Bio100’15, Medina
Chapter 3
The Molecules of Life
Objectives: I will be able to:
1. Explain the significance of the carbon element in carbon-based life forms.
2. Sketch the carbon skeleton of a compound as a chain of single bonds, double bonds, and in ring formation.
3. Make a table to compare and contrast the monomers, functions, main components, & examples of the 4 molecules of life.
4. Compare and contrast the origin, function & shape of 4 complex carbohydrates: starch, glycogen, collagen, and chitin.
5. Make simple sketches of the 4 different lipids: fats, sterols, phospholipids, & waxes.
6. Sketch and label a DNA nucleotide.
CONTENT
I.
Organic Compounds: carbon-based molecules
A. Carbon Chemistry
Hydrocarbons: simplest organic compounds
Sketch examples of single carbon-carbon bond chemical structures (Methane, Ethane, & Propane)
Sketch 2 examples of carbon-carbon double bonding:
Sketch the chemical structure of a ring structure with and without double bonding;
Functional groups are groups of atoms directly involved in chemical reactions.
Examples of functional groups: hydroxyl –OH, carboxyl –COOH, methyl -CH3
Sketch methanol (methyl alcohol, simplest alcohol)
B. Monomers form Polymers
Draw a collar made out of beads. Label the Polymer and its Monomers
Polymerization through dehydration (removal of water molecule)
Break down of polymers by hydrolysis (adding water)
II.
Large Biological Molecules
A. Carbohydrates: energy source; composition: C = H2O; water soluble; types:
Sketch a glucose molecule:  Monosaccharides (monomer)= simple sugars, ring shaped
Quick-but-brief; Examples: Glucose, fructose, galactose, ribose, deoxyribose
 Disaccharides (monomer)= 2 simple sugars
Examples: Maltose, lactose, sucrose
 Polysaccharides (polymer): many monomers, complex sugars, chains of glucose (i.e.
10,000 glucose units in cellulose), slow-but-persistent
1. Starch: main Energy storage in plants
2. Glycogen: primary short-term E storage in animals, released as glucose
3. Cellulose: structure to plants, major source of insoluble fiber for humans (whole
grains & fresh fruit). Most abundant on Earth,
4. Chitin: shape & strength in external skeleton of arthropods,
B. Lipids: composition: C, O, H, water insoluble? ____
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Bio100’15, Medina
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More Hydrogen, in relation to O, than in carbohydrates
Major function: Energy storage, insulation, & hormone production.
Fats (most common): Glycerol + fatty acids.
1. Mono, Di, or Triglycerides (90% lipid weight in food)
2. Head: glycerol (alcohol functional group)
3. Tail: Fatty acid chains of C (4-22) and H atoms with carboxyl functional group.
Usually different fatty acids bind to the 3 “slots” or “docking” points in glycerol
head.
a. Types of fatty acids:
Sketch a trans and cis fat configurations:
 Saturated: only single bonds (straight chain), tightly packed, solid at
room temperature, ex:__________
 Unsaturated (Mono/Poly): >1 double bond, disorderly packed, liquid
at room temp., ex:______ Cis or Trans configuration,
• Trans fats (created by hydrogenation of unsaturated fats):
vegetable oils made industrially by partial hydrogenation for
softness in baked goods & to extend shelf-life; natural source:
vaccenic acid (meat and dairy prod.)
Sketch a triglyceride
Sketch a Saturated triglyceride fat
Sketch an Unsaturated triglyceride fat
Types of Fats and their effects:
Saturated
C-C
Cis fats
Unsaturated
C=C
Trans fats
Plant oils
Omega-3, Omega-6
Unhealthy, animal fat, full-fat dairies Hydrogenated processed Unhydrogenated,
Healthy, some fish
foods, solid at room
usually liquid at room
and plant oils,
temperature
temperature
liquid at room
temperature
Lower HDL
Lower HDL, increase
Slightly lower HDL, no Increase HDL
LDL
change in LDL
HDL (high-density lipoprotein) carries cholesterol from body liver, a lot is GOOD
LDL (low-density lipoprotein) cholesterol from liver body (i.e. heart), a lot is BAD
Homework: From your pantry or refrigerator, make a list of the good unsaturated fat foods that you can
identify versus a list of bad saturated/trans fat foods. Look at the labels and write down the amount of
saturated, unsaturated and trans fats.
