UNIT 1: METABOLIC PROCESSES
Chapter 3: Photosynthesis
Explore an Issue – Take a Stand: Can Plants Cure Sick
Statement: Plants may be used as an effective treatment for sick building
Conduct library and/or Internet research to investigate:
(i) the indicators of SBS;
(ii) the possible causes of SBS;
(iii) procedures used to identify SBS;
(iv) the effectiveness of the use of plants in the treatment of SBS;
(v) the types of plants that some have found to be useful in the treatment
(a) As a plant biologist and consultant to the Canadian
Labour Congress, you will be attending an upcoming World Health Organization
(WHO) conference on Environmental Pollution in the Workplace. For
the conference, you must prepare a brochure if slide presentation
on the effectiveness of the use of plants in the treatment of SBS.
Building Syndrome Links
McGill University has assembled a list of Sick Building Syndrome Links
that include factsheets and symptom descriptions from around the world.
This well laid out site from the National Safety Council, USA, defines
Sick Building Syndrome and how it is recognized. Some causes and some
solutions are also addressed.
Building Syndrome Factsheet
Ohio State University’s Sick Building Syndrome Factsheet explains
how it has come to be that some buildings make some of us ill. The
site details steps taken in identifying a sick building, and offers
practical suggestions on what to do if you are affected.
about Sick Building Syndrome
Articles about Sick Building Syndrome provides links to press articles
about a large range of topics on indoor pollution and pollutants,
including a site that discusses plants that filter air.
Section 3.1 questions
10. Carnivorous plants like the Venus fly-trap (Dionaea
species) and the pitcher plant (Cephalotus species) obtain
nutrients by digesting small insects. Conduct library and/or Internet
research to determine:
a. whether these plants are autotrophs or heterotrophs;
b. why these plants digest animals.
Carnivorous Plant FAQ
The Carnivorous Plant FAQ site is maintained by the International
Carnivorous Plant Society. Carnivorous plant ecology, gardening, conservation
and taxonomy are organized as a large list of interesting questions.
The site has many great photos.
Section 3.1 questions
11. Many products containing chlorophyll are sold in pharmacies
and health food stores.
a. Identify and list three different products containing
chlorophyll you can buy at a pharmacy or other store.
b. Describe the suggested uses for each of these products.
c. Conduct library and/or Internet research to determine
the characteristics of chlorophyll that make it suitable for use in
these products. If you do not find suitable reasons, form your own
The producers of the Body Mint pill claim that if you take one pill
a day all of your body odour will be reduced from head to toe. Any
guess what the main ingredient is?
These ‘infomercial’ Web pages explain the health benefits
of Chlorella, the “richest natural food source of chlorophyll.”
It also includes a link to a brief description of chlorophyll’s
Wheatgrass Juice is marketed on this Web site as a healing agent.
Includes a brief, but long, list of its medical benefits that are
present, in part, because of its high chlorophyll content.
The Nature’s Sunshine herbal company explains the believed health
benefits of Chlorophyll and outlines the ailments that are best aided
by drinking it.
Section 3.2 questions
12. Conduct library and/or Internet research to answer the following
questions regarding leaves:
a. What are bracts?
b. What colour changes do bracts of poinsettia (Euphorbia
pulcherrima) plants undergo? At what time of year does this change
c. Describe the history of the poinsettia as a popular Christmas
This gardening info site provides basic information on the Poinsettia’s
worldwide role at Christmas. Included is some folklore and other interesting
tidbits about production and local traditions.
Pretty and Popular
Poinsettia: Pretty and Popular is an electronic version of a newspaper
article from Trinadad, where the plant is grown locally. It contains
some history of the plant's discovery and its ornamental use.
your Holiday Poinsettia Happy
From @discovery.ca, this article provides lots of information on Keeping
your Holiday Poinsettia Happy - this includes the special conditions
required for flowering.
Science and Myths of a Christmas Flower
The Science and Myths of a Christmas Flower, covers the science of
breeding poinsettias and explains the difference between the plant’s
bracts and flowers. From @discovery.ca, this article also answers
the question, is the poinsettia poisonous?
it or Throw it Away?
Nurture it or Throw it Away? - what to do with your poinsettia in
January. This article from Utah State University covers the history
of the plant’s popularity, its growing conditions, and explains
why the bracts are so colourful.
The Poinsettia Pages is a collection of interesting facts and legends
along with info on how to choose one a poinsettia, practical tips
for care, and more poinsettia links. This site comes from the University
Care and Selection
Poinsettia Care and Selection is a gardener's guide to the do’s
and don’ts of poinsetta care, plus tips on choosing a good one,
and how to encourage reblooming year after year.
Section 3.2 questions
13. Many lightbulb manufacturers produce fluorescent tubes labelled
as “growlights” that they claim emit “full-spectrum
light that imitates sunlight.” Conduct library and/or Internet
research to determine whether fluorescent tubes labelled as “growlights”
are more effective sources of artificial light for growing plants indoors
than tubes without this label.
