Saving for a Rainy Day

1
Saving for a Rainy Day
Interest Grabber
Section 8-1

• Suppose you earned extra money by having a
  part-time job. At first, you might be tempted to
  spend all of the money, but then you decide to
  open a bank account.
• 1. What are the benefits of having a bank
  account?
• 2. What do you have to do if you need some of
  this money?
• 3. What might your body do when it has more
  energy than it needs to carry out its
  activities?
• 4. What does your body do when it needs energy?

2
Section Outline
Section 8-1

• 81 Energy and Life
• A. Autotrophs and Heterotrophs
• B. Chemical Energy and ATP
• 1. Storing Energy
• 2. Releasing Energy
• C. Using Biochemical Energy

3
ENERGY AND LIFE

• Energy is the ability to do work and all living
  things need energy to survive and thrive.
• Autotrophs (Auto means self) are organisms that
  make their own food.
• Example Plants and some bacteria (Producers)
• -Many autotrophs use light energy from the
  sun to produce food. Some bacteria are
  classified chemoautotrophs, they use chemical
  compounds to produce food.
• Heterotrophs (Hetero means other) are organisms
  that obtain energy from the foods they consume.
• Example Animals (Consumers)

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Types of Heterotrophs
http//www.biology.ualberta.ca/courses.hp/bio366/g
eneral-energy-flow.htm

• Herbivore an organism that consumes living
  plants or their parts (e.g., moose Alces
  alces).
• Carnivore an organism (rarely a plant) that
  kills and eats other organisms, or parts of it
  (e.g., wolf Canis lupus and pitcher plant
  Sarracenia purpurea).
• Omnivore an organism whose diet is broad,
  including both plant and animal food more
  specifically, an organism that feeds on more than
  one trophic level (e.g., black bear Ursus
  americanus).
• Saprotrophs- Feed on dead organic matter by
  secreting digestive enzymes into it absorbing
  the products of digestion. (e.g. Fungi)

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Heterotrophs Continued

• Parasitism a form of symbiosis in which two
  organisms live in close association with each
  other, the one, a parasite, depending upon the
  other, the host, for some essential food factor
  (e.g., brown-headed cowbird Molothrus ater)
• Parasitiod any of a number of insects whose
  larvae live within and consume their host,
  usually another insect (e.g., Ichneumonidae wasp)
  
• Detritivore an organism that feeds on freshly
  dead or partially decomposed organic matter
  (e.g., bacteria)

http//www.biology.ualberta.ca/courses.hp/bio366/g
eneral-energy-flow.htm
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Energy from Food

• Energy flows through ecosystems from producers to
  the various levels of consumers. Each time an
  organism eats another, not all the energy is
  transferred. Only about 10 of the energy of a
  producer is transferred to the consumer that eats
  it. Therefore, there is a progressive loss of
  energy at each level of a food chain.

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BIOMAGNIFICATION

• Biological magnification is the tendency of
  pollutants to become concentrated in successive
  trophic levels. Often, this is to the detriment
  of the organisms in which these materials
  concentrate, since the pollutants are often toxic

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Adenosine Triphosphate - ATP

• All living things, plants and animals, require a
  continual supply of energy in order to function.
  The energy is used for all the processes which
  keep the organism alive. Some of these processes
  occur continually, such as the metabolism of
  foods, the synthesis of large, biologically
  important molecules, e.g. proteins and DNA, and
  the transport of molecules and ions throughout
  the organism. Other processes occur only at
  certain times, such as muscle contraction and
  other cellular movements. Animals obtain their
  energy by oxidation of foods, plants do so by
  trapping the sunlight using chlorophyll. However,
  before the energy can be used, it is first
  transformed into a form which the organism can
  handle easily. This special carrier of energy is
  the molecule adenosine triphosphate, or ATP.
  http//www.bris.ac.uk/Depts/Chemistry/MOTM/atp/atp
  1.htm

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ATP
Section 8-1
Adenine
Ribose
3 Phosphate groups
10
Its Structure

• The ATP molecule is composed of three components.
  At the center is a sugar molecule, ribose (the
  same sugar that forms the basis of DNA). Attached
  to one side of this is a base (a group consisting
  of linked rings of carbon and nitrogen atoms) in
  this case the base is adenine. The other side of
  the sugar is attached to a string of phosphate
  groups. These phosphates are the key to the
  activity of ATP.

