Lec. 2 Test Ch. 5

Front 1

All chemical reactions in an organism

Back 1

Metabolism

Front 2

Metabolic processes are guided by Eight statements:

Back 2

1. Ever cell acquires nutrients
2. Metabolism requires energy for light or catabolism of nutrients
3. Energy is stored in adenosine triphosphate (ATP)
4. Cells catabolize nutrients to form precursor metabolites.
5. Precursor metabolites, energy from ATP, and enzymes are used in anabolic reactions
6. Enzymes plus ATP form macromolecules
7. Cells grow by assembling macromolecules
8. Cells reproduce once they have doubled in size.

Front 3

What are the two major classes of metabolic reactions?

Back 3

1. Catabolic pathways
2. Anabolic pathways

Front 4

Metabolic reaction that breaks larger molecules into smaller products and is exergonic (release energy)

Back 4

Catabolic pathways

Front 5

Metabolic reaction that synthesize large molecules from the smaller products and is Endergonic (require more energy than released)

Back 5

Anabolic pathways

Front 6

Metabolic reactions involve the transfer of electrons, which carry energy from electron donor to electron acceptor:

• An electron acceptor is ____1____
• An electron donor is ___2___

Back 6

1. reduced
2. oxidized

Remember acronym: OIL RIG

Oxidation Involves Loss; Reduction Involves Gain

Hint 6

**electron acceptor are reduced because their gain in electrons reduces their overall electrical charge

**Molecules that lose electrons are oxidized because frequently their electrons are donated to oxygen atoms.

Front 7

Key factors of the chemical reactions of Metabolism: Oxidation and Reduction Reactions are...

Back 7

• Transfer of electrons from an electron donor to an electron acceptor
• Reactions always occur simultaneously
• Cells use electron carriers to carry electrons (often in H atoms)

Front 8

In Metabolic Oxidation and Reduction; What are the three important electron carriers?

Back 8

1. Nicotinamide adenine dinucleotide (NAD+)
2. Nicotinamide adenine dinucleotide phosphate (NADP+)
3. Flavin adenine dinucleotide (FAD)

Front 9

Metabolism: ATP Production and Energy Storage:

Back 9

• Organisms release energy from nutrients

-Can be concentrated and stored in high energy phosphate bonds (ATP)

• Phosphorylation - inorganic phosphate is added to substrate
• Cells phosphorylate ADP to ATP in three ways
• Anabolic pathways use some energy of ATP by breaking a phosphate bond

Front 10

Metabolism: ATP Production and Energy Storage:

Cells phosphorylate ADP to ATP in what three ways?

Back 10

1. Substrate-level phosphorylation
2. Oxidative Phosphorylation
3. Photophosphorylation

Front 11

What is the Role of Enzymes in Metabolism?

Back 11

Enzymes are organic catalysts with the main function of increasing the likelihood of reaction.

Hint 11

The effect of enzymes on chemical reactions. Enzymes catalyze reactions by lowering the activation energy--that is, the energy needed to trigger the reaction.

Front 12

The Roles of Enzymes in Metabolism: Naming and classifying enzymes:

What are the 6 categories of enzymes based on mode of action?

Back 12

1. Hydrolase
2. Isomerase
3. Ligase or polymerase
4. Lyase
5. Oxidoreductase
6. Transferase

Front 13

1. What is the reaction of the enzymeclass Hydrolase
   
2. Is it catabolic or anabolic?
   
3. Give example
   

Back 13

1. Hydrolysis
2. catabolic
3. lipase- breaks down lipid molecules

Front 14

1. What is the reaction of the enzyme class Isomerase
2. Is it catabolic or anabolic?
3. Give example
   

Back 14

1. Rearrangement of atoms within a molecule
2. neither
3. Phosphoglucoisomerase-converts glucose 6-phosphate into fructose 6-phosphate during glycolosis

Front 15

1. What is the reaction of the enzyme class Ligase or polymerase
   
2. Is it catabolic or anabolic?
   
3. Give example
   

Back 15

1. Joining two or more chemicals together
2. Anabolic
3. Acetyl-CoA synthetase-combines acetate and coenzyme A to form acetyl-CoA for the Krebs cycle.

