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82 Cards in this Set
- Front
- Back
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What is the IV and DV for the enzyme rate of reaction experiment |
IV: concentration of enzyme (Catalase)DV: amount of oxygen displacing water per minute.. |
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What equipment will we need for the enzyme rate of reaction experiment? |
-catalase (potato disks)-scalpel to cut potato-water-two test tubes with a rubber bung-delivery tube-thermometer-pipette -metal clamp (to hold test tube) -hydrogen peroxide-inverted measuring cylinder -stopwatch- |
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What are a few drawbacks of conducting the enzyme rate of reaction experiment? |
maintaining constant temperature as this may be increasing the rate NOT the catalase so the validity would be affected-pipette inaccurate when making different concentrations as they measure to the nearest mm3-some delay before adding rubber bung can allow oxygen to escape |
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How can we make our enzyme rate of reaction more reliable and prevent error? |
repeat experiment many times, and make sure different pipettes are used to prevent cross contamination. |
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What are our controls for the enzyme rate of reaction experiment? |
-temperature-pH (using pH buffer)-source of enzyme (liver or potato choose one)-substrate concentration-substrate volume |
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What does hydrogen peroxide break down into when catalyzed by catalase? |
-temperature -pH (using pH buffer) -source of enzyme (liver or potato choose one) -substrate concentration -substrate volume oxygen+water |
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Why does the rate of the reaction increase when more catalase is added to hydrogen peroxide? |
Because there are more enzymes available, there will be more collisions with the substrates and active sites forming more enzyme-substrate complexes which means that there will be more break down of the large substrates per minute so the rate of the reaction will increase. |
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EXPERIMENT ON Investigating plant mineral deficiencies: |
1)fill a tube with the all nutrients present solution (the control) and cover with foil on top pushing the stem of the mexican hat plant through it into the test tube. 2)cover with more aluminum foil and repeat with other solutions lacking these nutrients. 3)place near sunny window sill and measure height of shoot and appearance. |
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EXPERIMENT ON effect of antimicrobial properties of plants: |
1) take extracts from plants that you want to test first by drying and grinding each piece then soak in ethanol. Make sure extracts are the same size. 2)filter off liquid. 3)spread some bacteria on agar plate. 4)Dip discs of absorbent paper in the extracts (should be same size). 5)use also control disc dipped only in ethanol without the extract. 6) Place discs on agar plate. Incubate plate to allow growth. 7) areas around discs with no bacteria is called the inhibition zone. 8) size of inhibition zone tells us the strength of the antibacterial properties of the plant in terms of effectiveness. |
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What is the IV and DV for the daphnia experiment?
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IV: caffeine concentration
DV: heart rate of daphnia |
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What variables should we control in the Daphnia experiment?
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1) temperature
2) volume of solutions 3) stress of daphnia 4)size of daphnia 5)time of acclimatisation 6)species of Daphnia
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What equipment would you need for the Daphnia experiment?
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-microscope
-counter (or pen and paper) -cavity slide -dropping pipettes -stop clock -pond water (normal water has chlorine which can kill daphnia -test tubes -stop clock |
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If needed, how will you heat the water in the daphnia experiment?
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- Use a circular heating coil (around 6V)
-or place in a larger dish with warm water |
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Give one way you could reduce the daphnia overheating besides the amount of time you may live them under the microscope:
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Use a LED microscope as it produces less heat.
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How are Daphnia temperature sensitive?
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Daphnia are poikilothermic (cold-blooded) which means that whatever temperature environment they are put in will result in their own inner-body temperature becoming identical to it which changes the metabolic rate (we can see this by the heart rate)
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Why are Daphnia convenient for use when it comes to measuring the heart rate?
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-they are transparent
-they are cheap and easy to obtain |
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What are some of the few drawbacks of the Daphnia experiment?
