Why Photosynthesis Matters
Every meal on Earth, whether served on a porcelain plate or eaten quietly in a forest canopy, traces back to one physico-chemical process: photosynthesis. In this quiz you will explore the fundamental division of the living world into autotrophs and heterotrophs, and discover why green plants are the nutritional foundation of all life.
What you will practise
- The meaning of autotrophic and heterotrophic nutrition
- Why green plants must synthesise their own food
- The two great reasons photosynthesis is important
- Sunlight as the ultimate energy source for all living forms
This quiz follows Lesson 1 of the course and prepares you for the structural and biochemical detail that comes later. Read each question carefully and choose the single best answer.
Q1. Green plants are called autotrophs because they:
Green plants make or rather synthesise the food they need through photosynthesis, and this is precisely why they are called autotrophs.
Q2. All animals, including human beings, depend on plants for their food. Organisms that depend on green plants for food are called:
All other organisms that depend on the green plants for food are heterotrophs, since they cannot synthesise their own food.
Q3. According to the lesson, autotrophic nutrition is found:
The lesson states clearly that autotrophic nutrition is found only in plants.
Q4. Photosynthesis is best described as:
Green plants carry out photosynthesis, a physico-chemical process by which they use light energy to drive the synthesis of organic compounds.
Q5. Which statement about the energy source of life on earth is correct?
The lesson states that ultimately all living forms on earth depend on sunlight for energy.
Q6. The use of energy from sunlight by plants doing photosynthesis is described in the lesson as:
The use of energy from sunlight by plants doing photosynthesis is the basis of life on earth.
Q7. Photosynthesis is important for two reasons. One of them is that it is:
The lesson states that photosynthesis is important due to two reasons: it is the primary source of all food on earth, and it is responsible for the release of oxygen into the atmosphere by green plants.
Q8. Besides being the primary source of all food on earth, photosynthesis is also responsible for:
The second reason given for the importance of photosynthesis is that it is responsible for the release of oxygen into the atmosphere by green plants.
Q9. The lesson raises the question of what would happen if there were no oxygen to breathe. This question highlights that oxygen in the atmosphere is:
The lesson links this question to the fact that photosynthesis is responsible for the release of oxygen into the atmosphere by green plants.
Q10. The chapter on photosynthesis in higher plants focuses on:
The lesson states that the chapter focuses on the structure of the photosynthetic machinery and the various reactions that transform light energy into chemical energy.
Q11. In photosynthesis, light energy is used by green plants to:
Photosynthesis is the process by which green plants use light energy to drive the synthesis of organic compounds.
Q12. Which of the following correctly pairs an organism with its nutritional category as described in the lesson?
Green plants synthesise their own food and are autotrophs, while animals including human beings depend on plants and are heterotrophs.
Q13. The term autotroph essentially means:
The term autotroph means self-feeding, capturing the plant's ability to synthesise its own nourishment rather than seek it.
Q14. Which statement best explains why the autotroph stands at the beginning of the food chain?
The autotroph alone stands at the beginning of the food chain, converting energy into a form that can be passed along to other organisms.
Q15. Which of the following is NOT one of the two reasons given in the lesson for the importance of photosynthesis?
The lesson gives exactly two reasons: photosynthesis is the primary source of all food on earth and is responsible for the release of oxygen into the atmosphere by green plants. Minerals in soil are not mentioned as a reason.