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TYPE 3
• FCA: EXP. ¾ BIOMOLECULES
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• FCA: GIVE ONE EX OF EACH
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• FCA: ESSAY 5 PARAGRAPHS
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AGENDA
• Fill in Collins Folder w/ Type 3 ONLY!!!
• Assignment: BIOMOLECULES
• I will come around and give you your 1st
Quarter Grades.
TYPE 3
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• FCA: 3 GOALS FOR QUARTER 2
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Type One: Write 5 Observations
you see in this picture
Molecules can be represented in
many ways
Salt (NaCl)
sodium + chlorine  sodium
chloride
Electron arrangement determines
the chemical properties of an atom
• Electrons are arranged in shells
– The outermost shell determines the chemical
properties of an atom
– In most atoms, a full outer shell holds eight
electrons
Atoms whose shells are not full tend to
interact with other atoms and gain, lose,
or share electrons
Electron
Ionic bonds are attractions
between ions of opposite charge
• When atoms gain or lose electrons,
charged atoms called ions are created
– Electrical Attraction: Opposites Attract
– Metals + Non-Metals = Compound
Na
Sodium atom
Cl
Chlorine atom
+ Na
Sodium ion
+/ -
Cl–
Chloride ion
Covalent bonds, the sharing of electrons,
join atoms into molecules
• Atoms share outer energy level electrons
with other atoms
– Atoms joined together by covalent
bonds form molecules
– Non-Metals + Non-Metals
-- Share Electrons NOT Attraction
Covalent Bonds Share Electrons
And Form MOLECULES
Organisms are sensitive to
Acidic and Basic conditions
• A compound that releases H+ ions in
solution is an acid, and one that accepts
H+ ions in solution is a base
• Acidity is measured on the pH scale:
– 0-6 is acidic
– 8-14 is basic
– Pure water and solutions that are neither
basic nor acidic are neutral, with a pH of 7
• pH
scale
H+
OH–
Acidic solution
Increasingly ACIDIC
(Higher concentration of
H+)
pH scale
Neutral solution
Figure 2.15
Basic solution
Increasingly BASIC
(Lower concentration of
H+)
NEUTRAL
[H+] = [OH–]
Lemon juice; gastric juice
Grapefruit juice
Tomato juice
Urine
PURE WATER
Human blood
Seawater
Milk of magnesia
Household ammonia
Household bleach
Oven cleaner
How Do Cells keep pH at 7?
• Cells are kept close to pH 7 by BUFFERS
•Buffers are substances that
resist pH change
•They accept H+ ions when
they are in excess and donate
H+ ions when they are
depleted
Buffers are not foolproof
Connection: Acid Rain threatens
the environment
• Some ecosystems are threatened by acid rain
• Acid rain is formed when air pollutants from
burning fossil fuels combine with water vapor in
the air to form sulfuric and nitric acids
EFFECTS OF ACID RAIN
– These acids can kill fish, damage buildings, and injure
trees
– Laws, new technology, and energy conservation may
help us reduce acid precipitation
BIOMOLECULES
•
•
•
•
CARBOHYDRATES
LIPIDS
PROTEINS
NUCLEIC ACIDS
CARBOHYDRATES
• Biomolecules made up of SUGAR
molecules
• Major source of ENERGY for organisms
• 3 Major types of Carbohydrates:
– Monosaccharides
– Disaccharides
– Polysaccharides
MONOSACCHARIDES
•
•
•
•
Made up of only 1 sugar molecule
CH2O: Carbon, Hydrogen, Oxygen
Used by cells for ENERGY
Contains a HYDROXYL GROUP (-OH)
and a CARBONYL GROUP (C=O)
MONOSACCHARIDES:
Sugar Molecules can go from a
STRING to a RING !
DISSACHARIDES
• Form when 2 sugar molecules combine
Sucrose
Connection: How sweet is sweet?
• Various types of molecules, including nonsugars, taste sweet because they bind to
“sweet” receptors on the tongue
POLYSACCHARIDES :
• Many Sugar Molecules bonded together
Starch granules in
potato tuber cells
Glycogen granules
in muscle tissue
Cellulose fibrils in
a plant cell wall
Cellulose
molecules
Glucose
monomer
STARCH
GLYCOGEN
CELLULOSE
LIPIDS: Energy storing molecules
• Made up of carbon and hydrogen
• DO NOT mix with water
LIPIDS are also called
TRIGLYCERIDES
• TRIGLYCERIDES consists of one
glycerol molecule linked to three
fatty acids
Phospholipids, waxes, and
steroids are lipids
• Phospholipids are a major component of
cell membranes
• Waxes form waterproof coatings
• Steroids
are often
hormones
PROTEINS
• Proteins are involved in
– cellular structure
– movement
– defense
– transport
– communication
• Mammalian hair is composed proteins
• Enzymes regulate chemical reactions
Proteins are made up of
Amino Acids
• Each Amino Acids contains:
– an amino group
– a carboxyl group
– an R group, which distinguishes each of the 20
different amino acids
Amino
group
Carboxyl (acid)
group
How do Proteins Form?
• Cells link amino acids together by
dehydration synthesis
• The bonds between amino acids are called
peptide bonds
Carboxyl
group
Amino
group
PEPTIDE
BOND
Dehydration
synthesis
Amino acid
Figure 3.13
Amino acid
Dipeptide
NUCLEIC ACIDS
• Biomolecules that carry all information for
a cell:
– Blueprints for Protein-Making
– DNA & RNA: Control all cell processes.
• The subunits of nucleic acids are called
nucleotides
– Each nucleotide is composed of a sugar,
phosphate, and nitrogenous base
Nitrogenous
base (A)
Phosphate
group
Figure 3.20A
Sugar
• The sugar and phosphate form the
backbone for the nucleic acid
Nucleotide
Sugar-phosphate
backbone