basic components of a living system: microscopy, magnification and calibration

Question 1

what is the cell theory

Answer 1

• cells are the basic building blocks of life
• cells only develop from existing cells
• both plant and animal tissue is composed of cells

Question 2

benefits of using a light microscope

Answer 2

relatively cheap
easily available
can be used out in the field
can be used to observe living organisms as well as dead

Question 3

how a compound light microscope works

Answer 3

it has two lenses , objective lense (placed near to the specimen) and the eyepiece lens (where the specimen is viewed).
the objective lens produces a magnified image which is magnified again through the eyepiece lens
this configuration allows a higher magnification and a reduced chance of refraction that that of a simple light microscope

Question 4

what is differential staining

Answer 4

distinguishing between 2 different types of organisms that would otherwise be hard to identify
it can also differentiate between different organelles of a single organism within a tissue sample

Question 5

what are the two types of electron microscope

Answer 5

transmission electron microscope
scanning electron microscope

Question 6

transmission electron microscope

Answer 6

beam of electrons is transmitted through a specimen and focused to produce an image.
similair to light microscopy
bestt resolution of 0.5 nm

Question 7

scanning elecctron microscope

Answer 7

beam of electrons sent across surface of a specimen and the reflected electrons are collected.
resolving power of 3 - 10 nm
resolution isnt as good but 3d images are produced.