B2 - Principles Of Organisation And Digestion Flashcards
What is a tissue?
A tissue is an aggregation of cells with a similar structure and function
What is an organ?
An organ is an aggregation of tissues working together to perform a particular function
What is an organ system?
An aggregation of organs, which work together to form functioning organisms
What is a cell?
The basic building block of all living organisms
Why does food need to be digested?
To break down large, insoluble biological molecules into small, soluble ones by enzymes so that they can be absorbed in the bloodstream
What are the function of digestive enzymes?
Digestive enzymes convert food into small, soluble molecules that can be absorbed into the bloodstream
What digestive enzyme breaks down carbohydrates?
Carbohydrases.
Amylase is a carbohydrase which breaks down starch into maltose
What digestive enzyme breaks down protein?
Proteases
Example: Pepsin
What digestive enzyme breaks down lipids (fats)?
Lipases
What are the products of digestion used for?
The products of digestion are used to build new carbohydrates, lipids and proteins.
Some glucose is utilised in cellular respiration
Where is bile made, stored and released?
Bile is made in the liver, stored in the gall bladder and released into the small intestine
What is the function of bile?
Bile catalyses the digestion of lipids by converting large lipid droplets into smaller ones.
It is not an enzyme
Explain how bile increases the rate of lipid breakdown by lipase
Bile emulsifies lipids to form small droplets. This increases the S.A for enzymes to act on. Bile also is alkaline to neutralise HCI from the stomach (enzymes in the small intestine have a more alkaline pH than those in the stomach) so that the enzymes do not denature. These both increase the rate of lipid breakdown by lipase to form fatty acids and glycerol
(i) What is the qualitative reagent test for
carbohydrates/sugars? What is its positive result?
(ii) What are the different types of carbohydrate that can be tested for?
(i) Benedict’s solution.
Positive result: Blue -> Green/yellow/brick-red precipitate, depending on concentration
(ii) Glucose using Benedict’s and starch using iodine
How is the small intestine adapted for absorption?
Long in length at around 5m. This increases the surface area for absorption of the products of digestion
Interior is covered with villi. Microvilli on the surface increase the surface area further
Rich blood supply in vili. This allows for the bloodstream to remove the products of digestion, increasing the concentration gradient
Villi have a thin membrane. This ensures a short diffusion pathway
High yield of mitochondria in intestine lining cells to release energy for any molecules that cannot be absorbed into the bloodstream by diffusion and require active transport
What do carbohydrases break down carbohydrates into?
Simple sugars
What do proteases break down proteins into?
Individual amino acids, which are then absorbed into the bloodstream
What do lipases break down lipids into?
Glycerol and fatty acids. This makes the pH more acidic
What is the qualitative reagent test for starch? What is its positive result?
Iodine solution
Positive result: Orange -> blue/black
Where is amylase, a carbohydrase that breaks down starch into sugar (maltose), produced? [SgPSm]
Where does it work?
Produced in:
Salivary glands
Pancreas
Small intestine
Works in:
Mouth
Small intestine
Where is protease produced? [SPSm]
Where does it work?
Produced in:
Stomach
Pancreas
Small intestine
Works in:
Stomach
Small Intestine
Where is lipase produced? [SP]
Where does it work?
Produced in:
Pancreas and small intestine
Works in:
Small intestine