Cell Structure Flashcards
Define Mgnification
How much bigger an image seems compared to the origional object
Define Resolution
The clearness of an image produced by a microscope
Often said as the ability to distinguis between to points of a certain distance apart
What are 4 advantages of a light Microscope
Cheap
Easy to use
Portable (Field work)
Able to study whole organisms
How do Laser Scanning Microscopes form an image
Scan an object point by point and then transfer that onto a computer
What is the main difference between a TEM and SEM
Transmission electron microscopes fire electrons THROUGH the specimin, whereas SEM bounce electrons off the surface.
Why do you stain a specimin
In order to create contrast and see the specimin easier
What is known as the all purpose stain?
Methylene Blue
What stains DNA and chromosomes dark red
Acetic Orsin
What stains Cytoplasm
Eosin
What stains lipids
Sudan Red
What stains starch black
Potassium Iodide (Iodine)
What stains cellulose yellow?
Potassium Iodide (Iodine)
How do you use a stage micrometer to calibrate an eyepiece graticule
Place a stage micrometer on the stage and then compare it at your magnification to the eyepiece graticule
Then use I = A x M to work out the size of divisions
What feature of the nuclear envelope allows mRNA to move out
The nuclear pores
What is made in the Nucleolus
Ribosomes
What is the Structure and Function of RER
A system of membranes and fluid-filled cavities (cisternae), coated with ribosomes
RER is the transport system of the cell
When the ribosomes on the surface make proteins they instantly move into the RER where they are transported to the Golgi apparatus
What is the Stricture and function of the SER
System of membranes and Cisternae
Contains enzymes involved in synthesis of Cholesterol, lipids and hormones
Also used to transport and absorb lipids
What is the function of the Golgi apparatus
Modification and preparation of materials
E.g proteins can be modified by adding sugar or lipids to make glycoproteins and lipoproteins
Describe the structure of a ribosome
Made in the nucleolus as 2 separate subunits (40s and 60s)
Combine outside the nucleus to form a ribosome
What are the stages of protein synthesis
mRNA instructions made in nucleus
mRNA leaves nucleus through nuclear pore
Binds to a ribosome
Protein is then made in the RER by the ribosome
Pinched off as a vesicle by the RER
Vesicle fuses with Golgi apparatus
Protein is packaged and ready for release
Pinched off as a vesicle
Vesicle fuses with plasma membrane
Membrane opens to release protein outside the cell
