Question

1. explain the roles of the adaptive defenses including B cells, T-cells, antibodies-structure, function, classes.

2. Outline the process of digestion from mouth to anus. Be sure to discuss important structures along the way, enzymes, and process.

Answer 1

1. The immune responses are two types. Innate and adaptive defenses. The adaptive defense is composed by antibodies and lymphocytes. The cells of the adaptive immune system are B cells and T cells. B cells are derived from the bone marrow and produce antibodies. T cells mature in the thymus and helps in lymphocyte maturation or kill virus-infected cells.

Antibody structure: Antibodies are immune system-related proteins. Antibodies are Y shaped molecules and consists of four polypeptides. Composed of amino acid sequence.

Based on their structure and immune function, antibodies are divided into five major classes, IgM, IgG, IgA, IgD, and IgE.

Functions:  Antibodies block parts of the bacterial cell, glue together to foreign cells, phagocytosis, cell lysis, killing of inflamatory cells.

2. Digestion process:

It is a series of reactions of food with the digestive enzymes, hormones and juices and starts from mouth. Need of this process is to breaks down the proteins, fats, carbohydrates, vitamins, minerals into simpler forms. So that, those can be absorbed easily into the cells. The following changes happens in this process.

Proteins -------- amino acids,  Carbohydrates -------- simple sugars, Fats --------  fatty acids and glycerol.

Digestion process described in detail as below

In Mouth: Chewing is of food is initial action of entire process in which food mixes with saliva and breakdown of starch occurs here. Food moves to esophagus.

In Esophagus: Peristalsis is the movement in esophagus. this is defined as series of wave-like muscle contractions which helps the movement of bolus to different processing stations in the digestive tract. Food moves to stomuch.

In Stomuch: Churning of food is an action which leads the food mixing with stomuch acids and enzymes. This action helps in breakdown of proteins. Cells which are in line of wall secrete the pepsinogen, HCl and are essential for vitamin B12 absorption.

In small intestine: Food mixes with digestive juices because of peristalsis. Pancreas secrets pancreatic juice which mixes with food and helps in breakdown of starch, proteins. Liver produces bile juice and it acts on fat breakdown.

In Large intestine: Peristalsis happens and remaining food break down and finally leads to end of process.

Different chemical reactions and enzymatic actions in digestion process:

• Amylase converts starch into Maltose, polysaccharides into Disaccharides
• Enterokinase converts Trypsinogen into Trypsin,
• Trypsin converts proteins into Dipeptides, Chymotrypsinogen into Chymotrypsin, Procarboxypeptidase into Carboxypeptidase, Proelastase into Elastase,
• Chymotrypsin converts peptones into Dipeptides.
• Carboxypeptidase converts proteoses into Dipeptides.
• Elastase converts elastin into Dipeptides.
• Maltase converts maltose into glucose.
• Sucrase converts sucrose into glucose & fructose.
• Aminopeptidases convert peptides into amino acids.
• Dipeptidases convert dipeptides into amino acids