Transcript Chemistry Of Life

Chemistry Of Life:
Carbon & Macromolecules
Chapter 5
Carbohydrates
• Structure:
– Monosaccharides joined by glycosidic linkages
to form polysaccharides
• Function:
–
–
–
–
Precursor to other molecules
Structure
Cell ID (glycoproteins)
Energy storage
Monosaccharide Structures vary
due to…
•Number of carbon atoms
•Location of carbonyl (C=O) group
• Location of hydroxyl (-OH) group
• Linear and ring forms
Polysaccharides
• Polymerization
– Condensation reaction between two hydroxyl groups
called a glycosidic linkage.
Types of Polysaccharides
•
-glucose polymer = For STORAGE
• Starch (plants)
– Glycogen (animals)
•
-glucose polymer = For STRUCTURE
– Cellulose (plant cell walls)
– Chitin (fungi cell walls, some algae, many animal exoskeletons)
– Peptidoglycan (bacterial cell walls)
To Release Energy
• -Glycosidic Linkages Are Hydrolyzed by
Enzymes to Release Glucose
– Glycogen
• Phosphorylase
– Starch
• Amylase
•Glucose is then used to in the production
of ATP
Lipids
•Nonpolar
– Due to
hydrocarbons
•Hydrophobic
– Due to fatty acid
(hydrocarbon
chain bonded to
a carboxyl (—
COOH) group)
3 Types of Lipids Found in Cells
1. Fats (Triglycerides)
3 Types of Lipids Found in Cells
2. Steroids
Below: Cholesterol
3 Types of Lipids Found in Cells
3. Phospholipids
• Amphipathic
Selective Permeability of Lipid
Bilayers
Bond Saturation in the
Hydrocarbon Chain
• C=C can cause a “kink”
– Prevent close packing of tails
– reduce hydrophobic interactions
• Unsaturated fats
– Chains with at least one double bond
• Saturated fats
– No double bonds
– More chemical energy
Phospholipid Membrane
Factors That INCREASE
Membrane Permeability
•More C=C
•Shorter tail
•Fewer cholesterol molecules in the
membrane
•Increased Temperature
DNA
•Store and transmit biological information,
contained in the sequence of the bases.
•Carries the information required for the
growth and reproduction of all cells.
•Stable, resistant to degradation.
Nucleotides
Polymerization
DNA vs. RNA
• Differences:
1. RNA contains uracil instead of
thymine.
2. RNA contains ribose instead of
deoxyribose.
• The presence of the –OH group on
ribose makes RNA much more reactive
and less stable than DNA.
3. RNA is single stranded, can H+
bond with itself to create
loops/stems
Proteins
•
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•
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Structure
Storage
Transport
Defense
Catalysis
Signaling
Movement
Primary
o
(1 )
• Amino acid sequence
Structure
Secondary
• 3D shape from
H+ bonding
•
-helices

-pleated
sheets
o
(2 )
Structure
Tertiary
o
(3 )
Structure
• Interactions between R-groups or
between R-groups and the peptide
backbone
–
–
–
–
–
H+ bonds
hydrophobic interactions
van der Waals interactions
covalent disulfide bonds
and ionic bonds
Quaternary
o
(4 )
Structure
• Combinations of individual proteins that
make up larger, multiunit molecules
Denaturation: Protein loses shape due to improper
heat, pH, etc.