Paper 6 Revision for igcse biology 0610 2023-2025 syllabus

bio p6 ppt I found on dc

1. Enzymes
for 6 mark explain the overall shape and why it
happen
1)As temperature increase activity increase, as
higher temperature means higher kinetic energy and
collision, therefore more enzyme-substrate form
2)This is up until the optimum temperature of [data
on graph] where there are highest activity of
[data]
3)Afterward higher temp, lower activity, as active
site of enzyme denature and change shape which can
no longer form enzyme-substrate complex
4)[data] stop at blablba

2. Independent Variable: The variable you are changing to test
the effects on the dependent variable
Experimental terminology
Dependent Variable: The variable being tested and measured
Control variable: The variables that are kept constant with each
experiment to ensure its a fair test.
Control experiment: Test that show what normally happen so
comparison can be made when independent variable is change/see
effect

3. Common questions:
Formulate table of results
Identify IV, DV and CV
Purpose of the experiment
Safety hazards (e.g use of bunsen burner)
Experimental errors (Parallax error, experiment isnt
repeated, wider range isnt used)
Designing an experiment
Experiments

4. tt
Biological molecules
food tests

5. Testing for
starch
Reagent: Iodine
Results:
yellow-brown to blue
black

6. Procedure for starch in leaf
-Leaf is put into hot water to kill the cell and end all life process and soften the
leaf
-Leaf is place into ethanol in order to dissolve the chlorophyll removing green pigment
so that any color change from iodine is visible (and isn't affected by color from the
pigment)
+Hot water bath is used as ethanol is flammable
-> as all life process including photosynthesis has ended no starch will be produce and
interfere with result
-we then place the leaf in warm water again in order to remove ethanol and soften the
leaf again
-Add iodine onto the leaf ->if it contain starch, iodine turn blue black ->if not it
stays brown
Precaution: Heat and chemical

7. Testing for
reducing sugars
Test: Benedicts reagent
Results:
blue to brick red
(the closer the colour is to
brick red the more reducing
sugar is present)

8. Procedure
Add food sample to a test tube
Add benedicts solution to same test tube
Heat in a water bath at 80 degrees C
Observe colour change
IMP: this experiment uses heat, this is a precaution

9. Testing for
fats
Test: Ethanol emulsion
Results:
Cloudy-white emulsion
will be formed

10. Procedure
Add food sample to a test tube
Add ethanol to the test tube and shake
-This is because lipid is not soluble in water but is soluble
in ethanol
Add equal volume of cold water into the test tube
Precaution: Chemical

11. Testing for
proteins
Test: Biuret’s reagent
Results:
Blue to purple

12. Testing for
Vitamin C
Test: DCPIP solution
Results:
Blue to colourless
The less dcpip/sample
needed to turn solution
colorless means the
higher vitamin c
concentration is

13. Tables
IV is the rows
DV are the columns
Make a closed table
Show units in the headers.

14. Tables
78.5

15. Temperature/C
No. of test tubes
1
minute
2
minutes
3
minutes
4 minutes5 minutes
One test tube 78.5 65 61 58 55
three test tubes 67 64 62 61 60
seven test tubes 73 73 73 72 72
Tables

16. State IV with 3 examples (ph2,4,6) (1mark)
State DV (1 mark)
State minimum 3 CV (3 marks max)
State method (1-2+marks), apparatus used to keep CV constant
(1mark)
State precautions (1 mark)
Repeat each experiment minimum 3 times (1mark)
+If experiment measure quantity you can calculate average
6 marker Experiment Q

17. 6 marker Experiment Q
IV: The food
DV: Volume of O2 gas produced
CV: Volume of food, pH, temperature
Method: cutting / grinding of the food, mixing / stirring, of food and hydrogen peroxide, then using gas syringe OR
see displacement or count bubbles
Apparatus: balance / scales (to measure food)
REPEAT EXPERIMENT FOR RELIABILITY
Precaution: use gloves

18. 6 marker Experiment Q
IV: Intensity of exercise
DV: Breathing rate
CV: Gender, age, duration of exercise
Method: Exercise at different intensities and measure the breathing rate using pulse.
Record the observations and take at least 3 readings for each IV (e.g take take 3
readings for most intense exercise, medium etc)
Find avg breathing rate using the readings
REPEART FOR RELIABILITY
Preacution: take breaks between exercise

