organistion (B3,B4,B7) Flashcards
What is a tissue?
A tissue is a group of cells with a similar structure and function.
Define an organ.
An organ is a group of tissues working together for a specific function.
What are organ systems?
Organ systems are groups of organs that work together to form organisms.
List the three main components found in foods.
- Carbohydrates
- Proteins
- Lipids
Why can’t large molecules be absorbed into the bloodstream?
They are large molecules, so they have to be digested into smaller molecules.
What begins the digestion of starch in the mouth?
Enzymes in saliva.
What role does the stomach play in digestion?
Enzymes begin the digestion of proteins and hydrochloric acid helps the enzymes.
What is the churning action of the stomach?
It turns food into a fluid, increasing the surface area for enzymes to digest.
What does the pancreas release?
Enzymes that continue the digestion of starch and proteins and start the digestion of lipids.
What is the function of bile released by the liver?
It speeds up digestion of lipids and neutralizes the acidity from the stomach.
What happens in the small intestine regarding digestion?
Dare walls release enzymes to continue digestion of proteins and lipids. Small food molecules are absorbed into the bloodstream.
What is absorbed in the large intestine?
Water is absorbed into the bloodstream.
What is released from the body after digestion?
Faeces.
What is the function of enzymes?
Enzymes catalyse chemical reactions.
What is the active site of an enzyme?
A groove on the enzyme’s surface.
What breaks down proteins?
Proteases.
Where are proteases found?
In the stomach, pancreas, and small intestine.
What breaks down carbohydrates?
Carbohydrases.
What enzyme breaks down starch?
Amylase.
Where is amylase found?
In saliva and pancreatic fluid.
What does a lipid molecule consist of?
A molecule of glycerol attached to three molecules of fatty acids.
What enzyme breaks down lipids?
Lipase.
Where is lipase found?
In the pancreas and small intestine.
What is bile made from?
Liver
Bile is produced in the liver and stored in the gallbladder.
What role does bile play in digestion?
Speeds up the digestion of lipids but is not an enzyme
Bile emulsifies lipids, increasing the surface area for digestion.
What does bile do to lipid droplets?
Emulsifies them
Emulsification increases the surface area of lipid droplets.
What is the pH nature of bile?
Alkaline
Bile neutralizes stomach acid, which increases the rate of lipid digestion.
What theory explains enzyme specificity?
Lock and key theory
This theory states that the substrate must fit perfectly into the active site of the enzyme.
What happens to an enzyme’s activity at high temperatures?
The enzyme becomes denatured
High temperatures cause the enzyme molecule to vibrate, changing the shape of the active site.
What is the effect of temperature on enzyme activity?
Optimum temperature
Each enzyme has an optimum temperature at which its activity is maximized.
What happens to enzyme activity if the pH is too acidic or alkaline?
Activity drops to zero
The active site denatures under extreme pH conditions.
What structural change occurs to enzymes at high temperatures?
Shape of the active site changes
This change can lead to loss of function, known as denaturation.
