Chemicals of Life CH4

Question 1

What percentage of the body is made of water?

Answer 1

80%

Question 2

Define Metabolic reactions

Answer 2

Metabolic Reactions are the chemical reactions that take place inside a living organism

Question 3

What is water needed for in the body?

Answer 3

1. If the cell dries up, metabolic reactions will stop and the organism dies.
2. Substances are dissolved in water and are transported around the body.
3. Water is needed to dissolve enzymes and nutrients in the allimentary canal so that digestion can take place.
4. Water is needed to get rid of waste products.

Question 4

Name the 3 elements that make up Carbohydrates

Answer 4

Carbon
Oxygen
Hydrogen

Question 5

What is a Monosaccharide? Give and example

Answer 5

The Monosaccharides are the simplest kind of Carbohydrate known as simple sugars. Glucose is a monosaccharide.

Question 6

What is the Molecular formula for glucose?

Answer 6

C6H12O6

Question 7

Describe a Disaccharide. Give 2 examples.

Answer 7

A Disaccharide is a larger molecule formed when 2 monosaccharides are joined together. Sucrose and Maltose are examples of Disaccharides.

Question 8

Describe a Polysaccharide. Give 2 examples.

Answer 8

A Polysaccharide is an even larger molecule that is formed when many simple sugars are joined together.. Cellulose and Starch are Polysaccharides.

Question 9

Why do plants transport glucose as sucrose?

Answer 9

Being reactive, Glucose might get involved in reactions where is is not wanted. When dissolved, glucose would increase the concentration of the solution in the cell, which would damage the cell.

Question 10

Describe how you would test for reducing sugars.

Answer 10

Add Benedicts Solution to the food and heat it. Crush the substance up that is being tested. If reducing sugars are present then the solution will turn a brick red colour. If no reducing sugars are present then the solution will stay the colour of the Benedicts solution which is blue in colour,

Question 11

What are fats also known as?

Answer 11

Lipids

Question 12

Name the 3 elements that make up a fat molecule.

Answer 12

Carbon
Hydrogen
Oxygen

Question 13

What are the building blocks of a fat molecule?

Answer 13

Glycerol and Fatty Acids

Question 14

What is the Adipose Tissue?

Answer 14

The cells, in mammals, underneath the skin which become filled with large drops of fat. These stores can be used to release energy and act as an insulator.

Question 15

Describe how you would test for fats and oils.

Answer 15

You would use the Ethanol Emulsion test. Firstly you chop up the food being tested and shake it up in ethanol ( Fats dissolve in Ethanol). Pour the ethanol into water. If there are fats and oils present in the food being tested a white opaque layer forms at the top of the mixture.

Question 16

What 4 elements make up a protein molecule?

Answer 16

Oxygen
Carbon
Hydrogen
Nitrogen

Question 17

What are the building blocks of Proteins?

Answer 17

Amino Acids

Question 18

What are proteins used for?

Answer 18

1. Making New Cells
2. Making Antibodies
3. Enzymes are Proteins

Question 19

Describe how you would test for proteins.

Answer 19

You would use the Biuret test. This involves mixing the food in water and then adding dilute COPPER SULFATE solution. Then add dilute POTASSIUM HYDROXIDE solution. purple colour indicates that proteins are present. A blue colour indicates that no proteins are present.

Question 20

What does DNA stand for?

Answer 20

Deoxyribonucleicacid

Question 21

Describe DNA

Answer 21

DNA is the chemical that makes up our genes and characteristics in our chromosomes.

Question 22

What is a helix?

Answer 22

A Helix is created when the 2 strands of DNA are twisted together

Question 23

A,C,G,T. Which letters always link up?

Answer 23

A and T

C and G

Question 24

What is a catalyst?

Answer 24

A catalyst is a substance that increases the rate of a reaction but remains chemically unchanged by the reaction.

Question 25

What is an Enzyme?

Answer 25

An enzyme is a protein that acts as a biological catalyst.

Question 26

Name the catalysts that act on:
Starch
Protein
Carbohydrates
Lipids
Maltose
Sucrose

Answer 26

Amalayse
Protease
Carbohydrases
Lipases
Maltase
Sucrase

Question 27

What is meant by the terms:
Anabolic
Catabolic

Answer 27

Anabolic - Molecules are combined

Catabolic - Molecules are broken down

Question 28

Describe the lock and key mechanism

Answer 28

An enzyme works by allowing the molecule of the substance on which it is acting on to fit into it perfectly. In an enzyme controlled reaction you have a substrate, a product and an Enzyme Substrate Complex. The substrate fits into the Active Site of the enzyme perfectly, forming the Enzyme Substrate Complex forming a product either through Catabolic reactions or Anabolic reactions. The substrate is the key and fits perfectly into the active site which is the lock.

Question 29

What is the term used to describe the temperature that the enzyme works best at?

Answer 29

The Optimum Temperature.

Question 30

What does;

Denature mean and what does Inactive mean?

Answer 30

Denatured is when an enzyme is completley destroyed and cannot ever work again. Inactive is when the enzyme does not work but this is not permanent and can be reversed.