19. 6 marker Experiment Q

20. 6 marker Experiment Q
Indep: Light intensity (10w, 20w, 30w,..)
Dep: angle which seedling grow
Control: same plant, same water and mineral given, time
Method:
1) set up lamps with power of 10w, 20cm away from the seed using a meter
ruler
2) put a measuring cylinder with water filled 100cm^3 10cm away from seed
using meter ruler
3) Use timer/stopwatch wait for 2-3 days (48~72,...h)
4) use a protractor 5cm away from seed from the soil to tip of plant
5)repeat other experiment of different intensity using a lamp w different
power for 3 times
safety blabalabalbal

21. Graphs

22. Graphs

23. Graphs

24. Graphs

25. th
Plotting graphs
There are 3 types of graphs that you may be asked to plot:
Bar graph
Line graph Histogram

26. th
Plotting graphs
Rules:
X-axis is independent variable
Y-axis is dependent variable
Plot with 1/2 square accuracy
Use more than 50% of the graph
If you find a trend in shape (straight line or curve) draw a best fit line/curve
For best fit line use ruler and best fit curve use free hand (usually they will be
mentioned to draw best fit but sometimes you have to see the patterns)

27. th
Plotting graphs
Plotting bar graph:
This is our x-axis
All these readings would be considered as y-axis

28. th
Plotting graphs
Rate of movement per mm
Animal species
A

29. th
Rules for line of bestfit
It is not necessary for line of best fit to start at origin
Use a ruler to draw line of best fit (PLEASE DO NOT WING IT)
Line should touch MOST POINTS (it doesnt need to touch all)
Points that are too far away from the line will be considered as anomalous

30. th
Use more than 50% of the space given to you
No shading
Straight, sharp lines (NO BROKEN LINES)
Correct proportions
Correct details (e.g segments)
Diagram rules

31. Diagram

32. Diagram

33. Diagram

34. Diagram

35. th
Micrometer --> Millimeter x1000
Millimeter --> micrometer /1000
centimeter --> millimeter /10
millimeter --> centimeter x10
Magnification
MA
I
IMP:
Magnification has NO UNITS
BECAUSE ITS A RATIO

36. Calculating Magnification
89+-1
Magnification = image x actual
1.2 = 89 x actual
89/1.2 = actual
74.166...= actual
74mm = actual

37. tt
Sample Experiments

38. th
Investigate the factors that influence diffusion, limited to: surface area,
temperature, concentration gradient and distance
Experiment #1
Surface area
Independent variable: Surface area of agar cube (2cm^2,
4cm^2, 6cm^2)
Dependent variable: Time taken for agar to change color
completely
Control variables: Type of agar, volume, concentration of
coloring, same color, temperature

39. th
Investigate the factors that influence diffusion, limited to: surface area,
temperature, concentration gradient and distance
Experiment #1
Method
Prepare 3 test tube filled with 30ml of food coloring, put
in thermostatically controlled water bath
Add agar cube into test tube
Start stopwatch and measure how long it take for the cube
to turn completely into the color
Repeat experiment for each cube surface area 3 times
Food coloring stain on skin, splash into eyes- GGC

40. th
Investigate the factors that influence diffusion, limited to: surface area,
temperature, concentration gradient and distance
Experiment #1
For temp change IV as temp
For concentration gradient change IV to concentration of
diffusing substance
For distance change IV to thickness of cube

41. th
Investigate osmosis using materials such as dialysis tubing
Experiment #2
Independent variable:
Concentration of sugar solution
(1%,2%,3%)
Dependent variable: Change in mass
of dialysis tubing (u can also do
volume)
Control variables: Volume of water
and sugar solution, temperature,
time, type of sugar and dialysis
tubing

42. th
Investigate osmosis using materials such as dialysis tubing
Experiment #2
Method:
Make the solution of sugar with each concentration (20cm^3) and
add to dialysis tubing (knot 1 end first)
Use rubber band/knot two ends of dialysis tubing
Remove excess liquid off dialysis tubing and measure the mass
using a balance
Emerge dialysis tubing into 50cm^3 beaker
Use thermostatically controlled water bath/pad and add thermometer
to test tube, use stopwatch and wait for 10min
Remove excess liquid, measure mass again and calculate mass change
Repeat the experiment 3 times for each sugar solution
concentration

43. th
Investigate and describe the effects on plant tissues of immersing them in
solutions of different concentrations
Experiment #3
IV: Concentration of sugar solution
(0.1,1,2moldm^2)
DV: Mass of radish tissue
CV: Surface area of radish cube, type of radish
volume of sugar solution, time soak

