Practice MCQ Questions and answers on Biology-GK

Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down fats into fatty acids, which can be taken into the body by the digestive tract.

An adult's digestive tract is about 30 feet (about 9 meters) long. Digestion begins in the mouth, well before food reaches the stomach. When we see, smell, taste, or even imagine a tasty meal, our salivary glands in front of the ear, under the tongue, and near the lower jaw begin making saliva (spit).

Mechanical digestion of protein begins in the mouth and continues in the stomach and small intestine. Chemical digestion of protein begins in the stomach and ends in the small intestine. The body recycles amino acids to make more proteins.

When you eat food the body's digestive system breaks down the protein into the individual amino acids, which are absorbed and used by cells to build other proteins and a few other macromolecules, such as DNA.

Digestion of starch in mouth takes place by Ptyline.

In the second stage of swallowing, an important small flap of tissue called the epiglottis, folds over the voice box (larynx) at the entrance to the windpipe (trachea), preventing food from going down the wrong way.

Enzymes lowers the activation energy for the chemical reaction and speed up the rate of a chemical reaction.

Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products.

Enzymes are biological catalysts produced by all living organisms. They facilitate the biochemical reactions that enable microbes, plants and animals to function.

Contains fluoride to harden the tooth enamel is not a function of saliva.