green Yellow

Temperature of the air in the U-tube (oC)

28 (room temperature) 33

Conclusion Cigarette smoke contains tar which change the colour of the lungs to brown and it also contains nitrogen dioxide which is acidic. The hypothesis is accepted.

Number Activity 8.3 (Experiment)Title Studying the intraspecific and interspecific competitions in plantsAim To study the intraspecific and interspecific competitions in plantsProblem Statement

How do intraspecific and interspecific competitions affect the growth of maize and rice plants?

Hypothesis Intraspecific competition occurs between plants of the same species. Interspecific competition occurs between plants of different species. / The greater the competition among the seedlings, the greater the effect on the height of the seedlings.

Variables Manipulated variable: Types of seedlings Responding variable: Dry mass of seedlings / Height of seedling Fixed variable: Quantity and types of garden soil, amount of water, intensity

of sunlight, distance between each seedling and number of seedlingsMaterial Three seedling trays (2 m x 1 m each) with garden soil

A packet of maize seeds A packet of paddy seeds Distilled water

Apparatus Ruler Oven Compression balance Spade Waterproof paint Paintbrush

Technique used

Weight the dry mass of seedling with an electronic balance / Measure the height of seedling with a ruler

Procedure 1. Three seedling plots are prepared with each measuring 2m by 1m.2. The seeds are sowed with the distance of 5 cm between each seed.3. The seeds in each plot are watered daily and left to germinate and grow.4. After 30 days, 10 paddy plants are picked at random and removed from

plot A. The plants are washed to remove the the soil from the roots. The plants are then dried in an oven at 100-104 degree Celcius to obtain the average dry mass.

5. Step 4 is repeated for plots B and C (10 paddy plants and 10 maize plants).

Observation Plot Average dry mass of plants (g)Paddy Maize

A 23.5 -B - 29.7C 22.8 32.6

Conclusion1. The hypothesis is accepted. Paddy plants that grow together in plot A

shows intraspecific competition where the stronger ones are growing well while the weaker plants are dying.

2. In plot B, the stronger maize plants survive and grow, showing intraspecific competition.

3. In plot C, the maize plants and the paddy plants show interspecific competition. The maize plants survive and win in the competition.

Number Activity 8.5 (Field study)Title Investigating the distribution of plants (Mimosa pudica) using the quadrat sampling

techniqueAim To investigate the distribution of plants using the quadrat sampling techniqueMaterial String

NailsApparatus A quadrat measuring 1 m x 1 m

Pen Notebook

Technique used

Quadrat sampling technique

Procedure 1. An area of study in the school field is selected.2. Ten quadrats of 1 m × 1 m are placed randomly in the school field with each

quadrat subdivided into 100 small squares of 0.1 m × 0.1 m each.3. The number of Mimosa pudica in each quadrat is counted and recorded.4. An area covered is counted as 1 square grid if the area covered is more than

half the size of the square grid. The number of squares ia then multiplied by 0.01 m² to get the total coverage in each quadrat.

5. The results are tabulated. The density, percentage frequency and percentage coverage of Mimosa pudica are calculated.

Results Quadrat 1 2 3 4 5 6 7 8 9 10Area covered (m²) 0.3 0.4 1 0.

10.2 0.2 0.1 0 0.

40.3

Number of individual 5 7 0 2 3 2 1 0 6 4

Density = 5+7+2+3+2+1+6+4

10×1

= 30

10

= 3 individuals per m²

Percentage frequency = 8 × 100

10

= 80%

Percentage coverage = 0.3+ 0.4 + 0.1 + 0.2 + 0.2 + 0.1 + 0.4 0.3 × 100

10×1

= 2 × 100

10

= 20%

Conclusion 1. The density of Mimosa pudica is 3 individuals per m².2. The percentage frequency of Mimosa pudica is 80%.3. The percentage coverage of Mimosa pudica is 20%.

Title Estimating the population size of garden snails using capture, mark, release and recapture technique

Aim / Objective of the Study

To estimate the population size of garden snails using capture, mark, release and recapture technique

Material A bottle of Indian ink / A non-poisonous and waterproof ink

Apparatus Hammer Paintbrush Pen Notebook

Technique used

Capture, mark, release and recapture technique

Procedure 1. An area in the field was chosen as the place for the field study.2. A large number of garden snails were caught in the first sample and the

number was recorded as x.3. Each garden snail that was caught and marked on its shell using India ink.4. All the garden that were caught and marked were then set free.5. After 3 days, the garden snails were caught again at random in the same

place for field study. The number of garden snails caught in the second sample was recorded as y.

