Download Intro to Nutrients

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4.01 – Introduction to
Nutrients
Bi l
Biology
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Chemistry
y The branch of chemistry we will look at is
biochemistry and/or organic chemistry.
y We are interested in looking at organic
molecules – they contain carbon (C). Hydrogen
and oxygen are, also, typically, present.
y In proteins, nitrogen is also present.
Chemical Compounds
y Compounds are formed when 2 or more
elements are joined.
y They join by bonding – this is represented by a
bar or “line.”
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Bonding
y Bonds formed between atoms can be either:
a) Ionic – held together by opposite charges (like
a magnet)
b) Covalent – atoms share electrons to make
bonds.
e.g. Carbon can form 4 covalent bonds with other
atoms.
HONC 1234
Biochemistry
y What makes different organic molecules different are
what functional groups are attached to them:
y Hydroxyl
− OH
y Carboxyl
−COOH
y Amino
−NH2
A functional group is what
gives a molecule its specific
identity.
Reaction Basics: 3 Classes
1. Dehydration Synthesis - carbs
y Small molecules are bonded together into a
larger molecule by removing water.
y E.g. glucose + glucose − water = maltose
Maltose syrup
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2. Hydrolysis - Carbs
y Reversal of dehydration synthesis
y Add water to a larger molecule to split it into
smaller molecules.
y E.g. Sucrose + water = glucose + fructose
Sugars tend to be isomers of each other – same
chemical formula but different arrangement of
chemical bonds.
3. Condensation
y Condensation (removal of a water molecule)
links amino acids link together to form chains
called polypeptides.
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Macro Nutrients
y 4 main types:
1. Carbohydrates (carbs)
2. Proteins
3. Fats (lipids)
4. Nucleic Acids
All of the macronutrients start as
a small unit – a monomer – which
will link up with other monomers
to form longer chains called
polymers.
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Macro Functions
1. Production of energy.
2. for growth, repair and maintenance of hard
and soft tissue.
3. for regulation of the body’s processes.
1. Carbohydrates (= 4 cals)
y Most important source of energy and makes up the
majority of most diets.
y 3 classes:
A. Simple sugars – Monosaccharides: made up of single
sugar molecules or chains containing many sugar
molecules
B. Disaccharides – sugars made up of 2 sugar
molecules. E.g. sucrose (brown/white sugar)
C. Polysaccharides – Complex carbs – made up of many
monosaccharides
E.g. starch, cellulose, glycogen
2. Lipids (= 9 cals)
3 groups of lipids:
a) Fats/oils/waxes
b) Phospholipids
c) Steroids
When glycogen stores are full in animals, excess carbs
are converted into fat.
They are insoluble in water.
Share a common functional group as protein: carboxyl
group.
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Saturated vs. Unsaturated
Fatty Acids
y Saturated fats – have maximum number of hydrogen
atoms.
y Unsaturated fats – have double bonds and not the
maximum amounts of hydrogen atoms.
Cholesterols
1. HDL – high-density lipoprotein – “good”
2. LDL – Low-density lipoprotein – “bad”
These are groups of proteins covered with cholesterol
(lipoprotein).
Difference – HDL has more protein than cholesterol; LDL
has less protein.
Lipid Function
y Excellent energy source.
y Cholesterol is important in cell membranes. It also
makes up male and female sex hormones.
y Phospholipids make up cell membranes
membranes.
y Waxes create water-proof coating for plant leaves,
animal feathers, or furs.
y Cholesterol + other fats = plaque that blocks blood
vessels.
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3. Proteins
y Used by cells to build structures and used in
chemical activities.
y Giant molecules made up of hundreds of units
called amino acids.
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Proteins
y Not usually used for energy (like lipids and
carbohydrates).
y Not just used to build cells (muscle)
y Enzymes, hormones, antibodies, and
hemoglobin (molecule of the blood) are made
from proteins.
4. Nucleic Acids
y Nucleic acids are polymers essential for all
known forms of life.
y include DNA (deoxyribonucleic acid) and RNA
(ribonucleic acid)
y are made from monomers known as
nucleotides.
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