Basic Chemistry. Chemistry Review. Bio 250: Anatomy & Physiology

Transcription

1 Basic Chemistry Bio 250: Anatomy & Physiology Chemistry Review It is going to be your responsibility to review the basic principles of chemistry you learned in BIO 101 This basic set of notes will help direct you to what will be important in this course. Also use the Chemistry chapter in your A & P text to help you with this review. Don t put it off, we will be using some of this information as we discuss cell membranes and the ways materials enter and leave cells. 1 1

2 Basic Chemistry Physiology relates directly to chemicals and chemical reactions. Chemistry deals with composition of substances and changes in their composition. Matter has weight and occupies space. Elements Naturally occurring matter 92 elements 13 make up 99.95% of protoplasm Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, Phosphorus, Potassium, Sodium, Chlorine, Magnesium, Sulfur, Iron, Iodine and trace amounts of several others. A chemical element cannot be broken down into simpler material by chemical means. 2 2

3 Elements Elements may be found: In mixtures, or Chemically combined in molecules or compounds. Elements made of units called atoms Atoms of different elements vary in: size weight ways of interacting. 3 3

4 Atomic Structure 1 An atom consists of electrons surrounding an atomic nucleus containing protons and neutrons Electrons Protons Neutrons 4 4

5 Atomic Structure 2 Atomic number Atomic weight Neutral atom Naming of Elements Use letter that relates to name of element Use one or two letters First always upper case Second always lower case 5 5

6 Chemical Bonding (Chemistry) Atoms chemically combine with one another Lowers energy increases stability Form chemical bonds Form Molecules or Compounds Electron Shells Electrons occupy energy shells Called K, L, M, N, etc. Fill from lowest level upward Full shells = low energy = stability 6 6

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8 Ways Atoms Form Bonds When atoms combine they may: Share electrons- COVALENT BONDS Electrons may be shared equally, e.g H 2 Electrons may be shared unequally, e.g. H 2 0 Polar covalent bonds Due to the symmetry of the molecule, the whole molecule may be polar, e.g. H

9 Ways Atoms Form Bonds Atoms can gain or lose electrons- IONIC BONDS Atoms that gain or lose electrons are ions Ions may be + or 9 9

10 Molecules and Compounds Atoms of same element form molecule e.g. 2 H can form H 2 molecule Atoms of different elements form compound Examples H and O can form H 2 O C and O can form CO

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12 Formulas Molecular formula e.g. H 2 O Structural formula e.g. H O H 12 12

13 Chemical Reactions C 6 H 12 O O 2 6 CO H 2 O Reactants are on the left side of arrow Products are on right of side of arrow Arrow is chemical equals Must be the same number and kind of atoms on each side of arrow. C 6 H 12 O 6 represents one molecule of glucose 6 H 2 O represents six molecules of water Chemical Reactions Bonds broken and/or created Synthetic reactions 6 CO H 2 O ----> C 6 H 12 O O 2 Decomposition reactions C 6 H 12 O O > 6 CO H 2 O Exchange reactions NaCl + KF ---> KCL + NaF Synthetic and Dehydration reactions (H 2 0) 13 13

14 Energy in Chemical Reactions Exothermic (exergonic)reactions release energy 2 H 2 + O 2 > 2 H 2 O + E (energy) Endothermic (endergonic) reactions absorb energy 6 H 2 O + 6 CO 2 + E > C 6 H 12 O O 2 Energy in Chemical Reactions Decomposition reactions are usually exothermic Exothermic may occur spontaneously Synthetic reactions are usually endothermic Exothermic often supply the energy for endothermic 14 14

15 Inorganic compounds Small molecules Few atoms Little of no carbon Do not contain both carbon and hydrogen Terms Solute, e.g. sugar Solvent, e.g. water Solution: sugar water Not a chemical reaction The Golden Rule of Solubility- Like dissolves Like Geneally speaking, polar molecules dissolve in polar solvents and nonpolar molecules dissolve in nonpolar solvents

16 Water most common inorganic Makes up 60-75% of protoplasm *Powerful polar solvent Very stable High heat of vaporization High specific heat *Polar molecules have polar covalent bonds (unequally shared electrons) and molecular asymmetry

17 Ionization in Water Acids form H + ions in water Bases form OH ions in water Salts, minerals, electrolytes form when acids/bases neutralize each other 17 17

