Biological Molecules and Life's Components PDF - Carbohydrates, Lipids, and Proteins

Life’s Components: Biological Molecules Carbohydrates Lipids Proteins Nucleic Acids  Carbon: Central Element to Life Most biological molecules are built on a carbon framework  What is so special about Carbon??? Forms covalent bonds w/ other C atoms Great bonding capacity...

Life’s Components: Biological Molecules Carbohydrates Lipids Proteins Nucleic Acids  Carbon: Central Element to Life Most biological molecules are built on a carbon framework  What is so special about Carbon??? Forms covalent bonds w/ other C atoms Great bonding capacity 4 covalent bonds → Large complex molecules – Chains, Branches, Rings  What is so special about Carbon??? Electroneutral Never loses or gains electrons Always shares electrons equally Forms covalent bonds Forms stable bonds with variety of atoms  The complexity of living things is facilitated by carbon’s linkage capacity  4 Central Macromolecules Lipids Saturated Unsaturated Carbohydrates Simple sugars Complex Carbohydrates Starch Proteins Enzymes Muscle Nucleic acids RNA DNA  Lipids: several functions, including E storage ❑ Insoluble in water ❑ Nonpolar hydrocarbons ❑ Hydrophobic  “Hydro” “philic” – “Water Love” Love of Water Polar “Hydro” ”phobic” – “Water Fear” Fear of Water (repel water) Non-Polar chemical structure of olive oil What is Soap???  A sea turtle swims through a muck of oxidizing oil mingling with chemical dispersants used by BP to break up oil in the Gulf of Mexico (2010)— just a few weeks after the spill began. (Credit: nyt) COREXIT Study finds that Corexit in BP oilspill made the mixture 52 X more toxic than oil alone. (Rico-Martinez et al. Env. Poll. 2012) Oil spill dispersant  Lipids ▪ Non-polar 3 Types: ▪ Not dissolve in water ▪ ‘Greasy’ ▪ Store lots of E  Lipids Don’t have monomer-polymer structure No one structural element is common to all lipids.  Triglyceride Fats Glycerol: “head” region Fatty acid “tails” Solid @ RT Most fats people eat are triglycerides. Fats contain 2X more stored E than carbohydrate molecules Saturated vs. Unsaturated Fats Saturated: Unsaturated: 1C : 2 H C=C Straight –pack tightly so Crooked – can’t pack solid at room temp. together tightly so liquid at room temp.  Sterols: 4 Carbon Rings Cell membranes Hormones – regulate dev’l, memory, mood, sex Cholesterol (a) Four-ring steroid structure (b) Side chains make each steroid unique testosterone estrogen cholesterol Figure 3.11  Phospholipids Major component of cell membrane 2 fatty acids, glycerol, phosphate group (a) Phospholipid — structure variable phosphate glycerol group group polar head nonpolar tails (b) Phospholipid Like water Don’t like water orientation “like attracts like” nonpolar hydrophobic tails (fatty acids) exposed to oil oil (nonpolar) water (polar) polar hydrophilic heads exposed to water Figure 3.12  Waxes Important protection, prevent desiccation Most plants have protective waxy outer covering - cuticle  Carbohydrates Source of chemical energy (food) Structural Nutrient storage  Carbohydrates Suffix “–ose” C, H, O Primary fuel C-H bonds store lot of E Bonds easily broken  Carbohydrates Formed from monomer building blocks – simple sugars, such as glucose Monomers → larger polymers – polysaccharides or complex carbohydrates  Carbohydrates: simple sugars ❑ Fruits, Vegetables Complex Carbohydrates 4 polysaccharides critical to life – Starch nutrient storage form in plants. – Glycogen nutrient storage form in animals (liver, muscle). – Cellulose Rigid, structural in the cell walls of – Chitin Tough, forms exoskeleton of arthropods.  