Cell structure and Division

Question 1

What is magnification

Answer 1

how much bigger the image is than
the specimen

Question 2

DNA in prokaryotic cell

Answer 2

no nucleus, circular DNA
- one long coilded up strand
- not attached to any histone

Question 3

cell vaculoe function

Answer 3

• keep cell rigid
• stop plants from withering
• help maintain pressure inside the cell
• involve in isolation of unwanted chem inside cell

Question 4

what is virus

Answer 4

• acellular (not cells)
• just nucleic acid surrounded by protein

Question 5

how protein attachment in virus attach to host cell

Answer 5

• use their att pro to bind to complementary receptor protein on cell surface memb of host cell
• diff virus = diff att protein = require diff receptor on protein on host cell

Question 6

Optical Microscope

Answer 6

• use light to form an image
• max resu - 0.2 micrometeres, can’t use optical micro to view orga smaller than 0.2 microm
• max magnification - about x1500

Question 7

Electron microscope

Answer 7

• use electrons to form an image
• have higher resolution than optical micro, give more detailed image
• max reso = 0.0002 microm
• max magni = elec microscope about x 1500000
• produce black nd white image - often coloured by computer

Question 8

transmission electron microscope

Answer 8

• use elemag to focus beam of electron through the specimen
• denser part = ab more elec - make the image darker
• have higher resu - see internal stu of organells
• only view the specimen in vacuum - work for non living org
• need to have thin specimen

Question 9

Scanning electron microscope

Answer 9

• scan beam of ele on specimen
• knocks off ele - gahter by catheter ray tube - form an image
• image = show sure of speci , can be 3D
• good = can be used for thick spci
• only work on non living org
• low reso than TEM’s

Question 10

Temporary mount

Answer 10

where specimen is suspended ina drop of liquid on the slide
- also known as wet mount

Question 11

Stain

Answer 11

use to highlight obj in cell
- iodine in potassium iodide used too stain starch grains in plant cells
- Eosin used to make cytoplasm show up

Question 12

what is an artifact

Answer 12

things that you can see down microscope that aren’t part of cell or specimen that you’re looking at

Question 13

how scientist used to distinguish bet artefacts and organells

Answer 13

• use ele micro to distinguish
  by preparing specimens in different ways
• compare each view - if obj seen with one preparation tech but not another , more likely to be an artefact

Question 14

Function of mitosis

Answer 14

• growth of multicellular org
• reparing of damaged tissues

Question 15

Mitotic index

Answer 15

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