Biology experiments Flashcards
Test for starch
chemical used
iodine
Test for starch
initial colour
yellow/red
Test for starch
final colour
blue/black
Test for starch
how do you add iodine
with a dropper
Test for starch
what do you test
bread
Test for starch
what is the control
water
Test for starch
colour change in control
stays red/yellow the whole time
Test for reducing sugar
chemical used
Benedicts solution
Test for reducing sugar
what do we test
glucose syrup
Test for reducing sugar
initial colour of BS
blue
Test for reducing sugar
final colour of bs
orange/brick red
Test for reducing sugar
describe set up
equal amounts of substance and benedicts solution in a test tube
Test for reducing sugar
where does the test tube go?
in a water bath and heated gently
Test for reducing sugar
control
water
Test for reducing sugar
colour change in control
stays blue
Test for soluble protein
Name of test
biuret test
Test for soluble protein
what do we test
milk
Test for soluble protein
chemicals used
sodium hydroxide and copper sulphate
Test for soluble protein
what colour is sodium hydroxide
colourless
Test for soluble protein
what colour is copper sulphate
blue
Test for soluble protein
describe the setup
milk in a test tube with sodium hydroxide and a few drops of copper sulphate added in
Test for soluble protein
control
water
Test for soluble protein
final colour
purple
Test for soluble protein
colour change for control
stays blue
Test for Fat
describe experiment
rub fat on a piece of brown paper
Test for fat
what do we test
butter
Test for fat
control
water
Test for fat
change
a translucent stain appears and remains after drying
Test for fat
change in control
spot dries up after a day
MICROSCOPE
eyepiece magnification
x10
MICROSCOPE
objective lens magnification
x4, x10, x40
MICROSCOPE
what do you use coarse focus wheel with
with the low power lens
MICROSCOPE
what do you use the fine focus wheel with
high power lens
MICROSCOPE function of the focus wheels
focus the specimen
MICROSCOPE
stage
slide is placed here
MICROSCOPE
condenser/iris diaphragm
controls amount of light going onto the specimen
MICROSCOPE
lamp or mirror
shines light through the specimen
OBSERVING ANIMAL CELLS
how do you obtain the animal cells
using a clean cotton bud, remove a sample of chec cells from inside the mouth
OBSERVING ANIMAL CELLS
where do the animal cells go
place them on a slide
OBSERVING ANIMAL CELLS
2 things you could add to the slide
water
methylene blue
OBSERVING ANIMAL CELLS
to stain cells
methylene blue
OBSERVING ANIMAL CELLS
unstained cells
water
OBSERVING ANIMAL CELLS
how do you add the cover slip and why
place down from an angle of 45º to eliminate air bubbles
OBSERVING ANIMAL CELLS function of cover slip 2
protects specimen from drying out
protects the lenses
OBSERVING ANIMAL CELLS
what do you do before setting it up on the stage
dry excess fluid on the slide
OBSERVING ANIMAL CELLS
how do you secure the slide on the stage
clip it into position
OBSERVING ANIMAL CELLS
how do you locate suitable cells
using the low power objective lens
OBSERVING ANIMAL CELLS
how do you focus at the start
using the coarse focus wheel
OBSERVING ANIMAL CELLS
after you have located suitable cells
use a high power objective lens
OBSERVING ANIMAL CELLS
how do you focus using a high power objective lens
fine focus knob
OBSERVING ANIMAL CELLS
why do you only use a fine focus knob when using a high powered lens
the prevent damage to slide and lens
OBSERVING ANIMAL CELLS
how do you record the experiment
draw cells at high and low power
OBSERVING ANIMAL CELLS
how do you know where the nucleus is
the methylene blue stains the nucleus darker blue than the rest of the cells
OBSERVING PLANT CELLS
how do you obtain the cells?
