18 Questions
What is the equation for photosynthesis?
6CO2 + 6H2O + light energy → C6H12O6 + 6O2
How can we test if a plant has carried out photosynthesis?
By testing for starch, which is produced during photosynthesis and stored in leaves
What turns dark blue/black in the presence of starch?
Iodine
What is one of the by-products of photosynthesis?
Oxygen
How is oxygen collected and tested in an experiment to determine if a water plant has carried out photosynthesis?
Gas is collected in a test tube containing sodium hydrogencarbonate solution and tested with a glowing splint
How do plants gain mass and weight?
Plants gain mass and weight from absorbing water and minerals from the soil through their roots, and energy from sunlight through their leaves during photosynthesis
What did an experiment using a Coleus plant with variegated leaves indicate about chlorophyll and photosynthesis?
Only the green parts of leaves containing chlorophyll contained starch after an iodine test
What did an experiment wrapping some leaves of a plant in aluminum foil and leaving others uncovered show about photosynthesis?
Only uncovered leaves contained starch after 2 days
Why is photosynthesis important for both plants and animals?
Animals cannot produce their own food and rely on plants or other animals for food either directly or indirectly through food chains
What is the first link in a food chain?
Producers like plants
What role do decomposers like fungi and bacteria play in an ecosystem?
Break down dead or waste organic materials and return nutrients to the soil/environment for reuse by plants
What impact do disruptions in a food web have on an ecosystem?
Disruptions can impact the whole ecosystem
What are the steps to test for starch using iodine solution?
- Prepare the materials needed 2. Add a drop of iodine solution to a Petri dish as a control and record the color 3. Add a drop of starch solution and a drop of water to separate parts of another Petri dish 4. Add a drop of iodine solution to the starch solution and to the water separately 5. Observe and record any changes in color 6. Destarch the leaf sample by keeping it in darkness for 1-2 days
What are primary, secondary, and tertiary consumers based on?
What they feed on
How do respiration and photosynthesis affect atmospheric oxygen and carbon dioxide levels?
Respiration releases CO2 while photosynthesis absorbs it, maintaining balance
What is the purpose of keeping a leaf sample in darkness for 1-2 days before testing for starch?
To destarch the leaf sample
What do food chains show?
The transfer of energy from producers to consumers
What is the purpose of a food web?
To show the interconnected food chains in an ecosystem and energy transfer between organisms
Study Notes
Photosynthesis and Plants
- The equation for photosynthesis is not specified in this text, but it is typically 6CO2 + 6H2O + light energy → C6H12O6 (glucose) + 6O2
- To test if a plant has carried out photosynthesis, starch production can be checked, as it is a by-product of photosynthesis
- Iodine solution turns dark blue/black in the presence of starch
Testing for Photosynthesis
- Oxygen is a by-product of photosynthesis, and can be collected and tested in an experiment using a gas syringe or a bell jar
- To determine if a water plant has carried out photosynthesis, oxygen production can be measured using a gas syringe or a bell jar
Plant Growth and Development
- Plants gain mass and weight through photosynthesis, which produces glucose that provides energy for growth and development
- Chlorophyll is necessary for photosynthesis, as indicated by an experiment using a Coleus plant with variegated leaves
- Chlorophyll is present in the green areas of the leaves, which are capable of undergoing photosynthesis
Importance of Photosynthesis
- Photosynthesis is important for both plants and animals, as it provides energy and organic compounds for food chains
- The first link in a food chain is typically a producer, such as a plant that undergoes photosynthesis
- Decomposers like fungi and bacteria play a crucial role in an ecosystem by breaking down dead organic matter and recycling nutrients
Food Chains and Webs
- Primary consumers feed on producers, secondary consumers feed on primary consumers, and tertiary consumers feed on secondary consumers
- Disruptions in a food web can have a ripple effect throughout the ecosystem
- Food chains show the feeding relationships between organisms in an ecosystem
- A food web is a network of interconnected food chains
Testing for Starch
- To test for starch, a leaf sample is boiled in water to break down cell membranes, then treated with iodine solution, which turns dark blue/black in the presence of starch
- The purpose of keeping a leaf sample in darkness for 1-2 days before testing for starch is to deplete the leaf of starch, ensuring that any starch present after the test period is a result of photosynthesis
Learn about the process of photosynthesis and how to test for the presence of starch in plants. Explore the word equation and chemical equation for photosynthesis, as well as the by-product of oxygen. Test your knowledge with this quiz!
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