44. th
Investigate and describe the effects on plant tissues of immersing them in
solutions of different concentrations
Experiment #3
Method
Cut cylinders of root vegetable radish into 5x5x5cm cube
Prepare 50ml of sugar solution for each concentration
The cylinders are weighed using balance before placing into
the solutions
Place it in sugar solution, start timer for 15 minutes
Removed, dried to remove excess liquid and reweighed using
balance
Take new mass and subtract initial one to find change in mass
Precaution: Using knife - cut away from body and on hard
stable surface

45. th
Investigate and describe the effect of changes in temperature and pH on enzyme
activity with reference to optimum temperature and denaturation
This is a film sheet with protein gelatin crystal coated, but they can also use
sample like agar cube mix with protein
Experiment #4
Temperature (solid)
Independent variable: Temperature
(20C,30C,40C)
Dependent variable: Time taken for
film to become transparent
Control variables: size, type of
film, volume of protease and buffer,
concentration,type of protease

46. th
Investigate and describe the effect of changes in temperature and pH on enzyme
activity with reference to optimum temperature and denaturation
Experiment #4
Method
Add 50ml 2% protease solution and 10ml buffer into test tube with
thermostatic control water bath under for according temperature for 5 minutes
Add film into test tube, put a lid on and shake for 5 rounds and put them
back to water bath
Use stopwatch to measure how long it take for film to become clear
Repeat each temperature 3 times
Precaution: Protease on skin , eyes(rash, burn), Heat-Wear gloves, goggles,
lab coat

47. th
Investigate and describe the effect of changes in temperature and pH on enzyme
activity with reference to optimum temperature and denaturation
Experiment #4
Temperature (liquid)
Independent variable: Temperature
(20C,30C,40C)
Dependent variable: Time taken for iodine
to stop turning blue-black
Control variables: size, type of starch,
volume, conc of amylase and buffer
concentration, ph, time

48. th
Investigate and describe the effect of changes in temperature and pH on enzyme
activity with reference to optimum temperature and denaturation
Experiment #4

49. th
Investigate and describe the effect of changes in temperature and pH on enzyme
activity with reference to optimum temperature and denaturation
Experiment #4
Method
Add iodine to spotting tile
Add 50ml of starch solution with 50ml of amylase mix well and heated
using thermostatically controlled water bath
Use stopwatch, every minute use pipette/syringe to add droplet of
solution into iodine tile
Continue until iodine no longer turn blue-black and calculate total time
Repeat experiment 3 times
Precaution: Heat, amylase

50. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Chlorophyll (using variegated leaf)
IV: Presence of chlorophyll
DV: Presence of starch in leaf
Control: Type/species of plant, volume of iodine
solution, light exposure, CO2 concentration

51. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Method
A leaf is dropped in boiling water to kill the cells and break down the cell membranes
The leaf is left for 5-10 minutes in hot ethanol in a boiling tube. This removes the chlorophyll so colour
changes from iodine can be seen more clearly
The leaf is dipped in boiling water to soften it
The leaf is spread out on a white tile and covered with iodine solution
Repeat experiment 3 times
In a variegated leaf (one that is partially green and partially white),the white areas of the leaf contain no
chlorophyll and when the leaf is tested only the areas that contain chlorophyll stain blue-black
The areas that had no chlorophyll remain orange-brown as no photosynthesis is occurring here hence no starch
is stored

52. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Light
IV: Exposure to light (part of leaf covered
by foil, and part that isn’t)/(you can also
do cupboard experiment)
DV: Presence of starch in leaf
Control: Type/species of plant, volume of
iodine solution, CO2 concentration

53. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Method
Destarch plant by placing in a dark cupboard for 4 hours
-Ensures that any starch already present in the leaves will be used up and not affect the results
leaf of the plant can be partially covered with aluminium foil and placed in sunlight for a day
remove leaf and test for starch using iodine
Repeat experiment 3 times
Area of the leaf that was covered with aluminium foil will remain orange-brownas it did not receive
any sunlight and could not photosynthesize, while the area exposed to sunlight will turn blue-black
This proves that light is necessary for photosynthesis and the production of starch

54. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5

55. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Carbon dioxide
IV: Availability of carbon
dioxide
DV: Presence of starch in leaf
CV: Type/species of plant, light
exposure, time, humidity,
temperature, time

56. th
Investigate the need for chlorophyll, light and carbon dioxide for
photosynthesis, using appropriate controls
Experiment #5
Method
Destarch 2 plant in dark cupboard
Plant A (No CO2) Sealed with potassium hydroxide (KOH) to absorb carbon
dioxide.
Plant B (With CO2 ) Sealed with sodium hydrogencarbonate (NaHCO3 ) to supply
extra carbon dioxide.(u can also js put nothing)
After a day ,remove a leaf from each plant. Boil in water. Boil in ethanol. Rinse
with warm water. Add iodine solution and observe the color change.
Repeat experiment 3 times
Precaution: KOH is corrosive, ethanol is flammable, heat

