Lecture 2: Microbial Growth

Question 1

•Viruses that infect
bacteria
•Specific for host
bacterium
•Nucleic acid core
•Protein capsid

Answer 1

Bacteriophage

Question 2

Lytic versus Lysogenic Life Cycle

Answer 2

Lytic:

• Phage genome enters the cell
• Transcription of phage DNA
• Production of phage nucleic acid and proteins
• Assembly of phage
• Release of phage by cell lysis

Lysogenic:

• Adsorption
• Entry of phage genome into the cell
• Synthesis of the repressor protein
• Integration of viral DNA -prophage
• Attainment of lysogeny (Latency)

Question 3

Non-integrative Lysogeny versus Integrative?

Answer 3

Non-integrative lysogeny: phage becomes a plasmid

Integrative Lysogengy: integrated into the host genome, able to produce phages if explicitly activated

Question 4

What is a Prophage?

Examples?

Answer 4

genetic material of bacteriaphage integrated into the host genome, able to produce phages if explicitly activated

Examples:

–Cholera toxin of Vibrio cholerae

–Neurotoxin of Clostridium botulinum

–Enterotoxin ofStaphylococcus aureus

Question 5

Specialized Transduction?

Answer 5

A portion of host DNA is exchanged for Phase DNA

Detaches and replicates

cell lyses and releases phage capable of transducing host’s gene to other bacteria

Question 6

Specialized Transduction?

Answer 6

A portion of host DNA is exchanged for Phase DNA

Detaches and replicates

cell lyses and releases phage capable of transducing host’s gene to other bacteria

Question 7

Answer 7

Question 8

In bacteria, DNA undergoes replication and transcription simultaneously with RNA Translation? T/F

Answer 8

True

Question 9

What phase of growth are bacteria most susceptible to antibiotics?

Answer 9

Exponential Growth Phase

Question 10

Answer 10

Question 11

Speed of Bacterial metabolism relative to eukaryotic

Answer 11

Metabolism 10-100X speed of eukaryotic cells

Question 12

How many ATP from Aerobic respiration of 1 glucose molecule

Answer 12

C6H12O6+ 6O2+38 ADP + 38P → 6CO2+ 6H2O + 38 ATP

Question 13

During anaerobic respiration, oxygen not consumed what is consumed instead?

Answer 13

other inorganic molecules used such as nitrate (NO3-) or sulfate (SO42-)

Amount of ATP produced is less than that produced in aerobic respiration

Question 14

How many ATP molecules are produced from one molecule of glucose undergoing fermentation? When does the cell perform this? Products produced?

Answer 14

In the absence of O2and of other inorganic compounds, fermentation is used for the production of ATP. Endogenous organic compounds used

• 2 ATP molecules per molecule of glucose is produced
• Other waste products produced include lactic acid and alcohol

Question 15

Describe a Faculativec Aerobe

Answer 15

Can grow in absence of oxygen, prefers O2

Question 16

Describe a Microaerophillic

Answer 16

Can only handle low levels of oxygen

Question 17

Describe an Aerotolerant Anaerobe

Answer 17

can grow equally well in presence and absence of oxygen

Question 18

Major classes of Bacterial Growth Factors

Answer 18

–Amino acids: protein synthesis

–Purines and pyrimidines: nucleic acids

–Vitamins: enzyme cofactors

Question 19

Role of siderophores for Bacteria and Funghi

Answer 19

• They secrete siderophores(low molecular weight iron-binding molecules)
• Iron siderophore complex binds to siderophore receptor protein.
• Iron is transported inside the cell either directly or whole complex transported

Question 20

High iron can be indicative of certain infections (T/F)

Answer 20

FALSE: Low iron can be indicative of certain infections

• Microorganisms require iron.
• Little free iron available

Question 21

What is the class of bacteria that thrives at human temperatures?

Answer 21

mesophiles 20-45ºC (human pathogens)

Question 22

What environment do Halophiles thrive in?

Answer 22

High NaCl Concentration

Question 22

What environment do Halophiles thrive in?

Answer 22

High NaCl Concentration

Question 23

Answer 23

Question 23

Answer 23