Chapter 4 Matter, Energy and Life

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Chapter 4 Matter, Energy and Life
Energy utilization is one of the 7
characteristics of life. Energy is required to
do the work needed to stay alive .. Energy The
ability to do work Work changing an objects
position or physical form
And we all have work to docirculating blood,
building new muscle tissue, moving muscles,
keeping a heart pumping, maintaining
homeostasis..
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There are many forms of energy light,
potential and kinetic energy, heat.. But
according to the laws of nature and
thermodynamics, energy can neither be created nor
destroyed it can only be transformed from one
form to another..it cant just appear or
disappear.
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To illustrate this transformation of energy
Plants take sunlight, and with matter (e.g., CO2,
H2O), transform it into potential energy, i.e.
stored solar energy within molecules they create
(e.g., glucose)
Other organisms take in the molecules created by
plants, directly or indirectly, and transform the
stored solar energy into other forms of
energypotential, kinetic, heat
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Autotrophs Produce molecules from sunlight and
raw materials which serve as the stored energy
source (food) for other themselves and other
organisms
Heterotrophs Use the food molecules produced by
the autotrophs and extract the stored energy and
use it to do work or create other molecules from
the raw materials in the food. Waste from this
process serves as the raw materials to keep the
process going
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Energy transformations can be accomplished
through mechanical or chemical means Mechanical
a waterfall turning a water wheel which turns an
axel which generates electricity PE ? KE ?
electrical Chemical bonds breaking in
molecules release stored energy which in turn
does useful work or forms new molecules. Energy
transformations in living systems are driven by
chemical reactions are known as metabolism
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METABOLISM Involves the storage and release of
energy in molecules. It is the sum of all the
chemical reactions taking place in a cell.
METABOLISM anabolic processes
catabolic processes
Building up more complex molecules from less
complex ones
Breaking down complex molecules into simpler ones
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METABOLISM anabolic processes
catabolic processes
building up
breaking down
6CO2 12H2O Light energy ? C6H12O6 6O2
6H2O Photosynthesis The metabolic process used
by autotrophs to transform light energy into
potential energy. Energy is stored in the
chemical bonds made between the atoms in the
glucose molecule.
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METABOLISM anabolic processes
catabolic processes
building up
breaking down
C6H12O6 6O2 ? 6CO2 6H2O energy
heat Cellular Respiration This is the process
used by autotrophs AND heterotrophs to transform
the stored energy in food sources to useful work.
The stored energy in the chemical bonds of the
glucose molecule is released when the bonds are
broken to form new compounds.
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Catabolic processes provide the energy that drive
the anabolic processes that form more complex
molecules carbohydrates, proteins, fats
METABOLISM anabolic processes
catabolic processes
building up breaking
down
Anabolic processes provide the molecules to fuel
the catabolic processes of breaking down
carbohydrates, proteins, fats
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The captured sunlight/energy in plants becomes
the energy/fuel that runs the world..
Fish, fowl, beef, humans and all of our
conveniences..electricity, heating, planes,
trains and automobiles.all run on the stored
energy found in plants.
Humans access plant energy via food either
directly by eating plants, grains, fruits,
veggies indirectly by eating animals which
have eaten the plants and grains.
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What is food? Despite all of the delicious,
comforting or disgusting items that might come to
mind.
Food is a collection of molecules that when
