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Chemistry of

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

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Chemistry of

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  1. Chemistry of Living Systems

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

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

  4. Isotopes • Versions of the same element – but have different numbers of neutrons (N) Z= number of protons (P) A=N+Z

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

  6. Natural Elements in the Human Body

  7. 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.

  8. Nonpolar Covalent Bonds • Electrons are shared equally

  9. 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.

  10. Ionic Bonding • One atom gets extra electron(s) (becomes a negative ion) and one gives extra electron(s) (becomes a positive ion) the two ions attract each other.

  11. Hydrogen Bond • When water molecules are close together, their positive and negative regions are attracted to the oppositely-charged regions of nearby molecules. • The force of attraction, shown here as a dotted line, is called a hydrogen bond. • The hydrogen bond has only 5% or so of the strength of a covalent bond.

  12. CARBON Why is carbon so important in biological molecules? Carbon forms 4 covalent bonds giving it the ability to create massive molecular chains. Molecules with carbon are called ORGANIC Molecules without carbon are called INORGANIC

  13. What are the important molecules of life?

  14. Water

  15. Properties of Water Movie

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

  17. 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

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

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

  20. Walking on Water

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

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

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

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

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

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

  27. 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.

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

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

  30. 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.

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

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

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

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

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

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

  37. 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)

  38. Catalysts • Catalyst ~ enzymes which speed up processes in the body

  39. Chemical Reactions Reactants and Products • A chemical reaction is the process by which atoms or groups of atoms in substances are reorganized into different substances. Chemical reaction • Clues that a chemical reaction has taken place include the production of heat or light, and formation of a gas, liquid, or solid. Physical reaction

  40. Chemical Reactions Chemical Equations • Chemical formulas describe the substances in the reaction and arrows indicate the process of change. • Reactants are the starting substances, on the left side of the arrow. • Products are the substances formed during the reaction, on the right side of the arrow.

  41. Chemical Reactions • Glucose and oxygen react to form carbon dioxide and water.

  42. Chemical Reactions Energy of Reactions • Theactivation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

  43. Chemical Reactions • This reaction is exothermic and released heat energy. • The energy of the product is lower than the energy of the reactants.

  44. Chemical Reactions • This reaction is endothermic and absorbed heat energy. • The energy of the products is higher than the energy of the reactants.

  45. It does not increase how much product is made and it does not get used up in the reaction. Chemical Reactions Enzymes • A catalyst is a substance that lowers the activation energy needed to start a chemical reaction. • Enzymes are biological catalysts.

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

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