Metabolism

Question 1

What is metabolism?

Answer 1

All chemical reactions within organisms that enable them to maintain life.

Includes catabolism and anabolism.

Question 2

What are the two main categories of metabolism?

Answer 2

• Catabolism
• Anabolism

Question 3

Define chemical energy.

Answer 3

Energy contained in the bonds between atoms of a molecule.

Question 4

What is photosynthesis?

Answer 4

The process by which green plants use radiant energy from the sun to produce carbohydrates from carbon dioxide and water.

Question 5

What are metabolites?

Answer 5

Any substances produced during metabolism.

Question 6

What is a metabolic pathway?

Answer 6

A series of chemical reactions that either break down a large compound into smaller units or synthesize more complex molecules from smaller ones.

Question 7

What is catabolism?

Answer 7

Any metabolic process whereby cells break down complex substances into simpler, smaller ones.

Question 8

What is anabolism?

Answer 8

Any metabolic process whereby cells convert simple substances into more complex ones.

Question 9

What are the two major parts of a cell?

Answer 9

• Nucleus
• Cytoplasm

Question 10

What is the primary site of genetic information in the cell?

Answer 10

Nucleus

Question 11

What is cytosol?

Answer 11

The semifluid inside the cell membrane, excluding organelles.

Question 12

What is the function of mitochondria?

Answer 12

The sites of aerobic production of ATP, capturing energy from carbohydrates, proteins, and fats.

Question 13

What are cofactors?

Answer 13

Compounds required for an enzyme to be active.

Question 14

What are coenzymes?

Answer 14

Organic compounds that combine with an inactive enzyme to form an active enzyme.

Question 15

What is adenosine triphosphate (ATP)?

Answer 15

A high-energy compound that is the main direct fuel that cells use to synthesize molecules, contract muscles, transport substances, and perform other tasks.

Question 16

What is NADH?

Answer 16

The reduced form of nicotinamide adenine dinucleotide, acting as an electron carrier in cells.

Question 17

What is FADH2?

Answer 17

The reduced form of flavin adenine dinucleotide, acting as an electron carrier in cells.

Question 18

What is NADPH?

Answer 18

The reduced form of nicotinamide adenine dinucleotide phosphate, acting as an electron carrier in cells.

Question 19

Define biosynthesis.

Answer 19

Chemical reactions that form simple molecules into complex biomolecules.

Question 20

What is adenosine diphosphate (ADP)?

Answer 20

The compound produced upon hydrolysis of ATP and used to synthesize ATP.

Question 21

Fill in the blank: The process of converting excess acetyl CoA into ketone bodies is called _______.

Answer 21

ketogenesis

Question 22

What is glycolysis?

Answer 22

The anaerobic metabolic pathway that breaks a glucose molecule into two molecules of pyruvate.

Question 23

What is the result of glycolysis?

Answer 23

Two molecules of ATP and two molecules of NADH.

Question 24

What is the citric acid cycle also known as?

Answer 24

Krebs cycle or tricarboxylic acid (TCA) cycle.

Question 25

What is oxidative phosphorylation?

Answer 25

Formation of ATP from ADP and inorganic phosphate coupled to the flow of electrons along the electron transport chain.

Question 26

What is the Cori cycle?

Answer 26

The circular path that regenerates NAD+ and glucose when oxygen is low and lactate builds up in excess.

Question 27

What is gluconeogenesis?

Answer 27

Synthesis of glucose within the body from noncarbohydrate precursors.

Question 28

What do the terms glucogenic and ketogenic refer to?

Answer 28

* Glucogenic: Amino acids that can be converted into glucose * Ketogenic: Amino acids that can be converted into ketone bodies

Question 29

What is lipogenesis?

Answer 29

Synthesis of fatty acids, primarily in liver cells, from acetyl CoA.

Question 30

What is alcohol dehydrogenase (ADH)?

Answer 30

The enzyme that catalyzes the oxidation of ethanol and other alcohols.

Question 31

What is ketoacidosis?

Answer 31

Acidification of the blood caused by a buildup of ketone bodies.

Question 32

What is transamination?

Answer 32

The transfer of an amino group from an amino acid to a carbon skeleton to form a different amino acid.

Question 33

What is the role of pyruvate in metabolism?

Answer 33

Pyruvate is a pivotal point in the metabolic pathways, directing toward ATP production depending on oxygen availability.

Question 34

What is the function of carnitine?

Answer 34

Transport fatty acids from the cytosol into the mitochondria for beta-oxidation.

Question 35

What is the citric acid cycle?

Answer 35

A metabolic pathway that plays a key role in energy production.

Question 36

What is the role of pyruvate in metabolism?

Answer 36

A pivotal point that determines the metabolic pathway based on ATP levels and oxygen availability.

Question 37

When ATP levels are low, what happens to pyruvate?

Answer 37

It is converted to acetyl CoA or lactate depending on oxygen availability.

Question 38

What happens to pyruvate when ATP is abundant?

Answer 38

It is converted to oxaloacetate or the amino acid alanine.

Question 39

What is the irreversible reaction involving pyruvate?

Answer 39

The conversion of pyruvate to acetyl CoA.

Question 40

Can acetyl CoA be converted back to glucose?

Answer 40

No, acetyl CoA cannot be converted to glucose.

Question 41

What is formed from pyruvate when oxygen levels are low?

Answer 41

Lactate.

Question 42

What does the conversion of pyruvate to lactate produce?

Answer 42

NAD+.

Question 43

Why is NAD+ regeneration critical in glycolysis?

Answer 43

Without NAD+, glycolysis would stop.

Question 44

How does pyruvate convert to oxaloacetate?

Answer 44

It can react with acetyl CoA to start the citric acid cycle or provide building blocks for glucose.

Question 45

What is the significance of oxaloacetate in metabolism?

Answer 45

It is essential for acetyl CoA's entry into the citric acid cycle.

Question 46

What happens to acetyl CoA when energy is abundant?

Answer 46

It is used as building blocks for fatty acid synthesis.

Question 47

What hormonal factors regulate energy metabolism?

Answer 47

Insulin, glucagon, cortisol, and epinephrine.

Question 48

What does insulin stimulate in metabolism?

Answer 48

Glycogen, protein, and triglyceride synthesis.

Question 49

What occurs during feasting?

Answer 49

Anabolic processes such as glycogen and triglyceride synthesis are stimulated.

Question 50

What happens during fasting?

Answer 50

Catabolic pathways are favored, utilizing stored glycogen, fat, and protein.

Question 51

What fuels does the body adapt to use during prolonged starvation?

Answer 51

Increasing amounts of ketone bodies.

Question 52

What is the primary amino acid produced from pyruvate?

Answer 52

Alanine.

Question 53

What pathway does acetyl CoA enter when ATP is needed?

Answer 53

The citric acid cycle.

Question 54

What happens to acetyl CoA when oxaloacetate production is insufficient?

Answer 54

It is shunted to form ketone bodies.

Question 55

Fill in the blank: Acetyl CoA can enter major energy-producing and _______ pathways.

Answer 55

biosynthetic