Metabolism Flashcards
What is metabolism?
All chemical reactions within organisms that enable them to maintain life.
Includes catabolism and anabolism.
What are the two main categories of metabolism?
- Catabolism
- Anabolism
Define chemical energy.
Energy contained in the bonds between atoms of a molecule.
What is photosynthesis?
The process by which green plants use radiant energy from the sun to produce carbohydrates from carbon dioxide and water.
What are metabolites?
Any substances produced during metabolism.
What is a metabolic pathway?
A series of chemical reactions that either break down a large compound into smaller units or synthesize more complex molecules from smaller ones.
What is catabolism?
Any metabolic process whereby cells break down complex substances into simpler, smaller ones.
What is anabolism?
Any metabolic process whereby cells convert simple substances into more complex ones.
What are the two major parts of a cell?
- Nucleus
- Cytoplasm
What is the primary site of genetic information in the cell?
Nucleus
What is cytosol?
The semifluid inside the cell membrane, excluding organelles.
What is the function of mitochondria?
The sites of aerobic production of ATP, capturing energy from carbohydrates, proteins, and fats.
What are cofactors?
Compounds required for an enzyme to be active.
What are coenzymes?
Organic compounds that combine with an inactive enzyme to form an active enzyme.
What is adenosine triphosphate (ATP)?
A high-energy compound that is the main direct fuel that cells use to synthesize molecules, contract muscles, transport substances, and perform other tasks.
What is NADH?
The reduced form of nicotinamide adenine dinucleotide, acting as an electron carrier in cells.
What is FADH2?
The reduced form of flavin adenine dinucleotide, acting as an electron carrier in cells.
What is NADPH?
The reduced form of nicotinamide adenine dinucleotide phosphate, acting as an electron carrier in cells.
Define biosynthesis.
Chemical reactions that form simple molecules into complex biomolecules.
What is adenosine diphosphate (ADP)?
The compound produced upon hydrolysis of ATP and used to synthesize ATP.
Fill in the blank: The process of converting excess acetyl CoA into ketone bodies is called _______.
ketogenesis
What is glycolysis?
The anaerobic metabolic pathway that breaks a glucose molecule into two molecules of pyruvate.
What is the result of glycolysis?
Two molecules of ATP and two molecules of NADH.
What is the citric acid cycle also known as?
Krebs cycle or tricarboxylic acid (TCA) cycle.
What is oxidative phosphorylation?
Formation of ATP from ADP and inorganic phosphate coupled to the flow of electrons along the electron transport chain.
What is the Cori cycle?
The circular path that regenerates NAD+ and glucose when oxygen is low and lactate builds up in excess.
What is gluconeogenesis?
Synthesis of glucose within the body from noncarbohydrate precursors.
What do the terms glucogenic and ketogenic refer to?
- Glucogenic: Amino acids that can be converted into glucose
- Ketogenic: Amino acids that can be converted into ketone bodies
What is lipogenesis?
Synthesis of fatty acids, primarily in liver cells, from acetyl CoA.
What is alcohol dehydrogenase (ADH)?
The enzyme that catalyzes the oxidation of ethanol and other alcohols.
What is ketoacidosis?
Acidification of the blood caused by a buildup of ketone bodies.
What is transamination?
The transfer of an amino group from an amino acid to a carbon skeleton to form a different amino acid.
What is the role of pyruvate in metabolism?
Pyruvate is a pivotal point in the metabolic pathways, directing toward ATP production depending on oxygen availability.
What is the function of carnitine?
Transport fatty acids from the cytosol into the mitochondria for beta-oxidation.
What is the citric acid cycle?
A metabolic pathway that plays a key role in energy production.
What is the role of pyruvate in metabolism?
A pivotal point that determines the metabolic pathway based on ATP levels and oxygen availability.
When ATP levels are low, what happens to pyruvate?
It is converted to acetyl CoA or lactate depending on oxygen availability.
What happens to pyruvate when ATP is abundant?
It is converted to oxaloacetate or the amino acid alanine.
What is the irreversible reaction involving pyruvate?
The conversion of pyruvate to acetyl CoA.
Can acetyl CoA be converted back to glucose?
No, acetyl CoA cannot be converted to glucose.
What is formed from pyruvate when oxygen levels are low?
Lactate.
What does the conversion of pyruvate to lactate produce?
NAD+.
Why is NAD+ regeneration critical in glycolysis?
Without NAD+, glycolysis would stop.
How does pyruvate convert to oxaloacetate?
It can react with acetyl CoA to start the citric acid cycle or provide building blocks for glucose.
What is the significance of oxaloacetate in metabolism?
It is essential for acetyl CoA’s entry into the citric acid cycle.
What happens to acetyl CoA when energy is abundant?
It is used as building blocks for fatty acid synthesis.
What hormonal factors regulate energy metabolism?
Insulin, glucagon, cortisol, and epinephrine.
What does insulin stimulate in metabolism?
Glycogen, protein, and triglyceride synthesis.
What occurs during feasting?
Anabolic processes such as glycogen and triglyceride synthesis are stimulated.
What happens during fasting?
Catabolic pathways are favored, utilizing stored glycogen, fat, and protein.
What fuels does the body adapt to use during prolonged starvation?
Increasing amounts of ketone bodies.
What is the primary amino acid produced from pyruvate?
Alanine.
What pathway does acetyl CoA enter when ATP is needed?
The citric acid cycle.
What happens to acetyl CoA when oxaloacetate production is insufficient?
It is shunted to form ketone bodies.
Fill in the blank: Acetyl CoA can enter major energy-producing and _______ pathways.
biosynthetic
