- Messages
- 100
- Reaction score
- 142
- Points
- 53
So the biology paper 33 is tomorrow. Anyone have any notes or tips please share them here
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Biology 9700 Paper 33/32/31 Notes and tips
- Thread starter Jassim
- Start date
- Messages
- 3
- Reaction score
- 16
- Points
- 13
GRAPHS!
1.the value which is varying is always on the y-axis while the constant value is on the x-axis.
2.no unbroken lines
3.it must be neat and thin
4.the points can be joined using a ruler or by hand
5.do not draw beyond the plotted points.
6.blobs or centre points more than 1mm are NOT acceptable
7.if zero is present in the reading, ur graph MUST pass through zero.
8.label both axis!
9.use appropriate units
10.use appropriate scale
11.use sharpened pencil to plot
12.plot the dots within circles, of equal sizes, must be clear and not too big.
SOURCES OF ERRORS!
1.temp nt controlled
2.pH not controlled or nt measured accurately
3.difficulty in judging the colour.
4.difficulty in having the same time
5.inaccuracy in preparing serial dilution
6.inaccuracy of equipment, fr e.g. pipette/syringe
7.too short time.
8.evaporation of the solution which can cause the concentration to change.
LIMITATIONS OF ERRORS!
1.measure the volume accurately using syringe with narrow range of calibration
2.repeat more times at each pH/conc./temp
3.use range of pH/conc./temp
4.accurate specific measuring devices
5.use colorimeter to measure the degree of colourness.
6.use buffer to control pHs
7.use of water bath/thermostat to control temp
8.use thermometer to measure the temp.
9.thermostatically controlled environment.
10.repeat with each conc.
11.volume of the sample(e.g. enzyme/substrate) must be the same..cuz as volume increases, conc also increases
12.keep only one factor different, and all others must be the same.
Reliability.....take minimum of 3 readings!
repeat with mre pH/conc/temp
and find out their mean
Accuracy.....seing electronic thermostat
use of pippettes instead of measuring cylinders
KEY
1)read the whole question till the end
2)decide number of readings to take
3)don't go for more or less than 3 readings per conc/vol of any ques.
4)make a table
5)write down the UNITS in each coloumn of the table...e.g. conc/cm^3 , temp/°C
MICROSCOPY!!!
1)propotion of thickness must be correct.
2)draw the organelles where u see them, dont just draw anywhere within the cell! never draw what u know.
3)whenever u see the plant cells, draw the cell walls.
4)IN PLAN DIAGRAMS, NO DRAWING OF ANY CELLS, AND NO SHADING...if u'll do either of them, u'll lose the whole mark!!
5)when asked to draw 2 cells, draw the ones that are easiest to draw. and dont draw more then 2 cells!
6)fraw the adjacent (touching) cells.
7)drawing should be large, unshaded.
8)in plan diagrams show the relative thickness of each layer.
9)draw the exact shape, if its oval or round or has wavy outlines
10)label the diagram...simplest thing to label is cytopasm, nucleus and cell membrane.
11)if its a trachea cell, then label goblet cells, cilia, blood vessels, muscular tissue, cartilage cells (lacunae)
12) when asked to compare 2 diagrams....make a table (drawing a table itself has 1 mark!)....put atleast one similarity
ERRORS IN MESUREMENTS!
1)irregular in shape
2)difficulty in focusing
3)preperation is squashed
and yeahhhh one more thingg, the values must be whole numbers!!! e.g if its 8.5mm u round it off to a whole number which is 9!!
1.the value which is varying is always on the y-axis while the constant value is on the x-axis.
2.no unbroken lines
3.it must be neat and thin
4.the points can be joined using a ruler or by hand
5.do not draw beyond the plotted points.
6.blobs or centre points more than 1mm are NOT acceptable
7.if zero is present in the reading, ur graph MUST pass through zero.
8.label both axis!
9.use appropriate units
10.use appropriate scale
11.use sharpened pencil to plot
12.plot the dots within circles, of equal sizes, must be clear and not too big.
SOURCES OF ERRORS!
1.temp nt controlled
2.pH not controlled or nt measured accurately
3.difficulty in judging the colour.
