What are the reactants of Photosynthesis — Reading Comprehension

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This comprehensive science passage, aligned with NGSS standards for middle school, provides a detailed yet accessible explanation of photosynthesis. It focuses on the key reactants—carbon dioxide, water, and light energy—and their roles in the process. The passage explains how these inputs are transformed into the products, glucose and oxygen, within a plant's chloroplasts. It also highlights the critical role of chlorophyll and connects the process to the broader cycle of energy and gas exchange on Earth. The content is structured to be used for self-study, with clear, factual language and a logical flow from the basic definition to real-world connections. The text is designed to help students understand the fundamental concepts of how plants create their own food and sustain ecosystems.

CONTENT PREVIEW

Photosynthesis, showing the reactants (carbon dioxide, water, and light) and the products (glucose and oxygen).

Photosynthesis is the remarkable process used by plants, algae, and some bacteria to convert light energy into chemical energy. This chemical energy is stored in the form of glucose, a type of sugar. Photosynthesis is the foundation of most food webs on Earth, as it produces the food and oxygen that sustain nearly all life. Without this process, the flow of energy from the sun would not be captured and converted into a usable form for living organisms.

To create glucose, photosynthetic organisms need three primary ingredients: sunlight, carbon dioxide, and water. These "ingredients" are known as reactants. Plants absorb water (H2O) from the soil through their roots and take in carbon dioxide (CO2) from the atmosphere through tiny pores on their leaves called stomata. Sunlight provides the energy needed to power the chemical reaction. Inside the plant's cells, organelles called chloroplasts contain a green pigment called chlorophyll, which is specialized for capturing light energy.

The process of photosynthesis can be summarized by a simple chemical equation: 6CO2+6H2O+Light Energy→C6H12O6+6O2. The reactants, carbon dioxide and water, are transformed with the help of light energy into the products: glucose (C6H12O6) and oxygen (O2). Glucose provides the plant with the energy it needs to grow, while the oxygen is released as a byproduct into the atmosphere. This oxygen is vital for the respiration of animals and humans.

The interdependence between photosynthesis and cellular respiration is a critical concept in biology. Photosynthesis uses the carbon dioxide produced by animals and humans and releases the oxygen we need to breathe. In turn, plants use the glucose created during photosynthesis to fuel their own cellular respiration, just as animals do. This creates a balanced cycle of gas exchange that maintains life on our planet.

Fun Fact: Photosynthesis is responsible for creating most of the oxygen we breathe, but about half of the oxygen on Earth is produced by marine organisms like phytoplankton, which are microscopic, plant-like organisms in the ocean.

What are the three primary ingredients, or reactants, needed for photosynthesis?

Oxygen, glucose, and waterCarbon dioxide, water, and sunlightGlucose, sunlight, and oxygenWater, oxygen, and carbon dioxide

Where do plants absorb carbon dioxide for photosynthesis?

Through their rootsFrom the soilThrough stomata on their leavesDirectly from sunlight

What is the main purpose of chlorophyll in a plant cell?

To produce oxygenTo capture light energyTo absorb waterTo store glucose

The chemical equation for photosynthesis shows that carbon dioxide and water are converted into what two products?

Oxygen and chlorophyllWater and glucoseGlucose and oxygenCarbon dioxide and water

Which of the following is a byproduct of photosynthesis?

GlucoseWaterCarbon dioxideOxygen

Based on the passage, what is the relationship between photosynthesis and cellular respiration?

They are completely separate processes.They are two different names for the same process.The products of one process are the reactants of the other.Both processes produce glucose and oxygen.

If a plant is placed in a sealed jar with no access to light, what would be the most likely result for the plant?

It would produce a large amount of glucose.It would release oxygen but not produce glucose.It would be unable to perform photosynthesis.It would absorb more carbon dioxide.

Which of the following best describes the main idea of the reading passage?

The importance of stomata in gas exchange.A detailed explanation of the products of photosynthesis.A summary of the reactants and process of photosynthesis.The role of chlorophyll in creating plant color.