B1.1 Microscopy

Question 1

Who first observed cells and using what?

Answer 1

The first cells of a cork sere observed by Robert Hooke in 1665 using a light microscope

Question 2

Features of light microscope

Answer 2

-it has two lenses,an kbjective and eyepiece lens
-the objective lense produces a magnified image,which is then mangnified and directed into the dye by the eyepiece lens
-usually illumanted from underneath
-they have approx, maximum magnification of x2000 and resolving power (affects resolution so the ability to distinguish between 2 points) of 200nm ( the lower the RP, the more detail seen)
-used to view tissues,cells and sub-cellular structures
-magnification of 50x,100x,400x

Question 3

When was electron microscope created and what was it used for

Answer 3

In 1930 electron microscope was developed, enabling scientists to look at sub-cellular structures, such as mitrochondria, ribosomes, chloroplasts and plasmids

Question 4

Features of electron microscopes

Answer 4

-electrons, as opposed to light, are used to form an image because electrons have much smaller wavelength than that of light waves
-2 types: a scanning electron microscope that create 2D images and a transmission electron microscope which creates 2D images detailing organelles
-They have magnification of up to x2,000,000 and resolving power of 10nm and 0,2nm

Question 5

Common calculation and formula

Answer 5

Magnification of eyepiece lens x magnification of the objective lens= magnification of light microscope
-size of an object: size of image/magnification=size object (this can be rearranged)

Question 6

Equation traingle for microscopy

Answer 6

Magnification=size of image/ size of real object

Question 7

Example question for microscopy

Answer 7

Use a ruler size to measure image size of the nucleus in mm. the diameter kf the real nucleus is 0.01mm. Calculation magnification.

Size of the image is 45mm measured with ruler.

So size of image/ size of real object=45mm/0.01mm=4500x