Exam 2 Revieww

Question 1

What goes into the preparation of culture media?

Answer 1

Formulated from amino acids, purines, monosaccharides, polysaccharides, salts, fatty acids and lipids, etc.
Have to sterilize when done

Question 2

What is basic media, enriched media, differential, and selective media?

Answer 2

Basic (general): Allows bacteria to grow
Enriched: contains growth factors, vitamins, essential nutrients to promote growth of organisms that require those to be added as they do not make on their own
Differential: shows different colors that help to distinguish bacteria (ex. e. aerogenes turns blue, e. Coli stays green)
Selective: allows for growth of specific organisms

Question 3

What types of physical conditions should be taken into consideration when trying to cultivate bacteria?

Answer 3

things like pH, temperature, oxygen concentration, environment

Question 4

What is hydrolysis reactions? (ex.)
What is condensation reactions? (ex.)

Answer 4

Hydrolysis: adding water to break apart molecules (ex. starch hydrolysis - starch is hydrolyzed by amylase and converted to sugar, identifies bacteria that can hydrolyze starch)

Condensation: two molecules from larger molecule with a loss of smaller molecule which is water
this is how peptide bonds are formed (2 amino acids joined together through this process)

Question 5

Protein definition

Answer 5

long chain of amino acids joined together by peptide bonds

Question 6

Amino acids definition

Answer 6

small molecules that combine to form protein

Question 7

Lipids definition

Answer 7

compounds including fats, oils, etc. and are not soluble in water

Question 8

Monosaccharide definition

Answer 8

sugars that can not be broken down further
ex. glucose, fructose

Question 9

Disaccharide definition

Answer 9

sugar formed when two monosaccharides are joined by glycosidic linkage ex. sucrose, lactose

Question 10

Polysaccharide definition

Answer 10

large chain of molecules composed of tens of thousands of monosaccharides linked together by glycosidic linkage

Question 11

Carbohydrates definition

Answer 11

comprise carbon, hydrogen, and oxygen atoms
-will break down into glucose

Question 12

Nucleic Acids definition

Answer 12

composed of nucleotide chain
-carry genetic information

Question 13

What are enzymes and how do they work?

Answer 13

biological catalyst, reduces activation energy

Question 14

Compare potential energy with kinetic energy

Answer 14

Potential Energy: stored energy in an object due to position
Kinetic Energy: chemically changing into another

Question 15

Explain ADP/ATP cycle

Answer 15

Made through cellular respiration - ADP is continually converted to ATP (by ATP synthase) - ex. Sodium potassium pump - atp able to use the energy to balance out - keeps atp by fermentation or aerobic respiration
Can be broken back down to ATP by the same enzyme

Question 16

State general equation for aerobic respiration - be able to explain main steps involved

Answer 16

Metabolic pathway
Glucose + Oxygen –> (carbon dioxide) –> water + ATP
-Glycolysis: glucose is oxidized into pyruvate with a net gain of 2 atp and nadh molecule
-Krebs Cycle: oxidize glucose because the electrons have glucose, steal energy
-ETC: NADH being oxidized to NAD+, create imbalance of hydrogen (greater concentration outside), pass electrons to the final electron acceptor = oxygen to make ATP all through kinetic energy

Question 17

State general equation for anaerobic fermentation and significance of products of process

Answer 17

-process of breakdown of food in absence of oxygen
-end products can be lactic acid, CO2, or alcohol
-produces a small amount of energy

Question 18

Explain difference between acid and base

Answer 18

Acids: produce hydrogen ions
Bases: accept hydrogen ions

Question 19

Explain what acid indicator is (give ex.)

