CHAPTER 5 Test Your Knowledge
Driving Question 1
What are the photosynthetic organisms on the planet, and why are they so important?
By answering the questions below and studying Infographics 5.3 and 5.6, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
What do algae, cyanobacteria, and plants have in common?
Can animals directly use the energy of sunlight to make their own food (in their own bodies)?
What organelle(s) would a nonphotosynthetic alga need to be able to carry out photosynthesis?
a. mitochondria
b. nucleus
c. chloroplast
d. solar transformer
e. cell membrane
Why do many species of algae appear green?
Compare and contrast the ways photosynthetic algae and animals obtain and use energy.
USE IT
What would happen to humans and other animals if algae, cyanobacteria, and plants were wiped out? Would we only lose a food source (e.g., plants), or would there be other repercussions?
Why would a dark dust cloud that prevented sunlight from reaching Earth’s surface be potentially devastating to animal life?
Driving Question 2
What are the different types of energy, and what transformations of energy do organisms carry out?
By answering the questions below and studying Infographics 5.4 and 5.5, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
The energy of sunlight exists in the form of
a. glucose.
b. photons.
c. gamma rays.
d. ions.
e. particles.
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The energy in a cereal bar is_______energy. The energy of a cyclist pedaling is_______energy.
a. light; chemical
b. potential; chemical
c. chemical; kinetic
d. potential; potential
e. kinetic; potential
Kinetic energy is best described as
a. stored energy.
b. light energy.
c. the energy of movement.
d. heat energy.
e. any of the above, depending on the situation.
USE IT
If you wanted to get the most possible energy from photosynthetic algae, should you eat algae directly or feed algae to a cow and then eat a burger made from that cow? Explain your answer.
Driving Question 3
How do plants and algae convert the energy in sunlight into energyrich organic molecules? (And why can’t humans do this?)
By answering the questions below and studying Infographics 5.7, 5.8, and 5.9, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
Which of the following photon wavelengths contains the greatest amount of energy?
a. violet
b. red
c. green
d. yellow
e. blue
Glucose is a product of photosynthesis. Where do the carbon atoms in glucose come from?
a. starch
b. cow manure
c. molecules in air
d. water
e. soil
Mark each of the following as an input (I) or an output (O) of photosynthesis.
Oxygen____
Carbon dioxide____
Photons____
Glucose____
Water____
Photosynthetic algae are
a. eukaryotic autotrophs.
b. prokaryotic autotrophs.
c. eukaryotic heterotrophs.
d. prokaryotic heterotrophs
USE IT
Global warming is linked to elevated atmospheric carbon dioxide levels. How might this affect photosynthesis? If global warming should cause ocean levels to rise, in turn causing forests to be immersed in water, how would photosynthesis be affected?
Why are energy-rich lipids from algae more useful as a fuel than energy-rich sugars and other carbohydrates produced by photosynthetic organisms like corn and wheat?
Draw a concept map for photosynthesis that includes the following forms of energy and molecules: sunlight; carbon dioxide; glucose (stored chemical energy); water; ATP; heat.
Driving Question 4
How do algal biofuels compare to other fuels in terms of cost, benefits, and sustainability?
By answering the questions below and studying Infographic 5.2 and Table 5.1, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
Which of the following is/are necessary for biofuel production by algae?
a. sunlight
b. sugar
c. CO2
d. soil
e. all of the above
f. a and b
g. a and c
Why are algae considered more valuable for biofuel than plants (such as corn)?
a. because their photosynthetic products are an oil
b. because they are cheaper to grow
c. because they do not require as much CO2
d. because they do not require as much fertilizer
e. all of the above
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USE IT
Many types of algae can divert the sugars they make by photosynthesis into lipids that can be used to make biodiesel. Biodiesel is a promising replacement for fossil fuels. Describe the energy conversions required to make algal lipids for biodiesel and explain why biodiesel might be a more promising fuel than lipids extracted from animals.
What do you think are some of the advantages and disadvantages of growing algae in enclosed tubes or bags compared to growing them in open vats? Make a table listing the advantages and disadvantages of each approach and explain your reasoning.
Many biofuels require arable land for their production. Discuss competing needs for arable lands in the context of human needs for food and fuel, and how algae may alleviate this tension.
MINI CASE
A CEO of a new algal biofuel company is trying to select the site for a production facility. There are three possible options:
The desert of southern New Mexico (sunny, hot, mild winters, nonarable land, remote)
Denver, Colorado (sunny, cold winters, urban area with CO2 emissions from factories and cars)
Central Washington State (sunny, hot, a rich agricultural zone)
Discuss the pros and cons of each site and make a recommendation to the CEO.
BRING IT HOME
Richard Branson has committed his airline, Virgin Atlantic, to using a “green” fuel produced by microbes that use carbon monoxide (CO) from industrial emissions (such as from steel factories) as its carbon and energy source. Through a fermentation process that occurs in a reactor chamber, the microbes convert CO into usable ethanol, a viable green fuel. Consider how this fuel compares and contrasts with algal biofuel and corn ethanol. If this green fuel venture is successful, would Branson’s use of green fuel influence your decision to choose Virgin Atlantic over another air carrier? Why?
INTERPRETING DATA
The United States currently uses approximately 19 million barrels of oil per day. Of this, about half (9.67 million barrels per day) is imported, and the rest is from U.S. sources (offshore drilling or extraction from shale). The table shows production costs estimated for different oil sources. (The actual cost is driven by a variety of market and geopolitical factors, so we will use production costs as a substitute for actual cost.)
a. Using the data for cost per barrel of various oils, calculate the cost to produce oil to meet current U.S. daily use. Assume that approximately half the imports are from the United Arab Emirates (UAE), and the remainder is split equally between imports from Canada and from Brazil.
b. Let’s say that the United States replaces half of its current oil imports from the UAE with domestically produced algal biofuel. What will this do to the cost of production to meet our daily needs?
c. From what you’ve read in this chapter, how are algal biofuel companies working to reduce the costs of algal biofuel?