Presentation on theme: "1 Chapter 2: The Chemical Level of Organization. 2 Introduction to Chemistry Matter is made up of atoms Atoms join together to form chemicals with different."— Presentation transcript:
1 Chapter 2: The Chemical Level of Organization
2 Introduction to Chemistry Matter is made up of atoms Atoms join together to form chemicals with different characteristics Chemical characteristics determine physiology at the molecular and cellular level
3 Atomic Particles Proton: –positive, 1 mass unit Neutron: –neutral, 1 mass unit Electron: –negative, low mass
4 Particles and Mass Atomic number: –number of protons Mass number: –number of protons plus neutrons Atomic weight: –exact mass of all particles (daltons)
5 Isotopes 2 or more elements with equal numbers of protons but different numbers of neutrons Electron shell p+p+ p+p+ p + n n n e e e (a)Hydrogen-1 (electron-shell model) (b)Hydrogen-2 deuterium (c)Hydrogen-3, tritium
6 Elements in the Human Body Table 2–1
7 How do atoms form molecules and compounds?
8 Molecules and Compounds Molecules: –atoms joined by strong bonds Compounds: –atoms joined by strong or weak bonds
9 Chemical Bonds Ionic bonds: –attraction between cations (+) and anions (-) Covalent bonds: –strong electron bonds –Non polar covalent bonds: equal sharing of electrons –Polar covalent bonds: unequal sharing of electrons Hydrogen bonds: –weak polar bonds
10 Ionic Bonds Figure 2–3a Are atoms with positive or negative charge
11 Covalent Bond Formed between atoms that share electrons Hydrogen (H 2 ) Oxygen (O 2 ) Carbon Dioxide (CO 2 ) Nitric Oxide (NO) Molecule Electron-Shell Model and Structural Formula H–H O=O N=O O=C=O Free Radicals: Ion or molecule that contain unpaired electrons in the outermost shell. - Extremely Reactive -Typically enter into destructive reactions -Damage/destroy vital compounds
12 Hydrogen Bonds Attractive force between polar covalent molecules Weak force that holds molecules together Hydrogen bonds between H 2 O molecules cause surface tension Figure 2–6
13 How is it possible for two samples of hydrogen to contain the same number of atoms, yet have different weights? A.One sample has more bonds. B. One sample contains fewer electrons, decreasing weight. C. One sample contains more of hydrogen’s heavier isotope(s). D. One sample includes more protons, increasing weight.
14 Both oxygen and neon are gases at room temperature. Oxygen combines readily with other elements, but neon does not. Why? A. Neon has 8 electrons in its valence shell, oxygen has only 6. B. Neon cannot undergo bonding due to its polarity. C. Neon is exergonic. D. Neon’s molecular weight is too low to allow bonding.
15 Both oxygen and neon are gases at room temperature. Oxygen combines readily with other elements, but neon does not. Why? A. Neon has 8 electrons in its valence shell, oxygen has only 6. B. Neon cannot undergo bonding due to its polarity. C. Neon is exergonic. D. Neon’s molecular weight is too low to allow bonding.
16 Which kind of bond holds atoms in a water molecule together? What attracts water molecules to one another? A. polar covalent bonds; hydrogen bonds B. ionic bonds; charge interactions C. hydrogen bonds; charge interactions D. covalent bonds; hydrogen bonds
17 Why are chemical reactions important to physiology?
18 Energy Energy: –the capacity to do work Work: –a change in mass or distance
19 Forms of Energy Kinetic energy: –energy of motion Potential energy: –stored energy Chemical energy: –potential energy stored in chemical bonds When energy is exchanged, heat is produced - cells cannot capture it or use it for work
20 Break Down, Build Up Decomposition reaction (catabolism): AB A + B Synthesis reaction (anabolism): A + B AB Exchange reaction (reversible): AB + CD AD + CB If Water is Involved: Hydrolysis: A—B—C—D—E + H 2 O A—B—C—H + HO—D—E Dehydration synthesis (condensation): A—B—C—H + HO—D—E A—B—C—D—E + H 2 O
21 KEY CONCEPT Reversible reactions seek equilibrium, balancing opposing reaction rates Add or remove reactants: –reaction rates adjust to reach a new equilibrium
