Edexcel IGCSE Biology: Nature and Variety of Living Organisms — Practice Questions

These are original questions written for Marlbridge, in the style and at the standard of the examination. They are not reproduced past-paper questions — examination boards hold copyright in their own papers. Use these alongside the official past papers available free from your board.

Related: Nature and Variety of Living Organisms revision notes

---

Section A

1. List the eight characteristics of living organisms. [8]

2. Name the five kingdoms and give one example organism from each. [5]

Section B

3. Compare a plant cell and a fungal cell, giving three differences. [3]

4. Viruses are not placed in any kingdom.

(a) Give three reasons why viruses are not considered living. [3] (b) Describe the basic structure of a virus. [2] (c) Name one virus and the disease it causes. [1]

5. Fungi and bacteria both act as decomposers.

(a) Explain how a fungus obtains its nutrition. [3] (b) Explain the importance of decomposers in an ecosystem. [2]

6. For each pathogen type, name a disease and its causative organism: bacterium, fungus, protoctist. [6]

7. (Topic 2 sub-topic (a) content, recapped here for continuity.) Distinguish between a tissue, an organ and an organ system, giving one example of each, in the context of the human digestive system. [6]

8. Explain why excretion and egestion are not the same process, and explain why an increase in mass caused by taking up water is not classed as growth. [3]

---

Answers

1. Movement [1], Respiration [1], Sensitivity [1], Growth [1], Reproduction [1], Excretion [1], Nutrition [1], Control of internal conditions [1].

2. Animals — e.g. a human [1]. Plants — e.g. a maize plant [1]. Fungi — e.g. yeast or Mucor [1]. Protoctists — e.g. Amoeba or Chlorella [1]. Prokaryotes/bacteria — e.g. Lactobacillus or Pneumococcus [1].

3. Plant cell walls are cellulose, fungal walls are chitin [1]. Plant cells contain chloroplasts, fungal cells do not [1]. Plants store carbohydrate as starch, fungi as glycogen [1].

4. (a) They cannot reproduce independently — only inside a host cell [1]; they have no cytoplasm or organelles and do not respire [1]; they do not grow, excrete or respond to stimuli [1]. (b) A protein coat [1] surrounding a core of genetic material — DNA or RNA [1]. (c) Any correct pair, e.g. HIV → AIDS, or influenza virus → flu, or tobacco mosaic virus → TMV in plants [1].

5. (a) It secretes extracellular enzymes onto the food [1]; these digest the large insoluble molecules outside the organism [1]; the soluble products are then absorbed — this is saprotrophic nutrition [1]. (b) They break down dead organisms and waste [1], releasing mineral ions back into the soil for plants to reabsorb, so nutrients are recycled [1].

6. Bacterium — e.g. cholera, caused by Vibrio cholerae [1] [1]. Fungus — e.g. athlete’s foot, caused by a Tinea fungus [1] [1]. Protoctist — e.g. malaria, caused by Plasmodium [1] [1].

7. A tissue is a group of cells with similar structure and function, e.g. glandular tissue in the stomach lining, which secretes digestive enzymes [1] [1]. An organ is a group of different tissues working together to perform a specific function, e.g. the stomach, made up of glandular, muscular and epithelial tissue [1] [1]. An organ system is a group of organs with related functions, e.g. the digestive system, made up of the stomach, small intestine, large intestine and associated glands [1] [1].

8. Excretion is the removal of the waste products of metabolism — substances the organism’s own cells produced [1]. Egestion is the removal of undigested food from the gut, which was never absorbed into the body and so was never part of the organism’s metabolism [1]. Taking up water increases an organism’s mass but not its dry mass, and growth is defined as a permanent increase in dry mass, so a rise caused only by water uptake does not count [1].

---

Where marks are usually lost

• Missing one of the eight characteristics — learn MRS GREN plus control of internal conditions.
• Saying fungal walls are made of cellulose.
• Claiming viruses have a cell wall.
• Confusing the pathogen with the vector — mosquitoes carry Plasmodium, they are not the pathogen.
• Giving a tissue example that is actually a whole organ, or vice versa — a tissue must be a single type of cell performing one function, not a functioning structure made of several tissues.
• Describing egestion as “excreting undigested food” — egestion and excretion are named as opposites precisely because undigested food was never inside the organism’s cells or metabolism.
• Explaining growth only in terms of mass, without the “dry” qualifier that rules out temporary water uptake.

Self-test

1. What is Edexcel’s eighth characteristic of living organisms, alongside MRS GREN?
2. Give the correct order of the three steps in saprotrophic nutrition.
3. Why are viruses not classed as living organisms?
4. What do plants store as their carbohydrate reserve, and what do animals and fungi store instead?
5. Put the levels of biological organisation in order, from smallest to largest.

Answers: 1. Control of internal conditions (homeostasis). 2. Enzymes are secreted onto the food, digestion occurs outside the organism, and the soluble products are then absorbed. 3. They have no cytoplasm or organelles and can only reproduce inside a host cell, so they cannot carry out the characteristics of life independently. 4. Plants store starch and sucrose; animals and fungi store glycogen. 5. Organelle, cell, tissue, organ, organ system, organism.

For condensed recall notes on this topic, see the Nature and Variety of Living Organisms revision notes.