Front 16

1. What is the reaction of the enzyme class Lyase
   
2. Is it catabolic or anabolic?
   
3. Give example
   

Back 16

1. Splitting a chemical into smaller parts without using water
2. catabolic
3. Fructose-1, 6-bisphosphate aldolase- splits fructose 1, 6-bisphosphate into G3P and DHAP

Front 17

1. What is the reaction of the enzyme class Oxidoreductase
2. Is it catabolic or anabolic?
3. Give example
   

Back 17

1. Transfer of electrons or hydrogen atoms from one molecule to another
2. none stated
3. Lactic acid dehydrogenase- oxidizes lactic acid to form pyruvic acid during fermination

Front 18

1. What is the reaction of the enzyme class Transferase
2. Is it catabolic or anabolic?
3. Give example
   

Back 18

1. Moving a functional group from one molecule to another
2. may be anabolic
3. Hexokinase-transfers phosphate from ATP to glucose n the first step of glycolysis

Front 19

Many protein enzymes are complete in themselves, but others are composed of both protein and nonprotein portions. The proteins in these combinations are called ________.

Back 19

apoenzymes

***is inactive unless it is bound to its cofactors

Front 20

Apoenzymes are inactive if they are not bound to one or more of the nonprotein substances called _______.

Back 20

cofactors.

Front 21

Cofactors are either inorganic ions (such as iron, magnesium, zinc, or copper ions) or certain organic molecules called _______.

Back 21

coenzymes

Front 22

All coenzymes are either __1__ or the contain __1__, which are organic molecules that are required for metabolism but cannot be synthesized by certain organisms (especially mammals)

Back 22

1. vitamins

Front 23

Some apoenzymes bind with inorganic cofactors, some bind with coenzymes, and some bind with both.

The binding of an apoenzyme and its factor(s) forms an active enzyme, called a _______.

Back 23

holoenzyme

**can need more than 1 cofactor; both organic and inorganic

Hint 23

Front 24

Not all enzymes are proteinaceous; some are RNA molecules called _______.

Back 24

ribozymes

Front 25

The effect of enzymes on chemical reactions: Enzymes catalyze reactions by lowering the activation energy--the energy needed to trigger the reaction. Does this graph more closely represent a catabolic or and anabolic reaction?

Back 25

Energy of the product is lower than the energy of the reactants. Thus, the graph more closely represents catabolism.

Hint 25

About 3 times more energy is needed without enzyme.

Front 26

Enzymes fitted to substrates: The induced-fit model of enzyme-substrate interaction.

Back 26

An enzyme's active site is generally complementary to the shape of its substrate, but a perfect fit between them does not occur until the substrate and enzyme bind to form a complex.

Front 27

The process of enzymatic activity: Shown here is the lysis of fructose.

After the enzyme associates with the substrate, what happens in steps 1, 2, 3, 4?

Back 27

1. the two molecules bind to form an enzyme-substrate complex
2. As a result, the enzyme's active site is induced to fit the substrate; then, bonds within the substrate are broken
3. then the enzyme dissociates from the two products.
4. the enzyme resumes its initial shape and is then ready to associate with another substrate molecule.

Hint 27

This entire process occurs 14 times per second at 37 degrees Celsius (body temperature)

In Fig. 5.6 the substrate of Fructose 1, 6-bisphosphate is broken down into two separate 3 carbon sugars as the products.

Front 28

The Roles of Enzymes in Metabolism:

What are the 3 main factors that influence the rate of enzyme reactions?

Back 28

1. Temperature
2. pH
3. Substrate concentration or Saturation

Front 29

What is the optimal temperature for enzyme activity?

Back 29

37.5 degrees Celcius (body temp)

Front 30

What is the optimal pH for enzyme activity?