22 How do enzymes control metabolism?
23 Figure 2–7 Activation Energy Chemical reactions in cells cannot start without help Activation energy gets a reaction started
24 Materials in Reactions Reactants: –materials going into a reaction Products: –materials coming out of a reaction Enzymes: –proteins that lower the activation energy of a reaction
25 Energy In, Energy Out Exergonic reactions: –produce more energy than they use –Heat will be the by-product Endergonic reactions: –use more energy than they produce Most chemical reactions that sustain life cannot occur unless the right enzymes are present
26 In cells, glucose, a six-carbon molecule, is converted into two three- carbon molecules by a reaction that releases energy. How would you classify this reaction? A. endergonic B. exergonic C. decomposition D. B and C
27 In cells, glucose, a six-carbon molecule, is converted into two three- carbon molecules by a reaction that releases energy. How would you classify this reaction? A. endergonic B. exergonic C. decomposition D. B and C
28 Why are enzymes needed in our cells? A. to promote chemical reactions B. for chemical reactions to proceed under conditions compatible with life C. to lower activation energy requirements D. all of the above
29 What is the difference between organic and inorganic compounds?
30 Organic and Inorganic Molecules Organic: –molecules based on carbon and hydrogen Inorganic: –molecules not based on carbon and hydrogen
31 Essential Molecules Nutrients: –essential molecules obtained from food Metabolites: –molecules made or broken down in the body
32 Why is water so important to life?
33 Properties of Water Solubility: –water’s ability to dissolve a solute in a solvent to make a solution Reactivity: –most body chemistry uses or occurs in water High heat capacity: –water’s ability to absorb and retain heat Lubrication: –to moisten and reduce friction Water is the key structural and functional component of cells and their control mechanisms, the nucleic acids
34 Aqueous Solutions Figure 2–8 Polar water molecules form hydration spheres around ions and small polar molecules to keep them in solution
35 Electrolytes Inorganic ions: conduct electricity in solution Electrolyte imbalance seriously disturbs vital body functions
36 Molecules and Water Hydrophilic: –hydro = water, philos = loving –reacts with water Hydrophobic: –phobos = fear –does not react with water
37 Solutions Suspension: –a solution in which particles settle (sediment) Concentration: –the amount of solute in a solvent (mol/L, mg/mL)
38 What is pH and why do we need buffers?
39 pH: Neutral, Acid, or Base? pH: –the concentration of hydrogen ions (H + ) in a solution Neutral pH: –a balance of H + and OH — –pure water = 7.0 Acid (acidic): pH lower than 7.0 –high H + concentration, low OH — concentration Base (basic): pH higher than 7.0 –low H + concentration, high OH — concentration
40 pH Scale Figure 2–9 Has an inverse relationship with H + concentration: –more H + ions mean lower pH, less H + ions mean higher pH
41 KEY CONCEPT pH of body fluids measures free H + ions in solution Excess H + ions (low pH): Acidosis –damages cells and tissues –alters proteins –interferes with normal physiological functions Excess OH — ions (high pH): Alkalosis –Uncontrollable and sustained skeletal muscle contractions
42 Controlling pH Salts: –positive or negative ions in solution –contain no H + or OH — (NaCl) Buffers: –weak acid/salt compounds –neutralizes either strong acid or strong base
43 Why does a solution of table salt conduct electricity, but a sugar solution does not? A. Electrical conductivity requires ions. B. Sugar forms a colloid, salt forms a suspension. C. Electricity is absorbed by glucose molecules. D. Table salt is hydrophobic, sugar is hydrophilic.