57. th
Investigate and describe the effects of varying light intensity, carbon dioxide
concentration and temperature on the (rate) of photosynthesis
Experiment #6
Light intensity (aquatic plant)
Independent variable: Lamp power/intensity (2W, 4W, 6W) (u can also
use candela (cd))
Dependent variable: Volume of oxygen produced in measuring
cylinder/count number of oxygen bubbles (if ask for rate then vol of
oxy per min sec...)
Control variables: Color of light source, temperature, type of plant,
co2 source and concentration, time, volume of water, distance of light
to plant, sodium hydrogen carbonate concentration, volume

58. th
Experiment #6
Method
Set light source 80cm away from beaker using a 100cm meter ruler
Put the plant in beaker weighted down with an inverted funnel, place an inverted
measuring cylinder on top. Add 1% sodium hydrogencarbonate, water and thermometer in
beaker
Put a measuring cylinder with water filled 100cm^3 (also called as heat shield)40cm
away from beaker
Set timer for 2 minutes to let the plant adapt and another 10 minutes to measure
volume in measuring cylinder
Repeat each lamp power intensity at least 3 times
Precaution: water can contact with lamp/wire, place wire out of table/lamp far away
from water

59. th
Experiment #6
note: if u want to change
distance you have to keep
light intensity the same
if u want to change light
intensity u have to keep
distance the same
2nd note: in this pic they
used test tube, this is to
count number of bubbles
if you want to calculate
volume, use measuring cylinder

60. th
Investigate and describe the effects of varying light intensity, carbon dioxide
concentration and temperature on the rate of photosynthesis
Experiment #6
Carbon dioxide concentration
Same with the light intensity but change IV to
concentration of sodium hydrogen carbonate (1%, 2%, 3%)
The higher the sodium hydrogen carbonate concentration is
the higher carbon dioxide concentration
Same for temperature but change IV to temperature
(20,30,40C) and using thermostatically controlled hot plate
place under the beaker

61. th
Investigate and describe the effects of varying light intensity, carbon dioxide
concentration and temperature on the rate of photosynthesis
Experiment #6
Sometimes they ask on how this effect the rate as well
Just take volume/number of oxygen divide to time from
stopwatch

62. th
Investigate and describe the effect of light and dark conditions on gas exchange
in an aquatic plant using hydrogencarbonate indicator solution
Experiment #7
IV: Availability of light
DV: Color of hydrogencarbonate indicator
CV: Same type/species of plant, temperature, volume,
concentration of sodium hydrogencarbonate,

63. th
Investigate and describe the effect of light and dark conditions on gas exchange
in an aquatic plant using hydrogencarbonate indicator solution
Experiment #7
Method
Fill 2 test tubes with 50ml of hydrogencarbonate indicator solution.
Tube A (Light Condition): Place the aquatic plant in the test tube and leave it
in bright light.
Tube B (Dark Condition): Place the aquatic plant in the test tube and wrap it in
black paper/foil to block light.
Leave the tubes for at least 1 hour.
Observe the color changes in the hydrogencarbonate indicator.
Repeat experiment 3 times

64. th
Experiment #7

65. th
Experiment #7

66. th
Investigate, using a suitable stain, the pathway of water through the above-
ground parts of a plant
Experiment #8
Use water dye, food coloring
After few hours the leaves of
the plant will turn into that
color and when cut out xylem
vessel will be stained which
show that water (from above
ground) passes through the xylem
and into the leaves

67. th
Investigate and describe the effects of variation of temperature and wind speed
on transpiration rate
Experiment #9
FAN
WIND SPEED

68. th
Investigate and describe the effects of variation of temperature and wind speed
on transpiration rate
Experiment #9
Cut the shoot underwater to prevent air entering the xylem. Place it in the potometer tube.
Ensure all connections are airtight using Vaseline/petroleum jelly.
Dry the leaves to prevent external water interference.
Remove the capillary tube from water to form a single air bubble, then place it back.
Change either wind speed or temperature to see its effect.
Let the plant adjust for 5 minutes before measurements.
Record the starting position of the air bubble.
Leave for a 10 minutes period, then record the end position.
Open the tap to reset the bubble, then repeat the experiment for 3 times
The further the bubble moves, the higher the transpiration rate and vice versa

