2.1.1

Cell Structure

What does EGU stand for

Eyepiece graticule unit

Equation to find 1 EGU

1 EGU = real length/no.of EGU

Equation to find specimen size

Specimen size = EGU divisions x value of 1 EGU

How many micrometres in 1 millimetre

1000

What are the 3 different types of microscopes

1. Light Microscope

2. Transmission Electron Microscope

3. Scanning Electron Microscope

In a light microscope what is used to control the illumination entering the objective lens

Condenser Lens

What type of magnification does a microscope provide

Linear

Definition of resolution

The degree to which it is possible to distinguish between two objects that are very close together

How does coloured dyes used to stain tissues

These dyes absorb some colours of light and reflect others making the structures that bind the dye visible

What does staining does to the contrast

Increases

Name all 7 stains

(Every Smart Med Girl Has Interesting Aims)

1. Eosin

2. Sudan Red

3. Methylene Blue

4. Giemsa

5. Haematoxylin

6. Iodine in potassium iodide solution

7. Acetic orcin

What is the use of eosin

Stains cytoplasm

What is the use of sudan red

Stains lipids

What is the use of methylene blue

Stains animal cells to make nuclei more visible

What is the use of giemsa

Staining of cellular blood components and blood parasites

What is the use of haematoxylin

Stains nuclei blue-violet or brown

What is the use of iodine

Stains cellulose in plant cell walls yellow, starch granules blue/black

What is the use of acetic orcin

Binds to DNA and stains chromosomes dark red

How does charges affect stains

Stains can be positively or negatively charged and will be attracted to the opposite charged materials in the cytoplasm, leading to staining of cell components

What is differential staining

Differential staining is a staining process which uses more than one chemical stain.

Using multiple stains can better differentiate between different microorganisms.

What are the 6 membrane-bound organelles

1. Nucleus

2. Mitochondria

3. Chloroplast

4. Endoplasmic Reticulum

5. Golgi Apparatus

6. Lysosome

What are the 3 non membrane-bound organelles

Ribosomes

Centrioles

Cytoskeleton