Chapter 2: Introductory Chemistry—KEY 50 points

Focus on Wellness…DID YOU KNOW? (Pages 25 and 43)

  1. Your Aunt Mary tells you she is taking an herbal weight-loss supplement. “It’s natural, so it’s safe,” she says. In fact, it’s not working as well as it was two weeks ago, so she is now taking double the recommended dose. What do you say to her?1 point

_Natural does not necessary mean safe; natural chemicals are still chemicals. Something that is effective cannot be simultaneously harmless; anything can have harmful physiological effects at some dose. All drugs are toxic if you take too much!!! Note: herbal supplements are not regulated and their makers can say whatever they want.______

  1. Introduction To Chemistry ¼ each = 2 ½ points
  2. Define chemistry: _science of the structure and interactions of matter______
  3. Define matter: _anything that occupies space and has mass______
  4. Define mass: _amount of matter in any living thing______
  1. Chemical Elements and Atoms

4. _Chemical elements_ are substances that cannot be broken down into a simpler form by ordinary chemical means.

5. How many elements are recognized by scientists according to your textbook? _112_____

6. How many different elements are found in the human body? _26_____

7. Which four elements make up about 96% of the human body (list their name and chemical symbol)?

_carbon______C__ _hydrogen______H__

_oxygen______O__ _nitrogen______N__

8. Which elements make up about 3.8% of the human body (list their name and chemical symbol)?

_calcium______Ca_ _sodium______Na_

_phosphorus______P_ _chlorine______Cl_

_potassium ______K_ _magnesium______Mg_

_sulfur ______S_ _iron______Fe_

9. Which elements make up about 0.2% of the human body (list their name and chemical symbol)?

_aluminum______Al_ _manganese______Mn_

_boron______B_ _molybdenum______Mo_

_chromium______Cr_ _selenium______Se_

_cobalt______Co_ _silicon______Si_

_copper______Cu_ _tin______Sn_

_fluorine______F_ _vanadium______V_

_iodine______I_ _zinc______Zn_

10. What are the 14 elements listed in number 7 above called? _trace elements______

  1. Ions, Molecules, and Compounds

11. Distinguish between an ion, a molecule, and a compound. ¼ point

_ion: charged ion, gained or lost e-______

_molecule: 2 or more atoms share electrons______

_compound: a molecule containing 2 or more different elements______

12. Look at the molecular chemical formula given below: Identify the elements in it by underlining them, next identify the subscript by circling it, and finally identify the coefficient by drawing a rectangular shape around it. ¼ point

2 H2 O

13. What is a free radical? ¼ point

_ion or molecule with an unpaired electron in its outermost shell; highly unstable; destructive to other nearby_

Example: _superoxide______

CHECKPOINT:2 each = 4 points

  1. Compare the meanings of atomic number, mass number, ion, and molecule. _atomic number = number of protons n nucleus; mass number = protons + neutrons; ions are charged particle (atom) that has lost or gained an e-; molecule are formed when two or more atoms share electrons______
  2. What is the significance of the valence (outer) electron shell of an atom? _Chemically stable atoms have 8 electrons in their outer shells, and unlikely to form chemical bonds. Atoms without 8 electrons in their outer shell form chemical bonds easily because they want eight (octet rule)______
  1. Chemical Bonds ¼ each = 1 point

14. Define chemical bond: _forces that bind the atoms of molecules and compounds

together, resisting their separation______

15. When is an atom chemically stable?

_an atom with eight electrons in its outer electron shell______

16. Will chemically stable atoms form chemical bonds? _NO______

17. What is the octet rule? _atoms that do not have eight electrons in their outer shell,

given the right conditions, two or more of them can bond in ways the produce

chemically stable arrangements of eight electrons in the outer shell of each atom_____

  1. Ionic Bonds a-e ¼ point each = 1 ¼ points
  2. Define ionic bond: _force of attraction between ions of opposite charges______
  3. What is a cation? _protons exceeds electrons= positively charged atom______
  4. What is an anion? _electrons exceeds protons= negatively charged atom______
  5. In the human body, where are ionic bonds mainly found and for what purpose?

_In teeth and bones, where they give strength to the tissue______

  1. What is an electrolyte?

_an ionic compound that breaks down into cations and anions when dissolved____

  1. Below are diagrams of a Lithium atom with 1 electron in its outer shell and a Fluorine atom with 7 electrons in its outer shell. Using Figure 2.4 on page 26 of your textbook for help, in the space below depict with labels how an ionic bond would form between the lithium atom and the fluorine atom. Identify valence electron(s), cation, and anion. 1 point
  1. Covalent Bonds a-e ¼ each = 1 ¼ points
  2. How do covalent bonds form?

