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Biomolecules. H. C. H. H. H. Structural formula. Ball-and-stick model. Space-filling model. Models of Methane. The Molecular Logic of Life. Small molecules, common to all organisms, are arranged into unique macromolecules (Campbell p. 62). Macromolecules.
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H C H H H Structural formula Ball-and-stick model Space-filling model Models of Methane
The Molecular Logic of Life Small molecules, common to all organisms, are arranged into unique macromolecules (Campbell p. 62)
Macromolecules Many complex biological activities require large macromolecules Macromolecules are polymers poly: “many” mer: “units” ex: proteins, nucleic acids, starches
Polymers are built by covalently linking together small similar (or in some cases, identical) subunits/building blocks called monomers mono: “one” mer: “unit” ex: amino acids, nucleotides, monosaccharides
4 Classes of Organic Compounds“Biomolecules”Proteins are polymers of amino acidsNucleic acids are polymers of nucleotidesStarches are polymers of simple sugars called monosaccharidesLipids aren’t REALLY polymers, since they don’t have repeating chains. BUT they are important biomolecules. The building blocks (monomers) of some types of lipids are glycerol and fatty acids
Macromolecules- why are they so important? • Each macromolecule performs complex tasks with precision • The basic structure and function of each class of macromolecules is similar in all organisms (from the simplest bacteria to complex humans)– indicates an evolutionary link.
Carbohydrates • Sugars • Monomer =(CH2O)n • Monosaccharides:Glucose • Oligosaccharides: Sucrose • Polysaccharides: Cellulose • Energy storage and structure
Sugars • Monosaccharides • Five carbon: Ribose • Six carbon: glucose and fructose • Disaccharides • Sucrose • Lactose • Polysaccharides • Starch • Glycogen • Chitin • Cellulose
fructose glucose + H2O sucrose
Cellulose chains Starch chain
cellulose glycogen amylose (a starch)
Two Types for Storage • Glycogen – animal energy storage • animal energy storage product that accumulates in the liver/muscles • Highly branched • 2. Starch – plant energy storage • Helical • Easily digested by animals through hydrolysis
Lipids Functions: • Long-term energy storage/insulation (fats) • Structural components of cells (phospholipids) • Cellular messengers (hormones)
Lipids • Fats and oils • Monomer = CH2 • Fats 1,2 or 3 fatty acids attached to glycerol • Sterols- Cholesterol, Steroids • Waxes- Beeswax • Used for waterproofing, insulation and cell membranes
FATS • Triglycerides are composed of three fatty acids covalently bonded to one glycerol molecule • Fatty acids are composed of CH2 units and are hydrophobic • Fatty acids can be saturated (all single bonds) or unsaturated (one or more double bonds) • A fat (mostly saturated) is solid at room temp., while an oil (mostly unsaturated) is liquid at room temp.
hydrophilic head hydrophobic tails
stearic acid oleic acid linolenic acid
one layer of lipids one layer of lipids hydrophilic head two hydrophobic tails cell membrane section
Sterol backbone Cholesterol
Proteins • 50% dry weight of body • Mammal cell contains 10,000 proteins • Enzymes (regulate chemical reactions) • Structural elements (cell membrane, muscles, ligaments, hair, fingernails) • Carriers (regulate what goes into/out of cells) • Send and receive messages (hormones) • Movement
Proteins • Monomer= Amino Acid • Enzymes- Catalyze metabolic reactions • Transport proteins- move things across membranes • Structural proteins-keep the structure of cells
Amino group (basic) Carboxyl group (acidic) R group (20 kinds with distinct properties)
Protein Assembly • AA’s are linked together by joining the amino end of one molecule to the carboxyl end of another • Peptide bond forms a chain called a polypeptide http://www.biotopics.co.uk/as/aminocon.html
Protein Structure • Primary structure • Specific linear sequence of AA’s in a polypeptide • Determined from code in inherited genetic material • Changes in primary structure can alter proper functioning of the protein
one peptide group Linear primary structure
Secondary structure • the tendency of the polypeptide to coil or pleat due to H-bonding between R- groups • -helix, -pleated sheet, or random coil
Tertiary structure Secondary structure
Secondary structure Tertiary structure
Tertiary structure • shape of entire chain; folded, twisted, or • globular • shape related to function and properties
Quaternary structure • more than one polypeptide chain
heme group alpha chain beta chain helically coiled globin molecule beta chain alpha chain
Nucleic Acids • Polymers composed of monomer units known as nucleotides • Information storage • DNA (deoxyribonucleic acid) • Protein synthesis • RNA (ribonucleic acid) • Energy transfers • ATP (adenosine tri-phosphate) and NAD (nicotinamide adenine dinucleotide)
Nucleic Acids • Monomer: Nucleotide • ATP is a Nucleotide • Molecules of inheritance: hold the code for how to make proteins • Deoxyribose Nucleic Acid- DNA • Ribose Nucleic Acid- RNA
nitrogen- containing base Ball-and-stick model of ATP sugar 3 phosphate groups
Functions of Nucleic Acids • DNA – Physical carrier of genetic information • Restricted to nucleus • RNA – key component of protein synthesis • Messenger RNA (mRNA) – blueprint for construction of a protein • Ribosomal RNA (rRNA) – construction site where the protein is made • Transfer RNA (tRNA) – truck delivering the proper AA to the site of construction
Adenine (a base) Thymine phosphategroup sugar (deoxyribose) Guanine Cytosine
Single strand of DNA or RNA base phosphate connected by covalent bond sugar
covalent bonding in carbon backbone hydrogen bonding between bases