Biology 1001 - Chapter 7 Quiz

Questions and Answers

Which step of the Calvin cycle requires no extra energy?

Regeneration of RuBP

Generation of NADPH

Chemiosmosis of ATP

Carbon fixation by rubisco (correct)

Splitting of water

Generation of G3P

Carbon fixation involves the addition of carbon dioxide to _____.

RuBP

After 3-PGA is phosphorylated, it receives energized electrons from _____.

NADPH

How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?

6 Signup and view all the answers

In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?

3 Signup and view all the answers

Which of the following leaf types would be the most efficient at absorbing sunlight?

Large, broad leaves Signup and view all the answers

Which of the following structures allows for gas exchange between the tissues of a leaf and the atmosphere?

Stomata Signup and view all the answers

Guard cells open during the day to allow gases to flow through the stomata.

True Signup and view all the answers

Your teacher wants you to mix up the enzymes and substrates necessary to perform the Calvin cycle in a test tube. What components do you need to put into the test tube?

ATP, NADPH, and an extract from chloroplast stroma Signup and view all the answers

What is the purpose of a cuticle on a leaf?

To prevent water loss Signup and view all the answers

Which of the following equations represents photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2 Signup and view all the answers

In which of the following organelles does photosynthesis take place?

Chloroplast Signup and view all the answers

What connects the two photosystems in the light reactions?

An electron transport chain Signup and view all the answers

What two molecules are produced by the light reactions and used to power the Calvin cycle?

ATP and NADPH Signup and view all the answers

What provides electrons for the light reactions?

H2O Signup and view all the answers

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?

Carbon dioxide (CO2) Signup and view all the answers

What transports electrons from the light reactions to the Calvin cycle?

NADPH Signup and view all the answers

The light reactions take place in the _ and the Calvin cycle takes place in the _.

thylakoids; stroma Signup and view all the answers

Where is the most energy used in the Calvin cycle?

In the conversion of PGA to G3P Signup and view all the answers

How is the energy present in the electrons passed through electron transport chain II first used?

The energy is used to pump hydrogen ions into the thylakoid space. Signup and view all the answers

The light reactions of photosynthesis use _ and produce _.

Water...NADPH Signup and view all the answers

Why do plant leaves appear green?

The chlorophyll in leaves reflects green light. Signup and view all the answers

In what order do the steps of the light reactions occur?

Photosystem II, electron transport chain II, photosystem I, electron transport chain I Signup and view all the answers

How many molecules of carbon are fixed in each round of the Calvin cycle?

3 Signup and view all the answers

Chlorophyll a can absorb well in both the violet/blue end of the spectrum and the orange/red end of the spectrum. Why then is ultraviolet light considered a very good source of energy for photosynthesis?

Ultraviolet light has more energy per photon. Signup and view all the answers

Which cell type in a leaf performs the most photosynthesis?

Mesophyll Signup and view all the answers

Where are the electrons used in photosystem II found at the very end of the light reactions?

In NADPH Signup and view all the answers

_ has a longer wavelength than _.

Red...green Signup and view all the answers

When discussing photosynthesis, some people mistakenly talk about the light reactions and the dark reactions. Why is 'dark reactions' an inaccurate name for the Calvin cycle?

This implies that the Calvin cycle occurs only at night. Signup and view all the answers

You place a plant in a transparent box made of greenish-yellow plastic. How does this affect photosynthesis for the plant?

None of the plant pigments will be able to absorb the light. Signup and view all the answers

Which of the following summarizes photosystem I and the electron transport chain I in terms of exergonic and endergonic reactions?

The energy of sunlight is used to power the endergonic reaction of combining NADP+ with H+. Signup and view all the answers

Why do plants produce O2?

Because O2 is produced as a by-product when the plant creates H+ ions and free electrons from water. Signup and view all the answers

How is O2 involved in photosynthesis?

O2 is a product of the light reactions. Signup and view all the answers

Which of the following is most similar to the Calvin cycle?

A robot assembling a car. Signup and view all the answers

Which of the following describes the steps of photosystem II and electron transport chain II in terms of energy conversions?

Kinetic energy from sunlight is converted into potential energy in an electron. This then is converted to kinetic energy by pumping hydrogen ions. The kinetic energy of the ions flowing back through the membrane is converted to potential energy in ATP. Signup and view all the answers

Why do chloroplasts make energy carriers during the light reactions?

To provide energy for the synthesis of sugar. Signup and view all the answers

Study Notes

Calvin Cycle Key Processes

Carbon fixation by Rubisco occurs without additional energy expenditure, adding CO2 to RuBP.
Generation of G3P requires reduction of phosphorylated 3-PGA using electrons from NADPH.
To synthesize one glucose molecule, six carbon dioxide molecules must be added.
The regeneration of RuBP from five G3P molecules requires three ATP molecules.

Photosynthesis Overview

Photosynthesis is represented by the equation: 6CO2 + 6H2O → C6H12O6 + 6O2.
It takes place in chloroplasts, specifically within the thylakoid membranes for light reactions and the stroma for the Calvin cycle.

Light Reactions Components

The light reactions convert water into oxygen and produce ATP and NADPH for the Calvin cycle.
An electron transport chain connects the two photosystems involved in capturing light energy.

Leaf Anatomy and Function

Large, broad leaves are optimal for sunlight absorption due to their extensive surface area.
Stomata enable gas exchange, controlled by guard cells which open during daylight to facilitate this exchange.

Light Absorption and Energy

Chlorophyll primarily reflects green light, which makes leaves appear green while absorbing blue and red wavelengths.
Ultraviolet light provides more energy per photon, enhancing its role in photosynthesis.

Energy Dynamics in Photosynthesis

The highest energy usage in the Calvin cycle occurs during the conversion of PGA to G3P.
ATP generated in the light reactions is crucial for driving the endergonic reactions of sugar synthesis in the Calvin cycle.

Photosystems and Electron Transport

Photosystem II initiates the light reactions, leading to the generation of NADPH by extracting electrons from water.
Electrons move through an electron transport chain, ultimately contributing to the conversion of light energy into chemical energy.

Roles of Various Molecules

NADPH and ATP produced in the light reactions fuel the Calvin cycle by providing necessary energy and reducing power.
CO2 serves as the carbon source integrated into sugar molecules during photosynthesis.

Importance of Photosynthesis

Oxygen produced during photosynthesis is a by-product of splitting water molecules, supporting aerobic life.
The mesophyll cells in leaves are primarily responsible for photosynthesis due to their abundant chloroplasts.

Misconceptions and Clarifications

The term "dark reactions" is misleading as the Calvin cycle can occur in the presence of light.
A transparent box made of greenish-yellow plastic would block necessary wavelengths, halting photosynthesis.

Energy Conversion Processes

Energy from sunlight is converted into potential energy in electrons, subsequently transforming into kinetic energy as hydrogen ions are pumped, contributing to ATP formation.

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Description

Test your knowledge on Chapter 7 of Biology 1001 with this quiz focused on the Calvin cycle. Explore key concepts like carbon fixation and the roles of various molecules in the process. Perfect for students looking to reinforce their understanding of plant biology.