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The preferred IUPAC nomenclature for pyruvic acid is 2-Oxopropanoic acid.
Answer: True
Explanation: The preferred IUPAC nomenclature for pyruvic acid is indeed 2-Oxopropanoic acid, as established in chemical databases and literature.
Pyruvic acid possesses a melting point of approximately 53.2 °F (11.8 °C), indicating it is a solid at standard room temperature.
Answer: True
Explanation: Pyruvic acid has a melting point of 11.8 °C (53.2 °F), which is slightly above typical room temperature, meaning it can exist as a solid under ambient conditions.
Pyruvic acid is classified as a beta-keto acid due to its molecular structure.
Answer: False
Explanation: Pyruvic acid is classified as the simplest of the alpha-keto acids, not a beta-keto acid, due to the position of the ketone group relative to the carboxylic acid functional group.
Pyruvate is the conjugate acid of pyruvic acid.
Answer: False
Explanation: Pyruvate is the conjugate base of pyruvic acid. Pyruvic acid donates a proton (H+) to form its conjugate base, pyruvate.
Pyruvic acid is described as a yellow liquid with a pungent odor.
Answer: False
Explanation: Pyruvic acid is typically described as a colorless liquid with an odor similar to acetic acid, not yellow.
Pyruvic acid is found in atmospheric secondary organic aerosols.
Answer: True
Explanation: Pyruvic acid has been identified as an abundant carboxylic acid present within secondary organic aerosols found in the atmosphere.
The chemical formula C3H4O3 represents methylglyoxal, not pyruvic acid.
Answer: False
Explanation: The chemical formula C3H4O3 accurately represents pyruvic acid. Methylglyoxal has the formula C3H4O2.
Pyruvic acid has a molar mass of approximately 88.06 g/mol.
Answer: True
Explanation: The calculated molar mass for pyruvic acid (C3H4O3) is indeed approximately 88.06 g/mol.
The pKa of pyruvic acid is 2.50, indicating it is a moderately strong organic acid.
Answer: True
Explanation: With a pKa value of 2.50, pyruvic acid is considered a moderately strong organic acid, capable of readily donating a proton.
Pyruvic acid is miscible with water.
Answer: True
Explanation: Pyruvic acid exhibits miscibility with water, meaning it can dissolve in water in all proportions due to its polar nature.
The CAS Number for pyruvic acid is 127-17-3.
Answer: True
Explanation: The Chemical Abstracts Service (CAS) Registry Number uniquely identifying pyruvic acid is 127-17-3.
The systematic IUPAC name for pyruvic acid is 2-Oxopropionic acid.
Answer: True
Explanation: The systematic IUPAC name for pyruvic acid is 2-Oxopropionic acid, which precisely describes its chemical structure.
Pyruvic acid is poorly soluble in water.
Answer: False
Explanation: Pyruvic acid is miscible with water, indicating high solubility, not poor solubility.
The SMILES notation for pyruvic acid is O=C(C(=O)C)C.
Answer: True
Explanation: The Simplified Molecular Input Line Entry System (SMILES) string O=C(C(=O)C)C accurately represents the chemical structure of pyruvic acid.
The InChIKey for pyruvic acid is LCTONWCANYUPML-UHFFFAOYSA-N.
Answer: True
Explanation: The International Chemical Identifier (InChI) Key for pyruvic acid is LCTONWCANYUPML-UHFFFAOYSA-N, serving as a standardized identifier.
Pyruvic acid has a boiling point of 165 °C.
Answer: True
Explanation: The boiling point of pyruvic acid is reported to be 165 °C (329 °F).
The ChEBI identifier for pyruvic acid is CHEBI:32816.
Answer: True
Explanation: The Chemical Entities of Biological Interest (ChEBI) database assigns the identifier CHEBI:32816 to pyruvic acid.
The PubChem CID for pyruvic acid is 1060.
Answer: True
Explanation: The PubChem Compound ID (CID) for pyruvic acid is 1060, a unique identifier within the PubChem database.
Pyruvic acid is described as having a smell similar to propionic acid.
Answer: False
Explanation: Pyruvic acid is described as having a smell similar to acetic acid, not propionic acid.
Which of the following is a preferred IUPAC name for pyruvic acid?
Answer: 2-Oxopropanoic acid
Explanation: The preferred IUPAC name for pyruvic acid is 2-Oxopropanoic acid. Other names like 2-Oxopropionic acid are also systematic but 2-Oxopropanoic acid is generally preferred.
