ORGANISATION--4.2.2.1 The human digestive system (Animal Tissues and Organs) Flashcards
What is the purpose of the digestive system?
What does it help the body do?
The digestive system helps the body to digest and absorb food
What mechanism are enzymes related to?
Metabolism
Refers to the biochemical processes in living organisms.
What variable factors impact enzyme function?
Temperature and pH changes
These factors can influence the shape and efficiency of enzyme action.
What is the role of enzymes in living organisms?
What do they do to chemical reactions in the body?
Enzymes speed up (catalyse) chemical reactions in the body
What theory/model is used to explain enzyme action?
Lock and Key Theory
This model illustrates how enzymes fit with their substrates.
Where does the amylase enzyme act?
Which two areas of the body?
Mouth:
(starts breaking down starch)
Small intestine:
(continues breaking down starch into maltose)
Breaks down:
Starch → Maltose
What do digestive enzymes convert food into?
Small soluble molecules
These molecules can be absorbed into the bloodstream.
What do carbohydrases break down?
Carbohydrates
They convert carbohydrates into simple sugars.
What is the role of amylase?
Breaks down starch
Amylase is a specific type of carbohydrase.
What do proteases break down?
Proteins to amino acids
Proteases are crucial for protein digestion.
What do lipases break down?
Lipids (fats) to glycerol and fatty acids
Lipases are essential for fat digestion.
What are the products of digestion used for?
To build new carbohydrates, lipids, and proteins
Some glucose is also used in respiration.
Where is bile made and stored?
Made in the liver and stored in the gall bladder
Bile is essential for fat digestion.
What is the pH nature of bile?
Alkaline
Bile neutralizes hydrochloric acid from the stomach.
What is the function of bile in digestion?
Emulsifies fat to form small droplets that can easily be absorbed into the blood stream
This increases the surface area for fat breakdown by lipase.
True or False: Alkaline conditions increase the rate of fat breakdown by lipase.
True
Alkaline conditions enhance enzyme activity.
What are proteins are used in the body for
Growth and repair
Many important substances in the body are also proteins, e.g. enzymes, antibodies and some hormones.
Which chemical test shows the presence of lipids?
Does it turn cloudy or to a colour?
Ethanol is added - the solution turns cloudy
The addition of ethanol to a solution gives a cloudy white layer if lipids are present.
Where are carbohydrases produced?
Mouth, small intestine and pancreas
Carbohydrases – the enzymes that break down carbohydrates into sugars – are produced in the mouth (specifically amylase in saliva) in addition to the small intestine and the pancreas.
Which enzymes are produced in the stomach?
Proteases only
Proteases – which break down proteins into amino acids – are the only enzymes produced in the stomach. (Note that proteases are also produced in the small intestine and in the pancreas.)
Give two locations
Where is bile produced and then stored?
Produced in the liver and stored in the gall bladder
The two functions of bile are to
Emulsify lipids and provide an alkaline environment
Bile emulsifies lipids (breaks them down into smaller molecules, which provide a larger surface area for lipases to work on). In addition, as bile is an alkaline solution, it helps to provide an optimum pH (pH 8) for enzyme activity in the small intestine.
Where is the amylase enzyme produced?
Salivary glands and pancreas, (some in the small intestine)
