MRS GREN Life Scanner

MRS GREN: the characteristics of living organisms

This free game is part of our Pearson Edexcel iGCSE Biology (4BI1) course for exams in EXAM YEARS 2026-2028.

What does MRS GREN stand for?

MRS GREN is a way to remember the seven life processes that all living organisms carry out:

• M - Movement: the organism, or part of it, moves by itself.
• R - Respiration: chemical reactions in cells that release energy from food.
• S - Sensitivity: detecting and responding to changes in the surroundings.
• G - Growth: a permanent increase in size and complexity, made by cell division.
• R - Reproduction: making more organisms of the same kind.
• E - Excretion: removing waste products made by the body's chemical reactions.
• N - Nutrition: taking in or making food for energy and growth.

The golden rule: all seven

To be classed as living, an organism must carry out all seven life processes. Doing some of them is not enough. In the MRS GREN Life Scanner, you load specimens such as a rabbit, a sunflower, a mushroom, a bacterium, a virus, fire, a crystal, a cloud, a car and a robot into the scanner, predict whether each one is alive, and then watch it tested against every process.

Classic exam traps

• Fire seems to move, grow, use oxygen and "feed" on fuel, but it is not made of cells and cannot truly reproduce, so it is non-living.
• Respiration is not breathing. It happens inside every living cell, all the time.
• Plants excrete: oxygen is a waste product of photosynthesis, so releasing it counts as excretion.
• Viruses can only reproduce inside host cells, so most biologists do not classify them as living.
• Robots respond because they are programmed to. That is not sensitivity, which needs receptors and a nervous or hormonal system.
• One cell is enough: bacteria carry out all seven processes on their own.

Exam tips

• Learn a one-line definition for each of the seven processes. Definitions are common short-answer questions.
• For growth, say permanent increase in size. For movement, say the organism moves itself.
• If asked why something is non-living, name a specific life process it cannot carry out.