 Sterols: cholesterol & steroid hormones,
Sketch each lipid:
o Composition: 4 interlocking rings, differ by type of side chains
o Function: Reproduction and growth (estrogen and testosterone), fat break down
(cholesterol), precursor of male and female hormones.
 Phospholipids: major component of the cell membrane,
o Composition:
 Hydrophilic Head: glycerol attached to a phosphate (PO4-) group
 Hydrophobic Tail: Chains of 2 fatty acids
o Function: protects, contains, controls flow of chemicals
 Wax: single fatty acid linked to a glycerol head, nonpolar; water impermeable
C. Proteins (polymers): large folded chain of amino acids (monomers)
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Bio100’15, Medina
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AKA polypeptides contain amino (-NH2) and carboxyl (-COOH) groups
Composition: C, O, H , N, plus one of 20 different R groups
Function: structure, protection, regulation, contraction, transport.
Shape: twists, turns, and folds  unique 3-D shape determines ________. Four levels of
protein structure due to electrochemical bonding and repulsion forces. DEMO: use tube
cleaners and beads to make:
a. Primary structure: straight chain of amino acids
b. Secondary structure: first fold 
c. Tertiary structure: second fold 
d. Quaternary structure: 2 tertiary structures joined together
 Denaturing proteins: unfolding structures by heat, pH, mechanical stress
 Examples: enzymes: initiate and speed up chemical reactions, highly specific, bind to a
substrate to produce a product; lipoproteins (protein + lipid): HDL (lipid<protein), LDL
(lipid>protein); glycoproteins (protein + carbohydrate chains) act as fingerprints to identify
the type of cell.
D. Nucleic Acids (polymers): C, O, H, N
 Function: store information
 Types: DNA (deoxyribonucleic acid) holds genetic information; RNA (ribonucleic acid)
involved in protein synthesis, & ATP (adenosine triphosphate) cell’s usable form of energy.
 Composition: Sketch a DNA nucleotide (monomer) with its 3 basic components:
a. Nitrogen-containing base (Adenine-Thymine, Guanine-Cytosine)
b. deoxyribose sugar ring
c. phosphate group
Checking: Name the 4 molecules of life and provide their main function:
________________________, function:____________________
________________________, 3 functions: ____________________, __________________& _________________
________________________, 3 functions: _______________, __________________ & ______________________.
________________________ function: ______________________________
Answer Questions 1-10, and either 15 or 16 on page 53 of your textbook.
Fill in the missing information:
Biological Molecules
Carbohydrates
C, H2O
Lipids
C, O, H
Proteins
C, O, H, N, R-grp
Nucleic acids
C, O, H, N, sugar,
phosphate
Types
1. Simple sugars
2. Complex sugars
1. Fats: glycerol+1-3 fatty acid chains
2. Sterols: 4 joined rings
3. Phospholipids: Phosphate head + 2 chains
4. Waxes: glycerol+one chain
1. Enzymes
2. Lipoproteins: lipid+protein
3. Glycoproteins: carb.+protein
1. DNA
2. RNA
3. ATP
Monomers
Polar/Nonpolar
--------------------------------------------------------------END-----------------------------------------------------------------Homework Chapter 4
1. Make a table to compare and contrast prokaryotic and eukaryotic cells for at least 4 characteristics. (1 pt)
2.On white paper, sketch, color, & label ALL the structures of an animal cell and a plant cell (p. 59). No black &
white. Specifically, color mitochondria red, chloroplasts green, RER purple, & SER yellow (6 pts).
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