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(Bio)Chemistry and Cytology

(Bio)Chemistry and Cytology. BIOL241 Introduction or Recap of Cell Structure & chemistry. INTERCONNECTEDNESS. Matter and Energy Atoms, molecules, and chemical bonds Importance of organic and inorganic nutrients and metabolites

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(Bio)Chemistry and Cytology

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  1. (Bio)Chemistry and Cytology BIOL241 Introduction or Recap of Cell Structure & chemistry

  2. INTERCONNECTEDNESS • Matter and Energy • Atoms, molecules, and chemical bonds • Importance of organic and inorganic nutrients and metabolites • Structure and function of carbohydrates, lipids, proteins, and nucleic acids • Enzymes and ATP help run the metabolic reactions of the body

  3. Energy • The capacity to do work (put matter into motion) • Types of energy • Kinetic – energy in action • Potential – energy of position; stored (inactive) energy: chemical energy • Energy is easily converted from one form to another • During conversion, some energy is “lost” as heat

  4. Chemistry • Chemistry is the science that deals with matter • Matter is anything that takes up space and has mass • Smallest stable units of mass are atoms

  5. But I thought this was biology? • Mathematics (the language of science) • Physics (the structure of matter & energy) • Chemistry (organic and inorganic structure) • Biology: uses them all to understand Life.

  6. Atoms, Elements, Molecules • Elements are atoms of one particular type (see the periodic table) • Molecules are groups of atoms that (usually) contain more than one element 

  7. Biologically significant elements • 13 principal elements • Carbon (C) • Oxygen (O) • Hydrogen (H) • Nitrogen (N) • Calcium (Ca), phosphorus (P), potassium (K), Sulphur(S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe) • 13 trace elements • (e.g. zinc, manganese)

  8. Atoms with unfilled electron shells are reactive • Octet Rule • To become stable they form chemical bonds. • Three main types of chemical bonds • Intramolecular: • Ionic bonds (charged atoms resulting from the gain or loss of electrons) • Covalent bonds (electrons are shared) • Intermolecular • Hydrogen bonds

  9. Covalent & Ionic Bonds • Molecules: atoms held together by covalent bonds • Salts: molecules held together by ionic bonds Q: What are the strongest type of bonds?

  10. H2O The body is mostly water (~2/3rd of total body weight) so all chemical reactions in the body occur in water Covalent bonds are much stronger than ionic bonds in water

  11. H2O – “Special” Properties • Water can dissolve organic and inorganic molecules making a solution • Water is needed for chemical reactions • Water absorbs and retains heat • Water is an effective lubricant

  12. H2O • What is it about water that makes it so special? • Water has all these amazing properties due to its molecule’s ability to form hydrogen bonds

  13. H-bonds b/t + & - charges

  14. Mixtures and Solutions • Mixtures – two or more components physically intermixed (not chemically bonded) • Solutions – homogeneous mixtures of components • Colloids (emulsions) – heterogeneous mixtures whose solutes do not settle out • Suspensions – heterogeneous mixtures with visible solutes that tend to settle out

  15. Essential Molecules • Nutrients: • essential molecules obtained from food (you have to eat them to get them) • Metabolites: • molecules made or broken down in the body

  16. Organic vs. inorganic Organic molecules: • Always contain carbon with hydrogen, and sometimes oxygen • Often soluble in water Inorganic: Electrolytes, minerals, and compounds that do not contain carbon with hydrogen. • Important examples: oxygen, carbon dioxide, water, inorganic acids and bases, salts

  17. Vitamins and Minerals • Vitamins and minerals are essentialnutrients that are required in very small amounts for healthy growth and development. Examples? • They cannot be synthesized by the body and are essential components of the diet.

  18. Vitamins • Organic substances necessary for metabolism • There are 13 known vitamins (e.g. A, B1, D, K) • Some are fat soluble while others are water soluble • Are Coenzymes that help carry out the reactions of metabolism

  19. Minerals • Inorganic compound (often salts or elements) necessary for proper body function • Can be bulk or trace minerals • Are Cofactors in metabolic reactions

  20. Electrolytes • Inorganic ions (usually minerals) that conduct electricity in solution • Electrolyte balance is maintained in all body fluids; imbalance seriously disturbs vital body functions

  21. Electrolytes Table 2–3

  22. Biological Macromolecules • Life depends on four types of organic macromolecules: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids Can you think of an example of each?

