Biological Elements

Question 1

What are elements

Answer 1

Different types of atoms- distinguished by number of protons in nuclei

Question 2

What are a living things composed of

Answer 2

Carbon (C), Hydrogen (H), Oxygen (O) and Nitrogen (N)

Phosphorus (P) and sulphur (S) also have an important role in biochemistry of cells.

Question 3

How do atoms connect

Answer 3

With bonds

Question 4

What are two or more atoms bonded called

Answer 4

Molecules

Question 5

How does a covalent bond occur

Answer 5

Two atoms share a pair of electrons, electrons used to form bonds are unpaired and present in the outer orbitals of the atoms.

Question 6

What are the simple rules of bonding (determined by number of unpaired electrons present in the outer orbitals of different elements)

Answer 6

-Carbon atoms can form four bonds with other atoms
-nitrogen atoms can form three bonds with other atoms
-oxygen atoms can form two bonds with other atoms
-hydrogen atoms can form one bond with another atom.

Question 7

Difference between a cation and anion

Answer 7

-atom loses electron-positive-cation

-atom gains electron-negative-anion

Question 8

How does ionic bonding happen

Answer 8

-one atom in the pair donates an electron and the other receives it. This forms positive and negative ions that are held together by the attraction of the opposite charges.

Question 9

What are ions in solute called

Answer 9

Electrolytes

Question 10

Roles of calcium ions Ca2+ (cation)

Answer 10

-Nerve impulse transmission
-Muscle contraction

Question 11

Role of sodium ions Na+ (Cation)

Answer 11

-nerve impulse transmission
-kidney function

Question 12

Role of potassium ions K+. (Cation)

Answer 12

-nerve impulse transmission
-stomatal opening

Question 13

Role of hydrogen ions H+. (Cation)

Answer 13

-catalysis of reactions
-pH determination

Question 14

Role of ammonium ions. NH4+. (Cation)

Answer 14

Production of nitrate ions by bacteria

Question 15

Roles of nitrate ions NO3- (Anion)

Answer 15

Nitrogen supply to plants for amino acid and protein formation

Question 16

Roles of hydrogen carbonate ions HCO3- (anions)

Answer 16

Maintenance of blood pH

Question 17

Roles of chloride ions. Cl- (Anions)

Answer 17

Balance positive charge of sodium and potassium ions in cells

Question 18

Roles of phosphate ions PO4. 3- (Anion)

Answer 18

-cell membrane formation
-nucleic acid and ATP formation
-bone formation

Question 19

Roles of hydroxide ions OH- (Anions)

Answer 19

-catalysis of reactions
-pH determination

Question 20

Elements in carbohydrates

Answer 20

Carbon, hydrogen and oxygen

Question 21

Elements in lipids

Answer 21

Carbon, hydrogen and oxygen

Question 22

Elements in proteins

Answer 22

Carbon, hydrogen, oxygen, nitrogen and sulfur

Question 23

Elements in Nucleic acids

Answer 23

Carbon, hydrogen, oxygen, nitrogen and phosphorus

Question 24

What are polymers

Answer 24

Biological molecules are polymers. Polymers are long-chain molecules made up by the linking of multiple individual molecules (called monomers) in a repeating pattern. In carbohydrates the monomers are sugars (saccharides) and in proteins the monomers are amino acids.