44 How does an antacid help decrease stomach discomfort? A.by reducing buffering capacity of the stomach B. by decreasing pH of stomach contents C. by reacting a weak acid with a stronger one D. by neutralizing acid using a weak base
45 What kinds of organic compounds are there, and how do they work? Organic Compounds
46 Functional Groups of Organic Compounds Table 2–4 Molecular groups which allow molecules to interact with other molecules
47 Carbohydrates Consist of C:H:O in 1:2:1 ratio 1. Monosaccharides: –simple sugars with 3 to 7 carbon atoms (glucose) Glucose: important metabolic fuel 2. Disaccharides: –2 simple sugars condensed by dehydration synthesis (sucrose)
48 Simple Sugars Figure 2–10 Structural Formula: Straight-chain form Ring from 3-D Isomers: Glucose vs. Fructose: - Same chemical formula but different shape
49 Polysaccharides Chains of many simple sugars (glycogen) Formation: –Dehydration synthesis Breakdown: –Hydrolysis synthesis Figure 2–12 Glycogen: made and stored in muscle cells
50 Carbohydrate Functions Table 2–5 Polysaccharides Glycogen: made and stored in muscle cells Cellulose: structural component of plants Cattle, sheep, and deer -Ruminant Animals: Cattle, sheep, and deer
51 The Ruminant Stomach Ruminant stomach is polygastric: four compartments -Rumen -Reticulum -Abomasum -Omasum
52 Rumen Occupies 80% of the stomach Muscular Pillar Contract to mix feed Digest starch and fibers Microbes produce VFA’s Lined with Papillae pH of Provide a suitable environment for bacteria and protozoa
53 KEY CONCEPT Carbohydrates are quick energy sources and components of membranes Lipids have many functions, including membrane structure and energy storage –Provides 2x more energy then carbohydrates
54 Lipids Mainly hydrophobic molecules such as fats, oils, and waxes Made mostly of carbon and hydrogen atoms (1:2), and some oxygen –Less oxygen then carbon
55 Classes of Lipids Fatty acids Eicosanoids Glycerides Steroids Phospholipids and glycolipids
56 Fatty Acids Carboxyl group -COOH –Hydrophilic Hydrocarbon tail: –Hydrophobic –Longer tail = lower solubility Saturated vs. Unsaturated –Saturated: solid at room temp. Cause solid plaques in arteries –Unsaturated: liquid at room temp. Healthier Figure 2–13
57 Eicosanoids Used for cellular communication Never burned for energy 1. Leukotrienes: –active in immune system –Used by cells to signal injury 2. Prostaglandins: local hormones –Used for cell-to-cell signaling to coordinate events
58 Figure 2–16 Steroids 4 carbon ring with attached carbon chains Not burned for energy
59 Types of Steroids Cholesterol: –cell membrane formation and maintenance, cell division, and osmotic stability Estrogens and testosterone: –Regulation of sexual function Corticosteroids and calcitrol: –Tissue metabolism and mineral balance Bile salts: –Processing of dietary fats
60 Figure 2–15 Glycerides Glycerides: are the fatty acids attached to a glycerol molecule Triglyceride: are the 3 fatty-acid tails, fat storage molecule Fat Deposits are Important 1.Energy Storage 2.Insulation 3.Mechanical Protection -Knees and Eye Sockets
61 Phospholipids Vs. Glycolipids Combination Lipids Figure 2–17a, b Diglyceride Cell Membranes are Composed of these lipids Hydrophilic Hydrophobic
62 Phospholipids Vs. Glycolipids Combination Lipids Figure 2–17c Spontaneous formation of Micelle
63 5 Lipid Types Table 2–6
64 A food contains organic molecules with the elements C, H, and O in a ratio of 1:2:1. What class of compounds do these molecules belong to, and what are their major functions in the body? A.lipids; energy source B. proteins; support and movement C. nucleic acids; determining inherited characteristics D. carbohydrates; energy source
65 When two monosaccharides undergo a dehydration synthesis reaction, which type of molecule is formed? A.polypeptide B. disaccharide C. eichosanoid D. polysaccharide
66 Which kind of lipid would be found in a sample of fatty tissue taken from beneath the skin? A.eichosanoid B. steroid C. triglyceride D. phospholipid
67 Which lipids would you find in human cell membranes? A.cholesterol B. glycolipids C. phospholipids D. all of the above
68 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
69 Protein Functions 7 major protein functions: –support: structural proteins –movement: contractile proteins –transport: transport proteins –buffering: regulation of pH –metabolic regulation: enzymes –coordination and control: hormones –defense: antibodies
70 Proteins Proteins: –control anatomical structure and physiological function –determine cell shape and tissue properties – perform almost all cell functions
71 Amino Acid Structure 1.central carbon 2.hydrogen 3.amino group (—NH 2 ) 4.carboxylic acid group (—COOH) 5.variable side chain or R group Figure 2-18
72 Peptide Bond A dehydration synthesis between: –amino group of 1 amino acid –and the carboxylic acid group of another amino acid –producing a peptide
73 Figure 2–20a Primary Structure Polypeptide: –Linear sequence of amino acids How many amino acids were bound together What order they are bound