http//www.bris.ac.uk/Depts/Chemistry/MOTM/atp/atp
1.htm
11
ATP
Adenine
Phosphate Chain
Ribose
http//www.bris.ac.uk/Depts/Chemistry/MOTM/atp/atp
1.htm
12
How It Works

• ATP works by losing the endmost phosphate group
  when instructed to do so by an enzyme. This
  reaction releases a lot of energy, which the
  organism can then use to build proteins, contact
  muscles, etc. The reaction product is adenosine
  diphosphate (ADP), and the phosphate group either
  ends up as orthophosphate (HPO4) or attached to
  another molecule (e.g. an alcohol). Even more
  energy can be extracted by removing a second
  phosphate group to produce adenosine
  monophosphate (AMP).

http//www.bris.ac.uk/Depts/Chemistry/MOTM/atp/atp
1.htm
13
Figure 8-3 Comparison of ADP and ATP to a Battery
Section 8-1
ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) Phosphate
Adenosine triphosphate (ATP)
Partially charged battery
Fully charged battery
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Figure 8-3 Comparison of ADP and ATP to a Battery
Section 8-1
ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) Phosphate
Adenosine triphosphate (ATP)
Partially charged battery
Fully charged battery
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Using Biochemcial Energy

• As we discussed last chapter, a large amount of
  energy is used in active transport. This energy
  is supplied by ATP.
• -70 of the ATP in a nerve cell is used for
  active transport.
• Many cell membranes contain sodium-potassium
  pumps. They are protein pumps that pump sodium
  ions out of the cell and potassium ions into it.
  ATP provides the energy that keeps these pumps
  working.
• Na K pump

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Trapping Energy
Interest Grabber
Section 8-2

• Have you ever used a solar-powered calculator? No
  matter where you go, as long as you have a light
  source, the calculator works. You never have to
  put batteries in it.

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Interest Grabber continued
Section 8-2

• 1. A solar-powered calculator uses solar cells
  that are found in rows along the top of the
  calculator. Into what kind of energy is the light
  energy converted so that the calculator works?
• 2. Recall that plants use light energy from the
  sun to make food. Into what kind of energy is the
  light energy converted by plants?
• 3. Most plants, no matter what size or shape they
  are, have some parts that are green. Which parts
  of a plant are usually green?
• 4. What does the green color have to do with the
  plants ability to convert light energy into the
  energy found in the food it makes?

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Section Outline
Section 8-2

• 82 Photosynthesis An Overview
• A. Investigating Photosynthesis
• 1. Van Helmonts Experiment
• 2. Priestleys Experiment
• 3. Jan Ingenhousz
• B. The Photosynthesis Equation
• C. Light and Pigments

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Jan van Helmont (1579-1644)The Father of
Pneumatic Chemistry

• Jan van Helmont, a Dutch physician, set out to
  answer the question of where does the mass of a
  growing tree come from?.
• Procedure
• -Van Helmont carefully found the mass of a pot of
  dry soil and a small seeding.
• -He then planted the seedling in the pot of soil.
• -He took care of it and watered it regularly for
  five years.
• -At the end of five years, the seedling had
  gained about 75 kg.
• -The mass of the soil was roughly the same.
• -Van Helmont concluded that most of the mass must
  have come from water.
• Hydrate of carbohydrate has been discovered.

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Joseph Priestley (1733-1804)

• Priestly devised an experiment that gave us
  insights into photosynthesis.
• Procedure
• -Priestley took a candle, placed a glass jar over
  it, and watched as the flame gradually died out.
• -Priestley reasoned, that there is something in
  air that was necessary to keep a candle flame
  burning.
• -He then placed a mint spring under the jar and
  allowed a few days to pass.
• -He light the candle and it remained lighted for
  a while.
• -The mint spring produced the substance required
  for burning.
• OXYGEN

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Jan Ingen-housz (1730-1799)

• Jan Ingen-Housz showed the effects observed by
  Priestly occurred only when the plant was exposed
  to light.
• -He saw gas bubbles forming around the leaves and
  the green parts of the stems (A). When the system
  was placed in darkness, the bubbles stopped (B).