18 ph scale Exponential scale form 0 to 14 Below 7 is acidic; H + > OH Above 7 is basic; H + < OH 7 is neutral; H + = OH Basic is alkaline ph 2 is 10 times more acidic than ph 3 ph 2 is 100 times more acidic than ph4 ph 2 is 1,000 times more acidic than ph

19 Sources of ph change in body Production of Acids or Bases in body CO 2 forms carbonic acid in water Vigorous muscle activity produces lactic acid Ingestion of Acids or Bases in diet Sulfuric acid, phosphoric acid, citric acid in foods Inorganic Salts 4.4% of protoplasm Cations: Na +, K +, Ca ++, Mg ++ Anions: Cl, CO 2 3, HCO 1 3, PO 3 4 Extracellular ions (major): Na + and Cl Intracellular ions (major): K + and PO

20 Functions of Salts Maintain water balance in body Acid/Base balance (Chemical buffers) Blood Clotting Bones and Teeth Hemoglobin Nerve and muscle function Gases Oxygen (O 2 ) Carbon dioxide (CO 2 ) Nitrogen (N 2 ) Ammonia (NH 3 ) 20 20

21 Organic Compounds Large carbon containing molecules Proteins: 16% of protoplasm Carbohydrates: 0.6% of protoplasm Lipids: 13% of protoplasm Nucleic acids (DNA and RNA) 21 21

22 Proteins Polymers Composed of amino acids Type, number and sequence determine function About 20 different amino acids Contain C, H, O, N and some S Amino acid structure Central Carbon atom Amino group NH 2 Carboxyl (Acid) group COOH R group (About 20 different) Linked by peptide bonds -NHCO- formed and water is formed 22 22

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24 Organization of Proteins Primary structure: Sequence of amino acids Secondary Structure: Coiling into helix Tertiary Structure: Folding due to side chains Quaternary Structure: Subunits 24 24

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26 Protein Denaturation Heat Radiation Electricity ph changes Various chemicals 26 26

27 Functions of Proteins Structural parts of cells C.O.P. of blood Chemical messengers (hormones) Defensive molecules (antibodies) Fuel (Oxidize for energy) Enzymes Enzymes Initiate or speed chemical reactions Lower activation energy Effective in small amounts Not used up in reaction Can be damaged by heat, ph changes, etc

28 Carbohydrates Contain C, H, and O Include sugars and starches Major energy source Simple sugars (monosaccharides) Starches (polysaccharides) Liver can change to fat Lipids (Contain C, H, and O) Include fats and fat related compounds Source of stored energy Shock absorber Heat insulator Structural parts of cells Chemical messengers (hormones) 28 28

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31 Nucleic Acids Control cell activities Control cell division DNA stores genetic information RNA directs protein synthesis 31 31

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34 Metabolic Processes Metabolism: All chemical reactions in cells Anabolism: Synthetic reactions using energy Catabolism: Decomposition reactions releasing energy Cell Structure and Function Review 34 34

35 Living things composed of cells and cell products Basic unit of structure Basic unit of function Vary in size, shape and function Shape related to function 35 35

36 Cell composed of protoplasm including: Cell membrane Cytoplasm Nucleus 36 36

37 Cell membrane Separates outside from inside cell Selectively permeable Composed of proteins, lipids and carbohydrates 37 37

38 Plasma Membrane is a Lipid Bilayer Has polar hydrophilic head Has a non polar hydrophobic tail Membrane proteins include: Integral proteins embedded within bilayer Peripheral proteins attached to surface Glycoproteins with associated carbohydrates 38 38

39 Cell membrane Controls movement of molecules into and out of the cell Lipid soluble molecules dissolve through the lipid portion of the membrane Water soluble substances may pass through protein channels Water soluble substances may be transported by carrier proteins Membrane Systems of Cells Plasma membrane surrounds cell Endoplasmic reticulum Nuclear envelop Golgi complex Lysosomes Vacuoles or vesicles 39 39

40 Cytoplasm contains organelles Endoplasmic reticulum Ribosomes Golgi apparatus Mitochondria Lysosomes Rough and Smooth ER 40 40

41 Golgi Apparatus 41 41

42 Mitochondrion Others organelles include: Centrosome Vacuoles Microtubules Basal Bodies Cilia Flagella 42 42

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45 Cell Nucleus Double layered membrane Chromatin Nucleolus 45 45