74 Secondary Structure Figure 2–20b Hydrogen bonds form spirals or pleats
75 Figure 2–20c Tertiary Structure Secondary structure folds into a unique shape Global coiling or folding due to R group interaction
76 Quaternary Structure Figure 2–20d Final protein shape: –several tertiary structures together Fibrous proteins: - structural sheets Globular proteins: - soluble spheres with active functions
77 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 or pH
78 Enzymes Enzymes are catalysts: –proteins that lower the activation energy of a chemical reaction –are not changed or used up in the reaction
79 How Enzymes Work Figure 2–21 Substrates: reactants in enzymatic reactions Active site: location on an enzyme that fits a particular substrate
80 Enzyme Helpers Cofactor: –an ion or molecule that binds to an enzyme before substrates can bind Coenzyme: –nonprotein organic cofactors (vitamins) Isozymes: –2 enzymes that can catalyze the same reaction
81 Enzyme Characteristics Specificity: –one enzyme catalyzes one reaction Saturation limits: –an enzyme’s maximum work rate Regulation: –the ability to turn off and on
82 Conjugated Protein Glycoproteins: –large protein + small carbohydrate includes enzymes, antibodies, hormones, and mucus production Proteoglycans: –large polysaccharides + polypeptides promote viscosity
83 Proteins are chains of which small organic molecules? A.saccharides B. fatty acids C. amino acids D. nucleic acids
84 Which level of protein structure would be affected by an agent that breaks hydrogen bonds? A.the primary level of protein structure B. the secondary level of protein structure C. the tertiary level of protein structure D. the protein structure would NOT be affected by this agent
85 Why does boiling a protein affect its structural and functional properties? A.Heat denatures the protein, causing unfolding. B. Heat causes the formation of additional quaternary structure. C. Heating rearranges the primary structure of the protein. D. Heat alters the radical groups on the amino acids.
86 Why does boiling a protein affect its structural and functional properties? A.Heat denatures the protein, causing unfolding. B. Heat causes the formation of additional quaternary structure. C. Heating rearranges the primary structure of the protein. D. Heat alters the radical groups on the amino acids.
87 How might a change in an enzyme’s active site affect its functions? A.increased activity due to a better fit with the substrate B. decreased activity due to a poor substrate fit C. inhibited activity due to no substrate fit D. all of the above
88 Nucleic Acids C, H, O, N, and P Large organic molecules, found in the nucleus, which store and process information at the molecular level DNA – deoxyribonucleic acid RNA – ribonucleic acid
89 DNA and RNA DNA Determines inherited characteristics Directs protein synthesis Controls enzyme production Controls metabolism RNA Codes intermediate steps in protein synthesis
90 KEY CONCEPT DNA in the cell nucleus contains the information needed to construct all of the proteins in the body
91 Nucleotides Are the building blocks of DNA Have 3 molecular parts: –sugar (deoxyribose) –phosphate group –nitrogenous base (A, G, T, C)
92 The Bases Figure 2–22b, c
93 Complementary Bases Purines pair with pyrimidines: DNA: –adenine (A) and thymine (T) –cytosine (C) and guanine (G) RNA: –uracil (U) replaces thymine (T)
94 RNA and DNA RNA: –a single strand DNA: –a double helix joined at bases by hydrogen bonds
95 Protein Synthesis: Three forms of RNA messenger RNA (mRNA) –Protein blueprint or instructions transfer RNA (tRNA) –Carry amino acids to the place where proteins are being synthesized ribosomal RNA (rRNA) –Forms the site of protein synthesis in the cell Factory = ribosomes
96 High-Energy Compounds: ADP and ATP - Assembled using RNA Nucleotides - Bonds are broken easily by cells to release energy as needed -During digestion and cellular respiration: -energy from food is transferred to high energy compounds for quick and easy access.
97 ADP to ATP: Phosphorylation ADP vs. ATP: adenosine diphosphate (ADP): –2 phosphate groups (di = 2) adenosine triphosphate (ATP): –3 phosphate groups (tri = 3) Adding a phosphate group to ADP with a high- energy bound to form the high-energy compound ATP ATPase: –the enzyme that catalyzes phophorylation
98 Figure 2–24 The Energy Molecule Chemical energy stored in phosphate bonds
99 A large organic molecule composed of the sugar ribose, nitrogenous bases, and phosphate groups is which kind of nucleic acid? A.DNA B. ATP C. tRNA D. RNA
100 What molecule is produced by the phosphorylation of ADP? A.ATPase B. ATP C. Adenosine Diphosphate D. Uridine Triphosphate
101 Compounds Important to Physiology Table 2–8
102 SUMMARY Atoms, molecules, and chemical bonds control cellular physiology Metabolism and energy work within the cell Importance of organic and inorganic nutrients and metabolites
103 SUMMARY Role of water and solubility in metabolism and cell structure Chemistry of acids and bases, pH and buffers Structure and function of carbohydrates, lipids, proteins, and nucleic acids