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1) counting heart beats can be very inaccurate as the daphnia moves a lot
2)Overheating of the daphnia from the light microscope may lead to a change of heart rate not the caffeine so this affects the validity. 3) Heartbeat change may be due to daphnia attempting to escape cotton fibres.4) can be cruel as daphnia may die from caffeine 5) the daphnia's heart differs from ours so the sinoatrial node is actually made from spontaneously active nerves so it may be hard to generalize to humans. . |
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When observing the Daphnia, what should we make sure we are doing?
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-make sure that you are measuring the heart rate not the flapping of the gills or movement of the gut
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What is the hypothesis of our Daphnia experiment?
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- as the caffeine concentration increases, the mean heart rate of the Daphnia will also increase.
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What do Daphnia eat?
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-bread yeast or algae
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What equipment will you need for the totipotency tissue culture experiment?
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-white mustard seeds -agar -distilled water
-damp sponge -cling film -mcCartney bottles -weighing scales -plastic tray -250ml beaker -glass rod -scissors -sunny window |
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Why do you need to cover the mcCartney bottles with cling film? Give 2 reasons
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-to prevent any contamination and growth of pathogens.
-prevent water loss |
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Why do the seedlings continue to grow even when covered with cling film?
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the seedlings placed into the agar contain parts of the plant that are totipotent so it can grow and regenerate even though anaerobic conditions are not ideal.
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When carrying out the plant totipotency experiment, what should we avoid doing?
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-avoid contamination as this can grow unwanted pathogens.
-avoid putting the wrong piece of the plant into the gel (has no totipotent cells) |
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What are the advantages of micropropagation (growing plants from explants).
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-rapid growth
-independent of seasons -can be used to grow plants that are usually difficult to propagate. -grows plants that are virus free as infected stocks and species found in soil are not used. -plants with rare but useful characteristics can be cloned. |
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Why are narrow mcCartney bottles used instead of longer tubes?
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they are easier to place the explants into the agar medium.
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What is the IV for the beetroot experiment?
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temperature of water
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What is the DV for the beetroot experiment?
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the amount of pigment released measured using a colorimeter (absorbance levels)
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What variables should we keep controlled in the beetroot experiment?
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-volume of distilled water
-time left in water -size of beetroot piece -area in which the beetroot piece is extracted from (same tissue). -species of beetroot |
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What equipment do you need for the beetroot experiment?
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-raw beetroot -distilled water
-cork borer -stopclock -knife -syringe -ruler -thermometer -beaker -forceps -water baths boiling tubes |
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Where is the betalain dye found in the pigment of the beetroot?
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in the vacuole
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What are some drawbacks of how you conducted the beetroot experiment?
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-maintaining the temperature was difficult
-difficulty with dealing with excess pigment release during cutting process -cutting the beetroot into equal sizes -experimenting with DIFFERENT plants to give it more reliability. -repeating.
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What is the IV and DV for the vitamin C experiment?
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IV: source of vitamin c
DV: volume of juice required to decolourise 1cm3 of DCPIP |
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Which variables need to be controlled for the vitamin C experiment?
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-Temperature
-concentration of the DCPIP (1%) -# of times the test tube is shaken -same end point colour -volume of DCPIP |
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What are some drawbacks of the vitamin C experiment?
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-difficulty in controlling temperature
-shaking too much adds oxygen which will slightly restore the DCPIP to blue -end point difficult to judge -some loss of solution when transferring from one beaker to the next -accuracy of pipette/burette -cutting fruits before may result in oxidation so there is less vitamin c |
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What is the formula for standard error (for error bars)?
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standard deviation
________________________
√sample size |
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If the error bars are large in the data, what does this show?
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If the standard error is very big, then the data you collected might be less likely to represent the population.
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What does standard deviation show us?
what does 1SD on each side represent and what does 2 SD on each side represent on the graph? |
how spread out our data is.
