Chapter 3 - Organisation and the Digestive System Flashcards
Define the word tissue.
- A group of cells with similar structure and function working together.
Define organ.
- Collection of tissues performing specific functions.
Give 2-3 examples of organ systems.
- Respiratory system
- Digestive system
- Nervous system
What is the digestive system?
- An organ system where several organs work together to digest/absorb food.
Where is food mainly digested?
- Stomach and small intestine
Which organ produces bile?
- The liver produces bile
Explain the structure and function of carbohydrates.
- Carbohydrates are simple sugars
- Contains glucose and sucrose
- Provides long-term energy
Explain the structure and function of lipids.
- Made from fatty acids and glycerol
- Important energy source
Explain the structure and function of proteins.
- Made from a chain of amino acids.
- Builds/repairs cell/tissues
State which colour the iodine test for starch and the Benedict’s test for sugars turn when both are present.
Iodine test - Yellow-red solution turns Blue-Black in presence of starch.
Benedict’s test - Blue solution turns Brick-Red on heating.
What colour does blue Biuret reagent turn in the presence of protein?
- Purple
State which test is used to test for lipids and describe the gas produced.
- Ethanol test
- Gives a cloudy white layer in presence of lipids
What is the role of a catalyst?
- To increase the rate of reaction without chemical change.
Define metabolism.
- The sum of all reactions in a cell/body
What are enzymes and active sites?
- An enzyme is a biological catalyst.
- An active site is where the substrate binds to.
Explain the lock and key theory.
- Substrate fits into active site.
- Enzyme and substrate bind.
- Rapid reaction takes place.
- Substrate splits into products and breaks away.
What can effect enzyme activity?
- Temperature and pH
How does pH affect enzyme action?
- It affects the shape of the active site so that the substrate no longer fits in. The chains holding the active site are lost.
How does temperature affect enzyme action?
- Denatures the enzyme, changing the active sites’ shape.
State which enzyme breaks down carbohydrates and where it is made.
- Amylase
- Made in salivary glands and pancreas
State which enzyme breaks down protein and where it is produced.
- Protease
- Stomach, pancreas, small intestine
Give the enzyme which breaks down fats and where it is produced.
- Lipase
- Pancreas and small intestine
How does hydrochloric acid make digestion efficient?
- It gives the stomach a low pH for protease to work efficiently.