_Neither atom loses or gains electrons; atoms form a molecule by sharing one, two, or three pairs of their outer shell electrons______

  1. Do covalent bonds easily break apart in water? _NO______
  2. What type of bond is shown here O=O? _Double covalent bond______
  3. Explain the differences between structural formulas and molecular formulas. _Structural formulas show the covalent bonds by a straight line between chemical symbols for two atoms; molecular formulas the number of atoms in each molecule is noted by subscripts______
  4. Describe the difference between nonpolar and polar covalent bonds.

_Nonpolar covalent: atoms share the electrons equally-one does not attract the shared electrons more strongly than the other atom; always nonpolar between two identical atoms.______

_Polar covalent: sharing of electrons between atoms is unequal- one atom attracts the shared electrons more strongly than the other; partial charge indicated by lowercase Greek delta (δ) with a minus or plus sign______

Figure 2.5; Page 31:What is the main difference between an ionic bond and a covalent bond? _In ionic bonds atoms gain or lose electrons; in covalent bonds they share electrons__1 point______

  1. Hydrogen Bonds ¼ each = ½ point
  2. Are hydrogen bonds nonpolar covalent bonds or polar covalent bonds? _Polar ____
  3. Why are hydrogen bonds so weak and what is their function in molecules, like DNA? _formed from attraction of oppositely charged parts of molecules rather than sharing electrons; cannot bind atoms into molecules but do form links between molecules of different parts of a large molecule like DNA______
  1. Chemical Reactions ¼ each = ½ point

18. How do chemical reactions occur?

_They occur when new bonds form and/or old bonds break between atoms; process involves the transfer of energy______

19. What things are able to happen in human bodies because of chemical reactions?

_Body structures are built and body functions are carried out______

  1. Forms of Energy and Chemical Reactions ¼ each = ½ point
  2. List the two main forms of energy. _potential_ and _kinetic_
  3. What is chemical energy and where is it stored?

_It is a form of potential energy that is stored in the bonds of molecules______

  1. Synthesis Reactions
  2. Decomposition Reactions
  3. Exchange Reactions
  4. Reversible Reactions

CHECKPOINT:2 each = 4 points

  1. Distinguish among ionic, covalent, and hydrogen bonds. _ionic bond: attraction between ions of opposite charge; gain or lose e-. covalent bonds: no electrons lost or gained; atoms form molecules by sharing one, two, or three pairs of their outer shell electrons. Hydrogen bonds: Polar covalent bonds between hydrogen and other atoms is the third type of chemical bond; hydrogen is slightly positively charged and attracts another atom with a slightly negative charge/ attraction between oppositely charged parts of molecules rather than sharing of electron. _____
  2. Explain the difference between anabolism and catabolism. Which involves synthesis reactions? Which involves decomposition reactions? _All synthesis reactions are collectively referred to as anabolism; they built large molecules from small molecules; store energy. Decomposition reactions are collectively referred to as catabolism; they break down large molecules into smaller molecules; release energy______
  1. Chemical Compounds and Life Processes ¼ point
  1. Explain the main difference between inorganic and organic compounds and give examples of each type.

_Inorganic compounds lack carbon, are structurally simple, held together by ionic or covalent bonds; examples: water, many salts, acids, bases, and two-carbon containing compounds, carbon dioxide (CO2 ) and bicarbonate ions (HCO3-)______

_Organic compounds contain carbon, usually also contain hydrogen, always have covalent bonds; examples: carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate____

  1. Inorganic Compounds ¼ each = 1 ¼ point
  1. Water
  2. List and briefly discuss five reasons why water is vital to human health.
  1. _Excellent solvent: liquid or gas in which some other material (solute) has been

dissolved. Water carries nutrients, oxygen, and waste throughout the body___

  1. _Participates in chemical reaction; decomposition (hydrolysis: loosens or breaks

apart; enables nutrients to be absorbed into the body) and synthesis______

  1. _Absorbs and releases heat very slowly; moderates the effects of changes in

environmental temperature; maintaining homeostasis______

  1. _Needs a large amount of heat to change from a liquid to a gas; thus when sweat evaporates off the human body it takes large quantities of heat with it; excellent cooling mechanism______
  2. _Serves as a lubricant; major part of saliva, mucus, and other lubricating fluids;

enables organs to slide over one another and is needed in joints where bones , ligaments, and tendons rub against one another______

  1. Inorganic Acids, Bases, and Salts ¼ each = 1 ¼ point
  1. Chemicals that produce H+ ions in water are acids / bases (circle one)

Ex: HCl  _H+___ + _Cl____ hydrochloric acid

  1. Chemicals that produce OH- ions in water are acids / bases (circle one)

Ex: NaOH  _Na___ + _OH-___ sodium hydroxide (lye)