broken down provides energy to run life or
provides the raw materials for bio-synthesis.
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Food provides the energy or the raw materials for
subsequent building in the form of various types
of macromolecules. Macromolecules are large
complex molecules composed of many smaller or
similar molecules linked together.
Macromolecules found in food are Carbohydrates
Proteins Lipids
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Carbohydrates Organic compounds made of C, H and
O with O and H in a fixed ratio of 12. They
provide energy (4 Cal/1 gm) and building
materials. Carbohydrates are built of units
known as saccharides. Simple carbohydrates (aka
sugars) Monosaccharides basic units such
as glucose, galactose, fructose
C6H12O6
C6H12O6
Source http//rvgs.k12.va.us/faculty/jkowalsk/gsb
/secure/Biolabs/Carbolab.html
Notice that glucose and fructose have identical
formulas but their structures are different.
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Disaccharides 2 units together to form a new
saccharide. Still a simple carbohydrate.
GlucoseGlucose Maltose (beer sugar)
GlucoseFructose Sucrose (table sugar, more
commonly known as SUGAR)
Sourcehttp//www.eng.rpi.edu/dept/chem-eng/Biotec
h-Environ/FUNDAMNT/sugpoly.htm
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Complex carbohydrates aka
Polysaccharides many units together
Glycogen a branched chain of as many as 2000
glucose units. Storage form of glucose in
animals. Source http//www.degussa-health-nutriti
on.com/degussa/html/e/health/eng/kh/c4.htm
Starch storage form of glucose in plants. Aka
amylose. Similar to glycogen but not as branched.
Sourcehttp//www.rpi.edu/dept/bcbp/molbiochem/MBW
eb/mb1/part2/sugar.htm
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Starch vs celluloseidentical in composition but
not quite in structure. The bond joining the
glucose units together is different.our bodies
can break the bond in starch/amylose to get at
the individual glucose units but not in celluose.
Sourcehttp//www.rpi.edu/dept/bcbp/molbiochem/MBW
eb/mb1/part2/sugar.htm
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We tend to use the words sugar and starch and
carbohydrate loosely.
When we say a food is high in carbohydrates do
we mean the food is high in sugar or starch
or both? Potatoes and bread starchy foods and
are high in carbohydrates due to the starch
they contain. Fruits are high in carbohydrates
but we would never say they were starchy -
they contain almost all simple carbohydrates such
as sucrose, fructose.
We tend to say high in carbohydrates for foods
with a high level of the complex carbohydrates
known as starch. And for foods that have high
levels of the simplex carbohydrates, we tend to
say they are high in sugar. But sugar and
starch are really the same thing! Theyre both
made from glucose.
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Now just to make it more confusing
A friends child visited the other day and his
mother said..Dont let him have any sugar but
fruit is ok. I was confused so I said But
fruit is all sugar (with a few other things
thrown)!
Her response.Well I mean he cant have refined,
processed sugar but natural sugar is ok.
Still Confused?
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Proteins Chains of nitrogen-containing amino
acids monomers. Proteins are critical to the
structure and function of all living organisms.
Some proteins serve as structural materials in a
cell, as neurotransmitters, enzymes, hormones or
specialized molecules that regulate chemical
reactions in a cell. Proteins can also be an
energy source (4 Cal/1 gm)
Every amino acid has the same general structure
Source http//www.schoolscience.co.uk/content/5/c
hemistry/proteins/Protch2pg1.html
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Proteins Variability is achieved through the R
group or side chain..there are 20 possibilities
in naturally occurring amino acids. Each amino
acid has its own 3 letter designation.
FYI these are the 8 essential amino acidsmore
later
Source http//www.indstate.edu/thcme/mwking/amino
-acids.html
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Proteins
Amino acids are joined together through a
peptide bond - proteins are often referred to as
peptides.
     
