2 - Basic components of living systems Flashcards
What is a microscope?
instrument that enables you to magnify an object
What do microscopes allow us to discover?
how details of their structure relate to their function
When was the light microscope developed?
16th/17th century
What was the first microscope to be developed?
light microscope
Why could microscopes in the 19th century see individual cells?
had a high enough resolution
What does the cell theory state that both plant and animal tissues are composed of?
cells
What do cells only develop from?
existing cells
How was cell theory developed?
as microscopes had higher magnification/resolution
What is the availability like for light microscopes?
easily available
How expensive is the light microscope?
relatively cheap
What organisms can be observed under a light microscope?
living organisms as well as dead, prepared specimens
How many 2 lenses does a compound light microscope have?
objective and eyepiece lens
Where is the objective lens found on a compound light microscope?
near to the specimen
What is the eyepiece lens?
where specimen is viewed
How does a compound light microscope work?
objective lens produces a magnified image, which is then magnified again by eyepiece lens
What does the objective/eyepiece lens configuration allow for?
- higher magnification
- reduced chromatic aberration
Where is illumination usually provided by in a compound microscope?
light underneath the sample
What is sectioning?
specimens cut into very thin slices with a sharp blade
What is dry mount?
specimen placed on centre of slide and cover slip placed over sample
What are some examples of specimens that can be viewed using dry mount?
hair, pollen, dust (muscle tissue have to be sectioned first)
What is wet mount?
specimens suspended in a liquid e.g. water or immersion oil
How is the cover slip placed on wet mount?
at an angle
What specimens can be viewed using wet mount?
aquatic samples + other living organisms
What are squash slides?
wet mount first prepared, then lens tissue used to press down cover slip