Topic 1 - Biological Molecules

Question 1

What is the Atomic Number?

Answer 1

The Atomic Number is the number of Protons in the nucleus of one Atom.

Question 2

What is the Atomic Mass?

Answer 2

The Atomic Mass is the sum of the protons & neutrons in the nucleus of one Atom.

Question 3

What is a molecule?

Answer 3

A group of 2 or more Atoms that are chemically bonded together.

Question 4

What is a compound?

Answer 4

A compound is a group of 2 or more DIFFERENT atoms that are chemically bonded together.

Question 5

What are the 2 types of chemical bonds?

Answer 5

• Ionic bonds
• Covalent bonds

Question 6

How are ionic bonds formed?

Answer 6

• Ionic bonds are formed when an atom either receives or donates electrons.
• This causes the atoms involved in the transfer to become oppositely charged ions.
• This causes electrostatic forces to pull the ions together creating an Ionic bond.

Question 7

What is an Ionic bond?

Answer 7

• An ionic bond is where the atoms involved in the reaction donate or receive electrons.

Question 8

What is a covalent bond?

Answer 8

• A covalent bond is where the atoms involved in the reaction ‘share’ electrons.

Question 9

Why are molecules (such as water) that have been covalently bonded Dipolar?

Answer 9

• The electrons in covalent bonds are not evenly shared
• This causes one atom of the molecule to sometimes be more negatively/positively charged than the other.

Question 10

What is an Inorganic Ion?

Answer 10

An Inorganic Ion is a CHARGED atom or molecule that falls into one of two categories:

• CATIONS (positively charged)
• ANIONS (Negatively charged)

Question 11

What are the 2 important Anions and their functions?

Answer 11

• NITRATE IONS: Needed for the formation of amino acids & DNA.
• PHOSPHATE IONS: Needed for the formation of ADP & ATP as well as RNA & DNA.

Question 12

What are the 2 important Cations and their functions?

Answer 12

• CALCIUM IONS: For the formation of calcium pectate in the middle lamella between cell walls in plants, and for bone formation & muscle contraction in animals.
• MAGNESIUM IONS: For the production of chlorophyll in plants.

Question 13

Explain why there are hydrogen bonds in water?

Answer 13

• The Oxygen atoms are slightly more negative than the Hydrogen atoms in water molecules.
• This charge separation causes a weak bond between oxygen atoms and other hydrogen atoms.
• This weak bond is called a Hydrogen Bond.