Back 30

pH 7.2

Front 31

If a temperature rises beyond a certain critical point, or pH levels become extreme; this will cause the noncovalent bonds (such as hydrogen bonds between amino acids) within the enzyme to break and distort an enzymes structure. This causes the ________ of protein enzymes.

Back 31

Denaturation

(see Fig. 5.8 in hint)

Hint 31

Front 32

_______ is a substance that block an enzyme's active site. May be either competitive or noncompetitive and do not denature the enzymes.

Back 32

Inhibitors

Front 33

_______ inhibitors are shaped such that they fit into an enzyme's active site and thus prevent the normal substrate form binding.

Back 33

Competitive

**an increase in substrate concentration can "kick out" the competitive inhibitor.

Hint 33

Front 34

______ inhibitors do not bind to the active site but instead bind to another site of the enzyme (allosteric site) which will alter the shape of the active site so that the substrate cannot be bound.

Back 34

Noncompetitive

Hint 34

Front 35

In what two ways does the Allosteric site help control enzyme activity?

Back 35

1. changes the shape of the active site so that the substrate cannot bind.

2. Uses an allosteric activator to cause a change that makes it capable of binding substrate.

(see hint)

Hint 35

Front 36

A cellular control mechanism in which an enzyme that catalyzes the production of a particular substance in the cell is inhibited when that substance has accumulated to a certain level, thereby balancing the amount provided with the amount needed.

Back 36

Feedback inhibition

Hint 36

Operates similar to a thermostat: when the room gets warm enough, a sensor inside the thermostat changes shape and sends a signal to the heater to turn off.

Front 37

How can oxidation take place in an anaerobic environment, that is, without oxygen?

Back 37

because oxidation involves the loss of electrons (not oxygen)

Front 38

Carbohydrate Catabolism:

Many organisms oxidize carbohydrates as primary energy source for anabolic reactions.

What is the most common carbohydrate used?

Back 38

Glucose

Front 39

Glucose is catabolized by what two processes?

Back 39

1. Cellular respiration
2. Fermintation

Front 40

A metabolic process that involves the complete oxidation of substrate molecules and then production of ATP by a series of redox reactions.

Back 40

Cellular respiration

Hint 40

Front 41

The partial oxidation of sugar (or other metabolites) to release energy using an organic molecule from within the cell as the final electron acceptor.

Back 41

Fermentation

Hint 41

Front 42

_______ occurs in the cytoplasm of most cells. Involves the splitting of a six-carbon glucose molecule into two three-carbon sugar molecules--> which are then oxidized to pyruvic acid-->some of the energy released is stored in molecules of (net gain of 2) ATP and (2 molecules) NADH.

Back 42

Gycolysis

Hint 42

Front 43

What are the three stages of Glycolysis?

Back 43

1. Energy-investment stage
2. Lysis stage
3. Energy-conserving stage

**10 steps total (see hint)

Hint 43

***Understand what is happening

Front 44

Example of substrate-level phosphorylation.

High energy phosphate bonds are transferred from one substrate to another in this process.

What role does Mg^2+ play in this reaction?

Back 44

Mg^2+ is a cofactor of the enzyme

Hint 44

Front 45

_______ (short for reduction–oxidation reaction) is a chemical reaction in which the oxidation states of atoms are changed through the transfer of electrons between molecules, involving both oxidation and a complementary reduction process.

Back 45

Redox

Front 46

What are the 3 stages of cellular respiration?

Back 46

1. Synthesis of acetyl-CoA
2. Krebs cycle
3. Final series of redox reaction (electron transport chain)

Front 47

In fermentation what microbe(s) produces Swiss Cheese?

Back 47

Propionibacterium

Front 48

In fermentation: what microbe(s) produces cheddar cheese, yogurt and soy sauce?

Back 48

Aspergillus

Lactobacillus

Streptococcus

Front 49

In fermentation: what microbe(s) produces wine and beer?

