Organisation T1 Flashcards
What is a cell?
A cell is a basic unit of life, and makes up all living things
What is a specialised cell?
A cell which has been adapted to carry out a specific function
What is a tissue?
A group of specialised cells working together to perform a function
What is an organ?
A group of organs working together to carry out a function
What is an organ system?
A group of organs working together to perform a function
What is the digestive system?
- Large molecules of food in our food are too big to be absorbed
- The digestive system uses chemical and physical digestion to break down these larger molecules into smaller ones.
- Once these molecules are small emough, they can be absorbed into the bloodstream vid the wall of the small intestine.
What are villi?
- Villi are projections from the small intestines that increase the available surface are for diffusion to happen across.
- They also have smaller projections called microvilli.
- They are not cells, they are just the shape made by the outer surface of the small intestine.
What are enzymes?
Enzymes are biological catalysts, they increase the rate of a chemical reaction without being used up.
What is a substrate?
The molecule on which the enzyme acts upon. (the key)
What is an acitve site?
- An enzyme has a specific shape, this shape will fit into the molecule and break it apart.
- The part which of the enzyme where the molecule fits is called the active site. (the lock)
What happens when the substrate binds to the active site/enzyme?
- It is called an enzyme substrate complex
- The enzyme catalyses the substrate.
- It is broken down and diffused into the bloodstream
Which enzymes break down;
- Carbohydrates
- Proteins
- Lipids
- Carbohydrase/Amylase
- Protease
- Lipase
What are the products of these when broken down;
- Carbohydrates
- Proteins
- Lipids
- Sugars
- Amino acids
- Fatty acids
Where is carbohydrase found?
- In the mouth, pancreas and small intestine
Where is protease found?
- In the stomach, pancreas and small intestine
Where is lipase found?
- In the pancreas and small intestine
What is bile?
- Bile is produces in the liver and is stored in the gall bladder.
- It neutralises the stomach acid as it enters the small intestine to provide the right pH for the enzymes in the smal enzymes.
- It emulsifies (breaks down) large fat globules into smaller fat globules to provide a larger surface area to work.
What conditions can affect enzymes?
- Temperature
- pH
How do high temperatures affect enzymes?
- High temperatures start to break the bonds holding the enzyme together.
- The active site starts to change shape.
- Once the shape changes, the substrate will not be able to bind to it.
- The enzyme becomes denatured.
What is the optimum temperature?
The temperature at which the rate of reaction (of the enzyme) is the highest, and the temperature at which the enzyme works best.
How does pH affect enzymes?
- Bonds start to break
- The active site starts to change shape
- The active site changes shape so the subsrate cannot bind to it.
- The enzyme becomes denatured.
What is the food test for starch?
- Add two drops of iodine solution to the food sample
- If the iodine goes blue/black there is starch present in the sample
What is the food test for glucose/sugar?
- Mix the food sample with 3cm of Benedict’s solution in a boiling tube.
- Heat the mixture in a hot water bath for 3 minutes
- If the solution turns a brick red colour, the sample contains sugar.
What is the food test for protein?
- Mix a small sample of food with about 3cm of biuret solution.
- Leave for 2 minutes.
- If the mixture goes a pale purple colour, the sample contains protein.
What is the food test for lipid?
- Mix a small sample of food with about 1cm of ethanol in a dry test tube.
- Pour the ethanol into a test tube of cold water.
- If the wateer goes milky white, the food conatins lipids.
What is organisation?
Multicellular organisms are formed by smaller building blocks working together to perform specific functions.
