Biomolecules Ch - 2The Molecules of Life. Molecules are combinations of atoms What are the 4...
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Transcript of Biomolecules Ch - 2The Molecules of Life. Molecules are combinations of atoms What are the 4...
Biomolecules
Ch - 2The Molecules of Life
Molecules are combinations of atoms
• What are the 4 elements that make up 96% of living matter?
• Carbon C• Oxygen O• Nitrogen N• Hydrogen H
Importance of Carbon
• Carbon has 4 valence electrons• carbon can create strong skeletons or backbones
Carbon bonds with Carbon
• Biomolecules have carbon backbones – They are organic molecules
• C-skeletons: straight chain, branched chain, ring
Carbon bonds with Hydrogen
• Hydrocarbons are molecules composed of only hydrogen and carbon
• Are hydrophobic
Carbon bonds with functional groups
• Functional groups are groups of atoms that interact in predictable ways
• Functional groups attach to carbon backbones to create biomolecules
Hydroxyl Group
• alcohols• polar– Hydrophilic – Soluble in water
Found in sugars
Carbonyl
• Ketones (within) and aldehydes (on the end)• Polar• Found in sugars
Carboxyl Group
• carboxylic acids• Polar• Acidic • Found in fatty acids and proteins
Amino Group
• Amines• Polar• Basic• Found in amino acids (proteins)
Phosphate Group
• Store/transfer energy• Polar; water soluble• Found in nucleic acids • Found in ATP (adenosine triphosphate) = cell
energy
Monomers & Polymers
• Biomolecules are combinations of smaller molecules called monomers
• Monomers link together to form polymers
Building and breaking polymers
• dehydration synthesis = monomers combined to make polymers
Building and breaking polymers
• Hydrolysis = polymers are broken into monomers
4 Biomolecules
• All polymers are classified into one of 4 biomolecules:– Carbohydrates– Lipids– Proteins– Nucleic Acids
Carbohydrates!
Carbohydrates
• Ring shape • Provide and store energy; building material in
plants
Carbohydrates
• Carbs are hydrophilic– Full of hydroxyls and carbonyls
Monosaccharides
• 1 ring• Example: Glucose (C6H12O6)• energy source
Disaccharides
• Double Sugars (oxygen bridge)• Example: Sucrose • immediate energy or stored
Polysaccharides
• Long polymer of sugar monomers• Complex carbs• Starch: chain of glucose monomers– used by plants as sugar storage– Animals can break down starch to release glucose
and energy
Polysaccharides
• Glycogen– Used by animals to store extra sugar– Stored in the liver
Polysaccharides
• Cellulose– Used by plants for building material– Most animals cannot break down cellulose; passes
through body as fiber• Chitin– Used by fungi for building material
Lipids!
Lipids
• ALL hydrophobic
Lipids: Phospholipids
• Phospholipids: form cell membranes
Lipids
• Fats (triglycerides) 3 C backbone (glycerol) attached to 3 long chains of hydrocarbons (fatty acids)
• Store energy, cushion organs, insulate
Lipids: Fats• Saturated fats– all fatty acids have maximum H atoms– Solid at room T
• Unsaturated fats– One or more double bond in fatty acid chain, causing in to
kink
Which do you want to limit in your diet?
Lipids: Steroids
• C-skeleton of 4 fused rings• Steroids are chemical signals– Cholesterol = essential in cell membranes; building
block of other steroids
Proteins!
When there is something to do, it is a protein that does it.
Proteins
• Proteins have many important functions. Some are:– Antibodies– Receptors– Enzymes – Neurotransmittors– Energy Storage– Build and Repair muscles and tissue
Amino Acids
• Proteins are polymers made up of monomers called amino acids
• Amino Acids consist of one central C bonded to 4 partners:– H-atom– Carboxyl– Amino– An “R-group”
Polypeptides
• Amino acids link together forming peptide bonds
Protein Structure
• Polypeptides take shape to from a protein.• Each protein has its own unique 3-D shape
that determines its function• The shape of a protein is determined by how
its amino acids interact
Denaturation
• Proteins can be unraveled and changed by changes in temp, pH, or other changes in environment
Enzymes
Protein: Enzymes
• An enzyme is a biological catalyst• Lower the activation energy of a specific
reaction– allow chemical reactions in cells to occur at
normal temperatures
Protein: Enzymes
• Each enzyme has a specific job• Used again and again• Ability depends on shape
Protein: Enzymes
• Substrate molecules fit into active site, enzyme molds around substrate– enzyme-substrate complex
• Enzyme breaks up the substrate