Biology Chapter 8 Study Guide

Questions and Answers

What can plants and other living things use to make food?

Light energy from the sun

What are organisms that use light energy from the sun to make food called?

Autotrophs

What are heterotrophs?

Organisms that get energy from their food

What is adenosine triphosphate?

ATP, a compound that cells use to store and release energy Signup and view all the answers

What kind of activities do cells carry out with energy from ATP?

Active transport, synthesis of proteins and nucleic acids, and responses to chemical signals at the cell surface Signup and view all the answers

What is ATP made of?

Adenine, a 5-carbon sugar called ribose, and three phosphate groups Signup and view all the answers

What is adenosine diphosphate?

A compound similar to ATP Signup and view all the answers

What is the structure of ADP?

Two phosphate groups Signup and view all the answers

What can cells do when energy is available?

Store small amounts of energy by adding a phosphate group to ADP to form ATP (ADP + P --> ATP) Signup and view all the answers

How is energy stored in ATP released?

By breaking the bond between the second and third phosphate group (ATP --> ADP + P) Signup and view all the answers

What did van Helmont discover?

Found that plants gain most of their mass from water Signup and view all the answers

What did Priestly discover?

Found that plants release oxygen Signup and view all the answers

What did Ingenhousz discover?

Found that plants need sunlight to produce oxygen Signup and view all the answers

What is photosynthesis?

In the presence of light, plants change carbon dioxide into carbohydrates and give off oxygen Signup and view all the answers

What is the equation for photosynthesis?

6CO2 + 6H2O --(light)--> C6H12O6 + 6O2 Signup and view all the answers

What does photosynthesis use the sun's energy to do?

It uses the energy of sunlight to convert water and carbon dioxide into high-energy sugars and oxygen Signup and view all the answers

Where do plants get the carbon dioxide needed for photosynthesis?

From the air and from the water in which they grow Signup and view all the answers

What do plants use the sugars produced during photosynthesis for?

To make complex carbohydrates like starches Signup and view all the answers

What does photosynthesis require?

Light and chlorophyll Signup and view all the answers

What do plants use to gather the sun's energy?

Light-absorbing molecules called pigments Signup and view all the answers

What is the main pigment in plants?

Chlorophyll Signup and view all the answers

A compound that absorbs light also absorbs what?

The light's energy Signup and view all the answers

What happens when chlorophyll absorbs sunlight?

Much of the light energy is sent directly to electrons in the chlorophyll molecules, which in turn raises the energy levels of the electrons Signup and view all the answers

What is the visible spectrum made of?

Wavelengths of light you can see, contains all colors Signup and view all the answers

What does chlorophyll absorb and why do plants look green?

Chlorophyll absorbs light in the blue-violet and red regions of the visible spectrum well, and plants look green because chlorophyll does not absorb the green region of the spectrum well, so plants' leaves reflect the green light. Signup and view all the answers

Where does photosynthesis take place?

Inside the chloroplasts Signup and view all the answers

What are the saclike photosynthetic membranes that chloroplasts have?

Thylakoids Signup and view all the answers

What do proteins in the thylakoids do?

They organize chlorophyll and other pigments into clusters known as photosystems Signup and view all the answers

What are photosystems?

The light-collecting units of chlorophyll Signup and view all the answers

How do electrons gain energy?

When sunlight excites electrons in chlorophyll Signup and view all the answers

Describe the transfer of energy from electrons.

The electron transfers its energy to another molecule, the energy continues to move from molecule to molecule until it gets to the end of the chain. Signup and view all the answers

What two parts do the reactions of photosynthesis occur?

Light-dependent reactions and light-independent reactions Signup and view all the answers

What are light-dependent reactions?

They produce oxygen gas and convert ADP and NADP+ into ATP and NADPH; need light Signup and view all the answers

Where do light-dependent reactions occur?

In thylakoid membranes Signup and view all the answers

What are the four processes of light-dependent reactions?

Light absorption, oxygen production, electron transport, and ATP formation Signup and view all the answers

What do light-dependent reactions use, and what do they produce?

