Chapter 2 Learning Outcomes

Question 1

Name the chemical elements of the body from their symbols.

Answer 1

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N), Calcium (Ca), and Phosphorus (P).

Question 2

Define elements.

Answer 2

The simplest form of matter cannot be broken down.

Question 3

Define compounds.

Answer 3

Have multiple components can be broken down.

Question 4

State the functions of minerals in the body.

Answer 4

Minerals – inorganic elements extracted from soil by plants and passed to humans, 4% of body weight, mostly Ca and P (also Cl, Mg, K, Na, and S), Important for body structure (Ca crystals in teeth and bones), and enzymes’ functions.
Electrolytes – mineral salts needed for nerve and muscle function.

Question 5

Relate the number of electrons in an electron shell to an atom’s chemical stability and its ability to form chemical bonds.

Answer 5

All atoms are trying to get a “full” outer electron shell, the first shell holds 2 electrons, the rest of the shells hold 8. Once the atoms achieve a full outer shell, they become stable.

Question 6

Define the octet rule.

Answer 6

Atoms interact in order to have 8 electrons in their valence shell (or 2 e- if first shell is valence shell).

Question 7

Define protons.

Answer 7

Positive, found in the nucleus.

Question 8

Define neutrons.

Answer 8

No charge, found in the nucleus.

Question 9

Define electrons.

Answer 9

Negative charge, found in electron shell. In neutral atoms, number of electrons = the number of protons.

Question 10

Explain the basis for isotopes and radioactivity.

Answer 10

Element can have atoms with different number of neutrons called: Isotopes. Most Isotopes are stable. Intense radiation can be ionizing (ejects electrons, destroys molecules) and can cause genetic mutations and cancer. Used for radiation therapy and diagnostic procedures.

Question 11

Define atomic number.

Answer 11

The number of protons. Hydrogen (1 proton), Carbon (6 protons), Oxygen (8 protons).

Question 12

Define atomic mass.

Answer 12

Number of neutrons + number of protons.

Question 13

Define atomic weight.

Answer 13

Average number of mass numbers.

Question 14

Define Electrolytes.

Answer 14

Substances that ionize in water (acids, bases, or salts), form solution capable of conducting electric current.

Question 15

Define ions.

Answer 15

If the atoms gain or lose electrons. Charged particle (atom or molecule) with an unequal number of protons and electrons.

Question 16

Define ionization.

Answer 16

Transfer of electrons from one atom to another.

Question 17

Define cations.

Answer 17

Positively charged ions.

Question 18

Define anions.

Answer 18

Negatively charged ions.

Question 19

Define the term salt and give examples of physiological significance.

Answer 19

Electrolytes - mineral salts needed for nerve and muscle function.
Electrolyte importance - Chemical reactivity, osmotic effects, electrical excitability of nerve and muscle. Electrolyte balance is one of the most important considerations in patient care (imbalances can lead to coma or cardiac arrest).

Question 20

Define atoms.

Answer 20

Building blocks for each element.

Question 21

Define molecule.

Answer 21

Chemical particle composed of two or more atoms united by a chemical bond.

Question 22

Define compounds.

Answer 22

Molecule composed of two or more different elements.

Question 23

Define molecule formula.

Answer 23

Identifies constituent elements and how many atoms of each are present.

Question 24

Define structural formula.

Answer 24

Identifies location of each atom.

Question 25

Define chemical bonds.

Answer 25

Hold atoms together within a molecule or attract one molecule to another. Most important types of chemical bonds are ionic bonds, covalent bonds, and hydrogen bonds.

Question 26

With respect to non-polar covalent, polar covalent, ionic and hydrogen bonds:

Answer 26

Ionic bond – will transfer electrons (one atom loses e- and the other gains e-). Attractions between anions and cations, electrons donated from one atom to another, easily broken by water.
Covalent bond – will share electrons.
Single Covalent bond – one pair of electrons shared (2 hydrogen atoms).
Double Covalent bond – two pairs of electrons shared (CO2).
Nonpolar Covalent bonds – electrons shared equally.
Polar Covalent bonds – electrons shared unequally (spend more time near oxygen)
Hydrogen Bonds - Weak intramolecular or intermolecular attraction between a slightly positive hydrogen and a slightly negative oxygen (or nitrogen). Intermolecular hydrogen bond – between DNA bonds, Intramolecular – means inside Water bonds.

Question 27

List each type of bond in order by relative strength.

Answer 27

Strongest – Nonpolar Covalent bonds
2nd strongest – Polar Covalent bonds
3rd strongest – Ionic Bonds
Weakest – Hydrogen Bonds

Question 28

Provide biologically significant examples of each.

Answer 28

Ionic bonds – Salt (NaCl)
Single Covalent – H2
Double Covalent – Carbon dioxide (CO2)
Nonpolar Covalent – C2 bond
Polar Covalent – Water (H2O)
Hydrogen Bonds – between 2 DNA or 2 water molecules

Question 29

Define mixture and distinguish between mixtures and compounds.

Answer 29

Mixtures – physically blended but not chemically combined. Body fluids are complex mixtures of chemicals. Most mixtures in our bodies consist of chemicals dissolved or suspended in water.
Compounds – are chemically combined.

Question 30

Describe the biologically important properties of water.

Answer 30

Water is 50% to 75% of body weight.
Polar covalent bonds and a V-shaped molecule give water a set of properties that account for its ability to support life.

