PRACTICALS

• Hazard = broken glass can lead to cuts - Keep glass away from the edge
• hazard : scalpel can lead to cuts : ensure to cut away from the body
• ethanol : highly flammable : ensure there are no naked flames in the room
• boiling water : can lead to scalding : handle boiling water with care
• colorimeter : used to measure the % abosorvance of light though solution
• reducing sugars : Benedict’s reagent : colour change form green -brick red
• Non-reducing sugars : add HCL and Benedict’s solution : colour change from green to brick red
• Proteins: biuret reagent : colour change from pale blue - purple
• starch : iodine test : Orange-brown - blue black
• lipids : same volume water ,ethanol. and lipid sample shake and if positive white cloudy emulsion forms
• thermostatically controlled water bath
• Ice cold temperatures and isotonic : reduces the effect of kinetic energy and ensures enzyme action is in control , isotonic to allow for no osmotic effect
• buffer - used to maintain ph
• biosensor - produces an electrical signal which measures the concentration of chemical
• cell may be cut at different planes
• replenishing water stops the build up of bacteria and replenishes oxygen content
• staining allows the presence of chromosomes to be seen
• we can witness mitosis in the meristem tissue and root tip
• meiosis is occurring in anthers
• septum : muscular wall on the left and right side of the heart
• Potometer conditions : -must be assembled in water to ensure there are no air bubbles , grease joints with Vaseline to give a tight seal which prevents air from entering , cut shoot at an oblique angle to increase surface area for water absorption
• The higher the Simpsons diversty index the greater the biodiversity . From 0-1
• we place nail varnish on stomata as it makes it easier to look at stomata
• ways to increase reliability : repeat and calculate means
• increase validity : control your control variables
• increase accuracy : use apparatus with smaller divisions and investigate using more concentrations /Temperatures or Ph
• method for sampling : use tape measure at right angles , use a random number generator to pick coordinates
• 35.C is the optimum temperature for respiratory enzymes
• Total count includes viable and non-viable cells
• mathematical value for reliability : standard deviation .
• standard deviation allows for a look into more reliable results and indicates deviation from mean
• conditions for human gut bacteria : anaerobic and 37.C
• Differences in dry mass is caused due to water entering cells via osmosis
• root tips are squashed to allow light to pass through and prevent the damage of cells
• Percentage change allows for comparison if initial sizes or masses are different
• Chi - squared values : mention what critical value you got and if there is probability state there is less than a 5% probability the results are due to chance
• Normal distribution - bell shaped curve
• We cannot use chi-squared if the data Is continuous
• ways to ensure sampling method is representative

  1. use a random number generator
  2. use many quadrats
  3. Carry out sampling at the same times int the year in the same places before
• T-test - statistical test used to test if mean results are statistically significantly different