using a scalpel, remove a thin piece of onion skin
OBSERVING PLANT CELLS
how do you know if the piece is thin enough
you should be able to see light through it
OBSERVING PLANT CELLS
why do we want the piece to be so thin
so that individual cells can be seen
OBSERVING PLANT CELLS
what do you add to cell for unstained cell
drop of water
OBSERVING PLANT CELLS
what do you add to cell for a stained cell
drop of iodine
OBSERVING PLANT CELLS
where do you put the onion cells
on a glass slide
OBSERVING PLANT CELLS
how do you put on the cover slip and why
add at an angle of 45º to prevent air bubbles
OBSERVING PLANT CELLS
before putting slide on the stage
dry any excess fluid from it
OBSERVING PLANT CELLS
how do you tell where the nucleus is?
iodine stains the nucleus darker than the rest of the cells
TRANSVERSE SECTION OF A DICOT STEM
describe the stem you use
a young wet privet stem
TRANSVERSE SECTION OF A DICOT STEM
why does it need to be young
so that the vascular bundles can be easily seen
TRANSVERSE SECTION OF A DICOT STEM
why does it have to be wet
so that it is easy to cut thin sections of the stem
TRANSVERSE SECTION OF A DICOT STEM
how do you cut up the stem
support the stem with your hand, place the stem on a chopping board and use a scalpel to cut thin transverse sections of the stem
TRANSVERSE SECTION OF A DICOT STEM
where do you put the thin pieces of the stem and why
transfer them to a dish of water to keep them moist
TRANSVERSE SECTION OF A DICOT STEM
how do you choose which pieces to use
choose the thinnest pieces
TRANSVERSE SECTION OF A DICOT STEM
how do you transfer the thinnest pieces onto a slide
using a paintbrush
TRANSVERSE SECTION OF A DICOT STEM
what do you put on the slide 2
water for stained or iodine for unstained
TRANSVERSE SECTION OF A DICOT STEM
how do you record the experiment
draw the best section under low and high power
TO DEMONSTRATE OSMOSIS
what do you do first
cut a section of visking tube and soak it in water to soften it
TO DEMONSTRATE OSMOSIS
what is visking tube
an artificial semi permeable membrane
TO DEMONSTRATE OSMOSIS
what do you do at one end of the tubing
tie a knot
TO DEMONSTRATE OSMOSIS
what do you fill the tubing with
a starch solution
TO DEMONSTRATE OSMOSIS
after you fill with a starch solution
tie a knot at the other end of the tubing
TO DEMONSTRATE OSMOSIS
what do you do to the bag then 2
dry the outside of the bag and weigh the bag
TO DEMONSTRATE OSMOSIS
where do you suspend the bag
in a beaker of water
TO DEMONSTRATE OSMOSIS
how long do you leave the bag for
about 15 minutes
TO DEMONSTRATE OSMOSIS
how do you find the results
dry the outside of the bag and reweigh it
TO DEMONSTRATE OSMOSIS
what would be the control
the same thing but with water instead of starch solution
TO DEMONSTRATE OSMOSIS
result for starch
weighs more at the end, it swelled
TO DEMONSTRATE OSMOSIS
why does the visking tubing weigh more at the end
water has entered the visking tubing bag by osmosis from a solution with more water to a solution with less water
TO DEMONSTRATE OSMOSIS
change in control
no change
equation for demonstrating how catalase works
hydrogen peroxide –(catalase)—> water and oxygen
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
how do you keep pH constant
add pH buffer 9 into the graduated cylinder
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
what do you add to graduated cylinder
a drop of washing up liquid
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
what is the function of the washing up liquid
allows the foam to form as oxygen is a product of the reaction
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
what enzyme do we use
catalase
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
what is the source of catalase
we add fresh chopped celery into the graduated cylinder which is the source of catalase
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
what is the substrate
hydrogen peroxide
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
how do we get the hydrogen peroxide
drop some hydrogen peroxide into the test tube
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
where do you first put the graduated cylinder and test tube
in a water bath at 0ºc
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
after is it in a water bath at 0ºc
add in some hydrogen peroxide and stir gently
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
how do you find the rate of enzyme action
measure the height of foam produced per minute
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
why do you repeat the experiment
repeat at different temperatures to get more results
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
how do you calculate results
draw a graph
EFFECT OF pH ON THE RATE OF ENZYME ACTION
how do you keep the temperature constant
put in a water bath at 25ºc
EFFECT OF TEMPERATURE ON THE RATE OF ENZYME ACTION
how do you change the pH
add different pH buffers each time, eg. pH 2, pH 4 etc.
