Human Anatomy & Physiology Chapter 2: Chemistry Comes Alive
MATTER VS. ENERGY
Which of the following is not an example of matter? 1) Blood plasma 2) The air we breathe 3) An arm bone 4) Electricity
Which of the following is an example of conversion of potential energy to kinetic energy? 1) Synthesis of ATP from glucose 2) ATP hydrolysis to drive muscle contraction 3) Digesting a protein in the stomach
COMPOSITION OF MATTER
Figure 2.1 Two models of the structure of an atom. Nucleus Nucleus Helium atom 2 protons (p + ) 2 neutrons (n 0 ) 2 electrons (e ) (a) Planetary model Helium atom 2 protons (p + ) 2 neutrons (n 0 ) 2 electrons (e ) (b) Orbital model Proton Neutron Electron Electron cloud
Figure 2.2 Atomic structure of the three smallest atoms. Proton Neutron Electron Hydrogen (H) (1p + ; 0n 0 ; 1e ) Helium (He) (2p + ; 2n 0 ; 2e ) Lithium (Li) (3p + ; 4n 0 ; 3e )
Figure 2.3 Isotopes of hydrogen. Proton Neutron Electron Hydrogen ( 1 H) (1p + ; 0n 0 ; 1e ) Deuterium ( 2 H) (1p + ; 1n 0 ; 1e ) Tritium ( 3 H) (1p + ; 2n 0 ; 1e )
The subatomic particle which determines an atom s identity is the 1) Electron 2) Neutron 3) Proton 4) Quark
The element lithium has 3 protons and 4 neutrons in its nucleus. Its mass number is 1) 7 2) 3 3) 4 4) 1
The element lithium has 3 protons and 4 neutrons in its nucleus. Its atomic number is 1) 7 2) 3 3) 4 4) 1
MOLECULES AND MIXTURES
Figure 2.4 The three basic types of mixtures. Solution Solute particles are very tiny, do not settle out or scatter light. Colloid Solute particles are larger than in a solution and scatter light; do not settle out. Suspension Solute particles are very large, settle out, and may scatter light. Solute particles Solute particles Solute particles Example Mineral water Example Gelatin Example Blood
Water with particles dissolved into it such that the particles do not settle out, and are invisible is a 1) suspension 2) colloid 3) solution 4) all of the above
CHEMICAL BONDS
Figure 2.5a Chemically inert and reactive elements. (a) Chemically inert elements Outermost energy level (valence shell) complete 2e 8e 2e Helium (He) (2p + ; 2n 0 ; 2e ) Neon (Ne) (10p + ; 10n 0 ; 10e )
Figure 2.5b Chemically inert and reactive elements. (b) Chemically reactive elements Outermost energy level (valence shell) incomplete 1e 4e 2e Hydrogen (H) (1p + ; 0n 0 ; 1e ) Carbon (C) (6p + ; 6n 0 ; 6e ) 6e 2e 8e 1e 2e Oxygen (O) (8p + ; 8n 0 ; 8e ) Sodium (Na) (11p + ; 12n 0 ; 11e )
Figure 2.6a Formation of an ionic bond. Sodium atom (Na) (11p + ; 12n 0 ; 11e ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e ) (a) Sodium gains stability by losing one electron, and chlorine becomes stable by gaining one electron.
Figure 2.6b Formation of an ionic bond. + Sodium ion (Na + ) Chloride ion (Cl ) Sodium chloride (NaCl) (b) After electron transfer, the oppositely charged ions formed attract each other.
Figure 2.6c Formation of an ionic bond. CI Na + (c) Large numbers of Na + and Cl ions associate to form salt (NaCl) crystals.
Figure 2.7a Formation of covalent bonds. Reacting atoms Resulting molecules + or Hydrogen atoms Carbon atom Molecule of methane gas (CH 4 ) (a) Formation of four single covalent bonds: carbon shares four electron pairs with four hydrogen atoms. Structural formula shows single bonds.
Figure 2.7b Formation of covalent bonds. Reacting atoms Resulting molecules Oxygen atom + Oxygen atom Molecule of oxygen gas (O 2 ) (b) Formation of a double covalent bond: Two oxygen atoms share two electron pairs. or Structural formula shows double bond.