Back 49

Saccharomyces

Front 50

In fermentation: what microbe(s) produces nail polish remover and rubbing alcohol?

Back 50

Clostridium

Front 51

In Aerobic respiration:

1. Is oxygen required?
2. Type of phosphorylation?
3. Final electron (hydrogen) acceptor?
4. Potential molecules of ATP produced per molecule of glucose?

Back 51

In Aerobic respiration:

1. Yes
2. Substrate-level and oxidative
3. Oxygen
4. 38 in prokaryotes

36 in eukaryotes

Front 52

In Anaerobic respiration:

1. Is oxygen required?
2. Type of phosphorylation?
3. Final electron (hydrogen) acceptor?
4. Potential molecules of ATP produced per molecule of glucose?
   

Back 52

In Anaerobic respiration:

1. No
2. Substrate-level and oxidative
3. NO3-, SO4^2-, CO3^2-, or externally acquired organic molecules
4. 2-36
   

Front 53

In Fermentation:

1. Is oxygen required?
2. Type of phosphorylation?
3. Final electron (hydrogen) acceptor?
4. Potential molecules of ATP produced per molecule of glucose?

Back 53

In Fermentation:

1. No
2. Substrate-level
3. Cellular organic molecules
4. 2

Front 54

Ch. 5 Questions:

1. Breaks a large molecule into smaller ones

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 54

c. catabolism only

Front 55

Ch. 5 Questions:

2. Includes dehydration synthesis reactions

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 55

a. anabolism only

Front 56

Ch. 5 Questions:

3. Is exergonic

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 56

c. catabolism only

Front 57

Ch. 5 Questions:

4. Is endergonic

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 57

a. anabolism only

Front 58

Ch. 5 Questions:

5. Involves the production of cell membrane constituents

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 58

a. anabolism only

Front 59

Ch. 5 Questions:

6. Includes hydrolytic reactions

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 59

c. catabolism only

Front 60

Ch. 5 Questions:

7. Includes metabolism

a. anabolism only

b. both anabolism and catabolism (amphibolic)

c. catabolism only

Back 60

b. both anabolism and catabolism (amphibolic)

Front 61

Ch. 5 Questions:

8. Redox reactions ________

a. transfer energy

b. transfer electrons

c. involve oxidation and reduction

d. are involved in all of the above

Back 61

d. are involved in all of the above

Front 62

Ch. 5 Questions:

9. A reduced molecule _______

a. has gained electrons

b. has become more positive in charge

c. has lost electrons

d. is an electron donor

Back 62

a. has gained electrons

Front 63

Ch. 5 Questions:

10. Activation energy ________

a. is the amount of energy required during an activity such as flagellar motion

b. requires the addition of nutrients in the presents of water

c. is lowered by the action of organic catalysts

d. results from the movement of molecules

Back 63

c. is lowered by the action of organic catalysts

Front 64

Ch. 5 Questions:

11. Coenzymes _________

a. are types of apoenzymes

b. are proteins

c. are inorganic cofactors

d. are organic cofactors

Back 64

d. are organic cofactors

Front 65

Ch. 5 Questions:

12. Which of the following statements best describes ribozymes?

a. They are proteins that aid in the production of ribosomes.

b. They are nucleic acids that produce ribose sugars.

c. They store enzymes in ribosomes.

d. They process RNA molecules in eukaryotes.

Back 65

d. They process RNA molecules in eukaryotes.

