microbes lecture 1

Question 1

▪ 1347: Plague/”Black Death”: caused by

Answer 1

Yersinia pestis (bacterium).

Question 2

▪ Robert Koch: proved

Answer 2

bacteria cause diseases

Question 3

Koch’s postulates 4:

Answer 3

1.Respective microorganism present in sick individuals,
not healthy.

2. Isolate and grow in a pure culture.

3.Inoculate into a healthy host – same disease should
occur.

4. Re-isolate the same organism from the new diseased
   host

Question 4

discovered penicillin?

Answer 4

▪ Alexander Fleming

Question 5

Fannie Hesse:

Answer 5

use of agar instead of gelatine.

Question 6

who led to the use of agar instead of gelatine.

Answer 6

Fannie Hesse

Question 7

petri dish discoverer

Answer 7

▪ Richard Petri

Question 8

6 general characteristics of microbes

Answer 8

1. diverse in size, microscopic
2. less complex than animals and plants
3. rapid growth rates
4. ubiquitous, abundant
5. NB role in cycling of nutrients and functioning ecosystems
6. diverse metabolic pathways
   - metabolites used in medicine

Question 9

during decomposition of biological material what is released back into the environment by decomposers

Answer 9

C, N, S, P, etc

Question 10

what do denitrifers do

Answer 10

when organisms that contain N die, they return the N to the atmosphere completing the cycle

Question 11

certain prokaryotes convert N2 to what

for what?

Answer 11

Ammonia NH3

For building amino acids, DNA and other N containing molecules

Question 12

taxonomy hierarchy names

Answer 12

Dear King Philip Cried Out For Goodness Sake
Domain
Kingdom
Phylum
Class
Order
Family 
Genus
Species

Question 13

def of type strain

Answer 13

one strain of a species, usually the one which the most representative of the species

Question 14

Domain Eukarya includes what kingdoms

Answer 14

1. Fungi
2. Animalia
3. Plantae
4. Protista

Question 15

What domains are chemoheterotroph

Answer 15

fungi and animalia

Question 16

what domain is a photoautotroph

Answer 16

plantae

Question 17

evolution of Eukarya from prokaryotes involved 2 primary processes

Answer 17

1. membranous organelle: ER, nuclear membrane, golgi apparatus, lysosomes & vacuoles etc.
   - infolding of the plasma membrane
2. Mitochondria 1st, Chloroplast 2nd:
   - small prokaryotes established residence inside larger ones via endosymbiosis, deriving their outer membrane from plasma membrane of host cell
   - evolved interdependent relationship
   - Mitochondria= heterotrophic prokaryotes that had a great efficiency for aerobic respiration
   - Chloroplast= photosynthetic autotrophs

Question 18

which domain is the most primitive

Answer 18

archaebacteria

Question 19

Domain archae’s gene translation relates more to which domain and why

Answer 19

Eukarya

-Some genes have introns, which is completely absent in bacteria

Question 20

evolutionary relationship of the 3 domains

Answer 20

both Bacteria and Archaebacteria descended from a common ancestor and then Eukarya later split from Archaebacteria

Question 21

4 similarities of prokaryotes and eukaryotes

Answer 21

1. contain DNA as genetic material
2. cytoplasm is membrane bound
3. use ribosomes for protein synthesis
4. similar metabolic processes

Question 22

describe the bright-field microscope

Answer 22

• light microscope
• eyepiece with 10x magnifying power
• 3 objective lenses: 10x, 40x, 100x

Question 23

How does a light microscope work

Answer 23

• light rays pass through the specimen

- the objective and eyepiece lenses magnify the image

Question 24

why is it called a light microscope

Answer 24

light is passed through the specimen into our eyes

Question 25

what does a electron microscope use and what are the 2 types

Answer 25

• electron bean
  1. SEM-scaning= e-s emitted from object’s surface
  2. TEM-transmission= e-s pass through specimen, useful in studying internal organelles/virus particles

Question 26

EM has a higher resolution than light…what does this mean

Answer 26

the minimum distance between 2 points in a specimen can still be separated and seen as 2 pointd

Question 27

why are e- suitable radiation from microscope? 2

Answer 27

1. short wavelengh, therefore higher resolution

2. negative charge, easily focused using a electromagnet

Question 28

3 disadvantages of EM

Answer 28

1, specimen must be in a vacuum (otherwise air molecules would collide with e-=blurry image)

2. specimen must be dehydrated
3. only dead organisms can be examined