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Nutrients & Biochem
Definition of Homeostasis
 homeo
= same; stasis = standing
 Homeostasis is the term we use to describe
the constant state of the internal environment.
 Homeostasis is a state of
balance in the body.
 The processes and activities
that help to maintain homeostasis are referred
to as homeostatic mechanisms.
THINK!
 You
are exposed to ever changing environmental
conditions. For example, you may walk out of an
air conditioned room into the hot summer sun.
How do you feel? What does your body do to
adjust?
 How
many other examples of homeostasis can
you think of?
 For each of your examples, what would happen
to you if you could not maintain homeostasis?
A Temperature Control System
 To
help us understand homeostasis in living
organisms, let us first look at a non-living
system. We will use a temperature control
system for a room which has many similar
features to homeostatic mechanisms….
homeostasis animation-temperature control
 homeostasis
animation
A Review
 Example:
thermostatic heating system in a home
Components of an automatic control system
 Variable
is the characteristic of the internal
environment that is controlled by this
mechanism (internal temp in this example).
 Sensor
(receptor) detects changes in variable
and feeds that information back to the integrator
(control center) (thermometer in this example).
Example Continued
 Integrator
(control center) integrates (puts
together) data from sensor and stored "setpoint"
data (thermostat in this example).
 Set
point is the "ideal" or "normal" value of the
variable that is previously "set" or "stored" in
memory.
 Effector
is the mechanism (furnace in this
example) that has an "effect" on the variable
(internal temperature in this example).
Human Example of
Negative Feedback
 Human
example: shivering in response to
cooling of body during cold weather or
sweating when their core temperature gets
too hot.
 Homeostasis allows an
organism to remain in
balance with its environment.
 If homeostasis is not
maintained, it can harm
or kill the organism.
High-wire Artist Model
Variable: position of body
Setpoint: directly over the wire
Sensors: nerve receptors
(eyes, inner ears, muscle
stretch receptors, etc.)
Integrator: brain
Effectors: skeletal muscles
High-wire artist uses negative
feedback to maintain relatively
constant position on wire.
Biochemistry
The study of reactions and molecules which
react to ensure life.
Organic compound : molecule that
contains a significant amount of carbon C
(except CO, CO2, and CO3) or hydrocarbon
groups. Molecules which have a
“skeleton” of carbon and form an
important part of living cells.
Essential nutrients

Fall under two categories:
1. Macronutrients
2. Micronutrients.
Macronutrients

large complex organic molecules that
must be digested by an organism in order
to be used. There are 4 macronutrients:
carbohydrates, proteins, fats, nucleic
acids (nucleic acids will be studied in
detail in grade 12).
Micronutrients

small, simple substances that do NOT
need to be digested by an organism in
order to be used. These molecules are
already small enough to diffuse across a
plasma membrane. There are 3
micronutrients: minerals, vitamins &
water
1. Carbohydrates


Role : structural compounds and as energy
reserves to fuel life processes - short and long term.
(original source of energy)
Composed of the elements C, H and O in a 1:2:1 ratio.
Empirical formula is Cm(H2O)n
Carbohydrates (Structure)
Subunit (monomer)=
Monosaccharide or simple sugar : Formed of 3 to 7 atoms of carbon.
ex : glucose (primary energy source for cells), fructose (found in some fruit,
semen), galactose (not normally found in nature).

Disaccharide or double sugar: 2 simple sugars together. Ex : sucrose
(table sugar) = glucose + fructose, maltose = glucose + glucose,
Lactose (in dairy) = glucose + galactose

Polysaccharide (AKA complex carbohydrates): many simple sugars
together.
Ex : starch (energy storage in plants), glycogen (energy storage in animals),
cellulose (makes up the cell walls of plants).

saccharide and the suffix ose refer to sugar. i.e. glucose or
monosaccharide.
Monosaccharide
Disaccharide
(Monomer)
Polysaccharide (Polymer)
2. Lipids


Roles : stores nutritive substances and energy longterm (2,25 times more energy than carbohydrates),
insulation and protections of organs, makes hormones et
and structural component of the cell membrane.
includes fats and oils, waxes, phospholipids,
steroids, and some other related compounds.
Lipids (Structure)
Sub unit (monomer)=
Glycerol group + 3 fatty acids


Fatty acids can be long, short, saturated (solid), or
unsaturated (often liquid).
All Lipids are hydrophobic (don’t mix with water).
Consist of carbon, hydrogen and oxygen

