Photosynthesis Flashcards

Questions and Answers

What is the overall reaction for photosynthesis?

6 CO2 + 6 H2O ==> 6 O2 + C6H12O6

How does this compare to the overall reaction for cellular respiration?

They are opposites.

Where does the energy for photosynthesis come from?

The sun, or solar energy.

What plant pigments are involved in photosynthesis?

Chlorophyll a, chlorophyll b, and carotenoids. Signup and view all the answers

Explain why chlorophyll appears green to us.

Chlorophyll is green because it reflects all the reds and blues of white light, leaving green. Signup and view all the answers

How does the amount of energy in light change as the wavelength increases?

Less energy is produced. Signup and view all the answers

Which colors of light are most effective for photosynthesis?

Red and blue/violet range. Signup and view all the answers

In what organelle of plant cells does photosynthesis take place?

In the chloroplasts. Signup and view all the answers

What are the two stages of photosynthesis?

Light reactions and Calvin cycle. Signup and view all the answers

In which part of the chloroplast does each stage of photosynthesis occur?

Light reactions happen in the thylakoid membrane, and the Calvin cycle happens in the stroma. Signup and view all the answers

What happens to water molecules in the light reactions?

It's broken apart and the electrons go to photosystem II. Signup and view all the answers

What photosynthesis waste product is formed in the light reactions?

Oxygen. Signup and view all the answers

What two products of the light reactions are used up in the Calvin cycle?

NADPH and ATP. Signup and view all the answers

What happens to carbon dioxide molecules in the Calvin cycle reactions?

It's converted to sugar. Signup and view all the answers

How can cells store the sugar that is produced in photosynthesis?

They are stored as starch. Signup and view all the answers

What are the three parts of the Calvin cycle?

CO2 fixation, CO2 reduction, regeneration of RuBP. Signup and view all the answers

What do light reactions produce?

ATP and NADPH. Signup and view all the answers

What happens to the electrons in light reactions?

They are energized, move down the electron transport chain, pump H+ into the thylakoids, and are used to make ATP out of ADP. Signup and view all the answers

What happens in the Calvin cycle?

CO2 is attached to a 5-carbon RuBP molecule, resulting in a 6-carbon molecule, accelerated by Rubisco. It requires NADPH and ATP, and the 6-carbon molecule is made into carbs (glucose) and back into RuBP. Signup and view all the answers

How many photosystems do light reactions use?

PS-I and PS-II. Signup and view all the answers

What does PS-I do?

It captures light and then ejects the electron which bounces around and produces NADP. Signup and view all the answers

What does PS-II do?

It captures light energy. Signup and view all the answers

What is photosynthesis?

A process that captures solar energy and transforms it into chemical energy that is stored in a carbohydrate. Signup and view all the answers

Study Notes

Overall Photosynthesis Reaction

Photosynthesis equation: 6 CO2 + 6 H2O → 6 O2 + C6H12O6 + light energy.
Involves converting carbon dioxide and water into glucose and oxygen.

Comparison to Cellular Respiration

Photosynthesis and cellular respiration are opposite processes.
Photosynthesis produces glucose and oxygen, while cellular respiration consumes them.

Energy Source

The primary energy source for photosynthesis is sunlight or solar energy.

Plant Pigments

Key pigments involved in photosynthesis include chlorophyll a, chlorophyll b, and carotenoids.
These pigments aid in the absorption of light energy.

Appearance of Chlorophyll

Chlorophyll reflects green light while absorbing red and blue light, leading to its green appearance.

Wavelength and Energy Relationship

As wavelength increases, the energy content of light decreases; longer wavelengths have less energy.

Effective Light Colors for Photosynthesis

Red and blue/violet light are most effective for photosynthesis.
These colors are absorbed efficiently by chlorophyll pigments.

Location of Photosynthesis

Photosynthesis occurs in chloroplasts, specialized organelles in plant cells.

Stages of Photosynthesis

Two main stages: light reactions (light-dependent) and the Calvin cycle (light-independent).

Chloroplast Compartments

Light reactions take place in the thylakoid membrane.
Calvin cycle occurs in the stroma of the chloroplast.

Water in Light Reactions

Water molecules are split, and the electrons generated go to photosystem II.

Waste Product of Light Reactions

Oxygen is produced as a waste product during the light reactions.

Products Utilized in the Calvin Cycle

The light reactions generate NADPH and ATP, which are utilized in the Calvin cycle.

Carbon Dioxide in the Calvin Cycle

Carbon dioxide is transformed into sugar (glucose) in the Calvin cycle.

Sugar Storage

Cells store the glucose produced in photosynthesis as starch for energy reserves.

Parts of the Calvin Cycle

Three stages: CO2 fixation, CO2 reduction, and regeneration of RuBP.

Products of Light Reactions

Light reactions generate ATP and NADPH, essential for energy transfer.

Electron Flow in Light Reactions

Energized electrons move through the electron transport chain, pumping protons (H+) and synthesizing ATP from ADP.

Calvin Cycle Overview

Carbon dioxide binds to a 5-carbon molecule, resulting in a 6-carbon compound.
This process, catalyzed by Rubisco, requires NADPH and ATP.
The 6-carbon structure is converted into carbohydrates and regenerates RuBP.

Photosystems in Light Reactions

Two photosystems are involved: Photosystem I (PS-I) and Photosystem II (PS-II).

Function of Photosystem I

PS-I captures light energy and releases an electron, which contributes to NADPH production.

Function of Photosystem II

PS-II captures light energy, initiating the process of photosynthesis.

Definition of Photosynthesis

Photosynthesis is the process of capturing solar energy and converting it into chemical energy, stored in carbohydrates.

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Description

This quiz focuses on the fundamental concepts of photosynthesis, including the overall reaction, comparison with cellular respiration, energy sources, and the role of plant pigments. Perfect for students looking to reinforce their understanding of this essential biological process.