microscopes

Question 1

define maginification

Answer 1

.how much bigger the image is than the specimen

Question 2

define resolution

Answer 2

. how well the microscope distinguishes between two points that are close together

Question 3

how to calculate magnification

Answer 3

mag=image size/real size

Question 4

what are the two main types of microscopes

Answer 4

optical/light microscope
electron microscope

Question 5

how does light microscope work?

Answer 5

.uses wavelength of light
.low resolution
.low magnification
.alive specimens

Question 6

how does electron microscope work

Answer 6

.uses electrons to form an image
.higher resolution than optical microscope
.higher magnification
.organelles are clear

Question 7

what are the two types of electron microscopes

Answer 7

1.scanning electron microscope and 2.transmission electron microscope

Question 8

how does scanning work

Answer 8

.SEMS scan a beam of electrons across the specimen, they’re knocked off to a cathode ray to form an image
.3D image
.good for thick specimens. lower resolution that TEM

Question 9

how does transmission work

Answer 9

.uses electromagnets to focus on a beam of electrons, these are transmitted through the specimen so it has to be thin
.some parts are darker than others because they absorbed more electrons
.highest resolution

Question 10

what are the limitations of both electron microscopes?

Answer 10

.complex staining process
.must happen in vacuum so specimens must be dead
.image may contain artefacts( little man made things that accidentally end up on specimen)

Question 11

how would you identify starch grain in plant cell?

Answer 11

use iodine in potassium iodide solution to identify starch grains in plant cells.