6. From the second sample caught, the number of garden snails that were marked were counted and recorded as z.

7. The population size of garden snails was estimated by using the following formula:

X = number caught in the first sampleY = number caught in the second sampleZ = number marked in the second sample

Population size = xy ÷z

ResultNumber of garden snails

Estimated population

Number caught in first

sample

Number caught in the second sample

Number caught

Number marked

x y z xy ÷ z

Steps to increase the accuracy of the experiment1. Each sample must be caught at random.2. Number in each sample must be large.3. The marking on each garden snail should

Not be dangerous/poisonous Be waterproof

Not hinder the movement of the animal Not course the snail easily detected by the predator

Conclusion

The population size of garden snails is estimated by using the capture-mark-release and recapture method.

Number Activity 8.7 (Experiment)Title Studying the relationship of population distribution of an organism with the

changes of an abiotic factorAim To study the relationship of population distribution of an organism with the

changes of an abiotic factorIntroduction

Pleurococcus sp. is a unicellular green alga found on the bark of trees. The population distribution of Pleurococcus sp.is affected by abiotic factors such as humidity, temperature, light intensity and aspect.

Objective of the Study

To investigate the effect of light intensity on the population distribution of Pleurococcus sp. in its habitat.

Problem Statement

What is the effect of light intensity on the population distribution of Pleurococcus sp.?

Hypothesis The population distribution of Pleurococcus sp. is highest when there is optimum light intensity

Variables Manipulated variable: Light intensity Responding variable: Total surface are covered by Pleurococcus sp. Fixed variable: Temperature, pH and humidity

Material Paper Pen Notebook

Apparatus Quadrat measuring 10 cm x 10 cm A compass

Technique used

Quadrat sampling (estimate the total surface area covered by Pleurococcus sp.)

Procedure 1. A tree with pleurococcus sp. On its bark is identified.2. Five quadrat of size 10 cm × 10 cm are used and each quadrat is

labelled as P,Q,R,S and T.3. The quadrats are placed at the different aspects of the tree trunk:

a) Quadrat P on the tree trunk facing North (N)b) Quadrat Q on the tree trunk facing North East (NE)c) Quadrat R on the tree trunk facing South (S)d) Quadrat S on the tree trunk facing West (W)e) Quadrat T on the tree trunk facing East (E)

4. The total surface area covered by Pleurococcus sp. at different aspects is counted and recorded. Only squares which are covered by half or more than half are counted.

5. A bar chart of the population of Pleurococcus sp. and the quadrats is drawn.

ResultsAspect Total surface covered by Pleurococcus sp. (cm²)North 31

North East 48South 16West 22East 25

North North East

South West East0

20

40

60

Total surface covered by Pleu-rococcus sp. (cm²) against posi-

tion of quadrat on the tree trunk Total surface covered

by Pleurococcus sp. (cm²) against position of quadrat on the tree trunk

Conclusion The population distribution of Pleurococcus sp. is higher when light intensity is optimum for the growth of Pleurococcus sp. the hypothesis is accepted.

Number Activity 8.11 (Experiment)Title Studying the effects of temperature, pH, light intensity and nutrients on

the activity of yeastAim To study the effects of temperature, pH, light intensity and nutrients on

the activity of yeast.Objective of the Study

A) To study the effect of temperature on the activity of yeast.

Problem Statement

What is the effect of temperature on the activity of yeast?

Hypothesis The activity of yeast is optimal at 37˚CVariables Manipulated variable: Temperature of the water bath

Responding variable: Height of the coloured liquid in the manometer Fixed variable: Volume of yeast suspension, pH, light intensity and

time taken for the activity of yeastMaterial Yeast suspension (4 g of yeast in 100 cm3 of glucose solution)

Coloured liquid Ice cubes

Apparatus Boiling tubes Beakers Measuring cylinders Glass tubes Thermometers Clips Rubber stoppers Rubber tubing Manometer tubes Strings Ruler Stopwatch Water bath (Bunsen burner, tripod stand and wire gauze)

Technique used Measure and record the different heights of coloured liquid in the manometer with a ruler.

