Download Macromolecules

Macromolecules
WHAT MOLECULES ARE THE BUILDING
BLOCKS FOR LIFE?
Organic vs. Inorganic
-
Organic Compounds contain carbon and
are in living things
 - Inorganic compounds generally don’t
contain carbon atoms
 Carbon
can combine to form 4 covalent bonds;
can create a wide variety of many simple or
complex compounds
 -Functional
Groups are groups of
atoms that influence the properties of
their molecules and the chemical
reactions in which they participate.
 - Polymers are repeated, linked units
of a molecule
 - Monomers are simple molecules
formed by hydrolysis
Cellular Currency
 ATP- (Adenosine Triphosphate) is the energy
currency of the cell, Ex) Debit card not useful in
school building but cash is, much like glucose isn’t
useful to cell until it is broken down into ATP
through cellular respiration
4 Classes of Organic Compounds
 -Carbohydrates
 - Lipids
 -Proteins
 - Nucleic Acids
I.
Carbohydrates – organic compounds
 Made of carbon, hydrogen and oxygen in a 1:2:1 ratio
 A) Monosaccharide – simple sugar
 a. Examples are fructose, glucose, galactose
 b. Molecular formula is same (C6H12O6) but structures are
different, called isomers
Carbohydrates – organic compounds, con’t
 B) Disaccharide- double sugars
 a. Example is sucrose- made of fructose and glucose
 b. Complex molecule
 C) Polysaccharide- 3+ monosaccharide
 a. Examples are glycogen, starch and cellulose
 b. Very complex strands of sugar molecules tied together to
form long chains
II. Protein- organic compounds
 organic compounds made of carbon,
hydrogen, oxygen and nitrogen; formed from
amino acids linked together
 A) Amino Acids- 20 different ones


a. Share same basic structure and bond with a peptide
bond (covalent)
b. Polypeptides are long chains of Amino Acids
(building blocks of life)
 B) Enzymes- biological catalysts that speed
up or slow down chemical reactions

a. Environmentally sensitive – temperature, pH, etc.
III. Lipids- large, nonpolar
molecules
 Include: triglycerides, phospholipids, steroids,
waxes, and pigments
 A) Fatty Acids- unbranched carbon chains



a. Has polar and nonpolar end
b. Saturated fats have all carbons fully bonded to four atoms
c. Unsaturated fats may contain at least one or more double
bond
III. Lipids, con’t
 B) Triglycerides – fats, phospholipids and
waxes


a. Have high melting point and are hard when
saturated
b. Unsaturated are soft and usually liquids
 C)
Phospholipids- have a phosphate
attached to a glycerol which has two fatty
acids

a. Polar and nonpolar ends form ‘phospholipid
bilayer’ of the cell membrane
III. Lipids, con’t
 D) Waxes- long fatty acid chain with alcohol chain
hanging

a. Waterproof, form barriers in animals and coatings on
plants
 E) Steroids- 4 fused carbon rings with different
functional groups

a. Examples- testosterone, cholesterol
IV. Nucleic Acids
 A) DNA- Deoxyribonucleic Acid
 a. Large, complex molecule that determine all the traits of an
organism
 b. Contains nucleotides- 3 parts; a phosphate group, a 5carbon sugar and a ring shaped nitrogen base
(A-T-G-C-and U in RNA)
 B) RNA- Ribonucleic Acid
 a. Stores and transfers information from DNA
 b. Acts as enzymes
Importance of water
• Overview: The Molecule That
Supports All of Life
• Water is the biological medium
here on Earth
• All living organisms require
water more than any other
substance
13
Water Facts
• Three-quarters of the Earth’s
surface is submerged in water
• The abundance of water is the main
reason the Earth is habitable
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Water’s Polarity
• The polarity of water molecules
– Allows them to form hydrogen bonds
with each other
– Contributes to the various properties
water exhibits
–
Hydrogen
bonds
+
H
+
–
–
+
H
+
–
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Properties of water
• Six emergent properties of water
contribute to Earth’s fitness for life
1.Cohesion/Adhesion
2.Surface tension
3.Temperature Moderation
4.High specific heat
5.Evaporative cooling
6.Universal solvent
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Cohesion
• Water molecules exhibit cohesion
• Cohesion
– Is the bonding of a high percentage of
the molecules to neighboring water
molecules
– Is due to hydrogen bonding
– Like molecules bonding to each other
(water attracting other water
molecules)
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Cohesion
• Cohesion
– Helps pull water up through the
microscopic vessels of plants
(capillarity)
Water conducting cells
100 µm
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Surface Tension
• Surface tension
– Is a measure of how hard it is to break
the surface of a liquid
– Is related to cohesion
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Moderation of Temperature
• Water moderates air temperature
• By absorbing heat from air that is
warmer and releasing the stored
heat to air that is cooler
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Heat and Temperature
• Kinetic energy
– Is the energy of motion
• Heat
– Is a measure of the total amount of
kinetic energy due to molecular
motion
• Temperature
– Measures the intensity of heat
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Water’s High Specific Heat
• The specific heat of a substance
– Is the amount of heat that must be
absorbed or lost for 1 gram of that
substance to change its
temperature by 1ºC
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Specific Heat
• Water has a high specific heat which
allows it to minimize temperature
fluctuations to within limits that
permit life
– Heat is absorbed when hydrogen
bonds break
– Heat is released when hydrogen
bonds form
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Evaporative Cooling
• Evaporation
– Is the transformation of a
substance from a liquid to a gas
– Requires energy
• Heat of vaporization
– Is the quantity of heat a liquid
must absorb for 1 gram of it to be
converted from a liquid to a gas
– 100oC steam has MORE HEAT
than 100oC boiling water (540
calories)
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Evaporative Cooling
• Is due to water’s high heat of
vaporization
• Allows water to cool a surface
• Sweating cools the body as heat
energy from the body changes
sweat into a gas
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Insulation of Bodies of
Water by Floating Ice
• Solid water, or ice
– Is less dense than liquid water
– Floats in liquid water
– Insulates water & organisms
below ice layer
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