Final answer:
Bile is not secreted in the stomach but produced by the liver, smell of food stimulates digestive enzyme release, and an overly acidic duodenum can inhibit digestion. Pepsin's activity is reduced with increased pH, neutral pH is 7, and unsaturated fatty acids have at least one bend in their structure. correct option for the question is b.
Step-by-step explanation:
The original student question seems to relate to various aspects of the digestive system, which falls under the subject of Biology and is likely at the high school level based on the complexity of the concepts involved.
The correct option for the question is: False. Bile is not one of the digestive fluids secreted in the stomach; rather, it is produced by the liver and stored in the gallbladder before being released into the small intestine. The smell of food can indeed stimulate the release of digestive enzymes. This is part of the cephalic phase of digestion, where the body prepares for the intake and digestion of food.
If the pH in the duodenum was too low (acidic), it could inhibit the function of certain digestive enzymes that require a higher pH to operate efficiently, affecting nutrient absorption and digestion. The normal activity of pepsin, an enzyme in the stomach which breaks down proteins, would be hindered if the pH is raised significantly, as pepsin functions optimally in an acidic environment.
A neutral pH has a numerical value of 7. The statement that unsaturated fatty acids have straight chains is False; they typically contain at least one double bond that creates a kink in the chain. The statement that the DNA code carries instructions for the correct sequence of amino acids in a protein is True, as DNA contains the genetic code that determines the sequence of amino acids during protein synthesis. Phospholipids indeed make up cell membranes, which is also True. The function of proteins can be diverse, including serving as enzymes, transporters, and elements of cellular structure.
Regarding the statements about the pharynx and reflexes in the GI tract, it is important to analyze the provided information carefully to determine the correct or incorrect statements. For example, the pharynx has a role in swallowing but is not primarily involved in the chemical digestion of food. In the GI tract, short reflexes are indeed mediated by the enteric nervous system and are localized reactions to stimuli within the GI tract, while long reflexes involve communication with the central nervous system and can be initiated by food that distends the stomach.