  1. Circle the compound(s) below that will become acid in water:

Acids will disassociate into one or more H+ ions in water; bases disassociate into OH- ions in water; salts disassociate into cations and anions (Na+, Cl-)in water

KOHH2SO4NaClHNO3

  1. How are salts formed? _salts disassociate into cations and anions when dissolved in water; formed when cations and anions join together______
  2. Complete the “Chemical Compound’ portion part of your ‘Chemical Reactions and Compounds’ worksheet, now if you have not already done so.
  1. Acid-Base Balance: The Concept of pH
  1. Draw a simple pH scale below and place the following substances at the correct places: bile, blood, saliva, spinal fluid, stomach juices, and urine. 1 point

  1. Which of these substances is the most acidic?

_Stomach juices; saliva_ basic? _urine @8.0; bile, blood, spinal fluid__1/2 point___

  1. Maintaining pH: Buffer Systems

a. How does the body compensate for the intake of extremely acidic or alkaline foods? _Buffers convert strong acids or bases into weak acids and bases__1/4 point______

  1. Organic Compounds
  2. Carbohydrates ¼ each = 3 points
  3. Elements composed of: _C, H, O______
  4. Ratio of elements: approximately and usually 1:2:1
  5. What three major groups are carbohydrates divided into based on size? _monosaccharides, disaccharides, and polysaccharides______
  6. Which group(s) are the simple sugars? _monosaccharides and disaccharides______
  7. Which group(s) are the complex carbohydrates? _polysaccharides______

-Monosaccharides:

Monomer or building block of carbohydrates.

What is the primary function of glucose? _serve as source of chemical energy

for generating ATP to fuel metabolic reactions______

Examples of monosaccharides: _glucose, ribose, deoxyribose______

-Disaccharides:

What do they consist of? and what type of bond holds them together?

_two monosaccharides joined covalently______

What is lost when they are formed? and what is this type of reaction called?

_ formed through dehydration synthesis (water molecule lost)______

-Polysaccharides:

What type of reaction forms them? and what are they composed of?

_Dehydration synthesis; tens or hundreds of monosaccharides______

What type of reaction breaks down polysaccharides and disaccharides? and

what is added in order for this type of reaction to occur?

_Decomposition/hydrolysis-water is added to cut the molecules apart______

What is the main polysaccharide in the human body, where is it stored, and

what is its function?

_Glycogen;cells of the liver and skeletal muscles; when energy demands are

high it is broken down into glucose, when energy demands are low glucose is

built back up into glycogen______

Humans cannot digest a plant polysaccharide called cellulose, so why would we

consume plants? _It provides bulk/roughage or fiber that helps feces move

through large intestine______

  1. Lipids a-g ¼ each = 1 ¾ points
  2. Elements composed of: _C, H, O______
  3. Ratio of hydrogen to oxygen atoms smaller than in carbohydrates, thus fewer polar covalent bonds and lipids are hydrophobic
  4. What does it mean to be ‘hydrophobic’? _insoluble in water______
  5. What is the most plentiful type of lipid in the human body? _triglycerides______
  6. What form of matter does the lipid in item ‘d’ above exhibit at room temperature? _Either solids (fats) or liquids (oils)______
  7. How much energy does this particular lipid store compared to proteins and carbohydrates? _more than twice as much chemical energy per gram______
  8. What is adipose tissue? _Fat tissue______
  9. Draw and label the structure of a triglyceride molecule below, you do not need to show every single atom…show the molecules it is composed of. 1 point

Rest ¼ each = 3 points

  1. Fatty acids chains of triglycerides can be saturated, monounsaturated, or polyunsaturated. Describe the basic structure of each type below and list examples of products they are found in.

Saturated fats: _only single covalent bonds between fatty acid carbon atoms; saturated with hydrogen atoms; Example(s):cocoa, palm and coconut oils______

Monounsaturated fats: _one double covalent bond between two fatty acid carbons; Example(s):olive oil, peanut oil______

Polyunsaturated fats: _more than one double covalent bond between fatty acid carbon atoms; Example(s):margarine, vegetable shortening______

  1. How is the structure of a phospholipid different from that of a triglyceride? _Glycerol with only two fatty acids instead of three______
  2. Below is a picture of a phospholipid cell membrane that has two layers arranged nonpolar tail to nonpolar tail with the polar heads on the outer surfaces. The tails are hydrophobic and the heads are hydrophilic, what important property does this give to phospholipid bilayers(not in textbook, you’ll have to ponder)? _Waterproofing and control of enters and leaves______
  1. What is unique about the structure of steroids? _four rings of carbon atoms______
  2. Which steroid can be synthesized by the human body into other steroids? _cholesterol ______
  3. What is estradiol? _one of the estrogens of female sex hormones______
  4. What is testosterone? _main male sex hormone______
  5. What other three types of steroids can be synthesized by the human body?_cortisol, bile salts, and vitamin D______
  1. Proteins a-b ¼ each = ½ point
  2. Elements composed of: _C, H, O, N, and sometimes S______
  3. What are the roles of proteins in the human body?