This essay provides excellent coverage of the various Artificial Lighting
options for growing aquarium plants. There is lots of info on what products
are available and an explanation of the rationale behind the use of
each type of light.
plants: Artificial Light
House plants: Artificial Light describes the different types of artificial
light, what works and what doesn’t, and why. This easy-to-understand
site from the Alberta government explains what factors are important
in choosing lighting.
Section 3.3 Questions
16. Recent advances in remote sensing have made detection of
plant health possible on a large scale. Using satellite images, spectral
analysis, and other sensing technologies, farmers may now detect problems
in large fields of crops before they are identified at ground level.
Conduct library and/or Internet research about spectral remote sensing
as applied to plants to answer the following questions:
a. What characteristic(s) of plants do remote sensing systems
detect to provide information regarding a crop’s overall health?
b. Why would a farmer spend money to have crops tested by
these methods? What advantages are gained by the procedure?
Sensing and Vegetation Classification
Remote Sensing and Vegetation Classification gives details of the
varying plant properties that affect imaging, with explanations of
the scientific terms used. From the University of Calgary.
Q: How can a farmer monitor the health of his crops without going
into his field? A: Remote Sensing. This NASA site has several pages
with good explanations on how remote sensing works.
Agriculture: Crop Yield
Precision Agriculture: Crop Yield describes research being conducted
in association with NASA. It also details some of the benefits that
the use of remote sensing may have for farmers.
Applications of Remote Sensing
Potential Applications of Remote Sensing provides a good, but brief,
summary of the main factors that have determined the usefulness of
remote sensing in crop management. More info is available in a PDF
Section 3.4 Questions
11. Conduct library and/or Internet research to answer the following
questions regarding weeds:
a. What is a weed?
b. Of the ten most aggressive weeds in the world, eight
of them are C4 plants. Identify them and name three common North American
C4 pants that are classified as weeds.
c. Some of the world’s most productive crops are C4
plants. Identify and name three important North American crops that
are C4 plants.
d. How will escalation of the greenhouse effect (a result
of increased atmospheric carbon dioxide concentrations) affect the
competition between C3 and C4 plants in terms of crop productivity
and weed control?
Center for the Study of Carbon Dioxide
The Center for the Study of Carbon Dioxide’s site provides a
definition of C4 plants, with explanations of difficult terms. It
also examines some of the research on the effect of greenhouse gases
on C4 plants.
Colorado State University’s Weeds page features descriptions
and photos of the state’s most common weeds and indicates the
biological characteristics that make them difficult to kill.
of Increasing CO2 on C4 Crops and Weeds
This article briefly describes the results of an experiment that compared
the Influence of Increasing CO2 on C4 Crops and Weeds. It also states
the expected differences of increased CO2 on C4 versus C3 plants.
From the US Department of Agriculture.
Helps Weeds Take over Prairies
This article from ScienceNewsOnline magazine is about how greenhouse
gases are thought to affect C4 and C3 plants on Minnesota prairie.
In a nutshell, Pollution Helps Weeds Take over Prairies.
and Their Control
What is a weed? What are the most common species in the world? Which
ones are C4 plants? These questions and more are answered in Weeds
and Their Control, part of an online text for a course given by the
University of Hawaii.
of Elevated CO2 on Wetlands
This article discusses the results of some studies performed to date
that examine the Effects of Elevated CO2 on Wetlands and, in particular,
compare the response of C3 plants to C4 plants. The site is published
by the Smithsonian Environmental Research Center.
Rice from C3 to C4
Dr. Ku, a professor at Washington State University, wrote this news
release about his work on rice, a globally important crop. After explaining
the difference between C3 and C4 plants, Dr. Ku outlines his progress
in Converting Rice from C3 to C4.
The Ontario Ministry of Agriculture and Food’s Web site has
factsheets on a number of Ontario’s Weeds, as well as a weed
identification quiz and a good assortment of further Canadian weed
Explore an Issue – Take a Stand: Tropical Rain-Forest
Depletion: Is There Cause for Concern?
Statement: The governments of developing countries have the right to
make room for agriculture and industrialization by clearing tropical
- Add your own ideas to the above-mentioned points.
- Find information to help you learn more about the issue.
- In a group, discuss the ideas.
EarthAction, an environmental group, reports on two recent successful
campaigns to prevent governments from developing rainforest lands.
American Rainforest Update
Latin American Rainforest Update is a collection of four news stories
from 1995 discussing development and conservation of forests in
several Central American countries.
Controversy over Logging is a 2002 article detailing the public’s
response to the Australian government’s promotion of logging
in Papua New Guinea’s rainforests.
Section 3.6 questions
The diagram on the Unit 1 opening pages is part of a much larger
metabolic pathway chart that outlines almost all known metabolic reactions.
Conduct Internet research to see the complete chart and to answer the
a. Identify all of the major metabolic pathways you have
studied in this unit, and note the interactions among them.
b. Why do scientists produce such charts? How are they useful?
Wow! The complete Metabolic Pathways Chart looks complicated. Hint:
Once students have clicked on a section to zoom in, there is an option
at the bottom of the page for a keyword search. This should help students
locate all the major pathways studied in this unit.