Question 31

Define solvency.

Answer 31

Ability to dissolve other chemicals. Water is called the universal solvent. Metabolic reactions depend on solvency of water

Question 32

Define hydrophilic.

Answer 32

Water dissolves other polar molecules ionic compounds easily.

Question 33

Define hydrophobic.

Answer 33

Water does not dissolve these compounds (nonpolar or neutral (fats)) easily.

Question 34

Define adhesion.

Answer 34

Water adheres to other substances. Water adheres to large membranes reducing friction around organs.

Question 35

Define cohesion.

Answer 35

Water molecules cling to each other. Water is very cohesive due to its hydrogen bonds. Surface film on surface of water is due to molecules being held together by surface tension.

Question 36

Define chemical reactivity.

Answer 36

ability to participate in chemical reactions. Water ionizes into H+H+ and OH−OH−.

Question 37

Define hydrolysis.

Answer 37

Breaking down large molecules into smaller one.

Question 38

Define dehydration synthesis.

Answer 38

Join two simple molecules to form a large molecule.

Question 39

Define thermal stability.

Answer 39

Helps stabilize the internal temperature of the body. Water has high heat capacity—absorbs and releases large amounts of heat before changing temperature. Hydrogen bonds inhibit temperature increases by inhibiting molecular motion. Effective coolant.

Question 40

Distinguish among the term’s solution, solute, solvent, colloid, and suspension.

Answer 40

Solution – solutes small and dissolved in solvent.
Colloid – solutes larger (scatter light) but don’t settle out.
Suspension – solutes large and will settle out.

Question 41

Define the terms pH, acid, base, and buffer and give examples of physiological significance.

Answer 41

Acids – a substance that dissociates in solution to produce hydrogen ions (H+) and anions. Proton donors. HCl  H+ + Cl-
Base or Alkaline - a substance that dissociates in solution to yield cations and hydroxide ions (OH-). Or a Proton acceptor. NaOH  Na+ + OH-. Bicarbonate ion (HCO3–) and ammonia (NH3) are important bases in the body.
Salt - a substance that dissociates in solution producing cations and anions but not hydrogen ions or hydroxide ions. NaCl  Na+ + Cl-
pH – Acid-Base Concentration
Acidic – pH 0 – 6.99
Basic – pH 7.01 – 14
Neutral – pH 7.00
Buffers - Body fluids each have their own pH range they must maintain. Buffers help prevent large changes in pH.

Question 42

Define work.

Answer 42

All body activities are forms of work, to do work means to move something.

Question 43

Define energy.

Answer 43

Capacity to do work.

Question 44

Define potential energy.

Answer 44

Energy stored in an object, but not currently doing work.

Question 45

Define chemical energy.

Answer 45

Potential energy in molecular bonds.

Question 46

Define free energy.

Answer 46

Potential energy available in a system to do useful work.

Question 47

Understand how chemical reactions are symbolized by chemical equations.

Answer 47

Chemical reaction—a process in which a covalent or ionic bond is formed or broken.
Chemical equation—symbolizes the course of a chemical reaction. Reactants  products.

Question 48

List and define the fundamental types of chemical reactions.

Answer 48

Classes of chemical reactions - Decomposition reactions and Synthesis reactions
Decomposition reactions—large molecule breaks down into two or more smaller ones. AB —> A + B
Synthesis reactions—two or more small molecules combine to form a larger one. A + B —> AB
Reversible reactions- can go in either direction under different circumstances. Example: CO2 + H2O —><— H2CO3 —><— HCO3- + H+. Reach equilibrium when ratio of products to reactants is stable.

Question 49

Identify the factors that govern the speed and direction of a reaction.

Answer 49

Reactions occur when molecules collide with enough force and correct orientation.
Reaction rates increase when the reactants are more concentrated, the temperature rises, a catalyst is present.

Question 50

Define metabolism and its two subdivisions.

Answer 50

Metabolism - all chemical reactions of the body
Catabolism - energy-releasing (exergonic) decomposition reactions. Breaks covalent bonds. Produces smaller molecules.
Anabolism - energy-storing (endergonic) synthesis reactions. Requires energy input. Production of protein or fat.
Catabolism and anabolism are inseparably linked, anabolism is driven by energy released by catabolism.

Question 51

Define organic chemistry.

Answer 51

The study of compounds containing carbon (Carbohydrates, Lipids, Proteins, Nucleic acids) .

Question 52

Explain the relationship between macromolecules, monomers, and polymers.

Answer 52

Macromolecules - very large organic molecules with high molecular weights
Polymers - macromolecules made of a repetitive series of identical or similar subunits (monomers). Starch is a polymer of about 3,000 glucose monomers.

Question 53

Discuss the relevance of polymers to biology and explain how they are formed and broken by dehydration synthesis and hydrolysis.

Answer 53

Monomers are linked together by dehydration synthesis to form polymers. Polymers are broken apart by hydrolysis.
Hydrolysis – splitting a polymer by the addition of water.
Dehydration synthesis - monomers covalently bind together to form a polymer with the removal of a water molecule.

Question 54

With respect to carbohydrates, proteins, lipids, and nucleic acids
Identify the monomers and polymers.

Answer 54

Protein – polymer of amino acids.
Nucleic acids – polymers of nucleotides.

Question 55

STOPPED AT COMPARE AND CONTRAST GENERAL MOLECULAR STRUCTURE!!!

Answer 55

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