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Hint
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Answer
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1. make two ____ samples
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control
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take 2 flat bottomed tubes and add 5cm^3 ____ ____ to each
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milk suspension
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add 5cm^3 distilled water to one tube to indicate the ____ of enzyme activity
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absence/lack
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add 5cm^3 distilled water to the other to indicate the colour of a completely ____ sample
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hydrolysed
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2. take 3 test tubes and measure 5cm^3 milk into each and stand in a water bath at 10 degrees C for 5 minutes to ____
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equilibrate
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3. add 5cm^3 ____ to each tube simultaneously and start the timer
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trypsin
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this enzyme hydrolyses the ____ protein in milk, which, when hydrolysed, decolorises the milk
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casein
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4. record ____ taken for the milk samples to become colourless
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time
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5. repeat steps 2 to 4 at ____ of 20, 30, 40 and 50 degrees C
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temperatures
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6. find the mean time for the milk to be hydrolysed. rate of reaction = 1/____
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time
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1. heat standard hydrochloric acid solution in a ____ ____ at 60 degrees C
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water bath
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2. cut a small sample of the root tip using a ____
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scalpel
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3. transfer root tip to the HCl and ____ for 5 minutes
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incubate
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4. remove from acid, wash sample in cold ____ ____, and remove the tip using a scalpel
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distilled water
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5. place the tip on a microscope ____
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slide
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6. add a few drops of a stain such as ____ ____
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toluidine blue
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the stain makes the chromosomes visible and therefore shows which cells are undergoing ____
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mitosis
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7. lower the ____ ____ down onto the slide
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cover slip
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make sure there are no ____ ____ to interfere with the clarity of the image
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air bubbles
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ensure the cover slip does not slip sideways as this could damage the ____
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chromosomes
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8. place under a microscope and set the ____ lens to the lowest magnification
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objective
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9. focus using the coarse and fine ____ ____
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adjustment knob/focussing knob
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1. make a series of ____ of 1M sucrose solution at 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0M
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dilutions
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2. measure 5cm^3 of each dilution into separate ____ ____
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test tubes
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3. use a ____ ____ to cut out six potato chips
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cork borer
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4. use a ____ to cut them to identical lengths using a scalpel
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ruler
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5. take the ____ of each chip using a balance
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mass
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6. place each chip in a ____ test tube and leave for 20 minutes
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different
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7. remove each potato, pat ____ using a paper towel, and take the final masses
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dry
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8. calculate ____ change in mass for each chip
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percentage
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9. plot a graph of percentage change in mass against ____ concentration
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sucrose
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the point at which the line of best fit intercepts the x axis is the point where the solution is ____ to the potato
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isotonic
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1. cut beetroot into 6 identical cubes using a ____
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scalpel
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2. rinse to clean off any ____ released by cutting
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pigment
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3. place the cubes in test tubes containing an equal volume each of ____ ____
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distilled water
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4. place each test tube in a ____ ____ at 20, 30, 40, 50, 60, 70 and 80 degrees and leave for 20 minutes
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water bath
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5. set the colorimeter to the filter with the highest ____ (yellow/orange range)
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absorbance
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6. zero with a ____ of distilled water
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cuvette
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7. filter each sample into a cuvette using ____ paper
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filter
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8. measure the absorbance for each solution. a higher absorbance indicates higher pigment ____
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concentration
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higher pigment concentration indicates a more ____ membrane
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permeable
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as temperature increases, permeability increases because membrane proteins ____
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denature
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this creates gaps for the ____ molecules to pass through
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pigment
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at low temperatures, the ____ have little energy and are closely packed causing low permeability
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phospholipids
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1. wipe down surfaces with ____ cleaner
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antibacterial
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2. set up a Bunsen burner in the work space to create a ____ current to draw microbes away from the culture
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convection
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3. unscrew the bottle and flame the ____
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neck
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4. use a sterile pipette or ____ ____ to transfer bacteria from the broth to the agar plate
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inoculating loop
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5. use sterile forceps to place a multi-disc ____ ring on the plate
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antibiotic
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6. lightly tape a lid on, invert, and ____ at 25 degrees C for 48 hours
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incubate
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ensure the lid is not taped around the entire dish as this prevents ____ entering and promotes growth of harmful anaerobic bacteria
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oxygen
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7. ____ equipment and disinfect work surfaces
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sterilise
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the ____ ____ ____ is where bacteria did not grow