_acts as enzymes that speed up chemical reactions______

_responsible for contractions of muscles______

_act as antibodies to help defend to body against invading microbes______

_act as hormones or responsible for structure of body cells______

  1. Amino acids are the monomers or building blocks of proteins, label the three parts of their structure (side chain, amino group, and carboxyl group) below: ½ point

Rest ¼ each =1 ½ points

  1. Which is the only part of the amino acid structure that varies from amino acid to amino acid? _R-side chain______
  2. Describe what peptides, dipeptides, tripeptides, and polypeptides are below:

Peptides: _union or two or more amino acids______

Dipeptides: _name given to the molecule when two amino acids unite_________

Tripeptides: _Adding another amino acid to a dipeptide forms a tripeptide, now three amino acids united_______

Polypeptides: _contains three or more amino acids, large amount of amino acids__

  1. What is denaturation? _if protein encounter hostile environments in which temperature, pH, or ion concentration is significantly altered, it may unravel and lose its characteristics, no longer functional______
  1. Enzymes ¼ each =1 ¼ points
  2. What do enzymes do? _speed up chemical reactions by increasing the frequency of collisions between molecules and by properly orienting the colliding molecules____
  3. Enzymes are catalysts. What does this statement mean? _They are substances that can speed up chemical reactions without being used up themselves or altered_____
  4. List the three important properties of enzymes below and briefly explain each one:

(1). _Specificity: enzymes are specific in that each different type catalyzes particular chemical reactions that involve specific substrates (molecules upon which the enzymes act) and that they give rise to specific products (molecules produced by the reaction). Enzymes fit the substrate like a lock-and-key fit one another or they change shape to fit snugly around the substrate once the enzyme and substrate come together; over 1000 types known each with a characteristic 3-D shape______

(2). _Efficiency: under optimal conditions(right temperature, pH, inhibitors, concentration, genetics/PKU, chemical environment, cofactors/coenzymes), catalyze at a rate of millions to billions of times more rapidly than would occur without enzyme. Single enzyme produce molecules at rate of 600,000/second____

(3). _Control: subject to variety of cellular controls; i.e. rate of synthesis, their concentration at any given time=>cells’ genes control this. Exist in active and inactive forms, most require a cofactor or coenzyme to operate properly. Cofactors=ions of iron, zinc, magnesium, or calcium. Coenzymes= niacin, riboflavin, derivatives of B vitamins.______

  1. Nucleic Acids: Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
  2. Elements composed of: _C, H, O, P, and N____1/4 point______
  3. Nucleotides are the monomers or building blocks of nucleic acids. In the table below list the three parts of nucleotides found in DNA and RNA:1 point

DNA;double helix / RNA;single strand
5-C sugar/deoxyribose / 5-C sugar/ribose
4 nitrogenous bases= Adenine, Cytosine, Guanine, and Thymine / 4 nitrogenous bases= Adenine, Cytosine, Guanine, and Uracil
Phosphate group / Phosphate group
  1. We will discuss the functions of both of these molecules in detail in Chapter 3.
  1. Adenosine Triphosphate ¼ each = 1 ¼ points
  2. What is the main function of ATP? _’energy currency’ of the living organisms______
  3. List some of its cellular activities below:

_transfer energy from energy-releasing reactions to energy-requiring reactions that maintain cellular activities______

_Activities include: contraction of muscles, movement of chromosomes during cell division, movement of structures within a cell, transport of substances across cell membrane, and synthesis of larger molecules from small ones______

  1. What is adenosine composed of? _Adenine & ribose______
  2. What energy-transferring reaction releases energy from ATP? _hydrolysis______

CHECKPOINT: 2 points each = 14 points

1. How do inorganic compounds differ from organic compounds? _ Inorganic compounds lack carbon, are structurally simple, held together by ionic or covalent bonds; examples: water, many salts, acids, bases, and two-carbon containing compounds, carbon dioxide (CO2 ) and bicarbonate ions (HCO3-)

_Organic compounds contain carbon, usually also contain hydrogen, always have covalent bonds; examples: carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate_

2. What functions does water perform in the body? _catabolic and anabolic reactions aided by it (decomposition and synthesis reactions),excellent solvent, absorbs and releases heat very slowly as well as requires a great deal of heat to change from liquid to gas thus aiding to maintain homeostasis, and acts as a lubricant for and among body structures______

3. What is a buffer? _ a solution that resists changes in pH when acid or alkali is added to it. Buffers typically involve a weak acid or alkali together with one of its salts_