P5 Flashcards
Is it pure oxygen gas released in gas syringe ?
No , due to CO2 and water vapor from plant or microorganism respiration
How to get the rate of photosynthesis as volume of pure oxygen gas per unit time ?
volume of gas before adding oxygen absorbent - volume of gas after adding oxygen absorbent / Time
Plan an investigation to show that increasing light intensity increases rate of photosynthesis from plant
How to improve accuracy of the measurements?
- use colorimeter instead of judging color
- Use pH meter to measure the change in pH
How to get plant extract ?
- crush 20g of leaves to break cell using mortar and pestle
- Add 100 cm3 of alcohol to dissolve phospholipid bilayer using measuring cylinder
- filter to remove cell debris using filter paper
- evaporate excess alcohol by gentle heating for 1 min to concentrate the extract
How to immobilize the plant extract ?
- mix plant extract with sodium alginate using glass rod at low speed to have uniform mixture and avoid
damage of chloroplast - Titrate on CaCl2 solution using syringe to form Ca alginate beads \
- Remove beads using forceps immediately to avoid hardiness
- Wash beads with water to remove traces of NaCl
Plan an investigation to show that increasing light intensity increases rate of photosynthesis using immobilised beads
Why student should cut root before starting the experiment ?
- to fit to apparatus
- For less resistance to water molecules
- Dye molecules is large to cross cell membrane of root hair cells
How to calculate volume of water gained by the plant ?
- measure radius of capillary tube using ruler
- Measure the distance moved by dye (mm) x R = mm
How to get surface area of leaf ?
- using square grid count number of squares occupied by leaf full , more than half or half square
count it as 1 cm3 less than half dont count it
Plan an investigation to show that increasing light intensity increases rate of transpiration
HILLS REACTION
PLANT GROWTH
Serial dilution
simple dilution
How to prepare 1% sugar solution ?
use digital balance to measure out 1 g sugar and add 100 cm3 of distilled water using syringe
How you will make 200 cm3 of 5% sucrose ?
Prepare 1% of glucose solution using solid glucose
Dissolve 1g of glucose in 100cm3 water using syringe
Prepare 25% of sucrose solution as initial stock
dissolve 25g of sucrose in 100 cm3 water using syringe
Prepare 500 ml of 0.1% sucrose solution
Prepare 1 dm3 0.15 moldm3 of lactose ( molar mass of lactose = 342 )
Prepare 25 mmoldm3 of NaNO3 ( molar mass of NaNO3 = 85 )
Prepare 500 cm3 of 0.2 moldm3 urea ( molar mass of urea = 60.1 )
yeast respiration
There are two types of respirometer:
1 simple respirometer
2 complex respirometer
simple respirometer
Explain possible reason why the rate of respiration or Heart rate at the start of the experiment ( trial
1) was higher than remaining trials? ( 1 mark)
- As the organism was under stress and not left enough time for adaptation.
How student can measure the volume of oxygen gas consumed using simple respirometer ? (2 marks)
- Measure the radius of capillary tube using ruler
- Use formula: distance moved by colored liquid X 𝜋𝑟2= cm3
How you can calculate the rate of respiration as volume of oxygen gas consumed per unit mass of
organism ? (3 marks)
Volume of O2 gas ( distance moved by colored liquid X 𝜋𝑟2) / Time X Mass of organism = cm3/
min.g
Why the student divide the volume of oxygen gas consumed by the mass of organism ? ( 2 marks)
For fair comparison as the original masses of organisms used in investigation may be different.
How student can measure the rate of Co2 gas production using simple respirometer ? ( 2marks)
Way 1
Measure the difference in mass of soda lime before and after the experiment divide it by the time Using
digital balance and stop watch
Or
Way 2
Remove the soda lime Then measure the distance moved by colored liquid to the right then multiply it by
the area of the tube 𝜋𝑟2 and divide it by time
How student can calculate the RQ using simple respirometer? ( 4 marks)
- Measure the radius of the capillary tube using ruler
- In presence of soda lime ( volume of oxygen)
- Measure the distance moved by colored liquid X 𝜋𝑟2 In absence of soda lime ( volume of Carbon
dioxide) - Measure the distance moved by colored liquid X 𝜋𝑟2
- Divide the volume of carbon dioxide by the volume of oxygen gas consumed
How the student can measure the rate of anaerobic respiration using simple respirometer ? ( 3 marks)
- Add oxygen absorbent to absorb oxygen gas to maintain anaerobic respiration Allow organism to
respire anaerobically - Measure the distance moved by colored liquid to the right in constant time.
