Biology Unit 9: Plant Biology — Free Review Games.
This unit covers photosynthesis, plant structure and reproduction in plants — essential concepts for Biology. Use our interactive study games to test your understanding, or review questions in traditional format below.
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This unit covers photosynthesis, plant structure and reproduction in plants — essential concepts for Biology. Use our interactive study games to test your understanding, or review questions in traditional format below.
Key Concepts Breakdown
1 Photosynthesis
Photosynthesis is the process by which plants convert light energy into chemical energy stored as glucose. Students must know the overall equation, the roles of the light-dependent and light-independent reactions, and where each stage occurs in the chloroplast.
Key Points
- Overall equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
- Light-dependent reactions occur in the thylakoid membrane; they produce ATP, NADPH, and release O₂
- The Calvin cycle (light-independent) occurs in the stroma; it uses ATP and NADPH to fix CO₂ into glucose
- Chlorophyll absorbs mainly red and blue light; green light is reflected, making plants appear green
A student covers half of a leaf with foil for one week, then tests both halves for starch using iodine solution. The uncovered half turns blue-black; the covered half remains brown.
The uncovered half received light and performed photosynthesis, producing glucose that was converted to starch. The covered half had no light, so no photosynthesis occurred and no starch accumulated. This experiment demonstrates that light is a necessary raw material for photosynthesis.
2 Plant Structure
Plants have specialized organs — roots, stems, and leaves — each with tissues adapted for specific functions. Students must be able to identify the roles of xylem, phloem, and the adaptations of leaves for gas exchange and photosynthesis.
Key Points
- Xylem transports water and minerals upward from roots; it is made of dead, hollow cells
- Phloem transports dissolved sugars (products of photosynthesis) in both directions
- Leaves have a large surface area, thin profile, and stomata (pores) to allow CO₂ in and O₂ out
- Guard cells control stomatal opening; they open in light (when photosynthesis demand is high) and close in drought to reduce water loss
A celery stalk is placed in red-dyed water for 24 hours. When the stalk is cut in cross-section, red color appears only in specific small dots scattered through the stem.
The red dye moved upward through the xylem vessels, which appear as small dots in the cross-section. Phloem and other tissues remain unstained because they do not transport water. This demonstrates that xylem is the water-conducting tissue in plants.
3 Reproduction In Plants
Plants reproduce both sexually (involving flowers, pollination, and seeds) and asexually (without fertilization). Students must know the parts of a flower and their functions, the difference between self- and cross-pollination, and how seeds are dispersed.
Key Points
- Male structure: anther produces pollen (contains male gametes); female structure: stigma, style, and ovary containing ovules
- Pollination is the transfer of pollen to the stigma; fertilization occurs when a pollen tube reaches the ovule
- After fertilization: ovule → seed, ovary → fruit
- Asexual reproduction (runners, bulbs, cuttings) produces genetically identical offspring (clones); sexual reproduction produces genetic variation
A farmer wants all strawberry plants to have the same high-yield trait as the parent plant. Should the farmer use seeds or runners to propagate new plants?
The farmer should use runners, which are a form of asexual reproduction. Runners produce clones of the parent plant, guaranteeing the offspring inherit the identical high-yield genetic traits. Seeds result from sexual reproduction and may produce offspring with different characteristics due to genetic recombination.
Questions, answered.
What is Plant Biology?
Plant Biology is Unit 9 of Biology, covering photosynthesis, plant structure and reproduction in plants.
How to study for Biology Unit 9?
Start with the Quick Summary above, review the Key Concepts, then test yourself with our interactive study games. Aim for 80%+ accuracy before moving on.
How many questions are in this unit?
This unit has 25+ review questions across 5 different game modes.