Science 9 Week 8 - Photosynthesis

Summary

In this engaging life science lesson, Grade 9 students explore photosynthesis through interactive activities and discussions. They learn about biodiversity, population density, and extinction. The session covers the process of photosynthesis, including light-dependent and light-independent reactions, and factors affecting it. Students participate in games like 'Decode Me' and 'Like or Heart' to reinforce learning. The importance of evidence in science is highlighted through experiments demonstrating starch production, carbon dioxide uptake, and oxygen release.

Takeaways

• 📚 The class is a fun-filled learning experience focused on life science for grade 9 students.
• 📝 Students are reminded to use their real names, choose suitable workspaces, take notes, use the comment box appropriately, and respect each other.
• 🌿 The review involves questions about biodiversity, population density, and extinction to test students' knowledge.
• 🎮 A game called 'Decode Me' is played to engage students, where they identify words related to the lesson by combining the first letters of given pictures.
• 🌳 The lesson discusses how plants make food through photosynthesis, using sunlight, water, and carbon dioxide to produce oxygen and glucose.
• 🔬 The chemical formula for photosynthesis is presented: 6CO2 + 6H2O → 2C6H12O6 + 6O2.
• 🌱 The parts of a leaf and their functions in photosynthesis are explained, including the epidermis, stomata, mesophyll, and vascular bundles.
• 🍃 The structure of chloroplasts and their role in photosynthesis are detailed, including the outer and inner membranes, stroma, granum, thylakoids, and lumen.
• 🌞 The two stages of photosynthesis are explained: light-dependent reactions (occurring in the thylakoid membrane) and light-independent reactions (occurring in the stroma).
• 🔍 Evidence of photosynthesis is discussed, including the iodine test for starch, the necessity of carbon dioxide, and the release of oxygen.
• ⚖️ Factors affecting the rate of photosynthesis are identified as light intensity, carbon dioxide concentration, and temperature.

Q & A

What are the reminders given to the students at the beginning of the class?

The reminders include using real names, choosing a suitable workspace, taking notes, using the comment box appropriately, and respecting one another.

What is the first question asked in the review of past lessons?

The first question is about what term refers to the variety of living species on earth, including plants, animals, bacteria, and fungi. The correct answer is 'biodiversity'.

What is the average number of individuals in a population per unit of area or volume called?

The average number of individuals in a population per unit of area or volume is called 'population density'.

What is the term for the disappearance of a species when the last of its members die?

The disappearance of a species when the last of its members die is called 'extinction'.

How does the game 'Decode Me' work?

In the game 'Decode Me', students identify a hidden word by using and combining the first letter of each picture shown.

What is the process by which plants make their food?

Plants make their food through photosynthesis, which is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar or glucose.

What is the chemical formula for photosynthesis?

The chemical formula for photosynthesis is 6 CO2 + 6 H2O yields 2 C6H12O6 + 6 O2.

What are the main parts of a leaf involved in photosynthesis?

The main parts of a leaf involved in photosynthesis are the upper and lower epidermis, mesophyll, stomata, and vascular bundles.

What is the role of chlorophyll in photosynthesis?

Chlorophyll is a pigment in leaves that absorbs light, primarily from the sun, which is essential for the process of photosynthesis to occur.

What are the two stages of photosynthesis?

The two stages of photosynthesis are the light-dependent reactions, which occur in the thylakoid membrane and convert light energy to chemical energy, and the light-independent reactions, also known as the Calvin cycle, which occur in the stroma and use ATP and NADPH to produce glucose.

How can the presence of starch in leaves be used as evidence for photosynthesis?

The presence of starch in leaves can be detected through an iodine test, where the leaf turns blue-black when starch is present, indicating that photosynthesis has occurred.

What factors affect the rate of photosynthesis?

The factors that affect the rate of photosynthesis are light intensity, carbon dioxide concentration, and temperature.