1SD: 68.3% data represented 2SD: 95.4% data represented |
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What is the IV and DV for the enzyme rate of reaction experiment |
IV: concentration of enzyme (Catalase) DV: amount of oxygen displacing water per minute. |
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What equipment will we need for the enzyme rate of reaction experiment? |
-catalase (potato disks) -scalpel to cut potato -water -two test tubes with a rubber bung -delivery tube -thermometer -pipette -metal clamp (to hold test tube) -hydrogen peroxide -inverted measuring cylinder -stopwatch |
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What are a few drawbacks of conducting the enzyme rate of reaction experiment? |
-maintaining constant temperature as this may be increasing the rate NOT the catalase so the validity would be affected -pipette inaccurate when making different concentrations as they measure to the nearest mm3 -some delay before adding rubber bung can allow oxygen to escape -very high concentration of catalase can make it difficult to measure the rate of the reaction as it may occur too fast. -oxygen dissolves in water being displaced. |
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How can we make our enzyme rate of reaction more reliable and prevent error? |
repeat experiment many times, and make sure different pipettes are used to prevent cross contamination. |
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What are our controls for the enzyme rate of reaction experiment? |
-temperature -pH (using pH buffer) -source of enzyme (liver or potato choose one) -substrate concentration -substrate volume |
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What does hydrogen peroxide break down into when catalyzed by catalase? |
oxygen+water |
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Why does the rate of the reaction increase when more catalase is added to hydrogen peroxide? |
Because there are more enzymes available, there will be more collisions with the substrates and active sites forming more enzyme-substrate complexes which means that there will be more break down of the large substrates per minute so the rate of the reaction will increase. |
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What is equation between hydrogen peroxide and catalase? |
2H2O2 + Catalase >>> 2H2O + O2 |
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What is the IV and DV for the plant mineral deficiencies experiment? |
IV: minerals present DV: physical characteristics of plant |
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What are our control variables for the plant mineral deficiencies experiment? |
-volume of mineral solution -species of plant -pH of mineral solution -amount of light received -temperature -humidity |
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What equipment will we need for the plant mineral deficiencies experiment? |
-mexican hat plantlets or geranium leaves -7 test tubes -test tube holder -different mineral solutions lacking 1 nutrient and containing the rest -aluminium foil |
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What is the procedure that will be carried out for the enzyme rate of reaction experiment? |
1)Make up a range of different concentrations of catalase enzyme by using a different number of potato disks.2)Use different pipettes to prevent cross-contamination3)Allow a volume of hydrogen peroxide and catalase acclimatize and reach the same temperature. 4) mix the hydrogen peroxide and potato disks in test tube(may add pH buffer to maintain pH) and quickly place a rubber bung on the test tube (this test tube will be place in a water bath with water at room temp which is attached to a delivery tube that is submerged in water underneath an inverted measuring cylinder. Start the stopwatch and after one minute, measure how much oxygen has displaced the water. |
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What characteristics do leaves lacking in nitrates show and what is it needed for? |
-yellow leaves needed for making amino acids+proteins |
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What characteristics do leaves lacking in Phosphates show and what is it needed for? |
-purple leaves (needed for DNA) |
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What characteristics do leaves lacking in Potassium show and what is it needed for? |
discolored leaves (help enzymes in photosynthesis) |
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What characteristics do leaves lacking in Magnesium show and what is it needed for? |
yellow leaves (makes chlorophyll) |
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What characteristics do leaves lacking in Iron show? |
leaves turn white |
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What characteristics do leaves lacking in Calcium show? |
brown spots |
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What are some drawbacks of the plant deficiency experiment? |
-ensuring accurate measurement of solutions -air bubble caught in xylem of geranium (blocks nutrients) -microorganisms growing in the nutrient solution. -insufficient time to see effect |
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What characteristics do leaves lacking in phosphorus show? |
stunted growth |
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When carrying out the antibacterial properties of mint and garlic, how would we measure the inhibition zone? |
Place graph paper over petri dish and trace the area of inhibition and then count the squares to get the area |