Front 66

Ch. 5 Questions:

13. Which of the following does not affect the function of enzymes?

a. ubiquinone

b. substrate concentration

c. temperature

d. competitive inhibitors

Back 66

a. ubiquinone

Front 67

Ch. 5 Questions:

14. Most oxidation reactions in bacteria involve the _______.

a. removal of hydrogen ions and electrons

b. removal of oxygen

c. addition of hydrogen ions and electrons

d. addition of hydrogen ions

Back 67

a. removal of hydrogen ions and electrons

Front 68

Ch. 5 Questions:

15. Under ideal conditions, the fermentation of one glucose molecule by a bacterium allows a net gain of how many ATP molecules?

a. 2

b. 4

c. 38

d. 0

Back 68

a. 2

Front 69

Ch. 5 Questions:

16. Under ideal conditions, the complete aerobic oxidation of one molecule of glucose by a bacterium allows a net gain of how many ATP molecules?

a. 2

b. 4

c. 38

d. 0

Back 69

c. 38

Front 70

Ch. 5 Questions:

17. Which of the following statements about the Entner-Doudoroff pathway is false?

a. It is a series of reactions that synthesizes glucose

b. Its products are sometimes used to determine the presence of Pseudomonas.

c. It is a pathway of chemical reactions that catabolizes glucose

d. It is an alternate pathway to glycolysis

Back 70

a. It is a series of reactions that synthesizes glucose

Front 71

Ch. 5 Questions:

18. Reactions involved in the light-independent reactions of photosynthesis constitute the ____.

a. Krebs cycle

b. Entner-Doudoroff pathway

c. Calvin-Benson cycle

d. pentose phosphate pathway

Back 71

c. Calvin-Benson cycle

Front 72

Ch. 5 Questions:

19. The glycolysis pathway is basically _________.

a. catabolic

b. amphibolic

c. anabolic

d. cyclical

Back 72

a. catabolic

Front 73

Ch. 5 Questions:

20. A major difference between anaerobic respiration and anaerobic fermentation is ____.

a. in the use of oxygen

b. that the former requires breathing

c. that the later uses organic molecules within the cell as final electron acceptors

d. that fermentation only produces alcohol

Back 73

c. that the later uses organic molecules within the cell as final electron acceptors

Front 74

Ch. 5 Questions:

1. ______ Occurs when energy from a compound containing phosphate reacts with ADP to form ATP.

Back 74

Substrate-level phosphorylation

Front 75

Ch. 5 Questions:

2. _______ Involves formation of ATP via reduction of coenzymes in the electron transport chain

Back 75

Oxidative phosphorylation

Front 76

Ch. 5 Questions:

3. ______ Begins with glycolysis

Back 76

Carbohydrate catabolism

Front 77

Ch. 5 Questions:

4. ______ Occurs when all active sites on substrate molecules are filled.

Back 77

Saturation

Front 78

Ch. 5 Questions:

1. The final electron acceptor in cyclic photophosphorylation is ________.

Back 78

the original reaction center chlorophyll

Front 79

Ch. 5 Questions:

2. Two ATP molecules are used to initiate glycolysis. Enzymes generate molecules of ATP for each molecule of glucose that undergoes glycolysis. Thus, a net gain of _______ molecules of ATP is produced in glycolysis.

Back 79

2

Front 80

Ch. 5 Questions:

3. The initial catabolism of glucose occurs by glycolysis and/or the ______ and ______ pathways.

Back 80

pentose phosphate

Entner-Doudoroff

Front 81

Ch. 5 Questions:

4. ________ is a cyclic series of eight reactions involved in the catabolism of acetyl-CoA that yields eight molecules of NADH and two molecules of FADH2+

Back 81

the Krebs cycle

Front 82

Ch. 5 Questions:

5. The final electron acceptor in aerobic respiration is ______.

Back 82

Oxygen or 1/2 O2

Front 83

Ch. 5 Questions:

6. Three common inorganic electron acceptors in anaerobic respiration are _______ and ______.

Back 83

NO3-, SO4^2-, CO3^2-

Front 84

Ch. 5 Questions:

7. Anaerobic respiration typically uses (organic/inorganic) _______ molecules as final electron acceptors.

Back 84

inorganic

Front 85

Ch. 5 Questions:

9. The use of a proton motive force to generate ATP is _____.

Back 85

chemiosmosis

Front 86

Ch. 5 Questions:

10. The main coenzymes that carry electrons in catabolic pathways are ______ and _______.

Back 86

NAD+, FAD