Digestive System — Set 4
Biology · पाचन तंत्र · Questions 31–40 of 50
Which type of teeth are specifically used for tearing food in humans?
Correct Answer: C. Canines
Canines are the pointed teeth located next to the incisors. Humans have four canines, two in the upper jaw and two in the lower jaw. They are well-developed in carnivorous animals for gripping and tearing prey.
What is the pH of human saliva under normal conditions?
Correct Answer: B. Slightly acidic (around 6.8)
Saliva is slightly acidic, which is the optimal range for the enzyme salivary amylase. It also contains electrolytes and antimicrobial agents like lysozyme. The pH can vary depending on diet and overall health.
Which organ is the largest gland in the human body?
Correct Answer: B. Liver
The liver performs over 500 essential functions, including bile production and detoxification. It weighs about 1.5 kilograms in an average adult. It has a unique ability to regenerate its own tissue after injury.
The protein-digesting enzyme 'Pepsin' is active only in which medium?
Correct Answer: A. Acidic
The correct answer is 'Acidic'. Pepsin requires a low pH, usually between 1.5 and 2.5, provided by hydrochloric acid in the stomach. In an alkaline environment, the enzyme becomes denatured and loses its function. This ensures that it only works within the stomach cavity.
Which part of the alimentary canal is also known as the 'food pipe'?
Correct Answer: D. Esophagus
The esophagus is a muscular tube that connects the throat to the stomach. It is about 25 centimeters long in adults. It does not produce any digestive enzymes and serves purely as a transport passage.
What prevents the backflow of food from the stomach into the esophagus?
Correct Answer: B. Lower esophageal sphincter
The lower esophageal sphincter is a ring of muscle that acts as a valve at the entrance to the stomach. It opens to let food in and closes to keep stomach acid out. Failure of this valve leads to acid reflux or heartburn.
Which of the following enzymes is responsible for breaking down maltose into glucose?
Correct Answer: B. Maltase
Maltase is an enzyme found in the intestinal juice that completes the digestion of carbohydrates. It splits the disaccharide maltose into two molecules of simple glucose. Glucose is the primary sugar used by the body for energy.
The first part of the large intestine where the appendix is attached is the?
Correct Answer: D. Caecum
The caecum is a pouch-like structure that receives undigested material from the small intestine. It is more prominent in herbivores as a site for microbial fermentation. In humans, its main significance is the attachment of the appendix.
Which substance in the stomach protects its wall from the action of Hydrochloric acid?
Correct Answer: B. Mucus
Mucus forms a physical barrier and contains bicarbonate to neutralize acid near the stomach surface. Without this layer, the acid would digest the stomach's own protein-based walls. Damage to this barrier can result in gastric ulcers.
What is the function of the enzyme 'Lactase'?
Correct Answer: D. Breaking down milk sugar
Lactase breaks down lactose, the sugar found in milk, into glucose and galactose. Many adults lose the ability to produce enough lactase, leading to lactose intolerance. This enzyme is secreted by the cells lining the small intestine.