1. Introduction To Biological Molecules

Question 1

Name three ways in which atoms can combine with each other

Answer 1

Covalent bonding
Ionic bonding
Hydrogen bonding

Question 2

Describe covalent bonding

Answer 2

Atoms share a pair of electrons in their outer shells

As a result the outer shell of both atoms is filled and a more stable compound is formed

Question 3

Describe ionic bonding

Answer 3

Ions with opposite charges attract one another
This electrostatic attraction is known as an ionic bond
Ionic bonds are weaker than covalent bonds

Question 4

Describe hydrogen bonding

Answer 4

Electrons within a molecule are not evenly distributed but tend to spend more time at one position, which makes this region more negatively charged than the rest of the molecule
Molecule with uneven distribution of charge is polarised (polar molecule)
Negative region of one polarised molecule and positively charged region of another attract each other
Weak electrostatic bond is formed
Each bond is individually weak but can collectively form important forces that alter the physical properties of molecules

Question 5

What is a polymer?

Answer 5

A long chain of monomer subunits

Question 6

What is the name of the process in which polymers are formed?

Answer 6

Polymerisation

Question 7

What is the basic sub unit of a polysaccharide?

Answer 7

A monosaccharide

Question 8

What is the name of the reaction when a polymer is formed and a water molecule is released?

Answer 8

A condensation reaction

Question 9

What is a hydrolysis reaction?

Answer 9

A reaction in which water is used to break down a compound

Question 10

What is metabolism?

Answer 10

All the chemical processes that take place in living organisms

Question 11

How many particles does a mole contain?

Answer 11

One mole contains the same number of particles as there are in 12g of carbon-12 atoms
Avogadro constant = 6.02 x 10^23

Question 12

Describe a neutron

Answer 12

Occur in the nucleus of an atom
Have the same mass as protons
Have no electrical charge

Question 13

Describe a proton

Answer 13

Occur in the nucleus of an atom
Have the same mass as neutrons
Have a positive charge

Question 14

Describe an electron

Answer 14

Orbit around shells around the nucleus
Have a small mass (negligible)
Negatively charged
Their number determines the chemical properties of an atom

Question 15

What is the atomic number?

Answer 15

The number of protons in an atom

Question 16

What is the mass number?

Answer 16

The total number of protons and neutrons in an atom

Question 17

What is an isotope?

Answer 17

Isotopes are atoms of an element with the same number of protons but a different number of neutrons

Question 18

How is an ion formed?

Answer 18

The loss of an electron forms a positive ion

The gain of an electron forms a negative ion

Question 19

Name the element that contains one proton and one electron

Answer 19

Hydrogen