2.1.2: Elements And Ions

Question 1

What elements do carbohydrates contain?

Answer 1

C, H and O

Question 2

What elements do lipids contain?

Answer 2

C, H and O

Question 3

What elements do proteins contain?

Answer 3

C, H, O, N and S

Question 4

What elements do nucleic acids contain?

Answer 4

C, H, O, N and P

Question 5

What is the role of calcium ions (Ca²⁺) in biology?

Answer 5

Involved in muscle contraction and nerve impulse transmission

Question 6

What is the role of sodium ions (Na⁺) in biology?

Answer 6

Involved in co-transport, reabsorption of water in the kidney and nerve impulse transmission

Question 7

What is the role of potassium ions (K⁺) in biology?

Answer 7

Involved in stomatal opening and nerve impulse transmission

Question 8

What is the role of hydrogen ions (H⁺) in biology?

Answer 8

Involved in chemiosmosis, pH determination and catalysis of reactions

Question 9

What is the role of ammonium ions (NH₄⁺) in biology?

Answer 9

Involved in the nitrogen cycle, whereby bacteria convert ammonium ions into nitrate ions

Question 10

What is the role of nitrate (NO₃⁻) in plants?

Answer 10

Mineral ion absorbed by plants to provide a source of nitrogen to make amino acids

Question 11

What is the role of hydrogencarbonate (HCO₃⁻) in biology?

Answer 11

Maintains the pH of the blood

Question 12

What is the role of chloride (Cl⁻) in cells?

Answer 12

Provide a negative charge to balance positive sodium ions and potassium ions in cells

Question 13

What is the role of phosphate (PO₄³⁻) in biology?

Answer 13

Involved in the formation of phospholipids for cell membranes, nucleic acid and ATP formation and in making bones

Question 14

What is the role of hydroxide (OH⁻) in biology?

Answer 14

Catalysis of reactions and determining pH