Human digestive system - Coggle Diagram
Human digestive system
In the lock and key hypothesis,
Each enzyme has a specific active site
Each type of enzyme can usually catalyse only one type of reaction
The food substance (carbonhydrates,fats, protein) which an enzymes acts on is called substrate
Enzymes are not reactants and are not used up during the reaction.
Once an enzyme binds to a substrate and catalyzes the reaction, the enzyme is released, unchanged, and can be used for another reaction.
Required in minute amounts
They are active in very small quantities.
A small amount of enzyme is enough to convert a large quantity of substrate.
The enzymes remain chemically unchanged after the reaction.
Particular enzymes act on particular substrates only
Enzymes are also specific to a particular type of reaction. In some rare cases, the specificity may not be too strong.
Example:Bond, Group, Substrate, Optical, Co-factor, Geometric Specificity
Sensitive to change in temperature and pH
Enzymes are very sensitive to heat and temperature.
Enzymes will be inactive at very low temperatures. this is the reason for preserving food and vegetables in the refrigerator.
The enzymatic activity increases with the increase in temperature up to a certain level.
At higher temperature (60-70 degree Celsius), the enzyme is destroyed or denatured.
If enzymes are exposed to extremes of pH or high temperatures the shape of their active site may change.
If this happens then the substrate will no longer fit into the enzymes.
This means the key will no longer fit the lock.(Lock and Key)
They are thermolabile
Main parts of the digestive system
the mouth, esophagus, stomach, small intestine, large intestine, rectum and anus.
Chemical: Starch is broken down
Physical: Food is chewed to smaller pieces
increasing the food surface area allowing it to digest faster
Physical: Peristalsis(A series of muscle contractions which push foods down)
Chemical: no digestion happens
Physical: churning action
Breaks food into smaller pieces
Chemical: Gastric juices
(water, hydrochloric acid, and protease)
Hydrochloric acid function
Kill bacteria in the food
Provide acidic environment for proteases to work effectively
the process of dispersing two or more immiscible liquids together to form a semi-stable mixture.
Chemical: carbohydrates, fats and proteins
secrete intestinal juices and the pancreas secrete pancreatic juices
Physical: no physical change
absorb water and mineral salts
Chemical: produces no digestive enzymes
Supporting parts: the pancreas, gall bladder and liver.
Bile is produced in the liver and stored in the gall bladder
bile is not an enzymes
Function: break up fat molecules into fat globules
the most important roles of enzymes is to aid in digestion.
Turns proteins to amino acids
Turns fats to glycerol and fatty acid
Turns starch to maltose
Turns maltose to glucose
Digestion is important for breaking down large and complex food substance into smaller and simple food substances
Larger and complex food
Glycerol and fatty acid
Smaller and simple foods
The three main nutrients
Growth of new cells and tissues
Repair of damaged tissues
Sources when carbonhydrates and fats are not available
Source: meat fish and some dairy
Provide twice the amount of energy than carbonhydrates
Stored under skin to insulate excessive heat loss
Primary source of energy