Figure 2.7c Formation of covalent bonds. Reacting atoms Resulting molecules Nitrogen atom + or Nitrogen atom Molecule of nitrogen gas (N 2 ) (c) Formation of a triple covalent bond: Two nitrogen atoms share three electron pairs. Structural formula shows triple bond.
Figure 2.8 Carbon dioxide and water molecules have different shapes, as illustrated by molecular models.
Figure 2.10a Hydrogen bonding between polar water molecules. + + Hydrogen bond (indicated by dotted line) + + + + (a) The slightly positive ends ( + ) of the water molecules become aligned with the slightly negative ends ( ) of other water molecules.
A bond resulting from two atoms sharing a pair of electrons is a(n) 1) ionic bond 2) covalent bond 3) hydrogen bond 4) double bond
A bond resulting from one atom donating an electron to another is a(n) 1) ionic bond 2) covalent bond 3) hydrogen bond 4) double bond
Hydrogen bonds are like ionic bonds because 1) both form molecules 2) both are very strong bonds 3) both occur between like-charged atoms 4) both are due to opposite charge attractions
CHEMICAL REACTIONS
Figure 2.11a Patterns of chemical reactions. (a) Synthesis reactions Smaller particles are bonded together to form larger, more complex molecules. Example Amino acids are joined together to form a protein molecule. Amino acid molecules Protein molecule
Figure 2.11b Patterns of chemical reactions. (b) Decomposition reactions Bonds are broken in larger molecules, resulting in smaller, less complex molecules. Example Glycogen is broken down to release glucose units. Glycogen Glucose molecules
Figure 2.11c Patterns of chemical reactions. (c) Exchange reactions Bonds are both made and broken (also called displacement reactions). Example ATP transfers its terminal phosphate group to glucose to form glucose-phosphate. + Glucose Adenosine triphosphate (ATP) + Glucose phosphate Adenosine diphosphate (ADP)
BIOCHEMISTRY INORGANIC COMPOUNDS
Figure 2.12 Dissociation of salt in water. + + Water molecule Salt crystal Ions in solution
ACIDS AND BASES
Figure 2.13 The ph scale and ph values of representative substances. Concentration (moles/liter) [OH ] 10 0 10 14 10 1 10 13 [H + ] ph 14 13 Examples 1M Sodium hydroxide (ph=14) Oven cleaner, lye (ph=13.5) 10 2 10 12 12 10 3 10 11 11 Household ammonia (ph=10.5 11.5) 10 4 10 10 10 5 10 9 10 9 Household bleach (ph=9.5) 10 6 10 8 8 Egg white (ph=8) 10 7 10 7 7 Neutral Blood (ph=7.4) 10 8 10 6 6 Milk (ph=6.3 6.6) 10 9 10 5 5 Black coffee (ph=5) 10 10 10 4 4 10 11 10 3 3 Wine (ph=2.5 3.5) 10 12 10 2 2 Lemon juice; gastric juice (ph=2) 10 13 10 1 1 10 14 10 0 0 1M Hydrochloric acid (ph=0)
A substance that is very acidic may have a ph of 1-2; this means that it 1) has a high concentration of OH - ions 2) has an equal concentration of H + and OH - ions 3) has a low concentration of H + ions 4) has a high concentration of H + ions
ORGANIC COMPOUNDS
An organic compound is one that 1) is natural 2) is in the human body 3) contains carbon 4) is polar
Figure 2.14a Biological molecules are formed from their monomers or units by dehydration synthesis and broken down to the monomers by hydrolysis reactions. (a) Dehydration synthesis Monomers are joined by removal of OH from one monomer and removal of H from the other at the site of bond formation. + Monomer 1 Monomer 2 Monomers linked by covalent bond
Figure 2.14b Biological molecules are formed from their monomers or units by dehydration synthesis and broken down to the monomers by hydrolysis reactions. (b) Hydrolysis Monomers are released by the addition of a water molecule, adding OH to one monomer and H to the other. Monomers linked by covalent bond + Monomer 1 Monomer 2
Figure 2.14c Biological molecules are formed from their monomers or units by dehydration synthesis and broken down to the monomers by hydrolysis reactions. (c) Example reactions Dehydration synthesis of sucrose and its breakdown by hydrolysis + Water is released Glucose Fructose Water is Consumed Sucrose
