required pracs

Question 1

apparatus for microscopy

Answer 1

• microscope
• glass slide
  -coverslip
  -iodine
  -onion
  -paper towel
  -

Question 1

how to prepare a slide microscopy

Answer 1

1. pull off epidermal layer of onion
2. put into slide with a drop of iodine to keep flat
3. put on a drop of iodine to stain cells/make visable
4. use a needle to carefully lower the coverslip onto the slide with no air bubbles
5. use filter paper to soak up any excess on slide

Question 2

how to use the microscope, microscopy

Answer 2

1. place slide on stage
2. turn nosepeiece to select low power objective
3. use course adjustment knob until cover slip touches objective lense
4. then use the eyepiece and turn the knob until the image is in focus
   5.turn nosepiece to higher power objective, higher mag
5. Go back to eyepiece and turn course objective knob and fine adjustment knob
6. repeat this

Question 3

measuring in microscopy

Answer 3

1. make note of the magnification
2. use microscope to find number of cells along one line
3. put ruler under and measure how many dents representing mm there are on the line of cells
4. use actual x mag = image

Question 4

osmosis equiptment

Answer 4

• tissue eg potato- same length and no skin
• cork borer for cutting
• ruler
• balance
• range of solutions and water
• test tubes and rack
• paper towel

Question 5

preparing for osmosis practical

Answer 5

1. cut potatoes using cork borer into identical cyclinders
2. use knife to trim to same length and to remove skin
3. measure and record length and mass
4. measure 10cm of all of the sugar solutions and water
5. add each potato cylinder to each tube

Question 6

second half of osmosis practical

Answer 6

• leave tubes overngith on a rack
• remove potato cylinders and blot dry
• measure length and mass and record

Question 7

saftey in osmosis

Answer 7

• handle knife carefully
• do not eat or drink solution or potatoes

Question 8

result of osmosis practical

Answer 8

• when in distilled water it will gain most weight as it is less concentrated with water than the distilled water so it will move into the potato
• wehn in highly sugar concentrated water the water in the potato will move out to an area of lower water conc and so will lose weight

Question 9

preparation for food tests

Answer 9

1. grind food sample using motar and pestle
2. put in beaker and add water, stir
3. filter using filtration and collect in a flask so solution is clear
4. half fill a test tube

Question 10

test for sugar

Answer 10

1. add 10 drops of benedict solution to that in test tube
2. will go from blue to green/yellow/red depending on conc of sugar

Question 11

special extra work in test for sugar

Answer 11

1. heat water to point of boiling
2. put in beaker
3. put test tube of solution in beaker for five minutes

Question 12

test for starch

Answer 12

1. put a few drops of iodine into solution
2. will go from brick orange to blue black

Question 13

test for protien

Answer 13

1. add ten drops of buriet to solution
2. will go from blue to purple

Question 14

test for lipids

Answer 14

1. add ten drops of ethanol to solution
2. will go cloudy emulsion

Question 15

extra bit for lipids test

Answer 15

dont filter solution when preparing after mixing w water

Question 16

equiptment in food tests

Answer 16

• test tubes
• iodine/benedict/ buriet
• goggles
• food samply
• filter paper/motar and pestle
• pipette
• beaker

Question 17

saftey precautions for food tests

Answer 17

• do not eat any food
• wear goggles
• quickly wash off splashes on skin
• avoid scolding in hot water bath

Question 18

enzyme practical equiptment

Answer 18

-test tubes
- tube rack
-meaurisng cylinder
-spotted tiles
-starch solution/amaayse
- stop watch
-iodine solution
- buffered ph solutions

Question 19

enzyme practical events

Answer 19

1. label each tile with the time and add drop of iodine solution
2. place starch, iodine and buffered in a water bath
3. add together 2cm of each three solution in a tube in the water bath- at this point enzyme begins to digest starch
4. starch stop watch, every 30 s add the solution to the iodine to see if starch is present (it would go nlue black)
5. when the solution remains orange/brown the reaction has fully taken place
6. repeat with different ph levels as the buffer

Question 20

equiptment for photosynthesis

Answer 20

• pond weed, 10cm
• boiling tube
• ruler
• light source
  -0.2% sodium hydrogen carbonate
• rod
• rack
• stop watch

Question 21

photosynthesis practical

Answer 21

1. plae tube in rack 10cm away from light source
2. fill tube w SHC solution and push down the weed in it with a glass rod
3. leave to rest for 5 mins
4. start stop watch and count bubbles per min
5. record twice more
6. change distance by ten cm