Write a procedure a student can carry out to analyse the pigments present in different plants ?
disease detection and reaction time
disease analysis can be done by
urine test and blood test
urine test
blood test
color of urine
normally from light to dark yellow
orange urine
bacterial infection
red urnie
normal from menstruation or abnormal from virus infecting urinary system
clarity of urine
normally clear
turbid urine
something insoluble is produced in urine (proteins or cells)
odor and taste of urine
normally aromatic
sugary urine
glucose present
fruity urine
bacteria toxins is presen
Species gravity
: it has normal range but when something abnormal is produced in urine it increases the specific
gravity
Glucose test
- Benedict and Boil color changes from blue to green yellow orange or brick red ppt.
- Fehling A + B and Boil color changes from blue to green yellow orange or brick red ppt
- Dipstick
- Biosensor
Protein analysis
Biuret reagent
* Urine + NaOH + CuSo4
If protein presents then color changes from blue to purple. If protein absent then color remains blue.
Ketones analysis
Urine sample + ammonium Hydroxide + ammonium sulphate + sodium nitroprusside If ketones presents
color change from yellow to pink
If ketones absent color remains yellow
NaCl analysis
- add to urine sample excess silver nitrate
- ADD Fe 3+
- Silver nitrate is added to react with NaCl in urine
- Titrate with potassium thiocyanate
- Each drop will react with free silver nitrate remained unreacted
- After all silver nitrate reacted with potassium thiocyanate drops
- Excess potassium thiocyanate will react with Fe3+ ion giving red color
If urine sample contain high conc of NaC
will react with most of silver nitrate and leaves few molecules
of silver nitrate so it will take less number of drops to produce red color
Microscopical examination
Preparation of sample
dilute urine with water and mix well using glass rod
* Filter using filter paper to remove solid particles
* Drops of filtrate added to microscope slide to be viewed under microscope and examined for presence
of bacteria
blood analysis can be done by
Haemocytometer
Haemocytometer
- It is a way for counting any substance present in blood that can be seen by light microscope
- Use dye to stain dead cells using methylene blue and and distinguish it from unstained living cells
- It is used to count number of RBCs in blood samples
- It estimate an approximate number only not the actual
- We should use x40 as objective lens
stepf of haemocytometer
- Dilute sample with distilled water to avoid clumps of cells under microscope
- Take a uniform blood sample after stirring well using micropipette and add it to counting grid slide
- Count the average number of RBCs per square , includes the cells on top and left boundaries and exclude the cells
on bottom and right boundaries - Any overlapped cells count them by 2 cell only
- To get the total number of cells multiply the average number of cells per square by the total volume and divide by the
given volume 1 square
Experiment to show the effect of sucrose concentration on change in length of plant tissue
Experiment to show the effect of NaCl on change in-angle of bending of plant tissue per unit time
density
Plan an investigation to show differences in stomata density on upper and lower surface of leaf
Inverstigate the effect of different types of antibiotic against bacteri
Mark release recapture method
1.Catch random sample from environment ( N1)
2.Mark the sample, and make sure that the marking is not harmful to organism
3.Release the marked sample to environment and Allow enough time for random mixing
4.recatch another random sample ( N2)
5.Count number of marked organisms in second sample (m2)
6.Make sure to avoid birth or death between two sampling times
7. Use the formula of Lincoln-Petersen index
random sampling
Systematic sampling
2 types of sampling
mobile and note mobile
mobile sampling
mark release recapture method
not mobile sampling
quadrats
quadrats
If index of diversity is 0.5 or greater
r it means the area has high biodiversity
If index of diversity is less than 0.5
it means the area has low biodiversity
Why area with pesticides has lower index of biodiversity
- Pesticides kills pests so it decreases animal biodiversity
- Pesticides are non specific and it may kill pollinators decreasing pollination so it will decrease
plant and animal biodiversity
What is the effect of the washing liquid on the cell membrane ?
it contains lipase and protease which will disturbs phospholipid bilayer and increase
membrane permeability
Why was the mixture heated ?
- To denature DNASE
Why was the beaker heated for few minutes at 60 C not 90 C and then immediately
cooled ?
heated at 60 to denature DNASE and avoid denaturing of DNA at 90 then cooled to
avoid denaturing of protease K that will be added in the next step
What type of enzyme would be needed to separate the DNA into smaller pieces ?
restriction enzymes
DNA amplification using PCR
- Denature DNA by heating from 90 to 95 C to separate DNA double strands
- Cool down the temperature to 65C then add a primer that will form hydrogen bonds
- Then increase temperature to 72 C
- Add optimum concentration of MgCl
- Add taq polymerase and free nucleotides
- Taq polymerase is heat stable so will not denture at high temperatures
Importance of PCR
- DNA amplification
- Identification of virus
- Identification of mutations
What controls changes n temperature in PCR ?
- automatically controlled using thermal cycle
What are components of PCR ?
- DNA sample
- Primers
- Taq polymerase
- Free nucleotides
- MgC
