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Biochemistry of Cells
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Carbon-based Molecules
•Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules
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Organic chemistry is the study of all compounds that contain C – C bonds
Uses of Organic Molecules•Americans consume an average of 140 pounds of sugar per person per year
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Cellulose, found in plant cell walls, is the most abundant organic compound on Earth
Uses of Organic Molecules• A typical cell in
your body has about 2 meters of DNA
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A typical cow produces over 200 pounds of methane gas each year
Large Hydrocarbons:• Are the main
molecules in the gasoline we burn in our cars
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The hydrocarbons of
fat molecules provide energy for our bodies
Carbon is a Versatile Atom
• Two reasons why carbon is so important:
• 1. It has four electrons in an outer shell - so carbon can share its electrons with 4 OTHER atoms
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2. Carbon can use its bonds to attach to other CARBONS to form an endless
diversity of carbon skeletons
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4 Major Groups of Organic Macromolecules
•Proteins
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Lipids
CarbohydrateNucleic Acids
MACROMOLECULES•“giant” molecules made from joining smaller units together = polymers
•Mono = one
•Poly = many
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Make a chart like this in your notes:
Macromolecule
Examples Monomer Function
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Carbohydrates
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Carbohydrates
•Living things use carbohydrates as their main source of energy.
•Plants and some animals use carbohydrates for structural
purposes.
•Carbohydrates include:• Small sugar molecules•Long starch molecules
•
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Monosaccharides = 1
•Glucose is found in sports drinks
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Fructose is found in fruitsHoney contains both glucose & fructoseGalactose is called “milk sugar”
Polysaccharides = many
•Complex carbohydrates
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Composed of many sugar monomers linked together
Glycogen• Glycogen is an example
of a polysaccharide in animals
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Animals store excess sugar in the form of glycogen
Cellulose• Cellulose is an
example of a polysaccharide in plants.
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It is a major component of wood
It is also known as dietary fiber
Lipids
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Lipids
• - Include fats, waxes and oils• - Lipids are hydrophobic –”water fearing”
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They do NOT mix with water
FAT MOLECULE
Function of Lipids
- store energy- insulate the body- main component of cell membranes
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Many lipids are fatty acids.
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Nucleic Acids
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Nucleic Acids
•Store hereditary information
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Contain information for making all the body’s proteinsDNA & RNA
Nucleic Acids
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Nitrogenous base(A,G,C, or T)
Phosphategroup
Thymine (T)
Sugar(deoxyribose)
Phosphate
BaseSugar
Monomer: nucleotide
Nucleotide
Proteins
• monomers = amino acids (20 of them)
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Proteins are used by the body in many ways:
•catalysts
•structure (building)
•transport
•contracting (muscles)
Some Types of Proteins
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Structural
Contractile
Transport
Proteins as Enzymes (Catalyst)
• Many proteins act as catalysts or enzymes – they make chemical reactions go faster.
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Thousands of different enzymes exist in the body.
Enzymes fold into specific shapes so that they can “recognize” their substrate.
Chemical reactions involve breaking and reforming bonds
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reactants
substrate
products
Substrates are the reactants that enzymes work on
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Enzymes provide a site where reactants come together to react!
How the Enzyme Works
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Enzyme Key Points:
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• Enzymes make reactions go FASTER
• Enzymes are NOT used up
• Enzymes are SPECIFIC
• Enzymes are sensitive to temperature and pH
Denaturating Proteins
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Changes in temperature & pH can denature (unfold) a protein so it
no longer worksCooking denatures protein in eggs
Milk protein separates into curds & whey when it denatures
Effect of temperature and pH on enzymes
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Summary of Key Concepts
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Macromolecules
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Macromolecules
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Biochemistry Vocabulary
• Organic• macromolecule• carbohydrate• saccharide (mono, di, poly)• protein• amino acid• lipid• nucleic acid• nucleotide
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Organicmacromoleculecarbohydratesaccharide (mono, di, poly)proteinamino acidactive siteenzymesubstratecatalystlipidnucleic acidnucleotide
• active site• enzyme• substrate• catalyst
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