69. th
Investigate and describe the effect of physical activity on the heart rate
Experiment #10
IV: Distance run (5m,10m,20m)/u can do other activities base on question
DV: Heart beat per minutes on ecg/heart rate monitor
Control: Diet, body type, gender, age, health condition, recovery time before
next trial, environment condition
Method
Measure runner heart rate before running using ecg/hrm
Allow the runner to run the following distance
Afterward, use ecg/hrm to measure their heart rate
Repeat experiment for each distance 3 times and calculate average
Precaution: Fatigue - warm up before, monitor closely

70. th
Investigate and describe the effect of physical activity on the heart rate
Experiment #10

71. th
Investigate and describe the effects of physical activity on the rate and depth
of breathing
Experiment #12
Same with heart rate experiment but DV is number of breath
count per min(breath rate) and expansion of the chest using
measuring tape

72. th
Investigate the differences in composition between inspired and expired air
using limewater as a test for carbon dioxide
Experiment #11
Inhalation
Air drawn through boiling tube A
->Clear
Exhalation
Air is blown into boiling tube B
->Cloudy

73. th
Investigate and describe the effect of temperature on respiration in yeast
Experiment #13
Independent variable: Temperature
(20,30,40C)
Dependent variable: Time taken for test
tube to turn cloudy
CV: Concentration, volume of glucose
solution, volume of yeast suspension,
volume of lime water, time

74. th
Investigate and describe the effect of temperature on respiration in yeast
Method
Add glucose solution and yeast suspension with oil layer in
test tube attach to a delivery tube leading to a test tube
containing lime water
Place the flask in a water bath set at a specific temperature
Place white tile behind test tube
Start stopwatch and measure how long for lime water to turn
cloudy
Repeat experiment 3 times for every temperature
Precaution: Heat
Experiment #13

75. th
Investigate and describe gravitropism and phototropism in shoots and roots
Experiment #14
Have 3 set ups as shown:

76. th
Investigate and describe gravitropism and phototropism in shoots and roots
Experiment #14
The seedlings in A grow towards the light source
In B the effect of the light only coming from one direction has been
cancelled out by using a clinostat (it revolves slowly and repeatedly,
so the shoots are evenly exposed to light)
This means all sides of the seedlings get an equal amount of light so
they do not curve towards the light source but grow straight up
In C the seedlings grow straight up looking for light and the plant
becomes tall and slender with yellowing leaves due to the lack of
light

77. th
Investigate and describe gravitropism and phototropism in shoots and roots
Experiment #14

78. th
Investigate and describe gravitropism and phototropism in shoots and roots
Experiment #14
In the first petri dish, radicles grew downward (positive gravitropism) and
plumules grew upward (negative gravitropism), regardless of their initial position.
In the second dish, with a rotating clinostat, both grew in their original
directions, showing no gravitropic response. A lightproof box is needed to
eliminate phototropism.

79. th
Investigate and describe the environmental conditions that affect germination of
seeds, limited to the requirement for: water, oxygen and a suitable temperature
Experiment #15
A B C D
IV: Environmental
conditions
Dv: seed germination
CV: type of plant

80. th
TestTube Factor being tested
A
Control (o2, water and suitable temp
is given)
B No water is present
C
O2 (oil prevents oxygen from passing
through)
D Cold water
Investigate and describe the environmental conditions that affect germination of
seeds, limited to the requirement for: water, oxygen and a suitable temperature
Experiment #15
A B C D

81. th
TestTubeFactor being tested
Did seeds
germinate?
A Control Yes
B Water/moisture No
C Oxygen No
D
Suitable
temperature
No
Investigate and describe the environmental conditions that affect germination of
seeds, limited to the requirement for: water, oxygen and a suitable temperature
Experiment #15
A B C D

82. th
Fixing temperature as source of error
Use thermostatically controlled water bath
If experiment contain container-use lid
Insulate the container (foil, insulate container)
Why 10/many items are used instead of 1 (length)
Larger quantity allow to see larger change which will make calculation more accurate
to give a representative sample / to avoid bias
Why do they dry up the item
To remove excess solution
What is anomalous result
Result that doesn’t fit trend of the results
Short answer

83. th
Errors
Using the same syringe/dropper can cause contamination
Parallax error
No mixing or stirring
Measuring length instead of mass
Any variable that wasnt kept constant in the experiment
Judging colour by eye
Counting bubbles

84. th
Improvements
Use different syringe / dropper, clean it before next experiment
Take readings at eye level
Mix/stir so equal distribution of solution
Measuring mass is better for comparison, shape can be irregular hard to measure
length
Kept constant var controlled
Use colorimeter
Measure volume using syringe, measuring cylinder