1 Cell structure

Question 1

Types of microscopes

Answer 1

• light
• transmission electron
• scanning electron

Question 2

Light microscopes

Answer 2

• poor resolution due to the long wavelength of light
• living samples can be examined and a colour image is contained

Question 3

Transmission electron microscope

Answer 3

• high magnification and resolution
• electrons pass through the specimen to create an image

Question 4

Scanning electron microscope

Answer 4

• high magnification and resolution
• electrons bounce off the surface of the specimen to create an image

Question 5

Resolution

Answer 5

the minimum distance between 2 objects in which they can still be viewed as separate
optical- determined by the wavelength of light
electron- determined by the wavelength of the beam of electrons

Question 6

Magnification

Answer 6

how many times larger the image is compared to the object

Question 7

Magnification equation

Answer 7

I/AM

Question 8

Conversion

Question 9

Electron microscopes

Answer 9

• a beam of electrons has a very short wavelength=a high resolution (small organelles and internal structures can be visualised)
• image is created using an electromagnet to focus the beam of negatively charged electrons
• image is black and white and must use stains

Question 10

Why a vacuum must be used

Answer 10

• electrons are absorbed by air
• therefore only non-living specimens can be used