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Describe the observing mitosis experiment: |
1) Cut tip of a growing root of garlic should be around 5mm long. 2) Place root tip in watch glass with some hydrochloric acid. 3) add a few drops of Schiff's reagent 4) warm watch glass over bunsen burner 5) place root tip on microscope slide and use a mounted needle to break them open and spread them out in a thin layer(macerate them). 6) Add a few drops of stain and cover with a cover slip 7)warm slide to intensify stain 8)observe stages of mitosis. |
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What equipment do we need for the mitosis experiment? |
-garlic roots -sharp knife - 1 MOL HCL -Schiff's reagent -bunsen burner - watch glass -pipette -microscope slide -forceps -mounted needle -microscope. |
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What is the formula for calculating the mitotic index and what does it mean? |
it is the number of cells containing visible chromosomes in the field of view |
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Which stage will be to be the most common when watching mitosis and which will be the least common. |
most common: interphase least common: anaphase |
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What are some limitations and errors of the mitosis experiment? |
-resolution of microscope - human error in counting number of cells - not enough time in the solutions to enable successful maceration or staining. |
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Why would we use onion/garlic root cells for the mitosis experiment? |
-onions and garlic are easy to find and are cheap, -easier to view under microscope than animal cells as plant cells are larger |
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What does interphase look like? |
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What does prophase look like? |
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What does metaphase look like? |
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What does anaphase look like? |
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What does telophase look like? |
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What is you IV and DV for the strength of plant fibres? |
IV: source and type of fibre DV: the mass it can hold before the fibre breaks |
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What variables should we control for the experiment on the tensile strength of plant fibres? |
-length of fibre -sizes of the masses -temperature -humidity -diameter of fibre -age of fibres -consistency between plaiting or twisting |
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What equipment will you need when investigating the tensile strength of plant fibres? |
-clamp -weights -fibres from plants (same length) -goggles -white tile |
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What procedure will we use to carry out the tensile strength of plant fibres experiment? |
1) attach the fibre to a clamp stand and hang a weight to the other end. 2) keep adding weights one at a time until fibre breaks. 3)record mass needed to break fibre 4) repeat experiment using the same length to increase reliability. 5) wear goggles and protect feet from heavy weights. 6)keep humidity and temperature levels contestant. |
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Why should humid or hot environments be avoided when experimenting with the tensile strength of plant fibres? |
HUMID: the absorption of water from the environment affects the tensile strength. HIGH TEMPERATURES: more thermal degradation of natural fibres which results in the deterioration in mechanical properties of natural fibres. |
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What provides support in the the fibres of plants? |
the cellulose of the cell wall that is lignified with schlerenchyma cells. |
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What are some drawbacks of the tensile strength of plant fibres experiment? |
- the plant fibres may dry up becoming brittle so not valid measure of true strength -different stands have a different age even if they originate from the same plant |
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What is retting? |
to soak to a plant (usually in water) in order to loosen the fibre from the woody tissue |
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What is the IV and the DV for the antibacterial properties of plant experiment? |
IV: presence of different forms of plant (garlic, mint) DV: diameter of the zone of inhibition around disc |
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What variables would we need to control for the antibacterial properties of plant experiment? |
-same amount of ethanol (to maintain same concentration of plant material) -lawn of bacteria on petri dish -same volume of plant material on each disc. -temperature -humidity |
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What equipment will we need for the antibacterial properties of plant experiment? |
-Agar plate -plant material (garlic, mint) -pestle and mortar -alcohol -sterile pipette -petri dish -forceps -hazard tape - marker pen |
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What are a few drawbacks of the antibacterial properties of plant experiment? |
- difficult to ensure that there are any unwanted microorganisms on agar plates due to lack of sterility. -not shaking extract enough to ensure that enough is present in the solution. -inconsistency when adding plant extract to paper disks. -using wrong species of bacteria for lawn. |
