Lecture 4 Flashcards
(52 cards)
1
Q
Autotrophs
A
obtain carbon from inorganic carbon sources (CO2)
2
Q
Heterotrophs
A
Obtain carbon source from glucose and other molecules
3
Q
Phototrophs
A
Obtain energy from light
4
Q
Chemotrophs
A
Obtain energy from chemicals
5
Q
Why is nomenclature helpful?
A
certain strain, serotype, or morphotype of a bacteria can be pathogenic where as others are non-pathogenic Ex. E.Coli O157: H7 - ‘O’ refers to o-antigen - H7 refers to type of flagellar protein
6
Q
Photoautotrophs
A
- Obtain light as energy - Obtain Carbon dioxide as carbon source
7
Q
Photoautotrophs (example)
A
*Anoxygenic* - Green sulfur bacteria - Purple sulfur bacteria *Oxygenic* - Cyanobacteria (pro) - Algae (eu)
8
Q
Photoheterotrops
A
- Use light as energy source - Obtain carbon from organic molecules
9
Q
Photoheterotrophs (examples)
A
*anoxygenic*
- green non-sulfur bacteria - purple non sulfur bacteria *oxygenic* - some archaea
10
Q
Chemoautotrophs
A
- perform chemosynthesis (not photosynthesis)
- b/c energy is obtained from chemical reaction
ex: nitrifying bacteria
11
Q
Photoautotrophs (type)
A
- Oxygenic photosynthesis 2. Anoxygenic photosynthesis
12
Q
Most disease causing microorganism are (nutritional classification)
A
- Chemoheterotrophs - because disease causing microorganism have to be able to survive in conditions that we live in
13
Q
Chemoheterotrophs (type)
A
- Aerobic respiration: most animals, fungi, protozoans, most bacteria
- Fermentation: some animals, protozoans, bacteria, archaea
- Anaerobic respiration: some bacteria, yeast, and archaea
14
Q
Bacteriochlorophyl
A
In both green/purple non sulfur bacteria used as pigment instead of chlorophyll
15
Q
Bacteriorhodopsin
A
Extreme halophiles use this instead of a chlorophyl derivative - single component of energy synthesis (no need for ETC0
16
Q
Chemosynthesis
A
(compare to photosynthesis) - energy source comes from chemical reaction (instead of light)
17
Q
Nitrifying bacteria
A
- they are chemoautotrophs
- nitrosomonas – converts ammonium (NH4+) to nitrite (NO2-)
- nitrobacter – Converte nitrite (NO2-) to nitrate (NO3-)
18
Q
Giant tube worms
A
- example of chemoautotrophs
- concentrate H2S for bacteria that lives in it’s gut
- Symbiotic relationship
– Bacteria synthesizes food for the worm
19
Q
Typical growth curve
A
- Lag phase
- Exponential groth phase
- Stationary phase
- Death phase
20
Q
Lag phase
A
- the bacteria cultured from previous stationary/death phase have shut down their metabolism/protein synthesis
- so it takes time for the bacteria to get used to the new environment and restart their gene expression that that had previously shut down
21
Q
Exponential growth phase
A
- where bacteria are doubling very rapidly (at max speed)
- more growth than deate
22
Q
Stationary phase
A
- bacteria run out of food
- thus growth is slow/sluggish
- bacteria are growing/dying at the same rate
23
Q
Death phase
A
- more death than growth b/c nutrients are lacking
- poor environment
24
Q
Biofilms
A
- Organized complex community of a layered system of bacteria and other microbes
- prevent effectiveness of immune system and drugs due to gooy slime acting as a capsule
25
Cultivation of microbes (different composition of media)
1. Defined/synthetic
2. Complex
3. Enriched
26
Defined/synthtic growth media
- composition of chemical in media is known
27
Complex growth media
- the exact composition of media is unknown
28
Enriched growth media
- contain special nutrients in growth media for fastidious microorganisms
29
Chocolate agar
- enriched growth media
- best for fastidious bacteria like Neisseria
- contains lysed RBC (heme and NAD) for growth of bacteria (bacteria need these for growth)
30
Cultivation of microbes (different types of media)
- selective
-- allow growth of certain microbes while inhibiting others
- differential
-- distinguish one type of microbes from another
31
Example of Differential Complex media
Blood Agar
32
Beta-hemolysis
Protein in Streptococcus pyogenes
- complete digestion (lyse) of RBC
- able to diffrenciate this bacteria on blood agar
33
MacConkey agar
Selective growth media
- contains bile salts and crystal violet
--which inhibit growth of gram (+) bacteria
- contain lactose
-- allows us to see which bacteria can undergo fermentation
- contains neutral red
-- Turns red in low pH conditions (when lactic acid is synthsized from lactose fermentation)
34
barophiles
- Organisms that live under extreme pressure
- membrane and enzymes are dependent on the pressure to fold correctly
35
Growth Requirements
1. water
2. osmoric pressure
3. hydrostatic pressure
4. temperature
5. oxygen
36
Different type of organisms that grow in varying temperatuer
**Psychrophiles --\>** 0-20°C
**Mesophiles** --\> 10-45°C
- usually pathogens that affect humans
**Thermophiles** --\> 40-80°C
**Hyperthermophiles** --\> up to 113°C
37
Obligate aerobes
- use oxygen as final electron acceptor
- oxygen is essential for these organism
38
obligate anerobes
- oxygen is deadly for them
- are affected by:
1. Singlet oxygen
2. Superoxide raidcal
3. Perioxide anion
4. Hydroxyl radical
39
Singlet oxygen
- 1O2
- primarily a concern for photosynthetic organism
- photon excits an electron to a higher energy state
- too much of this will result in electron leaving the oxygen atom
40
carotenoids
- keep electrons from floating away by absorbing energy from overly excited electrons during photosynthesis
- prevent singlet oxygens from forming
- usually presnet in phototrophic organism
41
Superoxide radicals
- O2 -
- form during incomplete reduction of oxygen in aerobic and anaerobic respiration
- excited oxygen at the end of ETC leaves without being fully reduced to water
42
superoxide dismutase
- converts superoxide to hydrogen peroxide
- presnet in both aerobic and anaerobic respiration
- however hydrogen peroxide can dissociate to two more deadly oxygen derivatives
-- Peroxide anion
-- Hydroxyl radical
43
Catylase/Peroxidase
- Remove Peroxide anion and Hydroxyl radical
- react with hydrogen peroxide and produces oxygen (g)
- aerobed need either one of these proteins to get rid of toxic oxygen
- obligate anerobes have neither
44
Obligate aerobes
- Depend on oxygen to grow
- grow on top of the test tube
45
Obligate anaerobes
- Live in oxygen-free environment, may die in presence of oxygen (Clostridium botulinum)
- grow at the bottom of the tube
46
Facultative anaerobes
- Can grow with or without oxygen—do better near surface (E. coli)
- high concentration close to the top of the test tube
- low concentration at the bottom of the test tube
47
Aerotolerant anaerobes
- Can grow with or w/o oxygen present equally well but do not use oxygen
- growth is universal (have no preference)
48
Microaerophilic
Requires low oxygen to grow (H. pylori)
49
Capnophilic
- Low oxygen and high carbon dioxide required (Neisseria, Streptococcus)
50
Neutrophiles
- bacteria and protozoa that grow best in a narrow range around neutral pH (6.5-7.5)
- Human blood and tissue, perfect hosts
51
Acidophiles
- are acid-tolerant microorganism and useful for food industry
Examples: Lactobacillus, Streptococcus
52
Alkalinophiles
live in environments of high pH
