Save
...
Paper 1
Biol 112
Practicals
Save
Share
Learn
Content
Leaderboard
Learn
Created by
Pierre Gasly
Visit profile
Cards (33)
Why is 70% alcohol used for disinfectant of covid-19
It destroys the
lipid bilayer
and disrupts the
hydrogen
bonding
of
proteins
/
What is wax soluble in
Histoclear
What is DPX mountnt soluble in
Histoclear
Is alcohol solbule in water
No
it is
miscible
What is alcohol miscible in
Water
and
histoclear
Is histoclear miscible with water
no
What does eosin bind to
Proteins
What type of stain is eosin
Acidic
What does eosin stain
proteins
stain
red
What does haematoxylin stain
DNA blue
What type of stain is haemotoxylin
Basic
Is haemotoxylin water soluble
Yes
What charge molecules does eosin bind to
Positive
Does the brightfield microscope use fixed lenses
Yes
What does a reduction in the condensor aperture diameter of a brightfield microscope produce
Increased contrast
What type of cells is a brightfield microscope used for
living
What happens to depth of field as the magnification of a brightfield microscope increases
It will
increase
What is the maximum thickness of specimen for a brightfield microscope
10
microns
What is the equation for resolution of a light microscope
Resolution = (
0.61
*
lambda
) /
NA.
Where
NA
=
n
sin
alpha
and
Lambda
is the
wavelength.
What is NA in the resolution equation
It is
n
Sin alpha.
Where
alpha
is the
angle
that
light
enters the
lens
it is often
70
degrees.
n
is the
refractive
index
and is
1
for
air.
Calculate the resolution when The wavelength of light is 450 nm [show working to 3 sig fig]
Resolution = (
0.61
*
450
) / (
1
*
sin
70
) =
292
nm
=
0.292
microns
What is the refractive index of oil
1.5
Which microscope parameter has the highest improvement of resolution [Refer to resolution equation]
Wavelength
Why is a sucrose solution of 0.5M used to extract chloroplasts
The
0.5M
is
isotonic
to the chloroplasts and so prevents them from
swelling
and
bursting.
What does isotonic mean
The
concentration
of
solute
is
equal
outside
and
inside
the solution.
What is a hypotonic solution
The
concentration
of
solute
is
lower
outside
than
inside
the cell.
What is the effect of an isotonic solution
There is
no
net
movement
of
water
What is the effect of a hypotonic solution
The
net
movement
of
water
is
into
the
cell
causing it to
swell
and
burst.
What is the effect of a hypertonic solution
The
net
movement
of
water
is
out
of the
cell
and causes it to
shrink.
What is a hypertonic solution
The
concentration
of
solute
is
higher
inside
the cell than
outside.
What is the effect of criticcal point drying of extracts for microscopic analysis
It prevents
shrinking
What is used for critical point drying
Liquid carbon dioxide
Label the images and state where they come from
These are from a
plant
cell.
A)
Stomata
B)
Vascular bundle
C)
Chloroplast
D)
Granum
4