GRE Subject Test: Biology : Understanding Digestive Functions
Study concepts, example questions & explanations for GRE Subject Test: Biology
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Example Questions
Example Question #66 : Digestive System
Proteins
Amino Acids
Carbohydrates
All of these will be digested by 
Fats
Carbohydrates
The correct answer is carbohydrates.
Salivary amylase can only digest carbohydrates. Proteases further along in the digestive pathway breakdown proteins, while lipases digest fats. Amino acids are the product of digested proteins.
Example Question #1 : Understanding Digestive Functions
Which of the following macromolecules is broken down by pepsin in the stomach?
Carbohydrates
Proteins
Lipids
Nucleic acids
Proteins
Pepsinogen is released by chief cells into the stomach lumen. In the presence of hydrochloric acid (secreted by parietal cells), this inactive enzyme will be cleaved, creating pepsin. Pepsin is a protease responsible for breaking down proteins that enter the stomach.
Carbohydrates are digested by amylase enzymes, lipids are digested by lipases, and nucleic acids are digested by nucleases.
Example Question #2 : Digestive System
Which organ is responsible for creating bile?
Stomach
Liver
Gall bladder
Pancreas
Liver
Bile is a salt solution used to emulsify fats in the small intestine in order to facilitate absorption. It is created by the liver, but stored in the gall bladder. During digestion, the bile is released from the gall bladder into the duodenum.
The stomach is mainly responsible for mechanical digestion, caused by smooth muscle contractions, and a small amount of protease function. The pancreas secretes a number of digestive enzymes into the duodenum to facilitate digestion of macromolecules. Neither organ is involved in the production of bile.
Example Question #5 : Digestive System
Which is a correct association for cell type and products in the islets of Langerhans?
The islets of Langerhans contain the endocrine pancreatic cells. 3 cell types within are the 
Example Question #5 : Digestive System
A patient presents to the hospital with the complaint of pain in his abdomen. Imaging reveals ulcers in his upper small intestine. Further tests reveal that the ulcers are caused by acid entering the small intestine not being properly neutralized.
What organ in the digestive system is malfunctioning, causing these acidic secretions to harm the small intestine?
Stomach
Liver
Gall bladder
Pancreas
Pancreas
Answering this question requires you to know which organ assists in neutralizing acidic chyme once it enters the small intestine. This is the responsibility of the pancreas, which secretes bicarbonate ions. This helps raise the pH of the chyme in the small intestine, and prevents damage.
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