Procedure 1. Three boiling tubes are labelled as A,B and C.2. 10 ml of yeast suspension and 10 ml of glucose

solution are poured into each boiling tube.3. The apparatus is set up.4. The condition of the lime water is observed after

10 minutes.

ObservationsBoiling tube Temperature Condition of lime water

A 10 ClearB 35 CloudyC 70 Clear

Conclusion The activity of yeast is at optimum level at 35ºC. The hypothesis is accepted.


B) To study the effect of pH on the activity of yeast.

Problem Statement

How does pH affect the activity of yeast? / What is the effect of different pH values in the activity of yeast?

Hypothesis The activity of yeast is optimum in an acidic medium.Variables Manipulated variable: pH

Responding variable: Height of the coloured liquid in the manometer Fixed variable: Volume of yeast suspension, light intensity,

temperature and time takenMaterial Yeast suspension (4 g of yeast in 100 cm3 of glucose solution)

0.1 mol dm-3 hydrochloric acid 0.01 mol dm-3 hydrochloric acid 0.1 mol dm-3 sodium hydroxide solutions 0.01 mol dm-3 sodium hydroxide solutions Coloured liquid pH paper distilled water

Apparatus Boiling tubes Beakers Measuring cylinders Glass tubes Clips Rubber stoppers Rubber tubing Manometer tubes Strings Ruler Stopwatch Retort stand


Procedure 1. The boiling tubes are labelled A, B and C.2. The following contents are added to boiling tubes A, B and C

respectively.

Boiling tube ContentsA 10 ml of yeast suspension, 10 ml of

glucose solution, 2 ml of dilute hydrochloric acid.

B 10 ml of yeast suspension, 10 ml of glucose solution, 2 ml of sodium hydroxide solution.

C 10 ml of yeast suspension, 10 ml of glucose solution, 2 ml of distilled water.

3. The contents of each boiling tube are shaken and the pH value is determined using pH paper.

4. The apparatus is set up.5. The condition of the lime water is observed after 10 minutes.

Conclusion The activity of yeast is at optimum level in an acidic medium. The hypothesis is accepted.


C) To study the effect of light intensity on the activity of yeast.

Problem Statement

How does the intensity of light affect the activity of yeast? / What is the effect of light intensity on the activity of yeast?

Hypothesis The activity of yeast is higher at a lower intensity of light. / The lower the light intensity, the higher the activity of yeast.

Variables Manipulated variable: Intensity of light Responding variable: Height of coloured liquid in the manometer Fixed variable: Volume of yeast suspension, pH, temperature and

time takenMaterial Yeast suspension (4 g of yeast in 100 cm3 of glucose solution)

Coloured liquidApparatus Light bulb (60W)

Boiling tubes Beakers Measuring cylinders Glass tubes Clips Rubber stoppers Rubber tubing Manometer tubes Strings Ruler Stopwatch Retort stand


Procedure 1. Five boling tubes are labelled as A, B, C, D, and E.2. 10 ml of yeast suspension and 10 ml of glucose solution are put

into each boiling tube.3. Five sets of apparatus are set up.4. A light source is set up at a distance of 10 cm from set A, 20 cm

from set B, 30 cm from set C, 40 cm from set D and 50 cm from set E.

5. The time taken for the lime water to turn cloudy is recorded.Results

Boiling tube

Distance from light source

(cm)

Light intensity

( 1÷distance)

Time taken for lime water to turn cloudy

(minutes)A 10 0.100 12B 20 0.050 9C 30 0.033 5D 40 0.025 3E 50 0.20 2

Conclusion The activity of yeast increases when light intensity decreases. The hypothesis is accepted.


D) To study the effect of nutrients on the activity of yeast.

Problem Statement

How do nutrients affect the activity of yeast? / What is the effect of nutrients on the activity of yeast?

Hypothesis The concentration of nutrients affects the activity of yeast. / The higher the concentration of nutrients, the higher the activity of yeast.