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zone of inhibition
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1. draw a ____ line about 1cm from the bottom of the chromatography paper
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pencil
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2. cut a section of leaf and place it in a ____
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mortar
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3. add 20 drops of ____
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acetone
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4. use the ____ to grind up the leaf sample to release the pigments
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pestle
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5. use a ____ ____ to extract some of pigment and plot it onto the centre of the baseline
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capillary tube
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6. suspend the paper in the ____ so that the level of liquid lies below the pencil line
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solvent
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7. leave until the solvent has run up the paper near to the top, at which point remove and mark the ____ ____
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solvent front
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8. calculate the ____ value for each separated spot
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Rf
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9. compare the ____ values to a database
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experimental
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1. remove ____ from leaf samples
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stalks
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2. ____ using a pestle and mortar
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grind
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3. place into a chilled ____ ____
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isolation solution
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4. use a ____ ____ and funnel to filter the sample into a beaker
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muslin cloth
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5. suspend the beaker in an ____ ____ to keep the sample chilled
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ice bath
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6. transfer to ____ tubes and ____ at a high speed for 10 minutes to separate chloroplasts into the pellet
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centrifuge
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7. remove supernatant and add pellet to the fresh ____ ____ which should be stored on ice
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isolation medium
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8. set colorimeter to red filter and zero using a cuvette containing chloroplast extract and ____ ____
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distilled water
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9. place test tube in the rack 30cm from light source and add ____
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DCPIP
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10. immediately take a sample and measure ____. repeat every 2 minutes for 10 minutes
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absorbance
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11. repeat for different distances from the lamp to vary the ____ ____
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light intensity
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this experiment should be done in a ____ room
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darkened
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ensure the ____ is constant because samples very close to the lamp may have an increase
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temperature
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plot a graph of absorbance against time for each ____ from the light
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distance
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as light intensity decreases, rate of photosynthesis decreases because of slower ____
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photoionisation
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hence the DCPIP accepts less electrons so takes long to turn from blue to ____
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colourless
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therefore, a higher absorbance indicates a ____ rate
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slower
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1. set up ____ ____ at a range of temperatures
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water baths
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2. add 5cm^3 yeast and 5cm^3 glucose in ____ solution to three test tubes per temperature
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buffered
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3. place them in the water bath and leave them for 10 minutes to ____
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equilibrate
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4. add 2cm^3 ____ ____ to the test tubes and start the timer
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methylene blue
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5. ____ for 10 seconds and return to water baths
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shake
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6. record time taken to turn _____
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colourless
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7. find the mean of the results for each temperature and calculate average rate of respiration as 1/____
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time
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1. set up a ____ ____ to have 4 quadrants: high/low light intensity and high/low humidity
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choice chamber
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2. use dark ____ to block out the light on one half
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paper
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3. use wet paper towel to make ____ areas and a drying agent to make dry ones
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damp/humid
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4. place 10 ____ in the centre of the choice chamber using a spoon
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woodlice
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5. leave for 10 minutes and record how many are in each ____
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quadrant
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6. repeat several times and use the ____ ____ test to determine significance
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chi squared
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1. create a ____ ____ of glucose from concentrations 0 to 10 mmol dm^-3
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dilution series
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2. add 2cm^3 of each of the known samples to separate boiling tubes and add 2cm^3 ____ solution
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Benedict's
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3. place boiling tubes in a ____ ____ at 90C for 4 minutes
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water bath
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4. use ____ to remove the boiling tubes and leave to cool
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tongs
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5. use colorimetry to determine ____. use the red filter. glucose concentration will be directly proportional to ____
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absorbance
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6. plot a ____ ____ of concentration against absorbance
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calibration curve
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7. repeat with the urine sample and use the calibration curve to determine its ____ concentration
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glucose
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1. choose a 5x5m area to take ____ from
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samples
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2. use a ____ ____ ____ to generate 10 sets of random coordinates
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random number generator
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3. use two tape measures to create a set of ____ off which coordinates can be read
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axes
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4. place the ____ at each of the coordinates, placing the bottom left corner on the coordinate each time
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quadrat
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5. record ____ ____ of the chosen species
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percentage cover
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6. measure the ____ ____
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independent variable
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e.g. for light intensity, use a ____ to take a reading
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photometer
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