THE EFFECT OF HEAT DENATURING ON THE RATE OF ENZYME ACTION
what do you place in both graduated cylinders
pH buffer 9 and washing up liquid
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
what do you put only in the graduated cylinder in the real experiment
chopped boiled celery
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
what do you put only in the graduated cylinder in the control experiment
chopped fresh celery
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
what does boiling the celery do?
denatures the enzyme catalase in the celery
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
what do you put in both test tubes
hydrogen peroxide
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
where do you put all the apparatus for both experiments
into a water bath at 25ºc
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
how do you start the reaction
pour some of the hydrogen peroxide from each test tube into each graduated cylinder
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
before you add in the hydrogen peroxide
allow some time to reach 25ºC
EFFECT OF DENATURINGE ON THE RATE OF ENZYME ACTION
how do you calculate the results
measure the height of foam produced per minute using a stop watch
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
result from the real experiment
no foam produced as the catalase was denatured
EFFECT OF DENATURING ON THE RATE OF ENZYME ACTION
result from control experiment
foam was produced
THE PREPARATION OF AN IMMOBILISED ENZYME
the first thing you have to do
prepare a solution of sodium alginate
THE PREPARATION OF AN IMMOBILISED ENZYME
what is sodium alginate
the gel that traps the enzyme
THE PREPARATION OF AN IMMOBILISED ENZYME
what do you add to the sodium alginate
add yeast
THE PREPARATION OF AN IMMOBILISED ENZYME
why do we add yeast
it is the source of the enzyme
THE PREPARATION OF AN IMMOBILISED ENZYME
what do you do with the enzyme solution
take it into a syringe and drop into a beaker of calcium chloride to allow beads to form
THE PREPARATION OF AN IMMOBILISED ENZYME
what happens when the beads are formed
the sodium and calcium swap places and hard beads of calcium alginate are formed around the yeast cells
THE PREPARATION OF AN IMMOBILISED ENZYME
after the beads are formed
allow to stand for 5 minutes to allow time for the beads to form
THE PREPARATION OF AN IMMOBILISED ENZYME
how do you remove debris
filter the mixture
THE PREPARATION OF AN IMMOBILISED ENZYME
how do you remove any surface yeast
wash the beads
THE USE OF AN IMMOBILISED ENZYME
what do you put in the 2 funnels
A: Beads of immobilised yeast
B: free yeast and water
THE USE OF AN IMMOBILISED ENZYME
what is free yeast
yeast and water
THE USE OF AN IMMOBILISED ENZYME
what do you add to each funnel then
sucrose
THE USE OF AN IMMOBILISED ENZYME
why do you add sucrose
it is the substrate for the enzyme in yeast
THE USE OF AN IMMOBILISED ENZYME
how do you collect the product
open the taps and collect the product in beakers
THE USE OF AN IMMOBILISED ENZYME
what do you note in the beakers
note if they are cloudy or clear
THE USE OF AN IMMOBILISED ENZYME
what do you test for in each solution
reducing sugar
THE USE OF AN IMMOBILISED ENZYME
how do you test for reducing sure
using Benedict’s solution
THE USE OF AN IMMOBILISED ENZYME
which is cloudy, the product from immobilised or free?
the product from the free yeast is cloudy
THE USE OF AN IMMOBILISED ENZYME
what does it mean that its clear
no enzyme mixed with the product
THE USE OF AN IMMOBILISED ENZYME
what does it mean that it is cloudy
enzyme is mixed with the product
THE USE OF AN IMMOBILISED ENZYME
which one tests positively for reducing sugar
both
THE USE OF AN IMMOBILISED ENZYME
is sucrose a reducing sugar
no
THE USE OF AN IMMOBILISED ENZYME
how is a reducing sugar present in the product
the enzyme in the yeast has converted the sucrose into a reducing sugar
THE USE OF AN IMMOBILISED ENZYME
2 advantages of an immobilised enzyme
- enzyme can easily be recovered and reused
- the product is pure
