Vitamin B1 assists an organic catalyst in cell respiration. This vitamin functions as

A. a polypeptide

B. a coenzyme

C. a substrate

D. an inorganic catalyst

Answer Explanation:

B) a coenzyme

- Correct: Vitamin B1, also known as thiamine, functions as a coenzyme in cell respiration. Coenzymes are small molecules that assist enzymes in catalyzing biochemical reactions. In the case of thiamine, it serves as a coenzyme for several enzymes involved in the metabolism of carbohydrates, particularly in the citric acid cycle (Krebs cycle) and the pentose phosphate pathway, which are essential processes in cell respiration. Thiamine helps in the conversion of carbohydrates into energy, ultimately facilitating ATP production.

A) a polypeptide

- Incorrect: Polypeptides are chains of amino acids linked by peptide bonds, and they serve as the building blocks of proteins. Vitamin B1 is not a polypeptide itself but rather a small organic molecule.

C) a substrate

- Incorrect: Substrates are molecules upon which enzymes act to catalyze biochemical reactions. Vitamin B1 is not a substrate but rather a cofactor (coenzyme) that assists enzymes in catalyzing reactions.

D) an inorganic catalyst

- Incorrect: Inorganic catalysts are typically metallic ions or small inorganic molecules that facilitate chemical reactions but are not part of the reaction products. Vitamin B1 is an organic molecule derived from thiazole and pyrimidine rings and is not classified as an inorganic catalyst.

Therefore, the Correct Answer is B.

Q #1: If a person was unable to break down food particles into molecules that could be absorbed by the body, you would predict

A. there is a malfunction with the digestive system

B. there is a malfunction with the excretory system

C. there is a malfunction with the reproductive system

D. there is a malfunction with the circulatory system

Answer Explanation

A) there is a malfunction with the digestive system

- Correct: Inability to break down food particles into molecules that can be absorbed by the body suggests a malfunction with the digestive system. The digestive system is responsible for the mechanical and chemical breakdown of food into smaller molecules, such as carbohydrates, proteins, and fats, that can be absorbed by the intestines and utilized by the body for energy, growth, and repair. If the digestive system is not functioning properly, it can lead to malabsorption of nutrients, resulting in nutritional deficiencies and related health issues.

B) there is a malfunction with the excretory system

- Incorrect: The excretory system is responsible for removing waste products from the body, primarily through the kidneys, urinary tract, and skin. While the excretory system plays a role in eliminating some metabolic waste products generated from the breakdown of nutrients, it is not primarily responsible for the breakdown of food particles into absorbable molecules.

C) there is a malfunction with the reproductive system

- Incorrect: The reproductive system is responsible for the production of gametes (sperm and eggs) and the facilitation of reproduction. It is not directly involved in the breakdown and absorption of food particles in the digestive process.

D) there is a malfunction with the circulatory system

- Incorrect: The circulatory system, comprising the heart, blood vessels, and blood, is responsible for transporting nutrients, oxygen, and other substances throughout the body. While the circulatory system transports nutrients absorbed by the digestive system to various tissues and organs, it does not directly participate in the breakdown of food particles into absorbable molecules.
Q #2: In humans, chemical digestion is accomplished

A. by enzyme action that begins in the mouth and ends in the

B. esophagus

C. stomach

D. small intestine

Answer Explanation

C) small intestine

- Correct: Chemical digestion in humans is a complex process involving various enzymes acting on different nutrients. While digestion does begin in the mouth with the action of enzymes like salivary amylase on carbohydrates, the majority of chemical digestion occurs in the small intestine. Enzymes secreted by the pancreas (such as pancreatic amylase, lipase, and proteases) and the small intestine itself (such as maltase, sucrase, lactase, and peptidases) break down carbohydrates, fats, and proteins into smaller molecules. Additionally, bile salts produced by the liver and stored in the gallbladder aid in the emulsification and digestion of fats in the small intestine. Therefore, chemical digestion largely concludes in the small intestine before nutrients are absorbed into the bloodstream.

A) esophagus

- Incorrect: The esophagus is primarily involved in the mechanical process of swallowing, which pushes food down into the stomach. While some minor enzymatic activity may occur due to saliva coating the food during swallowing, significant chemical digestion does not occur in the esophagus.

B) stomach

- Incorrect: While the stomach does play a role in chemical digestion, particularly in the breakdown of proteins by the enzyme pepsin and the denaturation of proteins by hydrochloric acid, the majority of chemical digestion occurs in the small intestine. The stomach mainly serves to mechanically churn food and begin the process of protein digestion.

D) gallbladder

- Incorrect: The gallbladder stores and releases bile produced by the liver, which aids in the emulsification and digestion of fats in the small intestine. However, the gallbladder itself is not directly involved in chemical digestion, and the majority of digestive enzymes are not secreted or stored in the gallbladder.
Q #3: Which of these nutrients is absorbed mainly in the duodenum?

A. glucose

B. iron

C. sodium

D. water

Answer Explanation

b) iron

- Correct: Iron is mainly absorbed in the duodenum, particularly in its proximal portion. Iron absorption occurs through active transport mechanisms facilitated by specialized transport proteins in the duodenal epithelial cells. Once absorbed, iron can be transported into the bloodstream and utilized for various physiological functions, including the production of hemoglobin and other iron-containing proteins.

a) glucose

- Incorrect: Glucose is primarily absorbed in the small intestine, but its absorption occurs mainly in the jejunum and ileum rather than the duodenum. Glucose is absorbed through facilitated diffusion and active transport mechanisms in the epithelial cells lining the small intestine.

c) sodium

- Incorrect: Sodium is absorbed throughout the small intestine, including the duodenum, jejunum, and ileum. Its absorption occurs through active transport mechanisms in the epithelial cells lining the intestinal mucosa, primarily in conjunction with glucose and other nutrients.

d) water

- Incorrect: Absorption of water indeed takes place in the large intestine, particularly in the colon.

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Vitamin B1 assists an organic catalyst in cell respiration. This vitamin functions as

More Questions on TEAS 7 Science

Q #1: If a person was unable to break down food particles into molecules that could be absorbed by the body, you would predict

Answer Explanation

Q #2: In humans, chemical digestion is accomplished

Answer Explanation

Q #3: Which of these nutrients is absorbed mainly in the duodenum?

Answer Explanation

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