Lipids with fatty acids
Triglycerides (Fats and oils)
Phospholipids
Waxes

Lipids without fatty acids
Steroids
Lipids (Triglycerides)
Fats (solid at room temperature) and oils (liquid at
room temperature) are triglycerides.
Steroids (Sterols)
 Compact
hydrophobic molecules containing
four fused hydrocarbon rings
Examples:
 Cholesterol-precursor
to sex hormones and
vitamin D
 Sex hormones
Proteins
 Where
do we find Proteins?
 What do gelatin desserts, hair,
antibodies, spider webs, blood
clots, egg whites, tofu, and
fingernails all have in common?
They are all made of protein.
3. Proteins
Roles :
 Makes enzymes which facilitate chemical
reactions.
 Aids transport of substances across the cell
membrane or in the blood.
 Chemical messengers (hormones), like insulin.
 The majority of cellular components are made of
proteins. Ex: keratin (hair & nails), bone,
muscle, tendon, ligament, amylase (enzyme),
haemoglobin, etc.
Proteins (Structure)
Sub unit (monomer)=
Amino acids

Ex : amino acid + amino acid + a.a. + a.a. +...
= protein

Amino acids form polypeptides which form
proteins.

There are 20 a.a., but only 8 a.a. essential (we
cannot produce them, must consume them)
Amino acids > Proteins
(Monomer)
(Monomer)
(Monomer)
(Polymer)
The Peptide Bond
 Amino
acids are bonded together by peptide
bonds. So two amino acids bonded together
form a dipeptide. Many amino acids bonded
together form a polypeptide.
A polypeptide is many
peptides joined together
Complex protein
4. Nucleic acids

Roles : manage growth and development of all living
forms through a chemical code. Determines
characteristics and function of each cell (genetic code).
Ex: DNA, RNA
Nucleic acids (Structure)
Sub unit (monomer)=
Nucleotides which are formed of a
phosphate group, sugar (ribose or
deoxyribose) and a nitrogen base.
Ex:
 RNA: single strand of nucleotides which
contain ribose.
 DNA: double strand of nucleotides which
contain deoxyribose.
Nucleic acids
There are 5 nitrogen bases:
 Adenine
 Guanine
 Cytosine
 Thymine
 Uracil
Nucleic acid
Nucleotide – sub unit or
monomer of a nucleic
acid
Covalent Bonds: Polar & NonPolar
A covalent bond is when
two atoms share
electrons. This sharing
holds then together.
 Some atoms hold onto
their atoms more tightly
than others that is they
are more

electronegative.

The relative
electronegativities of the
two atoms that form a
covalent bond determine
whether or not a bond is
polar or non-polar.
Polar Molecules
H2O: two hydrogen atoms connected to an oxygen
atom by single covalent bonds.
 Oxygen is more electronegative than hydrogen
(oxygen has a stronger attraction for the electrons of a
covalent bond), so the electrons of the polar bonds
spend more time closer to the oxygen atom. This polar
bond is a result of the uneven sharing of electrons.
 In other words, the bonds that hold together the atoms
in a water molecule are polar covalent bonds.
 The water molecule is a polar molecule, meaning the
ends of the molecule have opposite partial charges.

Structure of water
 The
oxygen end of the molecule has a partial
negative charge, and the hydrogens have a
partial positive charge
Hydrolysis
Process by which a large polymers or macromolecules is cut into
monomers with the addition of water.
Hydro= water
So: Hydrolyse = cut
Lyse = cut
with water
Condensation or dehydration
synthesis
Process by which monomers attach together to form large polymers or
macromolecules, with the loss of a water molecule.
Bibliography
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http://www3.ntu.edu.sg/home/CXGuo/Eatingright_files/main_files/image003.jpg
http://www.synfusion.com/Expertise/Molecules_and_Integration.JPG
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/1-6branch2.JPG
http://lc.brooklyn.cuny.edu/smarttutor/core3_21/images/macro/2b.2.glucose.gif
http://www.chm.bris.ac.uk/motm/glucose/sucrose.gif
http://img4.cookinglight.com/i/2008/04/fats-types-0804p106-m.jpg
http://www.realfitnessblog.com/wp-content/uploads/2008/11/fat_f2.jpg
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lecture
s/Biochemistry/glycerol,%20fatty%20acids,%20triglyceride.gif
http://graphics8.nytimes.com/images/2007/08/01/health/adam/19823.jpg
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Tripeptide.gif
http://www.ks.uiuc.edu/images/ofmonth/2006-04a/secyh_big.png
http://ludwig-sun1.unil.ch/~vjongene/molbio/pics/amp.jpg
http://creationwiki.org/pool/images/b/b9/Nucleotides.png
http://media-2.web.britannica.com/eb-media/64/47664-004-7088EE3D.jpg
http://www.ustboniface.mb.ca/cusb/abernier/Biologie/Module1/Images/reactioncondensation.jpg
http://library.thinkquest.org/28751/media/review/figure/peptide.gif
http://porpax.bio.miami.edu/~cmallery/150/protein/c8.8x13.hydrolysis.sucrose.jpg