Microscopy And Organelles

Question 1

Light microscope

Answer 1

2 lens objective and eyepiece
X1500 magnification max
0.2 micrometers

Question 2

Laser scanning confocal microscope

Answer 2

Laser beams to scan specimen tagged w fluorescent dye
Focused through pinhole into detector creates 3D image
Look at different depths

Question 3

Electron microscopes

Answer 3

Use electrons to form image
Higher resolution give more detail
Transmission electron
Scanning electron

Question 4

Transmission electron microscope

Answer 4

Use EM transmitt through specimen denser parts absorb marking look dark
High resolution
only thin specimen
0.0002 micrometers resol
More than x1000000 mag

Question 5

Scanning electron microscope

Answer 5

Scan beam across specimen knocks off electrons gathered in cathode ray tube
Forms an image show surface of specimen in 3D
0.002 micrometer resol
X500000 magnification

Question 6

Magnification

Answer 6

Image size/object size

Question 7

Sample preparation

Answer 7

Dry mount
Wet mount - squash or smear

Question 8

Dry mount

Answer 8

Cut into v thin slices sectioning
Centre of slide and placed over sample

Question 9

Wet mount

Answer 9

Specimens suspend in liquid cover slip placed at angle can stain specimen before placing slip
Squash slide gently press down cover slip
Smear slide - edge of slide at 45 degree angle smear creating even coat cover slip placed on top

Question 10

Staining

Answer 10

Cytosol of cells is transparent stains incr contrast between components
Air dry sample and heat fix
Crystal violet and methylene blue attracted to negatively charged components
Nigrosin or Congo red repelled by cytosol cells in stained cells stand out from background

Question 11

Gran staining

Answer 11

Gram positive retain crystal violet appearing blue or purple (susceptible to penicillin strong cell walls)
Gram negative thinner cell walls lose stain appear red after counter stain

Question 12

Eyepiece graticule and stage micrometer

Answer 12

Line up stage microm and eyepiece graticule
Each div on stage microm is 0.1mm long
Work out number of divisions of eyepiece in 1 stage microm
Divide 0.1 by number of divisions
Times this number by how many counted divisions

Question 13

Nucleus

Answer 13

DNA to code for proteins
Histones form chromatin which coils and condenses forming chromosomes

Question 14

Nucleolus

Answer 14

Responsible for producing ribosomes

Question 15

Mitochondria

Answer 15

Cellular respiration forming atp
Inner membrane folded forming cristae
Interior= matrix
Contain mitochondrial dna producing own enzymes (smaller than dna circular genome )

Question 16

Vesicles

Answer 16

Membranous sacs
Single membrane
Transport inside cell

Question 17

Lysosomes

Answer 17

Specialised vesicles containing hydrolytic enzymes breaking down waste

Question 18

Cytoskeleton

Answer 18

Present in all eukaryotes
Network of fibres necessary for shape and struc of cell
Controls cell movement as well
Consist of micro filaments microtubules and intermediate fibres
Centrioles present in most

Question 19

Microfilaments

Answer 19

Contractile fibres formed from actin
Responsible for cell movement and during cytokinesis

Question 20

Microtubules

Answer 20

Globular Tubulin proteins polymerise forming scaffold like structures
Tracks for movement of vesicles
Spindle fibres in cell division made up of microtubules

Question 21

Intermediate fibres

Answer 21

Give mechanical strength to cells and help maintain integrity

Question 22

Centrioles

Answer 22

Component of cytoskeleton composed of Microtubules
2 associated centrioles form a centrosome involved in organistaion of spindle fibres

Question 23

Flagella and cilia

Answer 23

Each cilium contains 2 central Microtubules surrounded by 9 pairs of Microtubules
Parallel microtubules slide over each other