Microbial growth/genetics

Question 1

What are the 7 microbial growth requirements

Answer 1

oxygen, temperature, pH, moisture, osmotic pressure, light, food
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Question 2

What are the 3 classifications of organisms according to temperature and what do they prefer?

Answer 2

Psychrophilic = cold
Mesophilic = moderate
Thermophilic = hot

Question 3

What are the 2 types of culture media?

Answer 3

selective and differential

Question 4

What is selective media?

Answer 4

Contains substances that favor or inhibit the growth of particular organisms
Ex: Sabouraud dextrose
agar

Question 5

What is differential media?

Answer 5

Presence of visible changes in medium or differences in the appearance of colonies help differentiate organisms
Ex: Blood agar

Question 6

What is both a selective and differential culture medium?

Answer 6

MacConkey agar

Question 7

What are plasmids? (prokaryotic)

Answer 7

• Small molecules of extra- chromosomal DNA
• NOT essential for normal metabolism, growth, or reproduction
• Can confer survival advantages

Question 8

What are the 4 types of plasmids?

Answer 8

fertility factors (F plasmids)
resistance factors (R plasmids)
bacteriocin factors
virulence plasmids

Question 9

What is vertical gene transfer? (normal process in both prokaryotes and eukaryotes)

Answer 9

Organisms replicate their genomes and provide copies to descendants

Question 10

What is horizontal gene transfer? (prokaryotes)

Answer 10

Acquire genes from other microbes of the same generations

- May be different species

Question 11

What are the 3 types of horizontal gene transfer?

Answer 11

transformation, transduction, bacterial conjugation

Question 12

What is transformation gene transfer?

Answer 12

Recipient cell takes up DNA from environment

• Cells that take up DNA are called competent
• Occurs in only a few types of bacteria

Question 13

What is transduction gene transfer?

Answer 13

Transfer of DNA from one cell to another via a replicating virus

Question 14

What are the 2 types of transduction gene transfer?

Answer 14

Generalized
• Transducing phage carries random DNA segment from donor to recipient

Specialized
• Only certain donor DNA sequences are transferred

Question 15

What is a bacteriophage?

Answer 15

a virus that attacks bacteria

Question 16

What is conjugation gene transfer?

Answer 16

Transfer of DNA from one cell to another, mediated by conjugation pili

• Donor cell requires F plasmid (F+)
• Recipient cell LACKS F plasmid (F-)