  23. 1. Carbohydrates • Contain carbon, hydrogen and oxygen in a ratio of 1:2:1 • Account for less that 1% of body weight • Used as energy source • Called saccharides (sugars, starches)

  24. Glucose is a monosaccharide

  25. Disaccharides Sucrose Lactose

  26. Polysaccharides • Starch • Glycogen • Cellulose All are long strings of glucose molecules Difference lies in how they are bonded together

  27. Polysaccharides • Polysaccharides or polymers of simple sugars PLAY Polysaccharides Figure 2.14c

  28. Polymers • A polymer is any molecule made up of several repeating units. Starch is a polymer of glucose.

  29. 2. Lipids • Contain carbon, hydrogen, and oxygen but the ratio of C:H is 1:2 (much less O) • May also contain other elements, phosphorous, nitrogen, and sulfur • Form essential structures in cells • Are important energystores

  30. Lipids: Triglycerides(Fats and Oils) • Consist of 3 fatty acids and glycerol • Insulation • Energy • protection Q: What’s the difference between saturated and unsaturated?

  31. Lipids: Steroids and Cholesterol • All consist of a complex ring structure

  32. Lipids: Phospholipids Amphipathic

  33. 3. Proteins • Consist of chains of amino acids liked together by peptide bonds • Enzymes are proteins

  34. Protein Structure • Proteins are the most abundant and important organic molecules • Basic elements: • carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) • Basic building blocks: • 20 amino acids

  35. Protein Structure – 4 levels Primary: amino acid sequence Secondary: Hydrogen bonds form spirals or pleats (α-helix, β-sheet) Tertiary: Secondary structure folds into a unique shape Quaternary: several tertiary structures together: again: Shape!! Figure 2–20a

  36. Protein structure

  37. Shape and Function • Protein function is based on shape • Shape is based on sequence of amino acids • Denaturation: • loss of shape and function (due to heat, pH change or other factors)

  38. support: structural proteins movement: contractile proteins transport: transport proteins buffering: regulation of pH metabolic regulation: enzymes coordination and control: hormones defense: antibodies Protein Functions

  39. Activation Energy • Chemical reactions in cells cannot start without help • Activation energy gets a reaction started Figure 2–7

  40. Characteristics of Enzymes Figure 2.20

  41. Energy In, Energy Out • Exergonic reactions: • produce more energy than they use • Endergonic reactions: • use more energy than they produce

  42. KEY CONCEPT • Most chemical reactions that sustain life cannot occur unless the right enzymes are present

  43. How Enzymes Work • Substrates: • reactants in enzymatic reactions • Active site: • a location on an enzyme that fits a particular substrate

  44. Active site Amino acids + Enzyme (E) Substrates (S) Enzyme-substrate complex (E-S) H2O Free enzyme (E) Peptide bond Internal rearrangements leading to catalysis Dipeptide product (P) How EnzymesWork Figure 2–21

  45. 4. Nucleic acids • Contain C, H, O, N, and P • DNA and RNA are nucleic acids • Nucleotide consists of • Sugar • Phosphate group • Nitrogenous base

  46. Structure of DNA Figure 2.22b

  47. A nucleotide: ATP • Energy storage for cells • Many enzymes use ATP • Provides a way to run reactions that are otherwise endergonic (require energy)

  48. Membrane protein Pi P Solute Solute transported (a) Transport work ADP + ATP Pi Relaxed smooth muscle cell Contracted smooth muscle cell (b) Mechanical work Pi X P X Y + Y Reactants Product made (c) Chemical work ATP is the energy currency of the cell Figure 2.24

  49. Compounds Important to Physiology Table 2–8

  50. Summary • Energy and matter • Atoms, molecules, and chemical bonds • Importance of organic and inorganic nutrients and metabolites • Structure and function of carbohydrates, lipids, proteins, and nucleic acids • Enzymes and ATP help run the metabolic reactions of the body

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