Answer 19

substances which change color with pH - usually weak acids or bases, indicates amount of acid in substance
ex. phenol red (neutral is pH 7, hot pink above 7.4, yellow below 6.8)

Question 20

Explain how you could determine acid and gas production from the three carbohydrate sources (glucose, lactose, sucrose, mannitol) using durham tubes and phenol red

Answer 20

Negative carbohydrate fermentation: liquid stays red, no gas bubble in tube

Positive carbohydrate fermentation: yellow liquid, no gas bubble in tube

Positive carbohydrate fermentation and gas production: yellow liquid, gas bubble in tube

Question 21

Gelatin Hydrolysis
what does this test for
pos vs neg results
how does this impact body

Answer 21

ability to produce gelatinase
gelatin + H2O –> (arrow is gelatinase) amino acids
pos: gelatin is liquid (control is solid)
neg: gelatin is solid
able to liquify connective tissue and spread

Question 22

Starch Hydrolysis
what does this test for
pos vs neg results
how does this impact body

Answer 22

tests bacteria that can hydrolyze starch
starch + H2O –> (amylase) glucose
pos: clearing around growth
neg: no clearing around growth
-be able to break down starch

Question 23

Casein Hydrolysis
what does this test for
pos vs neg results
how does this impact body

Answer 23

test for if it can break down casein
casein + H2O –> (casease) amino acid
pos: clearing in agar
neg: no clearing around growth/agar
-break down into amino acids to get through cell wall

Question 24

Indole Test
what does this test for
pos vs neg results

Answer 24

testing to see if organism produces tryptophanase and can hydrolyze tryptophan
pos: kovac reagent forms pinkish layer
neg: kovac regent does not form layer

Question 25

Catalase Test
what does this test for
pos vs neg results

Answer 25

2H2O2 —–> arrow is catalse -> 2H20 + O2
pos: bubbles present
neg: no bubbles
-can protect bacteria from hydrogen peroxide that would kill them

Question 26

Methyl Red Test
what does this test for
pos vs neg results

Answer 26

detect organisms capable of performing a mixed acid fermentation
pos: after methyl red is added and it stays red
neg: after methyl red is added and it turns yellow

Question 27

Citrate Test
what does this test for
pos vs neg results

Answer 27

Citrate → (arrow is citrate lyase) to oxaloacetate and acetate to produce ATP
pos: blue, or there’s growth (with no color change) - citrate is present
neg: no color change or growth - citrate is not present

Question 28

Vogues-Proskauer Test
what does this test for
pos vs neg results

Answer 28

identify organisms that are able to ferment glucose to non acidic end products
pos: after addition of barritt’s A and b = turns yellow
neg: after addition of barritt’s a and b = stays red

Question 29

What is fermentation?

Answer 29

metabolic pathway where carbohydrates are oxidized so the cell can make 2 ATP molecules and use organic molecules as final electron acceptors

Question 30

Anaerobic vs. Aerobic Respiration

Answer 30

Anaerobic Fermentation: compound, glycolysis, pyruvate and 2 ATP, (no oxygen), end result = lactic acid, ethanol

Aerobic Respiration: compound, glycolysis, pyruvate and 2 ATP, (oxygen yes), end result = up to 36 ATP = CO2 and H2O

Question 31

Extracellular hydrolytic enzymes def/reasoning

Answer 31

testing for water breakdown outside of the cell with a biological catalyst

Question 32

What enzyme makes sucrose go to glucose?

Answer 32

Sucrase

Question 33

What is the enzyme that hydrolyzes lactose?
what does it do then

Answer 33

Beta galactosidase
make ATP and use lactic acid as FEA

Question 34

What are the two kinds of coliforms?

Answer 34

Fecal = can determine source of contamination
General = can’t determine source of contamination

Question 35

How is bacterial fermentation important for us?

Answer 35

Provides us with items like vitamins, alcohol, sour cream, wine

Question 36

Litmus Milk
what kind of reaction and name them

Answer 36

-single chemical and metabolic pathways
-such as fermentation, clot formation, digestion, alkaline reaction, reduction of litmus

Question 37

Litmus Milk
reaction types described

Answer 37

-Clot Formation: pink and white solid (clot not movable)
-Fermentation: lactic acid produced = pink
-Alkaline Reaction: blue medium/band at top
-Digestion: brown ish on top, purple on bottom
-Reduction of Litmus: white color in lower portion