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Lipids

Lipids. tucsoncitizen.com. Lipids. Organic compounds that are not soluble in water Small molecules that DO NOT form polymers. Grouped together because they are all hydrophobic . Contain mostly carbon and hydrogen. (Long hydrocarbon strands) Typically involved in energy storage

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Lipids

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  1. Lipids tucsoncitizen.com

  2. Lipids • Organic compounds that are not soluble in water • Small molecules that DO NOT form polymers. • Grouped together because they are all hydrophobic. • Contain mostly carbon and hydrogen. (Long hydrocarbon strands) • Typically involved in energy storage • 2X more energy per gram than carbs! • 3 main types: • Fats a.k.a. glycerides (most common) • Steroids • Phospholipids

  3. Lipids • Fats / glycerides • Large molecule in two parts • Alcohol “head” + 3 fatty acids • Glycerol = Alcohol with 3 Carbons, each bearing a hydroxyl (OH) group. • Fatty acid = Long Carbon skeleton with a carboxyl group (COOH) at one end.

  4. Lipids • Fats / glycerides • Large molecule in two parts • Alcohol “head” + 3 fatty acids chm.bris.ac.uk

  5. Lipids • Fats / glycerides • Large molecule in two parts • Glycerol “head” + 3 fatty acids chm.bris.ac.uk This bond between glycerol and each fatty acid is called an ester linkage and is formed by a dehydration reaction.

  6.  Note: The fatty acids that dock on the alcohol are not usually all of the same type as shown here.

  7. Lipids • Fats / glycerides • Saturated fatty acids – Lack double bonds between Carbon atoms, so the chains bond tightly together via hydrogen bonds. • Solid at room temperature • Usually animal-derived fats (also cocoa butter and coconut oil) • Causes an increase in cholesterol  heart disease

  8. Lipids • Fats / glycerides • Unsaturated fatty acids – Double bonds between Carbons create “kinks” in the chains. (polyunsaturated = 2+ double bonds) • Typically liquid (oil) at room temperature • Usually plant-derived fats

  9. Lipids • The danger of “trans fats” • Most unsaturated fats have cis double bonds • Oil that is repeatedly heated can switch to trans double bonds • Raisescholesterol • Linked tosome cancers

  10. Lipids • The danger of “hydrogenated oils” • Goal  make foods stable; change from oily to creamy. • Process  bubble Hydrogen through unsaturated oils. • Product  more saturated fat AND creation of trans fats. rtheyallyours.blogspot.com

  11. Lipids • Fat is not bad! • Compact, mobile energy source • Adipose (fat tissue) cushions our vital organs • Insulates the body • Needed for brain function! mindcreators.com photos.igougo.com

  12. Lipids • All fats are not created equal… • Saturated and trans fats  linked to health issues • Polyunsaturated fats  neutral or positive effects • Omega-3 fatty acids = healthiest of the fats; reduces growth of fatty deposits that clog arteries. • Note: Low-fat diets often lackthe omega-3 levels needed for healthy cell functioning. targetwoman.com

  13. Lipids • Phospholipids • Large molecule in three parts (similar to glycerides!) • Alcohol “head” + 2 fatty acids + phosphate group • Glycerol = Alcohol with 3 Carbons, each bearing a hydroxyl (OH) group. • Fatty acid = Long Carbon skeleton with a carboxyl group (COOH) at one end. • Phosphate group = Phosphorus atom surrounded by four oxygen atoms. Hasa negative electrical charge (=polar). telstar.ote.cmu.edu

  14. Lipids • Phospholipids • Hydrophilic “head” and hydrophobic fatty acid “tails” create the unique orientation. • Phospholipidbilayer = Two layers of these phospholipids. Orientation is key to the structureand function of cell membranes. biologycorner.com

  15. Lipids • Steroids • Synthetic drugs made in laboratories. • Close relatives of the male steroid hormones. isteroids.com

  16. Lipids • Steroids Composed of 4 Carbon rings • Different steroids have different side chains Cholesterol = an important steroid that forms the outer membrane of all animal cells. Cholesterol is the precursor to testosterone and estrogen.

  17. Lipoproteins • HDL and LDL are cholesterol transporters • HDL = High-density lipoproteins  • “Good cholesterol” • Carries less cholesterol • Moves cholesterol out of arteries and to the liver • LDL = Low-density lipoproteins  • “Bad cholesterol” • Carries high amounts of cholesterol to tissues (including heart) • Cholesterolon arteries can form plaque  heart disease.

