OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which type of organisms carry out photosynthesis?

1. Fungi

2. Animals

3. Green plants and algae

4. Bacteria

The correct answer is: Green plants and algae

The correct choice identifies the organisms that engage in photosynthesis, which primarily includes green plants and algae. Photosynthesis is the process through which these organisms convert light energy, usually from the sun, into chemical energy in the form of glucose. This process involves absorbing carbon dioxide from the air and water from the soil, using chlorophyll – the green pigment found in chloroplasts of plant cells and in algae – to capture sunlight. During photosynthesis, these organisms produce oxygen as a byproduct, which is vital for the survival of animals and many other life forms on Earth. The ability to perform photosynthesis is a defining characteristic of green plants and algae, categorizing them as autotrophs. This means they can produce their own food, distinguishing them from organisms like fungi and animals, which are unable to photosynthesize and must obtain their nutrients from other sources. While some bacteria can also perform photosynthesis, they typically do so through different mechanisms and are not as universally recognized for this process as green plants and algae are.