Figure 2.15a Carbohydrate molecules important to the body. Example Hexose sugars (the hexoses shown here are isomers) (a) Monosaccharides Monomers of carbohydrates Example Pentose sugars Glucose Fructose Galactose Deoxyribose Ribose
Figure 2.15b Carbohydrate molecules important to the body. (b) Disaccharides Consist of two linked monosaccharides Example Sucrose, maltose, and lactose (these disaccharides are isomers) Glucose Fructose Glucose Glucose Galactose Glucose Sucrose Maltose Lactose
Figure 2.15c Carbohydrate molecules important to the body. (c) Polysaccharides Long branching chains (polymers) of linked monosaccharides Example This polysaccharide is a simplified representation of glycogen, a polysaccharide formed from glucose units. Glycogen
The major function of carbohydrates in the body is 1) protein synthesis 2) as cellular fuel 3) being a genetic blueprint 4) forming the cell membrane bilayer
Figure 2.16a Lipids. (a) Triglyceride formation Three fatty acid chains are bound to glycerol by dehydration synthesis + Glycerol 3 fatty acid chains Triglyceride, or neutral fat 3 water molecules
Figure 2.16b Lipids. (b) Typical structure of a phospholipid molecule Two fatty acid chains and a phosphorus-containing group are attached to the glycerol backbone. Example Phosphatidylcholine Polar head Nonpolar tail (schematic phospholipid) Phosphoruscontaining group (polar head ) Glycerol backbone 2 fatty acid chains (nonpolar tail )
Figure 2.16c Lipids. (c) Simplified structure of a steroid Four interlocking hydrocarbon rings form a steroid. Example Cholesterol (cholesterol is the basis for all steroids formed in the body)
Which of the following is NOT a type of lipid? 1) steroid 2) triglyceride 3) disaccharide 4) fatty acid
Figure 2.17a Amino acid structures. Amine group Acid group (a) Generalized structure of all amino acids.
Figure 2.17b Amino acid structures. (b) Glycine is the simplest amino acid.
Figure 2.17c Amino acid structures. (c) Aspartic acid (an acidic amino acid) has an acid group ( COOH) in the R group.
Figure 2.17d Amino acid structures. (d) Lysine (a basic amino acid) has an amine group ( NH 2 ) in the R group.
Figure 2.17e Amino acid structures. (e) Cysteine (a basic amino acid) has a sulfhydryl ( SH) group in the R group, which suggests that this amino acid is likely to participate in intramolecular bonding.
Figure 2.18 Amino acids are linked together by peptide bonds. Dehydration synthesis: The acid group of one amino acid is bonded to the amine group of the next, with loss of a water molecule. Peptide bond + Amino acid Amino acid Dipeptide Hydrolysis: Peptide bonds linking amino acids together are broken when water is added to the bond.
Figure 2.19 Levels of protein structure. Amino acid Amino acid Amino acid Amino acid Amino acid (a) Primary structure: The sequence of amino acids forms the polypeptide chain. (b) Secondary structure: The primary chain forms spirals ( -helices) and sheets ( -sheets). -Helix: The primary chain is coiled to form a spiral structure, which is stabilized by hydrogen bonds. -Sheet: The primary chain zig-zags back and forth forming a pleated sheet. Adjacent strands are held together by hydrogen bonds. (c) Tertiary structure: Superimposed on secondary structure. -Helices and/or -sheets are folded up to form a compact globular molecule held together by intramolecular bonds. Tertiary structure of prealbumin (transthyretin), a protein that transports the thyroid hormone thyroxine in serum and cerebrospinal fluid. (d) Quaternary structure: Two or more polypeptide chains, each with its own tertiary structure, combine to form a functional protein. Quaternary structure of a functional prealbumin molecule. Two identical prealbumin subunits join head to tail to form the dimer.