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Requirements for Photosynthesis

• -The experiments performed by van Helmont,
  Priestley, Ingenhousz, and other scientists
  reveal that in the presence of light, plants
  transform carbon dioxide and water into
  carbohydrates and release oxygen.
• CO2 H2O ?(CH2O)n
  O2
• Carbon Dioxide Water ? Carbohydrate Oxygen
• 6CO2 6H2O ?C6H12O6 6O2
• Carbon Dioxide Water ? Glucose Oxygen

Light
Light
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Photosynthesis Reactants and Products
Section 8-2
Light Energy
Chloroplast
CO2 H2O
Sugars O2
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SUNLIGHT

• Nearly all organisms on Earth depend on the sun
  for energy.
• The sun bathes the Earth in a steady stream of
  light, that is made up of different wavelengths.
  
• White light ROYGBV
• Pigments are colored substances that absorb or
  reflect light. The principle pigment of green
  plants is known as chlorophyll.
• Chlorophyll absorbs red and blue light but does
  not absorb light in the middle region of the
  spectrum very well. Instead, it reflects these
  wavelengths.
• When chlorophyll absorbs light, much of the
  energy is transferred directly to electrons in
  the chlorophyll molecule, raising the energy of
  these electrons. These high energy electrons
  make photosynthesis work.

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Figure 8-5 Chlorophyll Light Absorption
Section 8-2
Absorption of Light by Chlorophyll a and
Chlorophyll b
Chlorophyll b
Chlorophyll a
V
B
G
Y
O
R
26

• The different sidegroups in the 2 chlorophylls
  'tune' the absorption spectrum to slightly
  different wavelengths, so that light that is not
  significantly absorbed by chlorophyll a, at, say,
  460nm, will instead be captured by chlorophyll b,
  which absorbs strongly at that wavelength. Thus
  these two kinds of chlorophyll complement each
  other in absorbing sunlight.

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• As the chlorophyll in leaves decays in the
  autumn, the green color fades and is replaced by
  the oranges and reds of carotenoids.

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Chlorophyll in Plants

• The chlorophyll molecule is the active part that
  absorbs the sunlight, in order to do its job
  (synthesising carbohydrates) it needs to be
  attached to the backbone of a very complicated
  protein. This protein may look haphazard in
  design, but it has exactly the correct structure
  to orient the chlorophyll molecules in the
  optimal position to enable them to react with
  nearby CO2 and H2O molecules in a very efficient
  manner. Several chlorophyll molecules are lurking
  inside this bacterial photoreceptor protein.

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A Look Into the Future
Interest Grabber
Section 8-3

• It is 100 years in the future and you are a
  research scientist. An enormous volcanic eruption
  has recently sent huge quantities of dust and ash
  into the atmosphere.
• Working with a partner, make a list of how this
  event will affect each of the following
• 1. photosynthesis
• 2. plant life
• 3. animal life
• 4. human societies

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Section Outline
Section 8-3

• 83 The Reactions of Photosynthesis
• A. Inside a Chloroplast
• B. Electron Carriers
• C. Light-Dependent Reactions
• D. The Calvin Cycle
• E. Factors Affecting Photosynthesis

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Chloroplasts
http//users.rcn.com/jkimball.ma.ultranet/BiologyP
ages/C/Chloroplasts.html

• A chloroplast is made up of 3 types of membranes
• 1. A smooth outer membrane which is freely
  permeable to molecules.
• A smooth inner membrane which contains many
  transport proteins that regulate the passage in
  and out of the chloroplast of
• Small molecules like sugars
• Proteins synthesized in the cytoplasm of the cell
  but used within the chloroplast.
• 3. A system of thylakoid membranes.

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Thylakoids
http//users.rcn.com/jkimball.ma.ultranet/BiologyP
ages/C/Chloroplasts.html

• Thylakoids are stack-like membranes located
  inside the chloroplasts. At various places
  within the chloroplast these are stacked in
  arrays called grana (resembling a stack of
  coins).
• Four types of proteins assemblies are embedded in
  the thylakoid membranes
• Photosystem I which includes chlorophyll and
  carotenoid molecules.
• Photosystem II which also contains chlorophyll
  and carotenoid molecules.
• Cytochromes b and f
• ATP synthase
• Photosystems are light collecting units.

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Stroma
http//www.ftexploring.com/photosyn/chloroplast.ht
ml

• The thylakoid membranes are surrounded by a fluid
  stroma. This is where the Calvin cycle takes
  place.
• The stroma contains
• all the enzymes, e.g., RUBISCO, needed to carry
  out the "dark" reactions of photosynthesis that
  is, the conversion of CO2 into organic molecules
  like glucose.
• A number of identical molecules of DNA, each of
  which carries the complete chloroplast genome.
  The genes encode some - but not all - of the
  molecules needed for chloroplast function.

