Cell Structure - Harder Flashcards
What does the objective lens do?
Focuses light and increases magnification.
What does the eyepiece lens do?
Increases magnification.
What does the light source do?
Shines light through a specimen so it can be seen clearer.
What is the role of an eyepiece graticule?
In eyepiece, used to measure the size of an object viewed under a microscope.
Has to be calibrated.
100 divisions with no scale.
What is the role of a stage micrometer?
- Used to calibrate eyepiece graticule.
- 1mm with 100 divisions - each division = 10 micrometers.
- Put in microscope as if it was slide.
Why is the cover slip lowered at an angle onto a slide?
To prevent bubbles.
What is differential staining?
- Using multiple stains.
- Each stain binds to different structures.
- Allows separate structures to be identified.
Advantages of staining?
Increases contrast.
Can differentiate between different cells/parts of cell.
Advantages of light microscopes?
- Cheap.
- Easy to use.
- Can observe living organisms.
Describe how a laser scanning confocal microscope works.
- Specimen treated with fluorescent dye.
- Laser causes components labelled with dye to reflect.
Advantages of laser scanning confocal microscope.
- High resolution due to the fact laser beam has small wavelength.
- Non invasive.
- Can view objects inside cells.
Structure of the nucleus
- Has membrane with pores to allow molecules in and out of nucleus.
- Stores cell’s DNA.
What is chromatin?
DNA + histones
Where are ribosomes produced?
Nucleolus
SER function
Synthesis of lipids
RER function
Protein synthesis for proteins to be outside of cell.