Figure 2.19a Levels of protein structure. Amino acid Amino acid Amino acid Amino acid Amino acid (a) Primary structure: The sequence of amino acids forms the polypeptide chain.
Figure 2.19b Levels of protein structure. -Helix: The primary chain is coiled to form a spiral structure, which is stabilized by hydrogen bonds. -Sheet: The primary chain zig-zags back and forth forming a pleated sheet. Adjacent strands are held together by hydrogen bonds. (b) Secondary structure: The primary chain forms spirals ( -helices) and sheets ( -sheets).
Figure 2.19c Levels of protein structure. Tertiary structure of prealbumin (transthyretin), a protein that transports the thyroid hormone thyroxine in serum and cerebrospinal fluid. (c) Tertiary structure: Superimposed on secondary structure. -Helices and/or -sheets are folded up to form a compact globular molecule held together by intramolecular bonds.
Figure 2.19d Levels of protein structure. Quaternary structure of a functional prealbumin molecule. Two identical prealbumin subunits join head to tail to form the dimer. (d) Quaternary structure: Two or more polypeptide chains, each with its own tertiary structure, combine to form a functional protein.
Which of the following is the building block for proteins? 1) monosaccharides 2) fatty acids 3) nucleotides 4) amino acids
Tertiary structure of a protein refers to 1) its amino acid sequence 2) its 3-dimensional structure 3) how it interacts with other amino acid sequences 4) the alpha helices and beta sheets
Figure 2.20 Enzymes lower the activation energy required for a reaction to proceed rapidly. WITHOUT ENZYME WITH ENZYME Activation energy required Less activation energy required Reactants Reactants Product Product
Figure 2.21 Mechanism of enzyme action. Substrates (S) e.g., amino acids + Active site Energy is absorbed; bond is formed. Water is released. Product (P) e.g., dipeptide Peptide bond Enzyme (E) Enzyme-substrate complex (E-S) 1 Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. 2 Internal rearrangements leading to catalysis occur. Enzyme (E) 3 Product is released. Enzyme returns to original shape and is available to catalyze another reaction.
An enzyme s substrate binds in the 1) active site 2) catalyst 3) peptide bond 4) allosteric site
An enzyme works by 1) speeding up reactions that would have happened anyway 2) making reactions happen that would not have otherwise happened
Figure 2.22 Structure of DNA. Phosphate Sugar: Deoxyribose Base: Adenine (A) Thymine (T) Sugar Phosphate (a) Adenine nucleotide Hydrogen bond Thymine nucleotide Sugar-phosphate backbone Deoxyribose sugar Phosphate Adenine (A) Thymine (T) Cytosine (C) Guanine (G) (b) (c) Computer-generated image of a DNA molecule
Figure 2.22a Structure of DNA. Sugar: Deoxyribose Phosphate Base: Adenine (A) Thymine (T) Sugar Phosphate (a) Adenine nucleotide Thymine nucleotide
Figure 2.22b Structure of DNA. Hydrogen bond Sugar-phosphate backbone Deoxyribose sugar Phosphate Adenine (A) Thymine (T) Cytosine (C) Guanine (G) (b)
Figure 2.23 Structure of ATP (adenosine triphosphate). High-energy phosphate bonds can be hydrolyzed to release energy. Adenine Phosphate groups Ribose Adenosine Adenosine monophosphate (AMP) Adenosine diphosphate (ADP) Adenosine triphosphate (ATP)
Figure 2.24a Three examples of cellular work driven by energy from ATP. Solute + Membrane protein (a) Transport work: ATP phosphorylates transport proteins, activating them to transport solutes (ions, for example) across cell membranes.
Figure 2.24b Three examples of cellular work driven by energy from ATP. Relaxed smooth muscle cell Contracted smooth muscle cell + (b) Mechanical work: ATP phosphorylates contractile proteins in muscle cells so the cells can shorten.
Figure 2.24c Three examples of cellular work driven by energy from ATP. + (c) Chemical work: ATP phosphorylates key reactants, providing energy to drive energy-absorbing chemical reactions.
A nucleotide 1) is the building block of nucleic acids 2) contains a pentose sugar 3) has a base (A, T, C, G, or U) 4) has a phosphate group 5) all of the above