Biology Chapter 7 Study Guide

Questions and Answers

What are autotrophs?

An organism that produces complex organic compounds from simple substances using energy from light or inorganic chemical reactions.

What are heterotrophs?

An organism that cannot fix carbon and uses organic carbon for growth.

What are producers?

Any green plant or various microorganisms that can convert light energy or chemical energy into organic matter.

What are photoautotrophs?

An organism that obtains energy from sunlight to convert inorganic materials into organic materials. Signup and view all the answers

Describe the structure of chloroplasts and their location in a leaf.

Chloroplasts are concentrated in the mesophyll cells, and thylakoid membranes house the machinery that converts light energy to chemical energy. Signup and view all the answers

How do plants produce oxygen during photosynthesis?

Oxygen is produced during photosynthesis as a byproduct when water is split and isotopes traced the source as H2O. Signup and view all the answers

What are the reactants and products of the light reactions in photosynthesis?

Reactants: H2O, ADP, NADP+. Products: Oxygen, ATP, NADPH. Signup and view all the answers

How do photosystems capture solar energy?

Chlorophyll captures photons and transfers energy through electron-transfer components to produce ATP. Signup and view all the answers

Explain how the electron transport chain and chemiosmosis generate ATP and NADPH.

ATP and NADPH are produced through chemiosmosis, which pumps protons to create a proton gradient. Signup and view all the answers

Describe the reactants and products of the Calvin cycle.

Reactants: CO2, ATP, NADPH. Products: G3P (which can be converted to glucose). Signup and view all the answers

How do C3, C4, and CAM plants obtain and use carbon dioxide?

C3 plants use the Calvin cycle directly, C4 plants have a modified pathway to minimize photorespiration, and CAM plants fix CO2 at night. Signup and view all the answers

Describe the greenhouse effect.

The greenhouse effect is a natural process that warms the Earth by trapping infrared radiation from the sun. Signup and view all the answers

Study Notes

Autotrophs and Heterotrophs

Autotrophs produce complex organic compounds using simple substances, energy is derived from light (photosynthesis) or inorganic reactions (chemosynthesis).
Heterotrophs cannot fix carbon and rely on organic carbon for growth.

Producers and Photoautotrophs

Producers include green plants and various microorganisms that convert light or chemical energy into organic matter.
Photoautotrophs, such as plants, use sunlight to transform inorganic materials into organic compounds for cellular functions.

Structure and Function of Chloroplasts

Chloroplasts are mainly found in the mesophyll cells of leaves, where they are essential for photosynthesis.
Thylakoid membranes within chloroplasts are the sites where light energy is converted to chemical energy.

Oxygen Production in Photosynthesis

Isotope tracing revealed that the source of oxygen produced during photosynthesis is water (H2O).

Light Reactions of Photosynthesis

Light-dependent reactions require water (H2O), ADP, and NADP+ as reactants, producing oxygen, ATP, and NADPH.
Light-independent reactions (Calvin Cycle) utilize ATP, NADPH, and carbon dioxide to produce glucose.

Photosystem Functionality

Chlorophyll captures sunlight, facilitating the conversion of light energy into chemical energy through a series of electron transfer reactions.
The process leads to the splitting of water molecules, resulting in oxygen as a byproduct.

ATP Generation in Light Reactions

ATP and NADPH are generated through electron transport chains and chemiosmosis, which create a proton gradient that drives ATP synthesis.

Calvin Cycle Overview

The Calvin Cycle operates in the chloroplast stroma, fixing carbon dioxide into glucose.
The cycle requires ATP and NADPH produced by light reactions, converting CO2 into G3P and regenerating RuBP for continuous operation.

Carbon Fixation Mechanisms

C3 plants directly fix carbon dioxide using the Calvin Cycle.
C4 plants utilize a modified pathway to efficiently capture carbon at higher temperatures and light intensities.
CAM plants fix carbon during the night to minimize water loss; examples include cacti and succulents.

Greenhouse Effect and Climate Change

The greenhouse effect is a natural phenomenon that warms the Earth by trapping infrared radiation from the sun.
Increased greenhouse gas emissions from human activities strengthen this effect, leading to global warming, impacting plant growth and ecosystems.

Description

Dive into the essential concepts of Chapter 7 in Biology with this study guide. Explore key terms like autotrophs, heterotrophs, and producers, along with their definitions and roles in the ecosystem. Perfect for preparing for exams and enhancing your understanding of biological classification.