What is the chemical formula for pyruvic acid?
Answer: C3H4O3
Explanation: The chemical formula for pyruvic acid is C3H4O3, indicating three carbon atoms, four hydrogen atoms, and three oxygen atoms.
Pyruvic acid is classified as the simplest type of which acid?
Answer: Alpha-keto acid
Explanation: Pyruvic acid is classified as the simplest of the alpha-keto acids, characterized by a ketone group adjacent to the carboxylic acid group.
What is the conjugate base of pyruvic acid called?
Answer: Pyruvate
Explanation: The conjugate base of pyruvic acid, formed upon the loss of a proton from the carboxylic acid group, is known as pyruvate.
Which of the following is NOT a common name for pyruvic acid listed in the source?
Answer: Propanoic acid
Explanation: Common names for pyruvic acid include 2-Oxopropionic acid, Acetylformic acid, and Pyroracemic acid. Propanoic acid is a different chemical compound.
What is the approximate molar mass of pyruvic acid?
Answer: 88.06 g/mol
Explanation: The molar mass of pyruvic acid (C3H4O3) is calculated to be approximately 88.06 grams per mole.
What is the pKa value of pyruvic acid?
Answer: 2.50
Explanation: The pKa of pyruvic acid is 2.50, indicating its acidity and its tendency to dissociate in aqueous solutions.
How is pyruvic acid described in terms of its physical state and solubility?
Answer: A colorless liquid, miscible with water
Explanation: Pyruvic acid is characterized as a colorless liquid that is miscible with water, indicating high solubility.
In which environmental context is pyruvic acid mentioned?
Answer: As an abundant carboxylic acid in secondary organic aerosols
Explanation: Pyruvic acid is identified as a significant component found within secondary organic aerosols present in the Earth's atmosphere.
Which of the following is a systematic IUPAC name for pyruvic acid?
Answer: 2-Oxopropionic acid
Explanation: Both 2-Oxopropanoic acid and 2-Oxopropionic acid are systematic IUPAC names for pyruvic acid. 2-Oxopropanoic acid is generally considered the preferred nomenclature.
What is the CAS Registry Number for pyruvic acid?
Answer: 127-17-3
Explanation: The CAS Registry Number for pyruvic acid is 127-17-3.
What is the relationship between pyruvic acid and pyruvate?
Answer: Pyruvate is the conjugate base of pyruvic acid.
Explanation: Pyruvate is the deprotonated form of pyruvic acid, making it the conjugate base. Pyruvic acid is the conjugate acid.
What is the approximate boiling point of pyruvic acid?
Answer: 165 °C
Explanation: The boiling point of pyruvic acid is approximately 165 °C (329 °F).
What does the SMILES notation O=C(C(=O)C)C represent?
Answer: Pyruvic acid
Explanation: The SMILES string O=C(C(=O)C)C is the standard representation for the chemical structure of pyruvic acid.
Jöns Jacob Berzelius named pyruvic acid because it was derived from the distillation of malic acid.
Answer: False
Explanation: Jöns Jacob Berzelius characterized pyruvic acid in 1835 and named it 'pyruvic acid' due to its derivation from the distillation of tartaric acid (Latin: 'pyrus' for pear, referring to malic acid, but the actual source was tartaric acid). The name reflects its origin from distillation processes.
Heating tartaric acid with potassium hydrogen sulfate is a recognized laboratory method for preparing pyruvic acid.
Answer: True
Explanation: The laboratory preparation of pyruvic acid can be achieved by heating tartaric acid in the presence of potassium hydrogen sulfate.
Théophile-Jules Pelouze isolated pyruvic acid in 1835.
Answer: False
Explanation: Théophile-Jules Pelouze first isolated pyruvic acid in 1834. Jöns Jacob Berzelius characterized and named it in 1835.
Pyruvic acid was first isolated by Jöns Jacob Berzelius.
Answer: False
Explanation: Jöns Jacob Berzelius characterized pyruvic acid in 1835, but Théophile-Jules Pelouze was the first to isolate it in 1834.
Who first isolated pyruvic acid, and in what year?
Answer: Théophile-Jules Pelouze, 1834
Explanation: Théophile-Jules Pelouze first isolated pyruvic acid in 1834. Jöns Jacob Berzelius characterized it the following year.
