Biotyping Based On Amino Acid Metabolism

Question 1

What are amino acids use for?

Answer 1

-building proteins

Question 2

An amino acid is built under what 3 structures?

Answer 2

• side change
• Amino group
• acid

Question 3

What can unneeded proteins be used for?

Answer 3

-can be converted into amino acids through hydrolysis

Question 4

What is amination?

Answer 4

-converts an organic acid (made from cell resp or fermentation) to an amino acid

NH3 (ammonia) + organic acid > amino acid

Question 5

What is transamination?

Answer 5

• when a cell has too much of one amino acid and not enough of another amino acid, it is balanced during this reaction
• Process: an amino acid and an organic acid react, resulting in a different amino acid and a different organic acid

Question 6

What is deamination?

Answer 6

-converts excess amino acids into organic acids

Amino Acid > Organic acid + Ammonia (NH3)

Question 7

Why is urea created?

Answer 7

-its how humans package their excess nitrogen after deamination because ammonia is toxic to human cells

Question 8

What happens during a urease reaction?

Answer 8

Reaction: Urea > Urease (enzyme)> Ammonia and CO2

• makes ammonia for amination (make amino acids)
• raises pH
• damages human cells

Question 9

What does the MIO medium test for?

Answer 9

Motility, indole production, ornithine decarboxylation

Question 10

The MIO medium is used to differentiate bacteria in which family?

Answer 10

-enterobacteriaceae

Question 11

What is the role of Ornithine Decarboxylase in bacteria when placed in the MIO medium?

Answer 11

• The MIO medium contains a small amount of glucose (0.1%)
  
  • Bacteria that ferment it will release acids that cause the pH indictator in the media to turn purple to yellow
  • After the glucose is completely consumed, the bacteria will then use the amino acids in the media as a source of energy.
• Some bacteria can breakdown the amino acid ornithine using the enzyme ornithine decarboxylase
  
  • when ornithine is broken down this way, its converted to putrescine> raise pH> turn purple

Question 12

How do some bacteria release the molecule indole?

Answer 12

• some bacteria possess the enzyme tryptophanase.

- this enzyme breaks down the amino acid tryptophan and releases the molecule indole

Question 13

How is Indole indicated in the MIO medium?

Answer 13

• by adding Kovacs reagent after the bacteria have grown
  
  • indole is made from the amino acid tryptophan

-Pink > red indicates the presence of indole

Question 14

What does the M in MIO stand for and how is it tested?

Answer 14

-Motility

• Non-motile bacteria will grow only near the stab line.
• motile bacteria are able to swim and spread out from the stab line due to MIO media having a relatively low concentration of agar

Question 15

Nutrient gelatin medium is used to identify species within which bacterial family?

Answer 15

Enterobacteriaceae

Question 16

What is the main ingredient in nutrient gelatin?

Answer 16

• a derivative of the collagen proteins found in animals, including people
  
  • collagens are strong, fibrous proteins found in connective tissues

Question 17

How is gelatin used in Nutrient gelatin?

Answer 17

• when added to a liquid medium, the unfolded collagen proteins thicken the medium
  
  • remain liquid at room temp
  -if cooled using refrigerator or ice bath, it will solidify into a gel= + for gelatin hydrolysis, if the medium did not solidify - test for gelatin hydrolysis

Question 18

What are gelatinases?

Answer 18

Enzymes that can digest denatured collagen

Question 19

What are Collagenases

Answer 19

Enzymes that can digest collagen in its denatured (gelatin) or non-denatured state

Question 20

What is the function of urease?

Answer 20

-breakdown urea into ammonia and carbon dioxide

Question 21

Urea Agar is used to identify species in which bacterial family?

Answer 21

Enterobacteriaceae

Question 22

What does a + and - result look like in a Urease reaction test?

Answer 22

• when the Enzyme urease converts urea to ammonia (raises pH) causes the indicator to turn fuchsia

Question 23

What are 2 advantages urease gives a bacterial species

Answer 23

• essential in the colonization of the host organism

- maintainance of bacterial cells in tissues

Question 24

Classify each processes as catabolic or anabolic

1) protease reaction
2) Amination
3) deamination
4) urease reaction
5) tryptophanase reaction

Answer 24

1) catabolic
2) anabolic
3) catabolic
4) catabolic
5) catabolic

Question 25

What do bacterial cells need to build amino acids?

Answer 25

1) carbon based molecules of the right size
2) source of fixed nitrogen
3) source of energy

Question 26

For amination reactions to occur, what kind of energy must be expended?

Answer 26

-ATP or other high energy compounds, NADPH

Question 27

Excess amino acids in bacterial cells can also be used as?

Answer 27

• can be converted into organic acids, and further broken down to release useable energy
  
  • this energy is often captured to build ATP

Question 28

What is the molecular structure of Urea?

Answer 28

-Characteristics: less toxic to human cells than ammonia