4.difficulty in having the same time
5.inaccuracy in preparing serial dilution
6.inaccuracy of equipment, fr e.g. pipette/syringe
7.too short time.
8.evaporation of the solution which can cause the concentration to change.
LIMITATIONS OF ERRORS!
1.measure the volume accurately using syringe with narrow range of calibration
2.repeat more times at each pH/conc./temp
3.use range of pH/conc./temp
4.accurate specific measuring devices
5.use colorimeter to measure the degree of colourness.
6.use buffer to control pHs
7.use of water bath/thermostat to control temp
8.use thermometer to measure the temp.
9.thermostatically controlled environment.
10.repeat with each conc.
11.volume of the sample(e.g. enzyme/substrate) must be the same..cuz as volume increases, conc also increases
12.keep only one factor different, and all others must be the same.
Reliability.....take minimum of 3 readings!
repeat with mre pH/conc/temp
and find out their mean
Accuracy.....seing electronic thermostat
use of pippettes instead of measuring cylinders
KEY
1)read the whole question till the end
2)decide number of readings to take
3)don't go for more or less than 3 readings per conc/vol of any ques.
4)make a table
5)write down the UNITS in each coloumn of the table...e.g. conc/cm^3 , temp/°C
MICROSCOPY!!!
1)propotion of thickness must be correct.
2)draw the organelles where u see them, dont just draw anywhere within the cell! never draw what u know.
3)whenever u see the plant cells, draw the cell walls.
4)IN PLAN DIAGRAMS, NO DRAWING OF ANY CELLS, AND NO SHADING...if u'll do either of them, u'll lose the whole mark!!
5)when asked to draw 2 cells, draw the ones that are easiest to draw. and dont draw more then 2 cells!
6)fraw the adjacent (touching) cells.
7)drawing should be large, unshaded.
8)in plan diagrams show the relative thickness of each layer.
9)draw the exact shape, if its oval or round or has wavy outlines
10)label the diagram...simplest thing to label is cytopasm, nucleus and cell membrane.
11)if its a trachea cell, then label goblet cells, cilia, blood vessels, muscular tissue, cartilage cells (lacunae)
12) when asked to compare 2 diagrams....make a table (drawing a table itself has 1 mark!)....put atleast one similarity
ERRORS IN MESUREMENTS!
1)irregular in shape
2)difficulty in focusing
3)preperation is squashed
and yeahhhh one more thingg, the values must be whole numbers!!! e.g if its 8.5mm u round it off to a whole number which is 9!!
- Messages
- 100
- Reaction score
- 142
- Points
- 53
Wow. Thanks!
- Messages
- 3
- Reaction score
- 16
- Points
- 13
you are welcome 
- Messages
- 60
- Reaction score
- 86
- Points
- 28
paper 31 is also tomorrow
- Messages
- 100
- Reaction score
- 142
- Points
- 53
Can anyone explain the difference between simple and serial dilution?
When they ask us to draw a low or high power diagram, do we have to take a certain measurement using the eyepiece graticule? And then take a specific magnification when drawing? We we simply approximate their sizes and draw normally without the need of measurements?
- Messages
- 100
- Reaction score
- 142
- Points
- 53
Low power diagrams usually show less oraganelles than high power drawings. They may also seem blurred. The difference between low and high power drawings is not really magnification, but resolution, which is defined as the ability to distinguish between two points effectively. Remember, all plant cells will have a cell wall, regardless whether you see it or not. You can trying googling plan diagrams for arteries, trachea, and veins. Also google vascular tissue plan diagrams. These help greatl
- Messages
- 671
- Reaction score
- 457
- Points
- 73
serial dilution is when concentration is halved with every sample eg: https://encrypted-tbn0.gstatic.com/...U1Tzvooy33a0GnYJxKGEV8KJkLQYo9ISogHf9qTb1HWGa
Simple dilution is when u use the c1v1=c2v2 equation to find the new concentration.
- Messages
- 5
- Reaction score
- 0
- Points
- 1
yes plssssssssssssssssss
so a post on fb saying enzymes but not which experiment