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.
Golgi function
Stores, modifies and packages proteins.
Lysosome function
Contains hydrolysing enzymes
