Biofuels A lot of energy is locked up in the chemical bonds of molecules made by plants. That energy can fuel consumers, as when an animal cell powers ATP synthesis by aerobic respiration. It can also fuel our cars, which run on energy released by burning biofuels or fossil fuels. Both processes are fundamentally the same: They release energy by breaking the bonds of organic molecules. Both use oxygen to break those bonds, and both produce carbon dioxide. Unlike fossil fuels, biofuels are a renewable source of energy: We can always make more of them simply by growing more plants. Also unlike fossil fuels, biofuels do not contribute to global climate change, because growing plant matter for fuel recycles carbon that is already in the atmosphere. Corn, soy, sugarcane, and other food crops are rich in oils, starches, and sugars that can be easily converted to biofuels. The starch in corn kernels, for example, can be enzymatically broken down to glucose, which is fermented to ethanol by bacteria or yeast. However, growing food crops for biofuel production typically requires a lot of energy (in the form of fossil fuels) and it damages the environment. Making biofuels from other plant matter such as weeds or agricultural waste requires additional steps, because these materials contain a higher proportion of cellulose. Breaking down this tough carbohydrate to its glucose monomers adds cost to the biofuel product. In 2006, David Tilman and his colleagues published the results of a 10-year study comparing the net energy output of various biofuels. The researchers made biofuel from a mixture of native perennial grasses grown without irrigation, fertilizer, pesticides, or herbicides, in sandy soil that was so depleted by intensive agriculture that it had been abandoned. The energy content of this biofuel and the energy it took to produce it were measured and compared with that of biofuels made from food crops (Figure 5.16). The production of which biofuel was most efficient (which had the highest ratio of energy output to energy input)?

EBK BIOLOGY TODAY AND TOMORROW WITHOUT

5th Edition

ISBN: 8220100557187

Author: STARR

Publisher: CENGAGE L

See similar textbooks

Concept explainers

Modes of Nutrition

It is a biological process of providing or obtaining food that is necessary for growth and health. It includes many physiological processes - absorption, ingestion, assimilation, catabolism, excretion, etc. In biology, the science that deals with nutriti…

Videos

Textbook Question

Chapter 5, Problem 3DID

Biofuels

A lot of energy is locked up in the chemical bonds of molecules made by plants. That energy can fuel consumers, as when an animal cell powers ATP synthesis by aerobic respiration. It can also fuel our cars, which run on energy released by burning biofuels or fossil fuels. Both processes are fundamentally the same: They release energy by breaking the bonds of organic molecules. Both use oxygen to break those bonds, and both produce carbon dioxide. Unlike fossil fuels, biofuels are a renewable source of energy: We can always make more of them simply by growing more plants. Also unlike fossil fuels, biofuels do not contribute to global climate change, because growing plant matter for fuel recycles carbon that is already in the atmosphere.

Corn, soy, sugarcane, and other food crops are rich in oils, starches, and sugars that can be easily converted to biofuels. The starch in corn kernels, for example, can be enzymatically broken down to glucose, which is fermented to ethanol by bacteria or yeast. However, growing food crops for biofuel production typically requires a lot of energy (in the form of fossil fuels) and it damages the environment. Making biofuels from other plant matter such as weeds or agricultural waste requires additional steps, because these materials contain a higher proportion of cellulose. Breaking down this tough carbohydrate to its glucose monomers adds cost to the biofuel product.

In 2006, David Tilman and his colleagues published the results of a 10-year study comparing the net energy output of various biofuels. The researchers made biofuel from a mixture of native perennial grasses grown without irrigation, fertilizer, pesticides, or herbicides, in sandy soil that was so depleted by intensive agriculture that it had been abandoned. The energy content of this biofuel and the energy it took to produce it were measured and compared with that of biofuels made from food crops (Figure 5.16).

Chapter 5, Problem 3DID, Biofuels A lot of energy is locked up in the chemical bonds of molecules made by plants. That energy

The production of which biofuel was most efficient (which had the highest ratio of energy output to energy input)?

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Chapter 5, Problem 2DID

Chapter 5, Problem 1SQ

Students have asked these similar questions

Most agricultural societies have developed ways to ferment the sugars in barley, wheat, rice, corn or fruit to produce alcoholic beverages. Historians argue that this was an effective way for farmers to preserve the chemical energy in grains and fruits in a form that would not be eaten by rats or spoiled by bacteria or fungus. Today, a great deal of interest has been regenerated in harvesting this energy in plant sugar as ethanol. Why does a great deal of chemical energy remain in the products of fermentation? Fermentation products like ethanol still contains some C-H bonds that can be reduced. Fermentation products like ethanol still contains some C-O bonds that can be oxidized. Fermentation products like ethanol still contains some C-H bonds that can be oxidized. Fermentation products like ethanol still contains some C-O bonds that can be reduced.

Light is a form of electromagnetic energy. The electromagnetic spectrum is made of various forms of electromagnetic energy, such as x-rays, UV, and microwaves. Visible light is used in photosynthesis. What is visible light? How are energy and wavelength related to each other? The overall goal of photosynthesis is to make harness the energy of the sun and store it in the chemical bonds of “food.” In your own words describe the goals of the two sets of reactions of photosynthesis: a.The goal of the light reactions b. The goal of the Calvin cycle

As the sun shines on Earth, plants use its energy to complete the process of photosynthesis. Energy is transformed during the process into chemical energy in the form of sugars, such as carbohydrates. However, the energy available at top consumers is much less than that produced by autotrophs. Why is this so?

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.

Solution Summary: The author explains that plants and other organic material other than fossils can be used as a source of energy. They compared the net energy output of various biofuels.

Concept explainers

Videos

Want to see the full answer?

Chapter 5 Solutions