Download Inquiry into Life Twelfth Edition

Biology 12 Unit A
The Chemistry of Life – Part 2
Macromolecules
• Made of organic molecules
Organic Molecules
• Always contain:
– Carbon (C) and Hydrogen (H)
– A carbon atom may share electrons with another carbon atom
Organic Molecules
• Always contain:
– Carbon (C) and Hydrogen (H)
– A carbon atom may share electrons with another carbon atom
Organic Molecules
• Many molecules of life are macromolecules.
(macromolecules contain many molecules joined together)
Organic Molecules
• Many molecules of life are macromolecules.
(macromolecules contain many molecules joined together)
– Monomers:
Simple organic molecules that exist
individually
– Polymers:
Large organic molecules form by
combining monomers
Organic Molecules
Organic Molecules
A meal containing carbohydrates, lipids, and proteins.
Organic Molecules
• Cells have mechanisms of joining
monomers to build polymers
Organic Molecules
• Cells have mechanisms of joining monomers to
build polymers
Organic Molecules
• Cells have mechanisms of joining monomers to
build polymers
• Dehydration Reaction: an -OH and -H are removed
• Hydrolysis Reaction: the components of water are added
Organic Molecules
• Macromolecules = BIG molecules
• Carbohydrates CH2O
• Lipids CHO
-don’t form true polymers, the number of
unit molecules that join together is limited
Proteins CHON
• Nucleic Acids CHONPS
Carbohydrates
• Some Functions:
– Quick fuel
– Short-term energy storage
– Structure of organisms
– Cell to cell recognition
Carbohydrates
• Simple Carbohydrates
Carbohydrates
• Simple Carbohydrates
– Monosaccharides are sugars with 3 - 7
carbon atoms
Carbohydrates
• Simple Carbohydrates
– Monosaccharides are sugars with 3 - 7
carbon atoms
– Pentose refers to a 5-carbon sugar
– Hexose refers to a 6-carbon sugar
Carbohydrates
Three ways to represent the structure of glucose.
Carbohydrates
• Disaccharides contain two monosaccharides.
Carbohydrates
• Polysaccharides are long polymers that
contain many glucose subunits.
Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
– Glycogen is the storage form of glucose in animals.
Carbohydrates
• Polysaccharides are long polymers that contain
many glucose subunits.
– Starch is the storage form of glucose in plants.
– Glycogen is the storage form of glucose in animals.
– Cellulose can be found in the cell walls of plants.
Carbohydrates: starch
Carbohydrates: cellulose
Carbohydrates: glycogen
A3 concept check-up questions
• What is the difference between
dehydration synthesis and hydrolysis?
• Why do lipids not form true polymers?
• Water is a by-product of condensation
reactions. Where does it come from?
• How does the use of glucose in a plant
differ from its function in an animal?
Lipids
Lipids
• Some Functions:
– Energy Storage
– Found in the plasma membrane
– Component of steroid hormones
Lipids do not dissolve in water
Lipids
• Some Functions:
– Energy Storage
– Found in the plasma membrane
– Component of steroid hormones
Lipids do not dissolve in water
Lipids are electrically neutral
Lipids
• Fats and Oils
Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
Lipids
• Fats and Oils
– Fats
• Usually of animal origin
• Solid at room temperature
– Oils
• Usually of plant origin
• Liquid at room temperature
Lipids
• Functions of Fats
Lipids
• Functions of Fats
– Long-term energy storage
– Insulation against heat loss
– Protection of major organs
Lipids
Synthesis and degradation of a fat molecule
Lipids
Emulsification
Lipids
• Saturated and Unsaturated Fatty Acids
Lipids
• Saturated and Unsaturated Fatty Acids
– Fatty acids are hydrocarbon chains that end
with -COOH.
Lipids
• Saturated and Unsaturated Fatty Acids
– Fatty acids are hydrocarbon chains that end
with -COOH.
• Saturated fatty acids: No double covalent
bonds between carbon atoms
• Unsaturated fatty acids: Double bonds
between carbon atoms
Lipids
Saturated Fatty Acid
Unsaturated Fatty Acid
Lipids
• Phospholipids
Lipids
• Phospholipids
– Comprised of 2 fatty acids + a phosphate group
– Primary components of cellular membranes
Lipids
Lipids
• Steroids
Lipids
• Steroids
– All steroids have four adjacent rings.
Lipids
• Steroids
– All steroids have four adjacent rings.
– Examples:
 Cholesterol
 Testosterone
 Estrogen
Lipids
A4 concept check up questions
• What is the defining characteristic of
lipids?
• What differences exist between fatty acids
from animal sources and fatty acids from
plant tissues?
• List the ways glycerides can be different
from each other.
• Name two types of lipids that do not
contain glycerol.
Proteins
• Proteins have important functions in cells.
– Proteins such as keratin and collagen have
structural roles.
– Proteins are also enzymes that speed up the
chemical reactions of metabolism.
– Proteins such as hemoglobin are responsible
for the transport of substances within the
body.
– Proteins also transport substances across cell
membranes.
Proteins
• Proteins have important functions in cells.
– Proteins form the antibodies of the immune
system that defend the body from disease.
– Proteins such as insulin are hormones that
regulate cellular function.
– Contractile proteins such as actin and myosin
allow parts of cells to move and muscles to
contract.
Proteins
• Proteins are comprised of amino acids.
Proteins
• Amino acids
– Amino group (-NH2)
– Acidic group (-COOH)
– R group (remainder)
Proteins
Proteins
• Peptides
– A polypeptide is a single chain of amino acids.
– A peptide bond joins two amino acids.
Proteins
Proteins
• Levels of Protein Organization
– The structure of a protein has three or four
levels of organization.
– The final shape of a protein is very important
to its function.
Proteins
Proteins
Proteins
A5 concept check-up questions
• Describe the common structure of amino acids.
• What type of bond is a peptide bond? Where
can one be found?
• What are two types of secondary structure in
proteins? What causes the formation of each?
• What types of bonds and what level of structure
is destroyed when a protein is denatured?
Nucleic Acids
• DNA (deoxyribonucleic acid)
Nucleic Acids
• DNA (deoxyribonucleic acid)
• RNA (ribonucleic acid)
Nucleic Acids
• DNA stores genetic information in double
helix.
• DNA codes for the order of amino acids in
a protein.
• RNA is an intermediary in the sequencing
of amino acids into a protein.
Nucleic Acids
• Components of a
nucleotide
– Phosphate
– Pentose sugar (ribose
or deoxyribose)
– Nitrogen-containing
base may be 2-ring
purine (A, G) or 1-ring
pyrimidine (C, T, U)
Nucleic Acids
DNA Structure
Nucleic Acids
Nucleic Acids
• ATP (Adenosine Triphosphate)
Nucleic Acids
• ATP (Adenosine Triphosphate)
– A high energy molecule
– ATP undergoes hydrolysis (enzyme ATPase)
and energy is released
– ATP can be converted to ADP and
“recharged” by phosphorylation when 3rd P
group is added back on
Nucleic Acids
A6 concept check-up questions
• How do the components of a DNA
nucleotide differ from those in an RNA
nucleotide?
• What’s the difference between a purine
and a pyrimidine?
• What two types of biochemicals make up
chromosomes?
• Describe the bonds between the
phosphates in ATP. What is their function?