1. The Chemistry
of Life
Heartlife 2012-2013
Teacher: Julie Pen
Science is Organized Knowledge

2. Elements of Life
• 96% of the human body is made up of:
– Oxygen
– Carbon
– Hydrogen
– Nitrogen
• Calcium, phosphorus, sulfur,
potassium, and other elements in trace
amounts

3. Organic Molecules
• Organic Compounds
– molecules within living things or arising from
previously living organisms
– contain Carbon
– ALSO contain C-H bonds
• nucleic acids
• fats (lipids)
• sugars (carbohydrates)
• proteins (+ enzymes)
• many fossil fuels
Carbon Atom

4. Carbon Bonding
• With four valence electrons,
carbon wants to form four
covalent bonds to become
stable (octet rule).
– many different bonding
configurations are possible
• straight chains
• rings
• branched chains
– many different molecule sizes
• 1 or 2 carbon atoms
• hundreds or thousands of carbon
atoms in a single molecule

5. Four Groups of Organic Molecules
• Carbohydrates
– fuel for cell functions
• Lipids
– stored energy and
membrane structure
• Nucleic Acids
– genetic information
• Proteins
– many cell functions

6. Carbohydrates
• Fuel for cell functions
• Made up of saccharides (sugars)
– Glucose
– Sucrose
– Dextrose
– Maltose
– Lactose
– Fructose
– Amylose
– Cellulose,
...and many more

7. Carbohydrates
I
Base (CH2O)n or H - C - OH
Structure: I
 Monosaccharides - simple sugars
made up of 3 to 6 carbons
 Disaccharides - 2 monosaccharides
covalently linked.
 Polysaccharides - polymers
consisting of chains of
monosaccharide or disaccharide
units.

8. Monosaccharides
Monosaccharides are simple sugars made up
of 3 to 6 carbons.
• The free ends of a straight
H
C
O monosaccharide chain often bond to
form a cyclic molecular structure
H C OH
HO C H
H C OH
H C OH
CH2OH
D-glucose

9. Disaccharides
Disaccharides are two monosaccharides covalently
linked.
• Maltose is made when starch is broken down – it is
simply two linked glucoses.
6 CH2OH 6 CH2OH
5 O 5 O
H H H H
H H
1 4 1
4 OH H OH H
OH O OH
3 2 3 2
H OH maltose H OH

10. Common Disaccharides
Other common disaccharides include:
Sucrose
(common
table sugar)
Lactose
(milk sugar)

11. Plant Polysaccharides
CH 2OH 6 CH OH CH2OH CH2OH CH 2OH
H O H H 5
2
O H H O H H O H H O H
Amylose often
H
OH H 1
H
4 OH H 1
H
OH H
H
OH H
H
OH H has 300 – 600
O O O O OH
OH
3 2
H OH
linked glucose
H OH H OH H OH H OH
amylose molecules
Plants store glucose as amylose or amylopectin, (commonly
called starch). Amylose is a glucose polymer.
• Cellulose (found in plant
roots, seed, fruits and tubers)
consists of long linear chains of
glucose.
– Cellulose provides strength
and rigidity to plant cell walls
and is not digestible by most
organisms (dietary fiber).

12. Animal Polysaccharides
CH2OH CH2OH
H O O
glycogen
H H H
H H
OH H OH H 1
O
OH
O
H OH H OH
CH2OH CH2OH 6 CH2 CH2OH CH2OH
H O H H O H H 5 O H H O H H O H
H H H H H
OH H OH H OH H 1 4 OH H OH H
4 O O
O O OH
OH 2
3
H OH H OH H OH H OH H OH
Glycogen is the glucose storage polymer in animals.
• The highly branched structure permits rapid release of
glucose from glycogen stores, e.g., in muscle during
exercise.
• The ability to rapidly mobilize glucose is more essential
to animals than to plants.