Table 3.3 Four Examples of Complex Carbohydrates Starch Glycogen Cellulose Chitin Structure Function Serves as a form of Serves as a form of Provides structural Makes up a large carbohydrate carbohydrate support for plants portion of the outer storage in many storage in animals and other organisms “skin” or cuticle of plants arthropods Example Starch granules Glycogen granules Cellulose fibers The chitinous cuticle within cells of a raw (black dots) within within the cell wall of a tick potato slice a liver cell of a marine algae cell Table 3.3  Starch Complex Carbohydrate ❑> 100’s of glucose molecules ❑ Barley, wheat, rye, corn, rice  Carbohydrates are important source of chemical energy  Carbohydrates → Glucose 3 fates of glucose in your blood Store E Long-term Short-term  Quick burst E sugars Slow release E Easily available Gradual breakdown Gone quick Retain E release longer Fruits Oatmeal, rice, pasta  Proteins Composed of monomers - amino acids (AA) Sequences of AA linked together → polypeptide chains  Proteins = String of Amino Acids AA – AA – AA – AA – AA – AA – AA – AA… Structural Hair, nails, Muscles tendons, cartilage Enzymes Hemoglobin  Amino Acids 20 different amino acids Amino Acid 1) Amino group 2) Carboxyl group 3) *Side chain 20 Amino Acids in Genetic Code The linkage of several amino acids... A typical protein would consist of hundreds of amino acids... produces a polypeptide chain like this: Figure 3.16 Four Levels of Structure in Proteins (a) Primary structure sequence of amino acids amino acid sequence (b) Secondary structure Structural motifs, alpha helix, beta pleated alpha helix sheets, random coils random coil beta pleated sheet (c) Tertiary structure folded polypeptide secondary structure interactions chain (d) Quaternary structure two or more polypeptide 2+ polypeptide chains chains Figure 3.18 Denature = looses shape … All Enzymes are Proteins that Catalyze Reactions  Enzymes are special types of proteins  “Misspelled” Proteins ❑ Incorrect amino acid sequence ❑ Active site disruptions Nucleic acids: Code Information Polymers composed of nucleotides  Two Types of Nucleic Acids ❑ Deoxyribonucleic acid (DNA) ❑ Ribonucleic acid (RNA) ❑ Bothdirecting production of proteins.  Nucleotides A-T DNA (deoxyribonucleic acid) C-G – Sugar (deoxyribose) – Phosphate group – Nitrogen-containing base (4 types) Repository of genetic information Base sequence codes for proteins and controls expression DOUBLE STRANDED (a) Nucleotides are the building blocks of DNA. Nucleotide nitrogenous sugar base (deoxyribose) DNA consists of two strands of nucleotides linked by hydrogen bonds phosphate group (b) A computer-generated model of DNA The outer “rails” of the double helix are composed of sugar and phosphate components of The rungs consist the molecule of bases hydrogen- bonded together DNA double helix Figure 3.19 DNA holds the genetic information to build an organism. Base-Pairing ❑A -T ❑G -C ❑ What is complimentary strand to: CCCCTTAGGAACC? CCCCTTAGGAACC GGGGAATCCTTGG  Information Storage ❑ Base Sequence (ATTCGGCTACG…) ❑ How genetic code is read  Nucleic Acids RNA (ribonucleic acid) A-U – Sugar (ribose) C-G – Phosphate group – Nitrogen-containing base Transports DNA code to sites of protein synthesis Types of RNA – Ribosomal, Transfer, Messenger SINGLE STRANDED  RNA differs from DNA in 3 ways… ❑ Sugar ❑ Ribose – RNA ❑ Deoxyribose - DNA ❑ Structure ❑ Singlestrand – RNA ❑ Double stranded - DNA ❑ N-Base ❑ Uracil (U) – RNA ❑ Thymine (T) - DNA  Table 3.5 Summary Table of Biological Molecules Type of Molecule Subgroups Examples and Roles Carbohydrates Monosaccharides Glucose: energy source Disaccharides Sucrose: energy source Polysaccharides Glycogen: storage form of glucose Starch: carbohydrate storage in plants; used by animals in nutrition Cellulose: plant cell walls, structure; fiber in animal digestion Chitin: external skeleton of anthropods Lipids Triglycerides: 3 fatty acids and glycerol Fats, oils (butter, corn oil): food, energy, storage, insulation Fatty acids: components of triglycerides Stearic acid: food, energy sources Steroids: four-ring structure Cholesterol: fat digestion, hormone precursor, cell membrane component Phospholipids: polar head, nonpolar tails Cell membrane structure Proteins Enzymes: chemically active Sucrase: breaks down sugar Structural Keratin: hair Lipoproteins: protein-lipid molecule HDLs, LDLs: transport of lipids Glycoproteins: protein-sugar molecule Cell surface receptors Nucleic acids Deoxyribonucleic acid (DNA) DNA contains information for the production of proteins Ribonucleic acid (RNA) One variety of RNA carries DNA’s information to the sites of protein production, the ribosomes; another variety of RNA helps make up ribosomes. Table 3.5