Source http//www.chem4kids.com/files/bio_aminoac
id.html
The number of amino acids joined can vary from
di-peptides to tri-peptides to polypeptides or
proteins.
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Proteins
The shape of a peptide dictates its functionality
and is controlled by.

• Sequence of amino acids the order in which the
  20 AAs are strung togethermuch like ABCs to make
  words/sentences
• The way the chain twists and curves on itself
• The way the chain folds on itself
• Inter-coilings with a second protein chain

Source http//www.schoolscience.co.uk/content/5/c
hemistry/proteins/Protch3pg1.html
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Lipids
Lipids are organic compounds containing C, H, and
O but not in a fixed ratio. Lipids include fats
and oils. They are essential for the energy they
contain (9 Cal/g) as well as forming portions of
cell membranes, body insulation and cushioning.
The most abundant lipids in our diets are the
neutral fats comprised of a glycerol molecule
with long chain fatty acid molecules attached
such as palmitic acid (C16), stearic acid (C18),
oleic acid (C18, cis9)
Such an arrangement is known as a triglyceride
and is an efficient way for the body to transport
fatty acids through the body.
Source http//biology.clc.uc.edu/courses/bio104/l
ipids.htm
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Lipids
The fatty acid molecules can be saturated or
unsaturated
Deconic or Capric acid
Cis-3-deconic acid
Source http//biology.clc.uc.edu/courses/bio104/l
ipids.htm
Notice how the saturated fatty acid forms a
straight chain but the unsaturated chains have
kinks in them. Consequence saturated fats tend
to be solids at RT and are called fats.
Unsaturated fats tend to be liquids and are known
as oils.
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Lipids
Fats and oils are not soluble in water.they are
hydrophobic
But by replacing one fatty acid on the
trigylceride with a group that is water soluble
(hydrophilic) the molecule becomes compatible in
both water and non-water environments. Ideal for
a cell membrane.
Source http//biology.clc.uc.edu/courses/bio104/l
ipids.htm
This is the same idea by which soap and
emulsifiers work!
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What do humans do with food? In addition to
craving food, enjoying food, playing with food,
we need it as fuel and as a source of raw
materials for building new structures.
But these are not accessible to the body in the
whole, intact food. The food must be broken down
into ever increasingly smaller units until the
energy and raw materials are in a form the body
can access and use.
Throughout these processes, physical and chemical
reactions are occurring and some of the chemical
reactions need a little help..
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Helping Chemical Reactions Along
Its essential that the energy in food be
extracted in a timely and efficient manner for it
to do us any good. Often chemical reactions need
a spark to get going..raising the temperature
will do it in many cases. But increasing the
temperature within a living organism is not
practical. Another way to spark a reaction is
to provide a catalyst another molecule that
helps the reaction along. In biological systems a
catalyst is known as an enzyme.
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The Role of Enzymes in Speeding Up Chemical
Reactions
Almost all chemical reactions have an energy
barrier to get startedsome initial energy must
be provided to get it going.
An enzyme acts as a catalyst to get the reaction
going. It holds the substrate creating a new
pathway to products that has a lower activation
barrier. Therefore the reaction goes faster
because more molecules have enough energy to get
over the barrier.
Both images courtesy of www.campbellbiology.com
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Enzymes and Chemical Reactions
Key points1) Enzymes or catalysts themselves are
not consumed during a reaction..they remain
unchanged and ready for another cycle
2) Enzymes are specific for a substrate. There is
a match based in part on shape between the
substrate and the enzyme.
3) Enzyme activity is dependent on acidity levels
to maintain the enzyme shape. Change the pH and
the shape changes the enzyme no longer fits with
the substrate and there is no catalysis.
Both images courtesy of www.campbellbiology.com
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The Digestive System
 Function break down foods for use by the body
and to rid the body of wastes. It involves a
series of mechanical breakdowns as well as
chemical reactions aided by enzymes to ultimately
extract the energy contained in the
foods. Components The GI Tract Accessory Organs
Liver Pancreas Various Glands
Mouth Esophagus Stomach Small intestine
Large intestine or colon
Source http//users.tpg.com.au/users/amcgann/body
/digestive.html
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The Digestive System and Processes

• Mouth take in food and begin breaking it down
• Mechanical squashing, grinding, tearing to
  breakdown into smaller units and to increase
  surface area
• Chemical mixing and reacting with enzymes
• salivary amylase digests starch
• lysozyme kill bacteria

• Esophagus a long muscular tube connecting the
  mouth and stomach
• The bolus from the mouth enters the esophagus
  via swallowing
• Rhythmic waves of muscular contractions,
  peristalsis, propel the bolus toward the stomach.

