methods of studying cells

Question 1

what is the first step before studying individual organelles

Answer 1

tissue is cut up

Question 2

what is tissue kept in after being cut up + why

Answer 2

cold, buffered, isotonic solution
cold - so any digestive enzymes don’t break up cells
buffered - so ph wont change
isotonic - WP same in + out of cells - otherwise cells would burst from osmotic shock

Question 3

how is tissue then further broken down

Answer 3

in a homogeniser

Question 4

what is the name of teh machine the prepared, blended tissue is spun in

Answer 4

ultracentrifuge

Question 5

what is the first spin in the centrifuge

Answer 5

low speed for 10 minutes

Question 6

what is the role of the homogeniser

Answer 6

to blend everything evenly

Question 7

what is the spun tissue called

Answer 7

supernatant 1,2,3

Question 8

what is the result of the first, low speed spin

Answer 8

nucleus is heaviest
will sink to bottom
removed from supernatant 1

Question 9

what is the part that sinks in after being spun called

Answer 9

sediment

Question 10

what is the second spin

Answer 10

medium speed

Question 11

what is the sediment in supernatant 2

Answer 11

chloroplasts + mitochondria

Question 12

why is the third and final spin

Answer 12

high speed

Question 13

what is found in supernatant 3

Answer 13

ribosomes

Question 14

what is separating organelles by spinning them called

Answer 14

cell fractionation

Question 15

what are the advantages of a compound light microscope

Answer 15

cheap
light and mobile
able to view living organisms
sows colour

Question 16

what makes compound light microscopes identifiable

Answer 16

2 lenses

Question 17

disadvantages to a compound light microscope

Answer 17

low magnification (x2000 max)

Question 18

what is identifiable about transmission electron microscopes

Answer 18

electron gun
4 lenses each with a different purpose
fluorescent screen

Question 19

advantages of transmission electron microscopes

Answer 19

much higher magnification
higher resolution

Question 20

disadvantages of a transmission electron microscope

Answer 20

expensive
large
non-living specimens only
no colour
2D images only
difficult to create slides
may produce artefacts

Question 21

what is the magnification of transmission electron microscopes

Answer 21

20,000-30,000 magnification

Question 22

what do scanning electron microscope
images do

Answer 22

takes images from different angles
electrons reflect off
3D image is created off of these images

Question 23

what is the magnification of optical light microscopes

Answer 23

1500-2000

Question 24

what is the magnification of transmission electron microscopes

Answer 24

up to 50,000,000

Question 25

what is the magnification of scanning electron microscope

Answer 25

up to 1,000,000

Question 26

what is the limitations of scanning electron microscopes

Answer 26

requires a vacuum
only dead specimens
may produce artifacts

Question 27

what are artefacts

Answer 27

features that appear in the image that aren’t part of the specimen
often come in the preparation process
there was a time where scientists could differentiae between atrifacts and organelles

Question 28

formula for magnification

Answer 28

IAM magnification =size of image/actual size of specimen