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Chemistry of Living Systems

Chemistry of Living Systems. Atom : smallest unit of matter Three components of an atom are… Electrons -1 Protons +1 Neutrons 0. Chemistry of Atoms. Found outside the nucleus. Found in the nucleus. Found in the nucleus. Isotopes.

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Chemistry of Living Systems

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  1. Chemistry of Living Systems

  2. Atom: smallest unit of matter Three components of an atom are… Electrons -1 Protons +1 Neutrons 0 Chemistry of Atoms Found outside the nucleus Found in the nucleus Found in the nucleus

  3. Isotopes • Versions of the same element – but have different numbers of neutrons

  4. Count the electrons! • # of electrons in the outer shell are clues! • Called Valence electrons • Provides hints on how and what types of bonds form • Greater than 4 in the outer shell will take from other atoms • Less than 4 in the outer shell will give to other atoms

  5. Chemistry - Reactions • Ready, Set, GO – Reactants are the starting materials in a reaction. • The reactants are what is put into the reaction. • What you get is your product – what comes out of the reaction

  6. Chemistry - reactions • In the cartoon, the skinny bird (reactant) and the worm (reactant) combine to make one product, a fat bird.

  7. Endothermic and Exothermic • Endothermic reactions energy is taken in from the surroundings • Exothermic reactions Heat energy is released (GET HOT) • ICE to WATER and WATER to ICE

  8. pH • Acids have low pH’s – less than 7 • Bases have high pH’s – more than 7 • Neutral items have a pH of 7

  9. Elements Essential to Life • About 25 elements are essential to living organisms • CHNOPS: Make up 97% of living matter

  10. Natural Elements in the Human Body

  11. Chemical Bonds Chemical Bonds are the attractive force that hold atoms together in a molecule Bonds form when electrons are shared OR transferred between atoms • Covalent bonds – sharing electrons (“co-” means to share as in cooperate) • Ionic Bonds – give and take electrons • Hydrogen Bonds – weak attractions between molecules Stronger atoms try to “steal” the H’s electron, but it keeps a tiny hold on it.

  12. Nonpolar Covalent Bonds • Electrons are shared equally

  13. Polar Covalent Bonds • Share electrons as in other covalent bonds, but the nucleus of one atom attracts the electrons more strongly so it is not equal.

  14. Bonds, types of bonds

  15. CARBON Why is carbon so important in biological molecules? Carbon is easy to synthesize (break down and be used). Molecules with carbon are called ORGANIC Molecules without carbon are called INORGANIC

  16. What are the important molecules of life?

  17. WATER

  18. The Structure of Water • “V” shaped molecule • Unequal sharing of electrons causes oxygen to have a slightly negative charge • called a polar molecule

  19. Properties of Water • Cohesion is the tendency of molecules of the same kind to stick to one another. • Water has stronger cohesion than most liquids

  20. Water molecules are also attracted to certain other molecules • Attraction between unlike molecules is called adhesion

  21. Cohesion pulls molecules at the surface tightly together, forming a film-like boundary • This is surface tension

  22. Carbohydrates(C,H, and O molecules in a ratio of 1:2:1) Carbohydrates are an important energy source for cells.

  23. TYPES OF CARBOHYDRATES Monosaccharide – simple sugars made of one sugar molecule. (ex. Glucose)

  24. TYPES OF CARBOHYDRATES • Disaccharides – (ex. Sucrose) 2 monosaccharides linked together

  25. TYPES OF CARBOHYDRATES • Polysaccharides – ex. Starch, Cellulose) More than two sugars linked together.

  26. Did you notice how the sugars all sound the same? • They all end in “-ose” (-ose = sugar) • Ex. Sucrose, Glucose, Fructose, Lactose

  27. TYPES OF CARBOHYDRATES • Simple Carbs ~ mono and disaccahrides • Complex carbs ~ starches, polysaccharides

  28. LIPIDS Made up of two parts: • A head (it is hydrophillic) • A tail made of a hydrocarbon chain (it is hydrophobic). This lets the lipids form bilayers creating waterproof barriers like in a cell’s membrane.

  29. LIPIDS • Fatty acids, waxes, fats, steroids and oils are formed by lipids (all are insoluble in water)

  30. Steroids and Cholesterol • Steroids include such well known compounds as cholesterol, sex hormones, birth control pills, cortisone, and anabolic steroids.

  31. Cholesterol • The best known and most abundant steroid in the body is cholesterol. • It is the major compound found in gallstones and bile salts. Cholesterol also contributes to the formation of deposits on the inner walls of blood vessels.

  32. Proteins • Molecules made up of one or more chains of amino acids. They are used for many functions…

  33. Proteins are used for… • Structure – they make collagen in skin and keratin in hair/nails/horn

  34. Proteins are used for… • Movement ~ actin and myosin in muscle stimulate the muscle to move

  35. Proteins are used for… • Defense ~ antibodies in bloodstream

  36. Proteins are used for… • Storage ~ corn seeds are predominately made of protein

  37. Proteins are used for… • Signals ~ growth hormones in your blood stream

  38. Proteins are used for… • Catalysis ~ enzymes which speed up processes in the body

  39. Nucleic Acids • Nucleic Acids (used in DNA or RNA) – long chains of pieces called nucleotides. A nucleotide has 3 parts… 1. five carbon sugar (ribose or deoxyribose) 2. phosphate group 3. Nitrogen base (A,T,C or G)

  40. Nucleic Acids

  41. So what is an Enzyme? An enzyme is used to speed things up or help break things down in your body.

  42. Words You Should Know • Enzyme (E): protein catalyst • Catalysts: speed up reactions without being changed by the reaction • Substrate (S): reactant(s) in the enzyme-catalyzed reaction • Active site: area of enzyme where substrate(s) bind(s)

  43. Enzymes • Enzymes are proteins with a SPECIFIC SHAPE • The active site is a part of the protein which recognizes and binds to the substrate • Cofactors (e.g. Zn 2+, Cu 2+, B vitamins) some enzymes won’t hook-up to a substrates without these

  44. Specificity • ‘Lock and Key Model’ – says there is a perfect fit between active site and substrate • Modified to ‘Induced Fit Model’ - active site can expand or contract to “fit” the substrate shape • The induced fit model allows for small differences (possibility of letting several different kinds of substrates hook up)

  45. How do enzymes speed up reactions? Enzymes lower the activation energy (EA=amount of energy that reactant molecules require to start a reaction)

  46. Enzymes • Are involved in every biochemical reaction and thereby control metabolism • Are named according to the reaction that they facilitateExamples: Sucrase breaks down sucrose into glucose and fructose • DNA Polymerase helps build DNA polymers

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