Bacteriology - Background 2

Question 1

What are the components of peptidoglycan?

Answer 1

• N-acetyl-glucosamine
• N-acetyl-muramic acide
  linked by peptide bridges

Question 2

The cytoplasmic membrane is present in Gram + and - bacteria. What is it also known as in Gram - ?

Answer 2

Inner membrane

Question 3

Do Gram + bacteria have an outer membrane?

Answer 3

No. Only a cytoplasmic membrane

Question 4

Does the cytoplasmic membrane have function?

Answer 4

Yes. Nutrient uptake and transport, electron transport to create energy for itself

Question 5

Which 3 characteristics don’t the Gram + have?

Answer 5

• Porin proteins
• Lipopolysaccharides (LPS)
• Phospholipids

Question 6

What is lipopolysaccharide (LPS) also known as?

Answer 6

Endotoxin, because it is a potent stimulator of the immune system. It causes the release of IL-1, IL-6 and TNFalpha which results in sepsis or endotoxic shock

Question 7

Which membrane of the Gram - bacteria is LPS found in?

Answer 7

The inner membrane

Question 8

What is contained in the cytoplasm of bacteria?

Answer 8

• Nucleoid
• Plasmids
• Ribosomes
• Endospores

Question 9

What are the characteristics of the nucleoid?

Answer 9

• No membrane

- Haploid, circular, double stranded chromosome

Question 10

What are the characteristics of plasmids?

Answer 10

• Circular dsDNA
• Can replicate independently of the chromosome
• Genetic information encoded is not necessary for survival
• Can be transferred to other bacterial cells and passed to daughter cells
• Can carry advantageous genetic information like antibiotic resistance

Question 11

What are the ribosome structure of Prokaryotes and Eukaryotes?

Answer 11

Prokaryotes: 70S (50S + 30S)
Eukaryotes: 80S (60S + 40S)

Question 12

Which bacteria can have endospores (Gram + or -)?

Answer 12

Gram+

Question 13

Which are examples of bacteria with endospores?

Answer 13

Bacillus and Clostridium

Question 14

Which are the factors affecting bacterial growth?

Answer 14

• Temperature
• Oxygen
• pH
• Salt

Question 15

What are organisms that cause spoilage of food called?

Answer 15

Psychrophiles

Question 16

What are bacteria that affect humans called?

Answer 16

Mesophiles (temp 32-40 degrees)

Question 17

Which are the 2 enzymes that certain bacteria carry that allows it to detoxify toxic oxygen radicals?

Answer 17

• superoxide dismutase which will take the toxic oxygen radical and convert it to hydrogen peroxide.
• hydrogen peroxide further needs to be made non-toxic and the enzyme that does that is catalase

Question 18

Do obligate anaerobes have superoxide dismutase and catalase?

Answer 18

No, therefore they are killed by toxic derivatives of oxygen.

Question 19

Do facultative anaerobes require oxygen?

Answer 19

No, they grow best in the presence of oxygen but can grow without it by using aerobic or anaerobic respiration or fermentation.

Question 20

What are aerotolerant anaerobes?

Answer 20

They can grow in the presence of oxygen, but are obligate fermenters.

Question 21

What are examples of facultative anaerobes?

Answer 21

• Staph aureus

- Streptococci

Question 22

Which cell type has a thicker peptidoglycan layer?

Answer 22

Gram+

Question 23

Which cell type contains foreign proteins?

Answer 23

Gram -