Use: water, ADP, and NADP+; Produce: oxygen, ATP, and NADPH Signup and view all the answers

What is the Calvin Cycle?

Light-independent reactions, DO NOT need light, uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars Signup and view all the answers

Where does the Calvin Cycle take place?

In the stroma of chloroplasts Signup and view all the answers

What does the Calvin Cycle use in its reactions?

Carbon dioxide Signup and view all the answers

What does the Calvin Cycle work steadily to do as photosynthesis proceeds?

To remove carbon dioxide from the atmosphere and turn out energy-rich sugars Signup and view all the answers

How many carbon dioxide molecules are needed to make a single 6-carbon sugar?

Six Signup and view all the answers

What factors affect the rate of photosynthesis?

Water availability, temperature, and the intensity of light Signup and view all the answers

The Calvin Cycle is another name for?

Light-independent reactions Signup and view all the answers

True or false: Plants gather the sun's energy with light-absorbing energy molecules called pigments.

True Signup and view all the answers

Energy from ATP is released when?

A phosphate group is removed Signup and view all the answers

Organisms that cannot make their own food and must obtain energy from the food they eat are called?

Heterotrophs Signup and view all the answers

Plants take in the sun's energy by absorbing?

Sunlight Signup and view all the answers

Explain how heterotrophs get their energy from the sun even though they can't make their own food.

Through eating autotrophs Signup and view all the answers

What gives ATP and when is energy released from it?

ATP: energy currency of the cell, made of adenosine, ribose, and triphosphate; releases energy when it releases a phosphate Signup and view all the answers

What are the three parts of an ATP molecule?

Adenosine, ribose, and triphosphate Signup and view all the answers

Study Notes

Photosynthesis Overview

Plants use light energy from the sun to create food through the process of photosynthesis.
Two types of organisms: autotrophs (produce their food) and heterotrophs (consume other organisms for energy).

Key Compounds and Energy

Adenosine triphosphate (ATP) serves as the primary energy carrier in cells, allowing energy for varied functions like active transport and protein synthesis.
ATP is composed of adenine, ribose, and three phosphate groups; energy is released by breaking the bond between the second and third phosphate.
Adenosine diphosphate (ADP) contains two phosphate groups and can be converted back into ATP by adding a phosphate group.

Historical Discoveries

Van Helmont discovered that plant mass primarily comes from water.
Priestly determined that plants release oxygen during photosynthesis.
Ingenhousz established that sunlight is necessary for plants to produce oxygen.

Photosynthesis Process

Photosynthesis transforms carbon dioxide and water into carbohydrates, releasing oxygen as a byproduct.
General equation: 6CO2 + 6H2O —(light)→ C6H12O6 + 6O2.

Light and Chlorophyll

Photosynthesis requires sunlight and chlorophyll, the main pigment in plants that absorbs light energy.
Chlorophyll absorbs blue-violet and red light while reflecting green light, making plants appear green.
Photosynthesis occurs mainly in chloroplasts, specifically in thylakoids that house chlorophyll.

Reactions of Photosynthesis

Comprised of two main stages: light-dependent reactions (need light) and light-independent reactions (Calvin Cycle).
Light-dependent reactions take place in thylakoid membranes and generate oxygen, ATP, and NADPH using water and light energy.
Key processes: light absorption, oxygen production, electron transport, and ATP formation.

The Calvin Cycle

The Calvin Cycle, occurring in the stroma of chloroplasts, does not require light and uses ATP and NADPH to synthesize high-energy sugars from carbon dioxide.
For producing a single 6-carbon sugar, six carbon dioxide molecules are required.
Operates continuously during photosynthesis, utilizing available carbon dioxide from the atmosphere.

Factors Influencing Photosynthesis

Rate of photosynthesis can be affected by the availability of water, carbon dioxide, temperature, and light intensity.

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Description

Review the essential concepts of Biology Chapter 8 with this study guide. This quiz covers important terminology like autotrophs, heterotrophs, and ATP. Test your understanding of how living things produce and use energy.