Which laboratory method involves heating tartaric acid to prepare pyruvic acid?
Answer: Distillation with potassium hydrogen sulfate
Explanation: Heating tartaric acid with potassium hydrogen sulfate is a known laboratory method for the preparation of pyruvic acid.
Which of the following is NOT listed as a laboratory preparation method for pyruvic acid in the source?
Answer: Reduction of oxaloacetate
Explanation: The source details methods such as heating tartaric acid with potassium hydrogen sulfate, oxidation of propylene glycol, and hydrolysis of acetyl cyanide. Reduction of oxaloacetate is not listed as a preparation method for pyruvic acid.
Glycolysis breaks down pyruvate into two molecules of glucose.
Answer: False
Explanation: Glycolysis is the metabolic pathway that breaks down glucose into two molecules of pyruvate. Pyruvate is not broken down into glucose by glycolysis.
In aerobic respiration, pyruvate is directly used in the citric acid cycle without further modification.
Answer: False
Explanation: In aerobic respiration, pyruvate must first be converted into acetyl-CoA by the pyruvate dehydrogenase complex before it can enter the citric acid cycle.
The pyruvate dehydrogenase complex produces acetyl-CoA and consumes carbon dioxide.
Answer: False
Explanation: The pyruvate dehydrogenase complex catalyzes the oxidative decarboxylation of pyruvate, producing acetyl-CoA, NADH, and carbon dioxide (CO2). Thus, it consumes pyruvate and produces CO2, not the other way around.
Pyruvate is converted to acetyl-CoA via the enzyme pyruvate kinase.
Answer: False
Explanation: The conversion of pyruvate to acetyl-CoA is catalyzed by the pyruvate dehydrogenase complex, not pyruvate kinase. Pyruvate kinase is involved in the final step of glycolysis.
The citric acid cycle is also known as the Krebs cycle or the tricarboxylic acid cycle.
Answer: True
Explanation: The citric acid cycle is indeed commonly referred to by its alternative names, the Krebs cycle and the tricarboxylic acid (TCA) cycle.
Which metabolic pathway breaks down glucose into pyruvate?
Answer: Glycolysis
Explanation: Glycolysis is the fundamental metabolic pathway responsible for the breakdown of one molecule of glucose into two molecules of pyruvate.
Under aerobic conditions, pyruvate is primarily processed through which cycle for energy production?
Answer: Citric Acid Cycle (Krebs Cycle)
Explanation: Under aerobic conditions, pyruvate is converted to acetyl-CoA, which then enters the Citric Acid Cycle (also known as the Krebs Cycle) for further oxidation and energy generation.
How many molecules of pyruvate are produced from one molecule of glucose during glycolysis?
Answer: Two
Explanation: The process of glycolysis cleaves one molecule of glucose into two molecules of pyruvate.
What is the intermediate molecule formed when pyruvate is processed for the Krebs cycle under aerobic conditions?
Answer: Acetyl-CoA
Explanation: Under aerobic conditions, pyruvate is converted to acetyl-CoA via the pyruvate dehydrogenase complex, which then enters the Krebs cycle.
Which enzyme catalyzes the final step of glycolysis, producing pyruvate?
Answer: Pyruvate kinase
Explanation: Pyruvate kinase is the enzyme that catalyzes the final, essentially irreversible, step of glycolysis, converting phosphoenolpyruvate into pyruvate.
What are the products of the pyruvate dehydrogenase complex acting on pyruvate?
Answer: Acetyl-CoA, NADH + H+, CO2
Explanation: The pyruvate dehydrogenase complex catalyzes the conversion of pyruvate into acetyl-CoA, producing NADH and releasing carbon dioxide (CO2).
Under aerobic conditions, pyruvic acid is primarily converted into lactate for energy production.
Answer: False
Explanation: Under aerobic conditions, pyruvic acid is primarily converted into acetyl-CoA for entry into the citric acid cycle. Lactate production occurs under anaerobic conditions.
When oxygen is insufficient, animals convert pyruvate to acetaldehyde.
Answer: False
Explanation: In animals, insufficient oxygen leads to the conversion of pyruvate to lactate. Acetaldehyde is an intermediate in alcoholic fermentation, which occurs in plants and microorganisms.
Alcoholic fermentation in plants involves the conversion of pyruvate directly to ethanol.
Answer: False
Explanation: Alcoholic fermentation involves a two-step process: pyruvate is first decarboxylated to acetaldehyde, which is then reduced to ethanol. The direct conversion of pyruvate to ethanol does not occur.
