Learning Outcomes Chapter 5

Question 1

Define Metabolism

Answer 1

Collection of controlled biochemical reactions that take place within a microbe

The ultimate function of metabolism is to reproduce the organism.

Question 2

Define the Catabolic pathway; give an example.

Answer 2

Break larger molecules into smaller products.
(Polymonomers to monomers)

Exergonic (energy release)

example - Cellular Respiration

Question 3

Define the Anabolic pathway; give an example.

Answer 3

Synthesize large molecules from the smaller
products of catabolism

Endergonic (require more energy than they
release)

ex - Photosynthesis

Question 4

Define Oxidation and Reduction reactions.

Answer 4

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)

Question 5

What are the three types of electron carriers?

Answer 5

Nicotinamide adenine dinucleotide (NAD+)

Nicotinamide adenine dinucleotide phosphate
(NADPH)

Flavin adenine dinucleotide (FAD)

Question 6

NAD+

Answer 6

Reduced to NADH –
When?
▪ Glycolysis
▪ Synthesis of Acetyl-CoA
▪ Krebs Cycle

Question 7

FAD

Answer 7

Reduced to FADH2
– When?
▪ Krebs Cycle

Question 8

In the presence of the
final electron acceptor
NADH and FADH2 will?

Answer 8

Oxidized to NAD+ and
FAD
–When?
▪ Electron Transport Chain

Question 9

Describe the structure of ATP.

Answer 9

Adenosine triphosphate is made of:
Adenine, ribose, and three phosphate groups

Question 10

ATP in Substrate-Level
Phosphorylation?

Answer 10

How ATP is made - A high-energy
phosphate from a pathway intermediate is
transferred directly to ADP to make ATP

Electron transport chain used? No

Used in? Glycolysis, Krebs cycle,
fermentation

Cell types that use it - Prokaryotic and
eukaryotic

Question 11

ATP in Oxidative Phosphorylation?

Answer 11

How ATP is made - ADP is recharged to ATP using electron transport chains powered by nutrients.

Electron transport chain used? Yes

Used in - Aerobic and anaerobic electron transport chains of cellular respiration

Cell types that use it - Prokaryotic and
eukaryotic

Question 12

Explain the naming enzyme and its classification based on the site of action, type of action
and rate of enzyme production

Answer 12

The names of enzymes usually end with the suffix -ase, and the name of each enzyme often incorporates the name of that enzyme’s substrate, which is the molecule the enzyme acts on. Based on their mode of action, enzymes can be grouped into six basic categories.

Hydrolases

Isomerases

Ligases, or polymerases

Lyases

Oxidoreductases

Transferases

Question 13

Define enzyme

Answer 13

Organic catalysts that speed up chemical reactions. Lower energy is required.

Question 14

Define substrate

Answer 14

A substrate is a molecule that an enzyme reacts with

Question 15

Describe the parts or components of a holoenzyme and RNA enzymes.

Answer 15

Holoenzyme - The binding of an apoenzyme (Apoenzyme are inactive if not bound to nonprotein)
and its cofactor (inorganic ions or coenzymes) forms an active enzyme called a holoenzyme

Ribozymes - RNA molecules functioning as enzymes.

Question 16

Define activation energy, enzyme, apoenzyme, cofactor, coenzyme, active site, and
substrate, and describe their roles in enzyme activity

Answer 16

Activation energy - The amount of Energy needed for a chemical reaction.

Apoenzyme - Apoenzyme are inactive if not bound to nonprotein.

Cofactor - inorganic ions or coenzymes

Coenzyme - Organic cofactor

Active site - The functional sites of an enzyme and its substrate. The shape of an enzyme’s functional site

Substrate - A substrate is a molecule that an enzyme reacts with

Question 17

Describe three stages of aerobic glucose catabolism (glycolysis, the Krebs cycle, and an electron transport chain), including their substrates, products, and net energy production.

Answer 17

Glycolysis - glucose ultimately breaks down into pyruvate and energy; a total of 2 ATP is derived in the process (Glucose + 2 NAD+ + 2 ADP + 2 Pi –> 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O).

Krebs cycle - Oxidation of citric acid (formed from acety CoA-oxaloacetic acid reaction) produces NADH, FADH2, and ATP Oxidation of molecules liberates electrons for an electron transport chain (ETC)
Using as ETC, ATP is generated by oxidative phosphorylation.

Electron Transport Chain - NAD+, FAD, water, and ATP.

Question 18

Describe the role of acetyl-CoA, the Krebs cycle, and the electron transport chain in carbohydrate catabolism

Answer 18

acetyl-CoA stores a large amount of petential energy which is released step by step in the Kreb cycle. Pyruvic acid cannot enter the Kreb cycle directly so it’s coverted to acetyl-CoA thru decarboxylation.

Question 19

Contrast electron transport in aerobic and anaerobic respiration.

Answer 19

Aerobic respiration uses oxygen.

Anaerobic respiration is respiration without oxygen; the process uses a respiratory electron transport chain but does not use oxygen as the electron acceptor.

Question 20

Identify four classes of carriers in electron transport chains

Answer 20

Flavoproteins
ubiquinones
metal-containing proteins
cytochromes