Root Tip

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Why is the root tip used?
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This is the region of active cell division by mitosis
Why is hydrochloric acid used?
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Breakdown the pectins in the middle lamella that hold the cells together. Helps produce a preparation that is one cell thick. Why is the stain used?
-makes chromosomes more visible why do we press down on cover slip? -
Forms a thin layer of cells with no overlapping cells present. Why do we heat?
-Helps intensify the stain.
Systematic errors
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Errors in calibration of measuring instrument

Random errors
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Possible contamination of plant by microorganisms
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Temperature fluctuations
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Inconsistent light intensity

Increasing Reliability of Experiment
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Repeat at least 3 times
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Repeat/ignore anomalies
Use of agar
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Water source and support
Why short-necked test tubes?
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Easier to insert explants
Cover with cling film?
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Prevent contamination / loss of moisture
Why not open tubes once they have been set up?
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Prevent contamination by pathogens
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Systematic Errors
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Calibration errors in measuring instrument Random Errors
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Temperature fluctuations
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Humidity levels
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Light intensity
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[Oxygen] and [carbon dioxide] in environment Increasing reliability -
Repeat at least 3 times
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Control variables
Anti-Microbial Properties of Plants
Procedure: Part One

Antimicrobial
Systematic error
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Error in calibration of syringe used Random error
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Possible contamination of microorganism
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Nutrient level in nutrient agar could have been diminished

1.1
Constant: temperature & size of Daphnia
Reliability – repeats
Validity – same Daphnia used
Explanation:
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Caffeine stimulates sympathetic nerves to transmit impulse sat a high frequency to the heart which causes an increase in heart rate Why is Daphnia used?
-Not an endangered species
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Bred for fish food and so will die either way

Enzyme]
Explanation:
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More free substrate molecules, more collisions, more ESC formed Random error:
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