Lactate dehydrogenase uses NAD+ to convert pyruvate to lactate.
Answer: False
Explanation: Lactate dehydrogenase catalyzes the reduction of pyruvate to lactate, utilizing NADH as the reducing agent and producing NAD+. Therefore, it consumes NADH, not NAD+.
The conversion of pyruvate to lactate regenerates NADH.
Answer: False
Explanation: The conversion of pyruvate to lactate consumes NADH and regenerates NAD+. This NAD+ is then available to sustain glycolysis.
What happens to pyruvate in animals when oxygen is lacking?
Answer: It undergoes fermentation to produce lactate.
Explanation: In the absence of sufficient oxygen, animals convert pyruvate to lactate through anaerobic fermentation, a process essential for regenerating NAD+ required for glycolysis to continue.
Which coenzyme is consumed during the reduction of pyruvate to lactate?
Answer: NADH
Explanation: The reduction of pyruvate to lactate by lactate dehydrogenase utilizes NADH as the electron donor (reducing agent), oxidizing it to NAD+.
In alcoholic fermentation by plants and microorganisms, what is the intermediate between pyruvate and ethanol?
Answer: Acetaldehyde
Explanation: In alcoholic fermentation, pyruvate is first decarboxylated to acetaldehyde, which is then reduced to ethanol. Acetaldehyde is the intermediate.
Pyruvate acts as a central hub connecting glycolysis to gluconeogenesis, fatty acid synthesis, and amino acid synthesis.
Answer: True
Explanation: Pyruvate is a pivotal intermediate in cellular metabolism, serving as a key intersection point that links glycolysis to anabolic pathways such as gluconeogenesis, fatty acid synthesis, and amino acid synthesis.
Oxaloacetate is synthesized from pyruvate and is essential for replenishing Krebs cycle intermediates.
Answer: True
Explanation: Pyruvate can be carboxylated to form oxaloacetate, a reaction catalyzed by pyruvate carboxylase. Oxaloacetate is a key intermediate in the Krebs cycle and plays an anaplerotic role by replenishing cycle intermediates.
Pyruvate kinase catalyzes the conversion of pyruvate to phosphoenolpyruvate in glycolysis.
Answer: False
Explanation: Pyruvate kinase catalyzes the final step of glycolysis, converting phosphoenolpyruvate (PEP) to pyruvate. The reverse reaction in gluconeogenesis requires different enzymes.
The reverse reaction of pyruvate to phosphoenolpyruvate in gluconeogenesis requires only one enzymatic step.
Answer: False
Explanation: The conversion of pyruvate back to phosphoenolpyruvate during gluconeogenesis is an energetically unfavorable process that requires two distinct enzymatic steps, involving pyruvate carboxylase and PEP carboxykinase, to bypass the irreversible step catalyzed by pyruvate kinase in glycolysis.
Pyruvate carboxylase uses ATP and CO2 to convert pyruvate into oxaloacetate.
Answer: True
Explanation: Pyruvate carboxylase is an enzyme that catalyzes the carboxylation of pyruvate to oxaloacetate, utilizing ATP and carbon dioxide as substrates.
Alanine is synthesized from pyruvate via a reduction reaction.
Answer: False
Explanation: Alanine is synthesized from pyruvate via a transamination reaction, not a reduction reaction. This process involves the transfer of an amino group.
In gluconeogenesis, the conversion of pyruvate to phosphoenolpyruvate requires the enzyme pyruvate carboxylase.
Answer: True
Explanation: The conversion of pyruvate to phosphoenolpyruvate in gluconeogenesis involves two steps. Pyruvate carboxylase catalyzes the first step, converting pyruvate to oxaloacetate, which is then converted to phosphoenolpyruvate by PEP carboxykinase.
Pyruvate can be converted into fatty acids after reacting with acetyl-CoA.
Answer: True
Explanation: Pyruvate is a precursor for acetyl-CoA, which is the primary building block for fatty acid synthesis. Thus, pyruvate indirectly contributes to fatty acid synthesis.
When pyruvate is transaminated to alanine, α-ketoglutarate is produced.
Answer: True
Explanation: The transamination of pyruvate to alanine, catalyzed by alanine transaminase, involves the transfer of an amino group from glutamate, resulting in the production of α-ketoglutarate as a co-product.