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The Digestive System and Processes

• Stomach saclike cavity of the GI which acts as a
  digestive and storage organ for food
• Food enters from the esophagus via the sphincter
  muscle
• Once in the stomach, a variety of substances are
  added, including HCl which kills bacteria and
  provides the correct pH for pepsin to digest
  protein
• Chyme, the liquefied substance, leaves the
  stomach and enters the small intestine via
  another sphincter muscle

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The Digestive System and Processes

• Small Intestines a highly coiled tube in the
  lower abdomen where final digestion steps and
  absorption of nutrients occurs
• Secretions from the lining of the small
  intestines re-adjusts the pH to a higher, more
  basic level and further breakdown occurs via
  substrate-specific enzymes amylase, protease,
  and lipase.
• Capillaries and veins drain nutrients away from
  the small intestine directly to the liver before
  circulating through the body.

Large Intestine a wider, thinner-walled tube
(aka colon) where water is reabsorbed and as well
as nutrients, from the bacterial break-down of
food.
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Accessory Organs of the Digestive System

• Liver a the largest internal organ in the body.
  The liver
• regulates blood levels of glucose, amino acid
  and fatty acids
• creates macromolecules (e.g., glycogen from
  glucose) via metabolic process
• stores glycogen and lipid reserves, iron, blood
  and fat-soluble vitamins
• detoxifies by inactivating toxins and metabolic
  waste products
• produces bile to aid in the digestion of
  hydrophobic fats

• Glands
• pancrease - secrets digestive enzymes (amylase,
  lipase, proteases) as well as hormones (insulin
  and glucagon)
• salivary produces amylase acts on starch in
  the mouth
• gastric produces pepsin acts on protein in
  the stomach
• intestinal produces peptidase, maltase,
  lactase, sucrase acts on polypeptides,
  disaccharides

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Overview of Cellular Respiration
Now that the food has been broken down into the
properly sized units, energy can be extracted in
the form of ATP molecules, the energy currency
for living organisms.

• Stage 1 Glycolysis initial breakdown of
  glucose into two C3 units (pyruvate) in the
  cytoplasm under anaerobic conditions
• Stage 2 Krebs Cycle completes the breakdown of
  pyruvate under aerobic conditions in the
  mitochondria. This stage is also a source of
  carbon skeletons for biosynthesis.
• Stage 3 Electron transport electrons are
  transferred between molecules which results in
  the storage of some of the electrons energy in
  ATP. Occurs in the mitochondria and requires O2
  as the final acceptor of transferred electrons to
  form water.

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• Cellular Respiration - The Recipe
• Take one molecule of glucose. Place in the
  cytoplasm of the cell for glycolysis. Turn until
  glucose splits into two molecules of pyruvate.
  Diffuse into the mitochondria. Save the two
  molecules of ATP that are produced.
• One at a time, add pyruvate to the Krebs cycle.
  Skim CO2 that is released. Save the two
  molecules of ATP produced. Diffuse protons or H
  into the intermembrame of the mitochondria.
• During electron transport, strain H from
  intermembrane space to matrix through ATP
  synthase while slowly adding O2. Save 34
  molecules of ATP produced and skim off water
  produced.
• No baking required, CR releases heat.
• Yield 1 glucose molecule 38 molecules of ATP

Overall C6H12O6 6O2 ? 6CO2 6H2O 38ATPs
heat
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How is each food type metabolized?
Carbohydrates
Lipids
Proteins
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Does all food provide energy and raw materials?
Does it matter what you eat?

• We need to eat a variety of foods to ensure that
  essential nutrients, substances that animals
  cannot make, are available.
• Essential amino acids 8 of them
• Essential fatty acids lineoleic
• Vitamins organic substances required in
  metabolism usually act as an enzyme. Fat (ADEK)
  and water-soluble
• Minerals non-organic substances required for
  normal function, e.g. K, Na, Ca2, Fe2

What you eat matters to your matter!
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Food for Thought.
So why do we really need food? Why do we need
oxygen? Is there an advantage to glycolysis
producing ATP under anaerobic conditions? What
are the advantages to eating low on the food
chain? Disadvantages? This chapter begins by
saying that all living systems require energy and
matter. For plants, what is the form of energy?
Of matter? For animals, what is the form of
energy? Of matter? Can you see now how life is
just a series of energy transfers of the original
source, sun?