Cells Flashcards
What is the function of the Golgi apparatus.
Packages proteins e.g. Goblet protein makes mucus.
How does an optical microscope work?
Uses a light source
Lots of lenses
Produces 2D image
Magnification of 1500
What are the advantages of using an optical microscope?
Very easy to use.
Low cost.
Samples can be living.
What are the disadvantages of using an optical microscope.
Low magnification.
Poor resolution.
It won’t work without a light source.
You can only see the surface of the sample, not inside.
How does a TEM work?
Electron gun makes beams of electrons
Electrons are focused onto the specimen by condenser
Produces a 2D image
Magnification of 1,000,000
What are the advantages of using a TEM?
Most powerful magnification.
Wide range of applications.
Easy to operate.
What are the disadvantages of using a TEM?
Very large and expensive.
Samples take a lot of prep and must be dead.
Requires special maintenance.
How does an SEM work?
Directs beam of electron onto the surface of the specimen.
A 3D image is produced.
Magnification of 500,000
What are the advantages of using an SEM?
Lots of applications.
Fast working.
Produces 3D image.
What are the disadvantages of using an SEM?
Very big.
Expensive.
Special training is required to operate it.
Small risk of radiation exposure.
What is homogenisation?
Breaking up cells but not the organelles so that you can isolate a certain organelle.
What is differential centrifugation?
Spinning test tubes with homogenate to separate organelles?
What is the order in which organelles will separate in a centrifuge?
Nucleus
Mitochondria
Both ERs and the Golgi
Ribosomes
What is a pellet?
The deposit of denser organelles left after centrifugation.
What is the purpose of the palisade leaf cell?
Large number of chloroplasts to absorb as much sunlight as possible.
What is the purpose of the waxy cuticle?
To waterproof the leaf
Protection
What is the purpose of the spongy mesophyll layer?
Air pockets for CO2 to collect
Some absorption of sunlight occurs.
What is the purpose of the stomata?
To allow CO2 to be released
How do the stomata release CO2?
Water diffuses into to guard cells making them turgid which causes them to open.
Name one adaptation of mitochondria
Large surface area to volume ratio.
What does SEM mean?
Scanning electron microscope.
What does TEM mean?
Transmission electron microscope.
What is the function of the nucleus?
It’s the control centre of the cell
