Molecules to metabolism

Question 1

What does molecular biology explain?

Answer 1

Life processes are explained including the chemical substances and reactions that are involved

Question 2

What are the chemical substances that make up the majority of living organisms?

Answer 2

Carbon-containing compounds such as carbohydrates, fats and proteins. These are known as organic compounds.

Question 3

What carbon compounds are not seen as organic?

Answer 3

Carbon dioxide, carbon monoxide, carbonates and hydrogen carbonates

Question 4

How many covalent bonds can carbon form?

Answer 4

• Carbon’s atomic number is 6, which means that it has 4 electrons in its outer shell (valency of 4)
• Carbon can form 4 covalent bonds

Question 5

Why can carbon form a diversity of stable compounds?

Answer 5

Because it has the ability to form four covalent compounds, with atoms of carbon or other elements.

Question 6

What four carbon-based compounds are found in living organisms?

Answer 6

Lipids, carbohydrates, proteins and nucleic acids

These are called macromolecules and also organic compounds

Question 7

What do the four types of macromolecules have in common and how do they differ?

Answer 7

• All of them contain carbon, hydrogen and oxygen atoms.
• Each of them contains other elements such as: nitrogen in proteins and nucleic acids
  phosphorus in some lipids (phospholipids).

Question 8

What are carbohydrates and lipids composed of?

Answer 8

• Carbohydrates are composed of three elements: carbon, hydrogen and oxygen. The ratio of hydrogen to oxygen is 2:1.
• Lipids contain multiple organic compounds. They include steroids (e.g. cholesterol), waxes, phospholipids and triglycerides.

Question 9

What are proteins and nucleic acids made out of?

Answer 9

• Proteins consist of amino acids that are arranged in long chains.
• Nucleic acids are also chains but formed by nucleotides.

Question 10

What do macro-molecules do and what are they composed of?

Answer 10

• Macromolecules build living cells and take part in biochemical reactions.
• They are made up of smaller monomers and join together to form larger structures called polymers.

Question 11

What monomers make up the fundamental macromolecules?

Answer 11

Carbohydrates- glucose which makes up cellulose and starch
Proteins- amino acids
Nucleic acids- ribose (nucleic acids)
Lipids- fatty acids

Question 12

Be able to draw ribose, alpha-D-glucose and beta-D-glucose.

Question 13

How can lipids be recognized from molecular diagrams?

Answer 13

Lipids include: triglycerides, phospholipids and steroids.

- They are recognized by the presence of the functional group (-COOH) which is attached to a long hydrocarbon chain

Question 14

How can amino acids be recognized on molecular diagrams?

Answer 14

By the presence of the functional groups (-COOH) and (NH2)

• COOH is called a carboxyl group
• NH2 which is called an amine group

Question 15

How can sugars be recognized in molecular diagrams?

Answer 15

If the number of hydrogen and oxygen atom is in the ratio of 2:1 then the monomer is a sugar.
To determine if it is either ribose or glucose, count the number of carbon atoms; ribose (5 carbon) or glucose (6 carbon).

Question 16

You need to be able to draw molecular diagrams of glucose, ribose, a saturated fatty acid and a generalised amino acid.

Answer 16

• Glucose can be either alpha-D or beta-D
• Ribose has a pentagon shape
• The saturated fatty acid does NOT have a double bond and the carbon atoms should be between 8-12
• The generalised amino acid should contain an amino group, hydroxyl group and an R-group

Question 17

What is metabolism?

Answer 17

Is all of the enzyme-catalysed reactions that take place inside a living cell.
Uses catabolism and anabolism

Question 18

What is anabolism?

Answer 18

• The synthesis of complex molecules from simpler molecules. Energy is used during this process.
• During anabolism, macromolecules are formed from monomers in a condensation reaction
• Opposite of catabolism

Question 19

What is catabolism?

Answer 19

The breakdown of complex molecules into simpler molecules and includes the hydrolysis reaction of macromolecules into monomers.
Energy is released during this process

Question 20

What is a hydrolysis reaction?

Answer 20

The breaking of chemical bonds by the addition of water molecules

Question 21

What is a condensation reaction?

Answer 21

When two smaller organic molecules combine to form a larger molecule, during which water is formed or some simple molecule

Question 22

What is the chemical formula of Urea and where is it used?

Answer 22

• CO(NH2 )2
• Human body uses it to excrete nitrogen
• Used as a nitrogen fertilizer
• Due to its large scale application, it is artificially synthesized