Base your answer to the following question on Which statement best expresses the information represented in the graph shown below?

A. The action of enzymes varies with pH.

B. A pH of 7 provides the optimum environment for digestive enzymes.

C. Gastric juice is active at a pH extending from 0 to 12.

D. Acids have a pH greater than 7.

Answer Explanation:

The action of enzymes vary with pH. Enzymes are proteins that catalyze biochemical reactions, and their activity is influenced by various factors including pH.

The pH level affects the ionization state of amino acid residues within the enzyme's active site. This, in turn, can affect the enzyme's ability to bind substrate molecules and catalyze reactions.

Different enzymes have different optimal pH ranges at which they exhibit maximum activity. This optimal pH range is determined by the specific environment in which the enzyme typically functions. For example, pepsin, which is involved in digesting proteins in the stomach, works optimally at an acidic pH around 2, whereas enzymes in the small intestine function optimally at a slightly alkaline pH around 7 to 8.

Extreme deviations from the optimal pH can denature enzymes, causing them to lose their structure and function. Therefore, maintaining the appropriate pH level is crucial for ensuring the proper functioning of enzymes in biochemical reactions.

Therefore, the Correct Answer is A.

Q #1: The digestion of food and subsequent absorption into the bloodstream is important because

A. absorbed food is toxic to the body

B. absorbed food stimulates reproduction

C. absorbed food is the raw material for metabolism

D. absorbed food aids in respiration

Answer Explanation

C) absorbed food is the raw material for metabolism

- Correct: The digestion of food and subsequent absorption into the bloodstream are essential processes because absorbed food molecules serve as the raw material for metabolism. Once nutrients from food are absorbed into the bloodstream, they are transported to cells throughout the body where they are used for various metabolic processes. Carbohydrates are broken down into glucose, which is used for energy production. Proteins are broken down into amino acids, which are used for building and repairing tissues, as well as for synthesizing enzymes and hormones. Fats are broken down into fatty acids and glycerol, which are used for energy production and for building cell membranes and certain hormones. Overall, absorbed food molecules provide the necessary energy and building blocks for cellular activities, growth, and maintenance of the body.

A) absorbed food is toxic to the body

- Incorrect: Absorbed food is not inherently toxic to the body. In fact, nutrients obtained from food are essential for the body's survival and proper functioning. However, certain substances in food may be harmful if absorbed in excessive amounts, such as certain vitamins or minerals. Generally, the body has mechanisms to regulate nutrient absorption and maintain homeostasis.

B) absorbed food stimulates reproduction

- Incorrect: While proper nutrition is important for overall health and fertility, absorbed food does not directly stimulate reproduction. Reproduction is regulated by various hormones and physiological processes within the body.

D) absorbed food aids in respiration

- Incorrect: While nutrients obtained from food are used by cells for energy production through respiration, absorbed food itself does not directly aid in respiration. Respiration is a complex physiological process that involves the exchange of gases (oxygen and carbon dioxide) in the lungs and cellular respiration within cells to produce energy.
Q #2: After food enters the small intestine, lipases, proteases, and amylases are secreted into the small intestine by the

A. liver

B. gallbladder

C. salivary glands

D. pancreas

Answer Explanation

D) pancreas

- Correct: After food enters the small intestine, lipases (for fat digestion), proteases (for protein digestion), and amylases (for carbohydrate digestion) are secreted into the small intestine by the pancreas. These digestive enzymes are produced by the pancreas and released into the duodenum, which is the first part of the small intestine. The pancreas plays a crucial role in providing these enzymes to aid in the breakdown of macronutrients (fats, proteins, and carbohydrates) into smaller molecules that can be absorbed by the intestinal lining.

A) liver

- Incorrect: The liver produces bile, which is stored in the gallbladder and released into the small intestine to aid in the emulsification of fats. While bile is important for fat digestion, it does not contain lipases, proteases, or amylases.

B) gallbladder

- Incorrect: The gallbladder stores and concentrates bile produced by the liver, but it does not secrete lipases, proteases, or amylases. Bile aids in the emulsification of fats but does not contain digestive enzymes.

C) salivary glands

- Incorrect: Salivary glands secrete saliva into the mouth, which contains amylase, an enzyme that begins the digestion of carbohydrates. However, after food enters the small intestine, digestive enzymes are primarily secreted by the pancreas, not the salivary glands.
Q #3: Bile is a secretion which aids in the digestion of

A. lipids

B. proteins

C. saccharides

D. starches

Answer Explanation

A) lipids

- Correct: Bile is a secretion produced by the liver and stored in the gallbladder. It aids in the digestion of lipids (fats) by emulsifying large fat globules into smaller droplets. This process increases the surface area of fats, allowing digestive enzymes such as lipase to more efficiently break them down into smaller molecules (fatty acids and glycerol) that can be absorbed in the small intestine.

B) proteins

- Incorrect: Bile does not aid in the digestion of proteins. Proteins are broken down by specific digestive enzymes such as pepsin in the stomach and proteases in the small intestine.

C) saccharides

- Incorrect: Bile does not aid in the digestion of saccharides, which are carbohydrates. Carbohydrates are broken down by enzymes such as amylase into simple sugars (monosaccharides) during the process of digestion.

D) starches

- Incorrect: Bile does not aid in the digestion of starches. Starches are complex carbohydrates

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Base your answer to the following question on Which statement best expresses the information represented in the graph shown below?

More Questions on TEAS 7 Science

Q #1: The digestion of food and subsequent absorption into the bloodstream is important because

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Q #3: Bile is a secretion which aids in the digestion of

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