Micro-organisms

Question 1

what is a microorganism

Answer 1

a microorganism or microbe is an organism that is usually unicellular but can be multicellular

Question 2

prokaryotic

Answer 2

cells that have nuclear material but no true nucleas

Question 3

eaukaryotic

Answer 3

cells that have a true nucleus

Question 4

akaryotic

Answer 4

have no cell with cytoplasm or nucleus

Question 5

types prokaryotic organisms

Answer 5

bacteria and archea

Question 6

examples of Eukaryotic organism

Answer 6

fungi and protists

Question 7

examples of akaryotic organisms

Answer 7

viruses

Question 8

where can microorganisms be found

Answer 8

in all parts of the biosphere where there is liquid water

Question 9

microorganisms are critical to nutrient recycling as they act as

Answer 9

decomposes and some can fix nitrogen

Question 10

tube

Answer 10

provides a pathway for the light from the objective to the eyepiece

Question 11

rotating nose piece

Answer 11

a disc containing different objective lenses that can rotate to allow the different objectives to be use

Question 12

objective (lens)

Answer 12

convex lenses of different strengths to enlarge the image

Question 13

stage clips

Answer 13

the stage clips keep the microscope slide in position of the stage

Question 14

diaphragm

Answer 14

can be opened and closed to allow less or more light to pass through the specimen

Question 15

condenser

Answer 15

is a lens that focuses the light from the light source into the specimen

Question 16

light source

Answer 16

an electric light or a mirror providing light that will be directed to the specimen

Question 17

eyepiece (ocular)

Answer 17

convex lenses to enlarge the image (magnification of 10x)

Question 18

arm

Answer 18

connect the upper part containing the lenses with the lower part containing the light source and the microscope is picked up at the arm

Question 19

stage

Answer 19

a platform that supports the microscope slide

Question 20

coarse adjustment

Answer 20

rapidly moves the stage up and down to focus the image when the smallest objective is being used

Question 21

fine adjustment

Answer 21

slowly moved the stage up and down to focus the image when longer objectives are being used

Question 22

base

Answer 22

a heavy large surface area that supports the weight of the microscope to prevent it from falling over

Question 23

what is a limitation of a light microscope

Answer 23

even with perfect illumination as well as a perfect lense a light microscope can’t distinguish an object smaller then half a wave length of light (we then use an electron microscope)

Question 24

functioning of an electron microscope

Answer 24

electrons are speeded up in a vacuum until there wavelength is extremely short, beams of this is focused on a cell sample that is absorbed or scattered by the cells to form an image of an electron

Question 25

Transmission electron microscope (TEM)

Answer 25

can enlarge a specimen, and shows the inside structure

Question 26

scanning electron microscope (SEM)

Answer 26

shows the outside surface view of a solid specimen

Question 27

what is the drawback of an electron microscope

Answer 27

since no living specimen can survive under the high vacuum they cannot show the ever changing movements that characterise a living cell

Question 28

Vibrio Cholera

Answer 28

• causes cholera
• it is spread via contaminated food and water
• symptoms ; profuse diarrhoea and can lead to death

Question 29

Salmonella

Answer 29

invade the intestinal lining cells
can cause typhoid
found in water or food and raw poultry products

Question 30

Clostridium botulinum

Answer 30

• Grows in the absence of oxygen (botulism)
• produces one of the most dangerous toxins known to man
• comes from sausages and canned food
• symptoms; Flaccid paralysis 18-36 hours after ingestion and causes respiratory paralysis

Question 31

viruses

Answer 31

they do not posses a cell (no nucleus no cytoplasm) so they cannot be classified as living organisms

Question 32

how are viruses named

Answer 32

named according to the host they infect and the symptoms they produce