Mastering Biology Chapter 10 Flashcards

Questions and Answers

The most important role of pigments in photosynthesis is to __________.

capture light energy

Which structure(s) on a leaf allow(s) carbon dioxide and oxygen to enter and exit by diffusion?

Stomata

G3P is used in which of the following processes?

Synthesis of amino acids

Synthesis of glucose

All of the listed processes can use G3P. (correct)

Synthesis of fatty acids

Why do the reactions of the Calvin cycle usually not occur at night?

The Calvin cycle requires products only produced when the photosystems are illuminated. Signup and view all the answers

During which process is molecular oxygen produced in photosynthesis?

The light reactions by linear electron flow Signup and view all the answers

What happens during the carbon fixation phase of the Calvin cycle?

The Calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five-carbon sugar named ribulose bisphosphate. Signup and view all the answers

Which of the following statements is a correct distinction between autotrophs and heterotrophs?

Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. Signup and view all the answers

The oxygen produced by photosynthesis comes from __________.

water Signup and view all the answers

What has the plant been using for an energy source while in the dark?

The plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules. Signup and view all the answers

Why could the Calvin cycle not occur without the light reactions?

ATP and NADPH produced in the light reactions provide the energy for the production of sugars in the Calvin cycle. Signup and view all the answers

Which of the following processes occurs during the second phase, the reduction phase, of the Calvin cycle?

G3P production Signup and view all the answers

In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.

carbon dioxide Signup and view all the answers

When chloroplast pigments absorb light, __________.

their electrons become excited Signup and view all the answers

Why are most autotrophs referred to as the producers of the biosphere?

They are the ultimate sources of organic compounds for all nonautotrophic organisms. Signup and view all the answers

Both mitochondria and chloroplasts __________.

use chemiosmosis to produce ATP Signup and view all the answers

Where do the electrons entering photosystem II come from?

water Signup and view all the answers

Chlorophyll molecules are in which part of the chloroplast?

Thylakoid membranes Signup and view all the answers

The light reactions of photosynthesis use chemiosmosis to produce ATP that will be used in the Calvin cycle. The electrochemical gradient that drives this chemiosmosis is formed across which structure(s)?

Thylakoid membrane Signup and view all the answers

The light reactions of photosynthesis supply the Calvin cycle with __________.

ATP and NADPH Signup and view all the answers

The energy used to produce ATP in the light reactions of photosynthesis comes from __________.

movement of H+ through a membrane Signup and view all the answers

What property of the pigment chlorophyll makes it appear green?

Chlorophyll absorbs all of the visible spectrum of light except green, which it reflects. Signup and view all the answers

Of the following, which occurs during the Calvin cycle?

CO2 is reduced. Signup and view all the answers

In photosynthesis, what molecule is oxidized and what molecule is reduced?

Water = oxidized Carbon dioxide = reduced Signup and view all the answers

Where does the Calvin cycle of photosynthesis occur?

Stroma Signup and view all the answers

A photosystem consists of which of the following structures?

All of the listed structures are parts of a photosystem. Signup and view all the answers

How does carbon dioxide enter the leaf?

Through the stomata Signup and view all the answers

Which of the following statements correctly describes the difference in carbon fixation between C3 and C4 plants?

The first product of carbon fixation in C4 plants is a four-carbon compound instead of a three-carbon compound. Signup and view all the answers

The light reactions of photosynthesis occur in the __________.

thylakoids Signup and view all the answers

In the light reactions of photosynthesis, ATP is produced by photophosphorylation. Which of the listed processes is most similar to photophosphorylation?

Oxidative phosphorylation in cellular respiration Signup and view all the answers

The light reactions of photosynthesis generate high-energy electrons, which end up in . The light reactions also produce and __.

NADPH; ATP; oxygen Signup and view all the answers

Study Notes

Photosynthesis Overview

Pigments in photosynthesis capture light energy for the process.
Stomata are the structures that allow carbon dioxide and oxygen to diffuse in and out of leaves.
G3P (glyceraldehyde-3-phosphate) is utilized in various metabolic processes.
The Calvin cycle, though not directly light-dependent, relies on products from illuminated photosystems.

Light Reactions and Electron Flow

Molecular oxygen is produced during the light reactions via linear electron flow.
Carbon fixation in the Calvin cycle involves attaching CO2 to ribulose bisphosphate, a five-carbon sugar.
Oxygen produced in photosynthesis originates from water molecules.

Autotrophs vs. Heterotrophs

Autotrophs can produce organic compounds from inorganic sources, while heterotrophs cannot.
Most autotrophs are considered producers as they provide organic compounds for nonautotrophic organisms.

Calvin Cycle Dependency

The Calvin cycle requires ATP and NADPH generated during light reactions for sugar production.
G3P production occurs during the reduction phase of the Calvin cycle.
Plants convert carbon dioxide into sugars through the Calvin cycle.

Chloroplast Functionality

Chlorophyll pigments absorb light, exciting electrons in the process.
Both chloroplasts and mitochondria utilize chemiosmosis to generate ATP.
The light reactions generate ATP and NADPH used in the Calvin cycle, driven by H+ movement across membranes.

Photosynthesis Mechanics

Chlorophyll reflects green light, giving it a green appearance.
Water is oxidized while carbon dioxide is reduced during photosynthesis.
The Calvin cycle occurs in the stroma of chloroplasts.

Photosystem Composition

A photosystem consists of various components, contributing to the photosynthesis process.
CO2 enters leaves through stomata, facilitating gas exchange necessary for photosynthesis.

C3 vs. C4 Plants

C4 plants initiate carbon fixation with a four-carbon compound, unlike C3 plants, which start with a three-carbon compound.

Light Reactions Specifics

Light reactions take place in the thylakoids of chloroplasts, generating high-energy electrons.
Photophosphorylation in light reactions is analogous to oxidative phosphorylation in cellular respiration.

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Test your knowledge on Chapter 10 of Mastering Biology with these flashcards. This chapter focuses on essential concepts of photosynthesis, including the roles of pigments and gas exchange in leaves. Perfect for reinforcing your learning and preparing for exams!