Variables Manipulated variable: Concentration of nutrients Responding variable: Height of coloured liquid in the manometer Fixed variable: Volume of yeast suspension, pH, light intensity and

temperatureMaterial Dry yeast

5% glucose solution 10% glucose solution

15% glucose solution Distilled water

Apparatus Boiling tubes Beakers Measuring cylinders Glass tubes Clips Rubber stoppers Rubber tubing Manometer tubes Strings Stopwatch Retort stand


Procedure 1. Five boiling tubes are labelled as A, B, C, D and E.2. Each boiling tube is filled as given below.

Boiling tube

Contents

A 10 ml of yeast suspension + 10 ml of distilled waterB 10 ml of yeast suspension + 10 ml of 5% glucose

solutionC 10 ml of yeast suspension + 10 ml of 10% glucose

solutionD 10 ml of yeast suspension + 10 ml of 15% glucose

solutionE 10 ml of yeast suspension + 10 ml of 20% glucose

solution3. The apparatus is set up.4. Each boiling tube is placed in a water bath at temperature 35ºC.5. The time taken for the lime water to turn cloudy is recorded.

ResultsBoiling

tubeConcentration of

glucoseTime taken for lime water to

turn cloudy (minutes)A 0 Remains clearB 5 7C 10 5D 15 3E 20 2

Conclusion When the concentration of nutrients increases, the activity of yeast increases. The hypothesis is accepted.

Number Activity 9.1 (Experiment)Title Comparing solid pollutants in the air of different environmentsAim / Objective of the Study

To compare solid pollutants in the air of different environments

Problem Statement

Does the air of different environments contain the same amount of solid pollutants?

Hypothesis The air of different environments does not contain the same amount of solid pollutants. / The air from the most polluted environment has the highest amount of solid pollutants.

Variables Manipulated variable: Air from different environments Responding variable: Amount of solid pollutants present Fixed variable: Time and size of cellophane tape

Material Cellophane tape

Apparatus Slides Petri dish Microscope

Technique used

Observe the amounts of solid pollutants with a microscope

Procedure 1. Five glass slides are cleaned, dried and labelled as P, Q, R, S and T.2. A piece of cellophane tape is sticked on each slide as shown in figure 9.6.3. Slide P is kept in a covered Petri dish.4. The other slides are put in the following places.

Q : in a classroomR : in the canteenS : in an air-conditioner roomT : Tied to the school gate

5. All the slides are left aside and collected after three days. They are observed under a microscope.

Conclusion The area in an air-conditioned room is the least polluted. The area around the school gate is the most pollute as it shows the most pollutants. The hypothesis is accepted.

Number Activity 9.2 (Experiment)Pg. 128Title Investigating the level of pollution in several different sources of waterAim / Objective of the Study

To investigate the level of pollution in several different sources of water. Industrial area Housing area From the hill / river Distilled water (control)

Problem Statement

What is the level of pollution in several different sources of water?

Hypothesis The water sample from the housing area drainage is the most polluted.Variables Manipulated variable: water samples from different sources.

Responding variable: Time taken for methylene blue solution to decolourise Fixed variable: Volume of water sample, size of reagent bottles, concentration

and volume of methylene blue solutionMaterial Methylene blue solution

Water samples Distilled water

Apparatus Reagent bottles (250 ml) with stoppers Beakers Syringes Stopwatch

Technique used

Measure and record the time taken for the methylene blue solution to decolourise by using a stopwatch

Procedure 1. Four samples of water are collected from four different sources. Four reagent bottles are labelled as P, Q, R and S.

2. Each reagent bottle is filled with one water sample.

Bottle Water sampleP Distilled waterQ From the hillR Industrial areaS Housing area

3. 1 ml of 0.1% methylene blue solution is added to each of the water samples using a syringe.

4. Each reagent bottle is closed immediately.CAUTION: DO NOT SHAKE THE BOTTLE.

5. All the bottles are placed in a dark area.6. The changed in the colour is checked every one hour.7. The time taken for the methylene blue solution to decolourise is recorded for

all the water samples.8. The results are recorded in a table.

Results Water sample

Time taken for methylene blue solution to decolourise (hour)

Distilled water

(blue colour remains)

From the hill 8Industrial

area4

Housing area 3Conclusion The metyhlene blue solution took the shortest time to decolourise in the watyer

sample from the river near the housing area. The water from this river is the most polluted. Hypothesis is accepted.

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