The Biochemical Pathways Chart looks just as complicated as the Metabolic
Pathways Chart, and is arranged the same way.
Chapter 3 Review
20. Conduct library and/or Internet research to study the historical
development of the endosymbiotic theory of the origins of the chloroplast.
Write a brief essay describing the development of the theory and the
social and professional challenges faced by its developer(s). In your
essay, describe rival theories in support of, and against, endosymbiosis.
Endosymbiotic Theory of Chloroplast Evolution
This well-organized site contains diagrams and tables that describe
The Endosymbiotic Theory of Chloroplast Evolution. The professor who
created the site for biology students at Indiana University obviously
supports this theory.
Origin of Chloroplasts
This site presents the notes from a lecture at the University of Minnesota
on The Origin of Chloroplasts, emphasizing the endosymbiotic theory.
It lists the alternate theories and briefly presents evidence for
and against the theory.
This site delivers in-depth coverage of The Endosymbiotic Theory,
with descriptions of prokaryotic and eukaryotic cells, and discussion
of some interesting supporting research. The site is part of a course
offered at Georgia Perimeter College.
Chapter 3 Review
21. Recently, some delegates at international conferences on
global warming have proposed that planting more trees can offset the
carbon dioxide emissions that produce the greenhouse effect and global
a. Identify two major greenhouse gases.
b. Why are these gases called greenhouse gases?
c. What is the greenhouse effect and how does it contribute
to global warming?
d. Write a supported position paper on the contention that
the strategy of planting more trees is an effective alternative to
reducing greenhouse gas emissions.
Global Warming is a colourful site from the United States Environmental
Protection Agency. It includes pages on greenhouse gases as well as
lots of additional information and statistics.
Trees to Reduce Global Warming
Plant Trees to Reduce Global Warming lists some links to a few tree
planting programs and a site with a negative view about tree planting’s
potential. At the bottom of the page is an excellent article from
New Scientist magazine that discusses global plans to plant
trees, and the effectiveness of this measure in combating warming
of Climate Warming
This Web page on the Causes of Climate Warming is part of a site on
Canada’s Arctic, from the University of Guelph. It explains
what greenhouse gases are, and how they relate to global atmospheric
Chapter 3 Review
22. Several biotechnology research companies are experimenting
with the possibility of producing plastic from plants, called “green
plastic.” One procedure turns sugar from corn and other plants
into polylactide (PLA), a plastic similar to polyethylene terephthalate
(PET), which is a petrochemical plastic used in pop bottles and clothing
fibres. Conduct Internet research to complete the following tasks:
a. Describe one or two other green plastics and their potential
b. Compare the costs and benefits of producing green plastics
on a large scale with producing conventional oil-based plastics.
Green are Green Plastics?
This article from a 2000 issue of Scientific American explores
the pros and cons and feasibility of using plants to produce plastics.
It asks, How Green are Green Plastics?
Chapter 3 Review
23. Biomass, plant matter such as trees, grasses, and agricultural
crops, may be used as a solid fuel or converted into liquid or gaseous
forms for the production of electric power, heat, or chemicals for use
in vehicles. Conduct library and/or Internet research to answer the
a. How is electricity generated from biofuel?
b. What proportion of electric power production in Canada
comes from biomass energy? What is the potential for increasing the
amount of electricity produced by biomass?
c. Compare the costs and benefits of producing automobile
fuel from biomass with producing fuel from petroleum.
This essay provides an introduction to Biomass Energy, by the California
Energy Commission. It provides some figures on the current use of biomass
to generate energy in the US and California and discusses some of its
The Growing Energy Resource
Biomass: The Growing Energy Resource is a well-organized site with good
coverage of topics ranging from where the energy comes from, how it’s
used, and biomass farming.
Biomass Energy Works
How Biomass Energy Works is an excellent site that details the main
plant sources of biomass, how biomass is converted into usable forms,
its environmental benefits, and its potential for use.
and Sustainable Development
Ethanol and Sustainable Development: A well thought-out article from
McGill University that examines the feasibility of farming corn for
the purpose of producing ethanol for energy. Suggests an alternative
crop that may prove to be the best source of farmed ethanol.
Alternative Energies: BioMass, from the Environmental Youth Alliance,
provides a brief description of the importance of this energy source
to Canada. A link to a PDF document is well worth viewing for its excellent
descriptions of the methods of converting plant matter into usable forms
of energy, with lots of diagrams and a quick facts page.
Want to know how to make your own Biofuels? According to this site,
it is easy. Includes tons of well-worded information on the methods
of making biofuel, as well as a library of links, a Biofuels News section,
and a searchable archive of items posted on their mailing list.
Biomass into Useful Energy
This site provides a well-organized overview of Converting Biomass into
Useful Energy from the National Energy Renewable Laboratory. The essay
covers the main methods of getting electricity from biomass, describes
the main biofuels, and briefs the benefits and challenges of the biofuel
industry. It also links to further info on biomass energy technology.