Question

PGW4 Digestion Name Bio112 - Spring 2019 Dr. Costanzo ate a dosat (or tw...bhe really likes doouts). Write out the steps of digestion and bsorption of the carbolbydrates from her donuts. For each step include the location, proteins involved (ensymes and transport proteins), and structures involved (e.g accessory organs).

Answer 1

​​​​Steps of digestion and absorption of carbohydrate:

1. In the mouth:

The process of digestion begins in the mouth. The saliva secreted from salivary gland contains contains enzyme called as salivary amylase which actively breaks down the sugars into carbohydrate while chewing.

2.In the stomach:

After chewing and mixing with saliva, the food is knows as bolus. Bolus passes from the mouth to the stomach via oesophagus which is also known as food pipe. When food reaches the stomach it is called chyme.

In the stomach gastric acid made of hydrochloric acid, potassium chloride and sodium chloride is released which kills the bacteria present in the chyme.

The stomach undergoes periodic churning to enhance the process of digestion.

3. In small intestine, pancreas and liver:

The pyloric sphincter is a muscular valve that open to descend the food into the first part of the small intestine known as duodenum. This stimulates the pancreas to release pancreatic amylase. This enzyme is responsible for breaking down chyme into dextrin and maltose.

Here, the small intestine begins to produce lacatase, maltase and sucrase. These enzymes break down sugar into monosaccharide or simple sugars.

The sugar in its monosaccharide form is absorbed into the small intestine.

After absorption, these sugar are processed by the liver and stored as glycogen. Glucose required by the body is supplied in the blood stream.

The pancreas releases a hormone called insulin that allows glucose to be utilized in the body in the form of energy.

4. Colon:

The waste food reaches the colon where it is broken down by intestinal bacteria.

Since, fibre cannot be digested or broken down in human body, it is excreted in the form of stool.