  18. Lipids • Lipid hormones act as signaling molecules. One cell releases a hormone and it “talks” to another cell far away. • Leptin= Protein-basedhormone produced byfat cells when the stomach is full so you stop eating. • ob/ob mouseGenetic defect resultsin the leptin not being sent. http://en.wikipedia.org/wiki/Ob/ob_mouse

  19. Nucleic Acids

  20. Nucleic Acids • Nucleotides = monomers of DNA/RNA (hereditary info) • Polynucleotides = polymers of nucleotides • Nitrogenous base • Pyrimidines = Single Carbon ring  Cytosine, Thymine and Uracil (C,T,U) • Purines = Double Carbon ring  Adenine and Guanine (A,G) • Pentose (5-Carbon) sugar • Ribose (RNA) • Deoxyribose (DNA) (lacks one Oxygen) • Phosphate group biologyjunction.com

  21. Nucleic Acids • RNA = Single polynucleotide chain. • Serve as the “copy” of DNA that gets transported out of nucleus. • DNA = Double polynucleotide chain – helix structure. • Blueprints for all the actions of a cell; stays in nucleus. • Chromosome = Single long DNA molecule (one double helix) each containing hundreds of genes. • Humans = 23 chromosome pairs. • Genome = Sum of all the genes in an organism. • Humans = 24,000 genes

  22. Nucleic Acids • Structure of DNA • 2 sugar-phosphate backbones are anti-parallel (divided highway) • Held together by Hydrogen bonds between the paired bases. Adenine (A) pairs with Thymine (T) Cytosine (C) bonds with Guanine (G) familyhistory101.com

  23. Complimentary strands = copying a strand of DNA means you are transmitting identical information on to daughter cells.

  24. The Central Dogma • DNA is the master copy • RNA is the message carrier • Proteins are the product DNA  RNA  Protein

  25. Proteins

  26. Proteins • Protein function… • Structural support • Storage (nutrients) • Transport • Cellular communications (EX: leptin) • Movement (motor proteins) • Defense against foreign substances (antibodies) • Catalyze chemical reactions (enzymes!)

  27. Proteins • Enzymes are a type of protein that are a biological catalyst • Catalysts = Speed up chemical reactions by lowering the activation energy (energy needed to start reaction) • Unchanged in process • Get recycled thousands upon thousands of times… in a single second • Ability to catalyze reactions depends on the enzyme’s shape

  28. Proteins • Protein structure… • Most structurally sophisticated molecules known • Thousands of different shapes • Composed of 1 or more polypeptides • Each type of protein has a unique conformation, or 3-D shape

  29. Proteins • Amino acids = organic monomers of polypeptides • Alpha Carbon • Amino group • Carboxyl group • Hydrogen atom • Side chain (R group) aloeveraibs.com

  30. Proteins • Polypeptides form when amino acids link together • Carboxyl group of one AA bonds to the amino end of another • Dehydration reaction  peptide bond R R R R

  31. Proteins • Side chains (R groups) • 20 different side chains, so 20 different amino acids. • Basis of thousands of types of proteins • The physical and chemical properties of the side chain determine the unique character of the amino acid. • Polar uncharged, polar acidic or polar basic • Nonpolar

  32. Examples of amino acids Nonpolar Polar Acidic  Polar  Polar Basic 

  33. Proteins • 4 levels of protein structure • Primary structure = Unique sequence of amino acids • Based on covalent bonds between amino acids • NOT RANDOM  specified in DNA sequence of nucleotides

  34. Proteins • 4 levels of protein structure • Secondary structure = Coils and folds that occur mostly due to hydrogen bonding between the amino and carboxyl groups • Not due to bonds between side chains wikipedia.org  sheet  helix

  35. Beta sheets dominate in fibrous proteins, such as a spider’s web silk Reinforcement of the hydrogen bonds makes silk stronger than steel of the same weight dearbornschools.org

  36. Proteins • 4 levels of protein structure • Tertiary structure = 3-dimensional structure of a polypeptide • Stabilized by lots of weak bondsand the hydrophobic/hydrophilicinteractions of the side chains.

  37. Proteins • 4 levels of protein structure • Quaternary structure = Multiple polypeptide subunits (2+) • Hemoglobin has four subunits

  38. Proteins • Side chains interact with each other to form an active site, which is where other molecules can bind to the protein. Ligand = any ion or molecule that bonds to the active site. Lock-and-key model = refers to the specificity of the bonding. student.biology.arizona.edu

  39. Protein activity! • Goals: Use beads and pipe cleaner to create the levels of protein structure and understand how an active site works. • Directions: • Arrange 10 beads on each pipe cleaner • Create one element of secondary structure (helix or sheet) • Orient each amino acid according to its chemical properties • Blackbeads = hydrophilic amino acids • White beads = hydrophobic amino acids

  40. Proteins • Shape is EVERYTHING when it comes to protein • Mutations can cause important changes in protein structure and therefore their function. • Glutamic acid  Valine in hemoglobincauses the disease sickle cell anemia

  41. Sickle Cell Disease

  42. Proteins • The environment can affect protein shape • Denatured = Tertiary structure is destroyed • Heat • Organic solvents (ethanol) • Acids (acetic acid) • Etc. wikipedia.org

  43. Staphylococcus

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