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Electron Carriers

• A carrier molecule is a compound that can accept
  a pair of high-energy electrons and transfer them
  along with most of their energy to another
  molecule. This process is called electron
  transport, and the electron carriers themselves
  are known as the electron transport chain.
• NADP (nicotinamide adenine dinucleotide
  phosphate) accepts 2 electrons and a hydrogen ion
  (H) and converts to NADPH. This is one way in
  which some of the energy of sunlight can be
  trapped into a chemical form.

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Figure 8-7 Photosynthesis An Overview
Section 8-3
Chloroplast
Chloroplast
NADP
ADP P
Light- Dependent Reactions
Calvin Cycle
ATP
NADPH
36
Concept Map
Section 8-3
Photosynthesis
includes
takes place in
uses
use
take place in
to produce
to produce
of
37
Figure 8-10 Light-Dependent Reactions
Section 8-3
Hydrogen Ion Movement
Chloroplast
Photosystem II
ATP synthase
Inner Thylakoid Space
Thylakoid Membrane
Stroma
Electron Transport Chain
Photosystem I
ATP Formation
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Figure 8-11 Calvin Cycle
Section 8-3
CO2 Enters the Cycle
Energy Input
ChloropIast
5-Carbon Molecules Regenerated
6-Carbon Sugar Produced
Sugars and other compounds
39
Video Contents
Videos

• Click a hyperlink to choose a video.
• ATP Formation
• Photosynthesis
• Light-Dependent Reactions, Part 1
• Light-Dependent Reactions, Part 2
• Calvin Cycle

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Video 1
Video 1
ATP Formation

• Click the image to play the video segment.

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Video 2
Video 2
Photosynthesis

• Click the image to play the video segment.

42
Video 3
Video 3
Light-Dependent Reactions, Part 1

• Click the image to play the video segment.

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Video 4
Video 4
Light-Dependent Reactions, Part 2

• Click the image to play the video segment.

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Video 5
Video 5
Calvin Cycle

• Click the image to play the video segment.

45
Internet
Go Online

• ATP activity
• Interactive test
• For links on Calvin cycle, go to www.SciLinks.org
  and enter the Web Code as follows cbn-3082.
• For links on photosynthesis, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-3083.

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Section 1 Answers
Interest Grabber Answers

• 1. What are the benefits of having a bank
  account?
• To save money and earn interest.
• 2. What do you have to do if you need some of
  this money?
• Go to the bank and take out the money you need.
• 3. What might your body do when it has more
  energy than it needs to carry out its
  activities?
• Students will likely say that the body stores
  the energy.
• 4. What does your body do when it needs energy?
• Student answers may include that energy is
  gotten from food.

47
Section 2 Answers
Interest Grabber Answers

• 1. A solar-powered calculator uses solar cells
  that are found in rows along the top of the
  calculator. Into what kind of energy is the light
  energy converted so that the calculator works?
• They convert light energy into electrical
  energy.
• 2. Recall that plants use light energy from the
  sun to make food. Into what kind of energy is the
  light energy converted by plants?
• Plants convert light energy into chemical
  energy.
• 3. Most plants, no matter what size or shape they
  are, have some parts that are green. Which parts
  of a plant are usually green?
• Leaves are green, as are some stems.
• 4. What does the green color have to do with the
  plants ability to convert light energy into the
  energy found in the food it makes?
• The green color is the pigment chlorophyll,
  which absorbs light energy from the sun and
  converts it to chemical energy in the process of
  photosynthesis.

48
Section 3 Answers
Interest Grabber Answers

• Working with a partner, make a list of how this
  event will affect each of the following
• 1. photosynthesis The rate of photosynthesis
  will decrease due to reduced sunlight.
• 2. plant life Plants will grow more slowly or
  die off due to decreased rate of
  photosynthesis.
• 3. animal life Animal populations will decrease
  after a while due to fewer plants for
  herbivores to eat. Fewer herbivores will
  eventually result in fewer carnivores. Also, less
  oxygen will be available.
• 4. human societies Human societies will have to
  adjust their eating habits as some food
  species die out.

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End of Custom Shows

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