13. Lipids
• Formed from fatty acids
• Non-polar (hydrophobic) compounds
• Functions:
– Stored energy & insulation
• Triglycerides
– Cell membrane structure
• Phospholipids
– Steroids
• cholesterol
• testosterone
• estrogen
• bile acids
• Vitamin D
...and many more

14. Fatty Acids
Most fatty acids, the simplest lipids, are non-polar
acids
and thus repel water.
• If every carbon atom in a fatty
acid chain is joined to another
carbon atom by a single bond
(and 2 H atoms), it is said
to be saturated.
saturated
• from animals
• If a pair of carbon atoms is
joined by a double bond, it is
said to be unsaturated.
unsaturated
• vegetable and fish

15. Stored Energy Lipids
• Triglycerides are the
main form of lipid used
to store energy in the
body.
• They have a glycerol
backbone with three
fatty acid tails.
• When lipids are
metabolized (broken
down for use), they
produce LOTS of energy

16. Cell Membrane Lipids
Cell membrane lipids are amphipathic, having a non-polar
amphipathic
(hydrophobic) end and a polar (hydrophilic) end.
Phospholipids
have a
phosphate
group plus two
fatty acid tails.
Hydrophobic
tails hover
together while
the polar
heads align to
form a cell
membrane.

17. Steroids
HO
Cholesterol
• Steroids have a four fused carbon rings and a short branched
hydrocarbon tail.
• Cholesterol is a steroid found in membranes, and is the
precursor for synthesis of hormones (testosterone, estrogen,
etc.), bile acids and vitamin D.

18. Nucleic Acids
• Store, carry, and aid in the transmission of genetic information
• Only 2 types:
– deoxyribonucleic
acid (DNA)
– ribonucleic acid
(RNA)
• Made from
chains of
nucleotides

19. Nucleotide Structure
• Each nucleotide has three parts:
– Nitrogen base
• Adenine
• Cytosine
• Guanine
• Thymine or Uracil
– 5-carbon sugar
• Ribose or Deoxyribose
– Phosphate group
Sugar-Phosphate Backbone

20. DNA
Deoxyribonucleic acid
– Double-stranded helix
– Has the sugar Deoxyribose
– Forms chromosomes
• carry genetic information
– Uses four nucleotide bases
• Adenine
• Guanine
• Cytosine
• Thymine

21. RNA
Ribonucleic acid
– single stranded (usually)
– Has the sugar Ribose
– Transcribes DNA to
make proteins
– Four nucleotide bases
• Adenine
• Guanine
• Cytosine
• Uracil (instead of Thymine)

22. Proteins
• Made from 20 different amino acids
• Seven major functions (S3CDET):
– Storage: iron, amino acid storage
(seeds, milk & egg whites)
– Structural proteins: support and shape
(collagen in hair/nails,
microtubules/microfilaments)
– Signaling: membrane receptor proteins &
chemical messengers
– Contractile: cell movement
(cilia/flagella/pseudopodia, muscle)
– Defensive: against foreign substance and
disease-causing organisms (antibodies)
– Enzymes: biological catalysts
– Transport: hemoglobin

23. Amino Acids
• Amino acids are the building blocks of proteins.

24. Protein Structure
• Each protein is made from a specific sequences of amino acids
joined together by peptide bonds.
– There are 1,000s of different proteins!
• The sequence of amino acids will determine the physical
structure of the protein (how it folds).
 A single substitution
may result in a
protein that is not
folded properly
(sickle-cell anemia)
Protein Folding Video

25. Proteins
• Proteins have many different jobs
• function is often dictated by shape
• shape is determined by the amino
acid sequence that affects folding
• Examples: hemoglobin, flagella,
membrane receptors, hair, antibodies

26. Summary
• Carbohydrates
– Easy-access (fast) fuel for cell functions
– Formed from simple “sugars” or saccharides
– Glucose, Sucrose, Dextrose, Maltose, Lactose, Fructose,
Cellulose, Amylose
• Lipids
– Formed from fatty acids
– Mainly non-polar (hydrophobic) compounds
– Functions:
• Triglycerides - stored energy & insulation
• Phospholipid bilayer – cell membranes
• Steroids – cholesterol, estrogen, bile acids, Vitamin D, etc.
• Nucleic Acids
– Store, carry, and aid in the transmission of genetic information
– DNA & RNA - made from (chains of) nucleotides
– Each nucleotide has three parts:
• Phosphate group
• Nitrogen
• 5-carbon sugar (Ribose or Deoxyribose)
• Proteins
– Made from amino acids
– Seven major functions (S3CDET):
• Storage, Structure, Signaling, Contractile, Defensive,
Enzymes and Transport

27. Week 4 Lab
Microscope Orientation
Proper Use and Care
Newsprint wet mount
Salt crystals