Pyruvic acid is primarily used in the synthesis of nucleic acids.
Answer: False
Explanation: Pyruvic acid's primary roles are in energy metabolism (glycolysis, aerobic respiration) and as a precursor for other molecules like fatty acids and amino acids, not directly in nucleic acid synthesis.
Pyruvate is involved in gluconeogenesis, the process of synthesizing glucose from non-carbohydrate precursors.
Answer: True
Explanation: Pyruvate serves as a key substrate in gluconeogenesis, enabling the synthesis of glucose from non-carbohydrate precursors.
Pyruvate serves as a crucial intersection point connecting glycolysis to which other metabolic processes?
Answer: Gluconeogenesis, fatty acid synthesis, and amino acid synthesis
Explanation: Pyruvate is a central metabolic hub, linking glycolysis to anabolic pathways including gluconeogenesis, fatty acid synthesis, and the synthesis of various amino acids.
How does gluconeogenesis achieve the conversion of pyruvate back to phosphoenolpyruvate?
Answer: Via two separate enzymatic steps involving pyruvate carboxylase and PEP carboxykinase.
Explanation: The conversion of pyruvate to phosphoenolpyruvate in gluconeogenesis is accomplished through a two-step process: first, pyruvate is carboxylated to oxaloacetate by pyruvate carboxylase, and then oxaloacetate is decarboxylated and phosphorylated to phosphoenolpyruvate by PEP carboxykinase.
Which enzyme catalyzes the carboxylation of pyruvate to oxaloacetate, requiring ATP?
Answer: Pyruvate carboxylase
Explanation: Pyruvate carboxylase is the enzyme responsible for the ATP-dependent carboxylation of pyruvate to form oxaloacetate.
What is the role of alanine transaminase in pyruvate metabolism?
Answer: Catalyzes the transamination of pyruvate to alanine
Explanation: Alanine transaminase facilitates the transamination reaction where pyruvate accepts an amino group, typically from glutamate, to form the amino acid alanine.
Pyruvic acid can be converted back into carbohydrates like glucose through which process?
Answer: Gluconeogenesis
Explanation: Gluconeogenesis is the metabolic pathway responsible for the synthesis of glucose from non-carbohydrate precursors, including pyruvate.
What is the primary role of pyruvate in cellular metabolism?
Answer: To act as a central intersection point connecting various metabolic pathways
Explanation: Pyruvate functions as a critical metabolic crossroads, linking glycolysis to numerous other pathways involved in energy production, biosynthesis, and amino acid metabolism.
Scientific evidence strongly supports pyruvate's effectiveness as a weight-loss supplement.
Answer: False
Explanation: A systematic review indicates that credible scientific evidence supporting pyruvate's effectiveness for weight loss is limited, citing methodological weaknesses in studies and a minor effect size.
Diarrhea and bloating are potential adverse effects of pyruvate supplementation.
Answer: True
Explanation: Gastrointestinal disturbances, including diarrhea and bloating, have been reported as potential adverse effects associated with the supplementation of pyruvate.
Pyruvate supplementation has been shown to decrease low-density lipoprotein (LDL) cholesterol levels.
Answer: False
Explanation: Research indicates that pyruvate supplementation may be associated with an increase, rather than a decrease, in low-density lipoprotein (LDL) cholesterol levels.
Pyruvate may enhance cardiac function by stimulating NADH production.
Answer: True
Explanation: Studies suggest that pyruvate can potentially improve cardiac metabolism by stimulating NADH production, which may contribute to enhanced cardiac function.
What adverse effects have been associated with pyruvate supplementation, according to the source?
Answer: Gastrointestinal issues and increased LDL cholesterol
Explanation: Reported adverse effects of pyruvate supplementation include gastrointestinal disturbances such as diarrhea and bloating, as well as an increase in LDL cholesterol levels.
What does the source suggest about the scientific evidence for pyruvate as a weight-loss supplement?
Answer: There is limited credible evidence, with methodological weaknesses noted.
Explanation: The source indicates that scientific evidence supporting pyruvate's efficacy for weight loss is limited, citing methodological concerns in existing studies and a modest observed effect size.
What potential benefit of pyruvate related to cardiac function is mentioned?
Answer: It improves cardiac metabolism by stimulating NADH production.
Explanation: Research suggests that pyruvate may enhance cardiac metabolism through the stimulation of NADH production, potentially benefiting cardiac function.