Photosynthesis and Stomata MCQs with Answers: Download 100 Biology MCQs PDF
Why do guard cells open a stomatal pore? What does Rubisco do? Which tissue carries food through a plant? These are standard biology topics, and they appear again and again in practice papers and tests.
This PDF brings 100 multiple-choice questions on stomata, guard cells, xylem, phloem and photosynthesis into one file. This post explains what is inside, who can use it, and how to study from it.
Key Concepts to Revise Before Practising
How Stomata Work
Stomata are tiny pores, mostly in the leaf epidermis, surrounded by two guard cells. When guard cells take in water and become turgid, the pore generally opens. When they lose water, the pore generally closes. Through open stomata, carbon dioxide enters for photosynthesis and water vapour leaves during transpiration.
Xylem vs Phloem
| Feature | Xylem | Phloem |
|---|---|---|
| Main job | Carries water and mineral salts | Carries organic food, mainly sucrose |
| Key cells | Vessel elements, tracheids | Sieve tube elements, companion cells |
| Movement | Upward (ascent of sap) | Source to sink |
| Wall strengthening | Lignin | Sieve plates at end walls |
Two Stages of Photosynthesis
- Light-dependent reactions happen in the thylakoid membranes. Water is split, oxygen is released, and ATP and NADPH are made.
- Calvin cycle happens in the stroma. Rubisco fixes carbon dioxide using RuBP, and the energy from ATP and NADPH is used to build sugars.
Who Should Download This PDF?
This PDF may be useful for:
- Students of general biology and botany who want to practise plant physiology
- Candidates preparing for science or biology-based tests, including teaching tests that include a science or biology section (check your own syllabus)
- Teachers who need ready-made practice questions for class
- Anyone revising General Science for competitive exams
- For jobs preparation, like PPsc, upsc, Fpsc, NTs etc.
Always check the official syllabus of your own test, because the topics covered differ from test to test.
Frequently Asked Questions (FAQs)
What is the main function of stomata?
Stomata allow gas exchange and are the main route for water vapour leaving the leaf during transpiration.
What do guard cells do?
Guard cells regulate the opening and closing of stomata.
What is the difference between xylem and phloem?
Xylem transports water and mineral salts. Phloem transports organic food, mainly sucrose.
Where does the Calvin cycle take place?
In the stroma of the chloroplast.
Is the PDF free?
Yes, you can download it from this page.
Conclusion
Stomata, vascular tissues and photosynthesis are connected: stomata let in carbon dioxide, xylem supplies water, the chloroplast makes sugar, and phloem moves it around. Practising these MCQs will help you test how well you know each link.
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