Chapter 8: Microbial Metabolism

Question 1

Define: catabolic

Answer 1

• break down substances and release energy
• generally hydrolytic and exergonic
  ex. ) cell breaking down sugars into carbon dioxide and water

Question 2

Define: anabolic

Answer 2

• combine energy and molecules to build new substances
• dehydration synthesis reactions tend to be endergonic
  ex. )

amino acids build proteins

nucleotides build nucleic acids

Question 3

Define: amphibolic

Answer 3

-dual role, can be used for both breaking down and building substances

Question 4

Define: ATP

Answer 4

• (adenosine triphosphate) made by catabolic reactions and provides the energy for anabolic reactions
• made of adenine, ribose, and three phosphate groups

Question 5

Define: ADP

Answer 5

-ADP is produced when ATP removes a phosphate group by dephyosphorylation which releases energy producing ADP

Question 6

Define: AMP

Answer 6

• molecule made of adenine and one phosphate group; formed when cells dephosphorylate ADP

Question 7

Define: Catalyst

Answer 7

• increases the reaction rate
• only needed in small amounts
• not consumed or permanently changed by a reaction

Question 8

Define: reaction rate

Answer 8

• speed at which a reaction occurs

Question 9

Define: active site

Answer 9

-the site of an enzyme that interacts with the substrate to start a chemical reaction

Question 10

Define: activation energy

Answer 10

-the minimum amount of energy required to start a chemical reaction

Question 11

Define: reactant

Answer 11

-ingredients of a chemical reaction

Question 12

Define: product

Answer 12

-substances generated as a result of a reaction

Question 13

Define: coenzyme

Answer 13

• organic nonprotein cofactors that range from free molecules that can move about to factors anchored to the enzyme they assist
• vitamins
• NAD+, FAD, NADP+, FMN

-basically energy storage molecules (electron carriers)
etc.

Question 14

Define: enzyme

Answer 14

-protein catalysts that help chemical reactions occur under cellular conditions

Question 15

Define: cofactor

Answer 15

• nonprotein components that some enzymes need to function
• iron, zinc, magnesium, calcium

Question 16

Define: ribozymes

Answer 16

-enzymes made of the nucleic acid RNA; more limited range of substrates than protein enzymes

Question 17

Define: denatured

Answer 17

• term applied to enzymes and proteins, that through exposure to high temp or other conditions, lose their 3D structure and become nonfunctional

Question 18

Define: allosteric activation

Answer 18

-when a regulatory molecule increases enzyme activity by binding to the enzymes allosteric site

Question 19

What factors affect enzyme activity?

Answer 19

• noncompetitive inhibitors decrease enzyme activity by binding to the enzyme at a site other than the active site
• competitive inhibitors slow reactions by competing with a substrate for the target enzyme’s active site

(part of feedback inhibition)

Question 20

Feedback Inhibition

Answer 20

Question 21

Factors that affect enzyme activity continued….

Answer 21

• allosteric activation occurs when regulatory molecule increases enzyme activity by binding to enzymes allosteric site
• allosteric inhibition a regulatory molecule binds to the enzymes allosteric site and leads to decrease in the enzymes activity

Question 22

continueeeeedddddd :(

Answer 22

Temperature- lowering temp lowers enzyme activity; increasing temp increases enzyme activity

pH- pH above or below optimal pH will alter enzyme structure

Phosphorylation- kinases add phosphate groups( phosphorylation); phosphatases remove phosphate groups (dephosphorylation)

Question 23

Catabolism process of cell respiration: aerobic, anaerobic, fermentation

Answer 23

Question 24

*Be able to diagram an ATP molecule

Answer 24

Question 25

Steps of aerobic respiration (glycolysis)

Answer 25

- requires six carbon glucose and investment of energy (2ATP) to start reaction - 6 carbon glucose is split into two 3-c molecules of pyruvic acid - 2 NAD+ are reduced to 2 NADH - net gain of two molecules of ATP for each molecule of glucose oxidized during glycolysis

Question 26

steps of aerobic respiration (intermediate step)

Answer 26

-pyruvic acid that was made in glycolysis proceeds to **pyruvate oxidation** **-**converts both molecules into a 2 carbon acetyl-CoA and releases two carbon dioxide -produces two NADH (energy storage molecule)

Question 27

steps of aerobic respiration (Krebs Cycle)

Answer 27

- a series of redox reactions - **decarboxylation reactions (**CO2 is removed)

Question 28

Steps of aerobic respiration (electron transport chain)

Answer 28

Question 29

Where cellular respiration occurs (prokaryotes and eukaryotes)

Answer 29

Question 30

What is ATP synthase?

Answer 30

-an enzyme in the electron transport chain that captures energy of the flowing protons and uses it to recharge ADP to ATP

Question 31

Fermentation

Answer 31

- sustains ATP production by glycolysis - NADH passes its electron passengers to an inorganic molecule like pyruvic acid - recycling of NADH into NAD+ - NAD+ is essential in making more ATP

Question 32

Various end products of anaerobic fermentation? Why are we concerned about these products?

Answer 32

**Homolactic Fermentation**: pyruvic acid reduced to lactic acid **Heterolactic Fermentation:** pyruvic acid reduced to lactic acid, ethanol, and carbon dioxide **Alcohol Fermentation:** pyruvic acid converted to ethanol and CO2 **Mixed Acid Fermentation:** pyruvic acid into a variety of acidic end products and gases **Butanediol Fermentation:** converts pyruvic acid into butanediol and ethanol

Question 33

How are lipids and proteins catabolized to make ATP?

Answer 33

Question 34

How do bacteria use biosynthesis to make macromolecules?

Answer 34

**biosynthesis:** the construction of biological molecules

Question 35

What energy sources do microbes use to make ATP?

Answer 35

Question 36

Metabolic tests to identify bacteria

Answer 36

Amino Acid Catabolism test- looks for deaminases and decarboxylases Fermentation test- media contains protein, a single carbohydrate, a pH indicator and sometimes an inverted Durham tube; fermentation pathways can produce acids-accumulation of acidic end products will lower the pH of the broth; change color