C4 REPRODUCTION OF BACTERIA

Question 1

factors regulating microbial growth

Answer 1

1. nutrients
2. moisture
3. temperature
4. gases : oxygen n air
5. pH
6. osmotic pressure
7. light and radiation

Question 2

1. nutrients

Answer 2

• heterotrophs = organism that can’t make its own food supply
  
  • carbon
  • nitrogen - nitrogen-fixing bacteria = bacteria that obtain nitrogen directly from atmosphere
  • phosphorus
  • sulphur
  • vitamins

Question 3

3. temp

Answer 3

• normal = 37 C
• cold = slow the growth
• hot = killing
• steam sterilization n boiling for killing PATHOGENIC ORGANISM
  
  • psychrophiles - cold-loving bacteria, 0-20
  • psychrotrophs - cause spoilage of food stored under refrigeration
  • mesophiles - most human pathogen
  • thermophiles - heat loving

Question 4

4. oxygen

Answer 4

• obligate aerobes
• obligate anaerobes
  
  • can grow only in free oxygen environment
• facultative anaerobes -
  *prefer O2 but can live without it
• microaerophilic bacteria
  
  • require O2 but at low concentration
• aerotolerant anaerobes
  *don’t use O2 but can tolerate it

Question 5

representative anaerobic pathogen

Answer 5

1. clostridium tetani
   * agent of tetanus
   * produces muscle spasm or spastic paralysis (kejang otot)
   * muscle of the jaw first affected, called LOCKJAW
2. clostridium botulinum
   *causative agent of botulism, occur after eating home canned alkaline vegetables that not enough heated
   * result flaccid paralysis
3. clostridium perfringes n clostridium sporogenes
   * infection known as GAS GANGRENE
4. clostridium difficile
   * a side effect of antibiotic treatment which eliminate the normal flora

Question 6

microaerophiles

Answer 6

1. the streptococci
   - group A
   - group D, streptococcus faecalis
   * frequent cause of bladder infections

Question 7

5. pH

Answer 7

• acidophiles = acid loving
• neutrophiles = most human pathogen
• alkaliphiles = alkali loving

Question 8

6. salt

Answer 8

• halophiles = bacteria can adopt to high salt environment

Question 9

microorganism reproduction

Answer 9

• bacteria
  
  • binary fission (division in half)
• virus
  
  • lysogenic cycle
  • lytic cycle
• fungi (sporulation)
  
  • sexual n asexual

Question 10

bacterial growth curve

Answer 10

1. lag phase
2. exponential phase
3. stationary phase
4. death phase

Question 11

1. lag phase

Answer 11

• no antibiotic here
• period of adjustment

Question 12

2. exponential phase

Answer 12

• active phase
• most rapid growth phase

Question 13

3. stationary phase

Answer 13

• population size begin to stabil
• cell division begin to slow down
• factors that slow down microbial growth
• growth = death
  
  • accumulation of toxic waste material
  • acidic pH
  • limited nutrients
  • insufficient oxygen supply
• endospores would form now

Question 14

culture medium

Answer 14

• a nutrient material prepared for the growth of microorganism in lab

Question 15

differences between lytic cycle and lysogenic cycle for virus

Answer 15

• lytic cycle
  
  • the cells dies at the end of this cycle
• lysogenic cycle
  
  • the cell remain alive in this cycle
  • some virus (DNA) enter the host cell but remain DORMANT for years WITHOUT DESTROYING the host cells
  • the viral DNA is incorporated into the host chromosome known as PROPHAGE
• at some point, viral DNA become active, produces new viruses, destroy the host cell .

Question 16

lysogenic cycle

Answer 16

• attachment
  
  • virus attach to cell
• penetration
  
  • insert DNA into host cell
• integration
  
  • viral DNA integrate into the host chromosome
• replication
  
  • host cell n viral DNA replicate n divide - remain in dormant state
  **tgk slide page 54