biology

Question 1

magnification

Answer 1

The eyepiece and objective lenses each have
their own magnification value.

To calculate the magnification of the image,
multiply these values together

Changing the eyepiece lens rotating the nosepiece to use another
objective lens can give different magnifications.
Always start with a
lower magnification.

The focusing knob(s) do not magnify the image
– they
make it clearer.
Always focus away from the
object.

Question 2

what are the parts of microscope

Answer 2

observer’s eye
eye piece lens
eye piece
focusing knob
rotating nose piece
objective lens
slide cover slip
specimen
slide
slide clip
stage
mirror
lamp

Question 3

petri dish

Answer 3

The petri dish is coated with
agar – a gel-like substance
containing nutrients to help
the microbes to grow.The lid will help prevent unwanted microbes landing on the agar,
contaminating the culture.
The plate will be stored in an incubator at a constant temperature for
microbes to reproduce. With enough food, warmth and oxygen, the
microbes will reproduce to form a colony.

Question 4

aseptic techniques do

Answer 4

DO…

…sterilise all apparatus before use;

…keep the lid on the petri dish as much as possible when preparing the
plate;

…label your cultures carefully;

…keep the dish upside-down after preparation;

…ensure the lid is only loosely taped while the cultures are growing;

…dispose of used cultures in
strong disinfectant;

…wash your hands and
wipe down all surfaces
when finished.

Question 5

aseptic techniques do not

Answer 5

DO NOT…

…eat or drink during the experiment;

…grow microbes that are known to be
harmful;

…mix different microbes on the same plate;

…cough or sneeze on your plate;

…incubate microbes at temperatures close to
body temperature;

…unseal or open the plate once the microbe
colony has grown.

Question 6

…

Answer 6

…