IGCSE · Practice questions · Specialised cells and levels of organisation

From one cell to a whole organism.

Six original Cambridge-style questions on where new cells come from, specialised cells and their functions, and classifying structures as cells, tissues, organs or organ systems.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Structure always explains function.

New cells come only from the division of existing cells.
Seven specialised cells: ciliated, root hair, palisade mesophyll, neurone, red blood cell, sperm and egg.
Link a feature to a job: large surface area for absorption, chloroplasts for photosynthesis, no nucleus for more haemoglobin.
Levels: cell, tissue (similar cells), organ (several tissues), organ system (several organs), organism.

Recall

[6 marks]

State the function of each of these specialised cells: (a) ciliated cell, (b) root hair cell, (c) palisade mesophyll cell, (d) neurone, (e) red blood cell, (f) egg cell.

(a) Movement of mucus in the trachea and bronchi. ✓
(b) Absorption (of water and mineral ions). ✓
(c) Photosynthesis. ✓
(d) Conduction of electrical impulses. ✓
(e) Transport of oxygen. ✓
(f) Reproduction: it is a female gamete. ✓

Recall

[1 marks]

State how new cells are produced.

By the division of existing cells. ✓

Calculation

[2 marks]

A single cell divides into two, and then every new cell divides once every 20 minutes. Calculate how many cells there are after 2 hours, assuming none die.

2 hours = 120 minutes, so 120 ÷ 20 = 6 divisions. ✓
The number doubles each time: 2⁶ = 64 cells. ✓

Analysis

[4 marks]

Classify each of these as a cell, tissue, organ or organ system: (a) the stomach, (b) a sperm cell, (c) the digestive system, (d) a layer of palisade mesophyll cells.

(a) Organ. ✓
(b) Cell. ✓
(c) Organ system. ✓
(d) Tissue. ✓

Explain

[3 marks]

Explain how the structure of a red blood cell is related to its function.

Its function is the transport of oxygen. ✓
It is full of haemoglobin, which carries oxygen, and has no nucleus, so there is more room for haemoglobin. ✓
Its biconcave shape gives a large surface area for oxygen to move in and out. ✓

Explain

[2 marks]

Explain the difference between a tissue and an organ, using the leaf as an example.

A tissue is a group of cells with similar structures working together for a shared function, such as palisade mesophyll tissue. ✓
An organ is made of several different tissues working together; the leaf contains epidermis, palisade and spongy mesophyll, xylem and phloem, so it is an organ. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.