13 WJEC Biology AS Level - Marianne Izen - 2nd Edition

Question 1

Living organisms need a variety of ——– ions to survive.

Answer 1

Living organisms need a variety of inorganic ions to survive.

Question 2

Inorganic ions are also called ———

Answer 2

Inorganic ions are also called electrolytes or minerals

Question 3

What is the importance of inorganic ions?

Answer 3

They are important in many cellular processes, including

1. muscle contraction
2. nervous coordination
3. maintaining water potential in cells
4. maintaining water potential in blood.

Question 4

What are the two groups of inorganic ions?

Answer 4

There are two groups:

1. macronutrients, needed in small concentrations
2. micronutrients, needed in minute (trace) concentrations

Question 5

Name two micronutrients

Answer 5

1. copper
2. zinc

Question 6

Name four macronutrients

Answer 6

1. Magnesium (Mg2+)
2. Iron (Fe2+)
3. Calcium (Ca2+)
4. Phosphate (PO4)3-

Question 7

Inorganic (Key Term)

Answer 7

A molecule or ion that has no more than one carbon atom

Question 8

What is the role in living organisms for the element magnesium?

Answer 8

Magnesium (Mg) is an important constituent of chlorophyll and is therefore essential for photosynthesis.

Plants without magnesium in their soil cannot make chlorophyll and so the leaves are yellow, a condition known as chlorosis. Growth is often stunted from lack of glucose.

Mammals need magnesium for their bones.

Question 9

What is the role in living organisms for the element iron?

Answer 9

Iron (Fe2+) is a constituent of haemoglobin, which transports oxygen in red blood cells.

Lack of iron in the human diet can lead to anaemia.

Question 10

What is the role in living organisms for the element phosphorus?

Answer 10

Phosphate ions (PO4)2- are used for making nucleotides, including ATP.

They are a constituent of phospholipids, found in biological membranes.

Question 11

What is the role in living organisms for the element calcium?

Answer 11

Calcium (Ca2+), like phosphate, is an important structural component of bones and teeth in mammals

It is a component of plant cell walls, providing strength.

Question 12

What are the key things to know about structure of chlorphyll?

Answer 12

1. Porphyrin ring combines with protein
2. The metal ion it contains is magnesium

Question 13

What are the key things to know about structure of haemoglobin?

Answer 13

It contains:

1. a1 polypetide and a2 polypeptide
2. b1 polypeptide and b2 polypeptide
3. haem (non-protein group, iron-containing group)

Question 14

What are the key things to know about structure of ATP molecule?

Answer 14

It contains:

1. adenine
2. ribose
3. three phosphate groups

Question 15

What did ‘organic’ and ‘inorganic’ originally mean?

Answer 15

Originally ‘organic’ meant being derived from living organisms and “Inorganic’ meant not derived from living material.

Question 16

What is the relation of the term ‘organic’ in ‘organic food’ to the structure of the food’s molecules?

Answer 16

The meaning of ‘organic’ in the term ‘organic food’ is not related to the structure of the food’s molecules.