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Plants are living things - Alive or not alive

Grade 3Cambridge (IGCSE)

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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All plants are living things because they carry out the seven life processes summarized by the acronym MRS GRENMRS \ GREN.

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MovementMovement: Unlike animals, plants do not move from place to place, but they move their parts (e.g., leaves turning toward the light).

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RespirationRespiration: Plants break down food to release energy. This process involves taking in oxygen and releasing carbon dioxide.

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SensitivitySensitivity: Plants respond to their environment, such as growing towards a light source or closing leaves when touched.

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GrowthGrowth: Plants increase in size as they get older, growing from seeds into adult plants.

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ReproductionReproduction: Plants create new life by producing seeds, spores, or runners.

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ExcretionExcretion: Plants get rid of waste products, such as releasing excess oxygen during the day.

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NutritionNutrition: Plants are 'producers' because they make their own food using sunlight, water, and carbon dioxide.

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Things can be classified into three categories: Living (shows all 7 processes), Non-living (never lived), and Once-living (part of a living thing that has died).

📐Formulae

Carbon Dioxide+Water→SunlightGlucose+Oxygen\text{Carbon Dioxide} + \text{Water} \xrightarrow{\text{Sunlight}} \text{Glucose} + \text{Oxygen}

MRS  GREN=Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition\text{MRS \ GREN} = \text{Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition}

💡Examples

Problem 1:

A plastic flower looks exactly like a real rose. Explain why the plastic flower is considered 'non-living' while the real rose is 'living'.

Solution:

The plastic flower is non-living because it does not perform the 77 life processes.

Explanation:

A real rose grows (GG), breathes (RR), and needs nutrition (NN) from the sun and soil. A plastic flower does not grow, does not need water or light for food, and cannot reproduce to make more seeds.

Problem 2:

If a plant is kept in a dark cupboard for a long time, it will eventually die. Which life process is it unable to perform properly in the dark?

Solution:

NutritionNutrition

Explanation:

Plants need sunlight to perform photosynthesis and create their own food. Without light, the process of NutritionNutrition stops, and the plant cannot survive.

Problem 3:

Classify the following items as 'Living', 'Non-living', or 'Once-living':

  1. A piece of paper
  2. A pebble
  3. A seedling

Solution:

  1. Once-living, 2. Non-living, 3. Living

Explanation:

Paper is made from trees which were once alive. A pebble is a rock and has never carried out MRS GRENMRS \ GREN. A seedling is currently growing and performing life processes.