Organisation T1

Question 1

What is a cell?

Answer 1

A cell is a basic unit of life, and makes up all living things

Question 2

What is a specialised cell?

Answer 2

A cell which has been adapted to carry out a specific function

Question 3

What is a tissue?

Answer 3

A group of specialised cells working together to perform a function

Question 4

What is an organ?

Answer 4

A group of organs working together to carry out a function

Question 5

What is an organ system?

Answer 5

A group of organs working together to perform a function

Question 6

What is the digestive system?

Answer 6

• 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.

Question 7

What are villi?

Answer 7

• 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.

Question 8

What are enzymes?

Answer 8

Enzymes are biological catalysts, they increase the rate of a chemical reaction without being used up.

Question 9

What is a substrate?

Answer 9

The molecule on which the enzyme acts upon. (the key)

Question 10

What is an acitve site?

Answer 10

• 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)

Question 11

What happens when the substrate binds to the active site/enzyme?

Answer 11

• It is called an enzyme substrate complex
• The enzyme catalyses the substrate.
• It is broken down and diffused into the bloodstream

Question 12

Which enzymes break down;
- Carbohydrates
- Proteins
- Lipids

Answer 12

• Carbohydrase/Amylase
• Protease
• Lipase

Question 13

What are the products of these when broken down;
- Carbohydrates
- Proteins
- Lipids

Answer 13

• Sugars
• Amino acids
• Fatty acids

Question 14

Where is carbohydrase found?

Answer 14

• In the mouth, pancreas and small intestine

Question 15

Where is protease found?

Answer 15

• In the stomach, pancreas and small intestine

Question 16

Where is lipase found?

Answer 16

• In the pancreas and small intestine

Question 17

What is bile?

Answer 17

• 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.

Question 18

What conditions can affect enzymes?

Answer 18

• Temperature
• pH

Question 19

How do high temperatures affect enzymes?

Answer 19

• 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.

Question 20

What is the optimum temperature?

Answer 20

The temperature at which the rate of reaction (of the enzyme) is the highest, and the temperature at which the enzyme works best.

Question 21

How does pH affect enzymes?

Answer 21

• 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.

Question 22

What is the food test for starch?

Answer 22

• Add two drops of iodine solution to the food sample
• If the iodine goes blue/black there is starch present in the sample

Question 23

What is the food test for glucose/sugar?

Answer 23

• 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.

Question 24

What is the food test for protein?

Answer 24

• 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.

Question 25

What is the food test for lipid?

Answer 25

• 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.

Question 26

What is organisation?

Answer 26

Multicellular organisms are formed by smaller building blocks working together to perform specific functions.