a substance that cannot be broken down to other substances by chemical reactions, ei, oxygen
Atoms with incomplete valence shells
Share or transfer valence electrons with certain other atoms.
The potential energy of chemical bonds.
2) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into
4) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope?
5) To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology?
6) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation?
7) When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of
9) Prokaryotic and eukaryotic cells generally have which of the following features in common?
Bacteria and Archaea
10) Prokaryotes are classified as belonging to two different domains. What are the domains?
) Limit the burning of fossil fuels and regulate our loss of forested areas.
11) Global warming, as demonstrated by observations such as melting of glaciers, increasing CO2 levels, and increasing average ambient temperatures, has already had many effects on living organisms. Which of the following might best offer a solution to this problem?
12) A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?
Domain Eukarya, Kingdom Fungi
13) A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism?
Near universality of the genetic code
14) Which of these provides evidence of the common ancestry of all life?
It requires genetic variation, results in descent with modification, and involves differential reproductive success.
15) Which of the following is (are) true of natural selection?
Carbon, hydrogen, nitrogen, oxygen
1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
Virtually all organisms require the same elements in the same quantities.
3) Which of the following statements is false?
Both the relative abundances of the elements and the emergent properties of the compounds made from these elements
4) What factors are most important in determining which elements are most common in living matter?
Each element has a unique number of protons in its nucleus.
5) Why is each element unique and different from other elements in chemical properties?
both the number of protons and the chemical properties of the element
6) Knowing just the atomic mass of an element allows inferences about which of the following?
They have the same number of electron shells.
7) In what way are elements in the same column of the periodic table the same?
8) Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom?
The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.
9) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
Molybdenum atoms can have between 50 and 58 neutrons.
10) Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following can be true?
Some carbon atoms in nature have more neutrons.
11) Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?
The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample.
13) The precise weight of a mole of some pure elements like silicon (Si) can vary slightly from the standard atomic mass, or even from sample to sample. Why?
16) The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?
An electron may move to an electron shell farther away from the nucleus.
17) Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
It has 8 electrons in its outer electron shell and it is inert.
18) The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?
15 protons and 15 electrons.
19) From its atomic number of 15, it is possible to predict that the phosphorus atom has
Be both chemically inert and gaseous at room temperature
20) Atoms whose outer electron shells contain 8 electrons tend to
must have the same number of protons + neutrons.
22) Two atoms appear to have the same mass number. These atoms
23) Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?
It would form ions with a +2 charge.
27) An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms.
29) A covalent chemical bond is one in which
30) If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed?
31) What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
32) Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
one of the atoms sharing electrons is much more electronegative than the other atom.
35) A covalent bond is likely to be polar when
Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons.
37) In comparing covalent bonds and ionic bonds, which of the following would you expect?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
38) What is the difference between covalent bonds and ionic bonds?
NH4, with a charge of +1
39) In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl. What is the cation of NH4Cl?
40) The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
41) How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4?
42) Which bond or interaction would be difficult to disrupt when compounds are put into water?
43) Which of the following explains most specifically the attraction of water molecules to one another?
electrons are not symmetrically distributed in a molecule.
44) Van der Waals interactions result when
van der Waals interactions
45) What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)?
48) What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.
50) Which of the following correctly describes chemical equilibrium?
The rate of the forward reaction is equal to the rate of the reverse reaction.
51) Which of the following correctly describes any reaction that has reached chemical equilibrium?
a test tube of living cells
52) Which of these systems is least likely to be at chemical equilibrium?
53) Refer to the figure above (first three rows of the periodic table). If life arose on a planet where carbon is absent, which element might fill the role of carbon?
63) How many neutrons are present in the nucleus of a phosphorus-32 (32P) atom (see the figure above)?
65) Based on electron configuration, which of these elements in the figure above would exhibit a chemical behavior most like that of oxygen?
will form hydrogen bonds with water molecules.
66) The illustration above shows a representation of formic acid. A formic acid molecule
The element is required in very small amounts.
76) In the term trace element, the modifier trace means that
the existence of unpaired electrons in the valence shell.
78) The reactivity of an atom arises from
The atom has more electrons than protons.
79) Which statement is true of all atoms that are anions?
The rates of the forward and reverse reactions are equal.
80) Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
82) The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound:
Polar Covalent Bond
1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
2) The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
The electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom
3) The partial negative charge in a molecule of water occurs because
Will not form hydrogen bonds with each other.
4) Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S
Kinetic energy in the drink decreases.
7) Which of the following takes place as an ice cube cools a drink?
Absorption and release of heat when hydrogen bonds break and form.
10) Liquid water's high specific heat is mainly a consequence of the
The release of heat by the formation of hydrogen bonds
12) Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
The water molecules with the most heat energy evaporate more readily
13) Why does evaporation of water from a surface cause cooling of the surface?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
14) Why does ice float in liquid water?
Nonpolar substances that repel water molecules.
15) Hydrophobic substances such as vegetable oil are
180 grams of glucose and 6.02 × 1023 molecules of glucose.
16) One mole (mol) of glucose (molecular mass = 180 daltons) is
(90/180) × 6.02 × 1023
17) How many molecules of glucose (C6H12O6 molecular mass = 180 daltons) would be present in 90 grams of glucose?
26) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
It is a strong acid that ionizes completely in water.
27) A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
acidic: will give H+ to weak acids, but accept H+ from strong acids
28) A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?
Gastric juice at pH 2
32) Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
concentration of H+ has increased tenfold (10X) and the concentration of OH- has decreased to one-tenth (1/10) what they were at pH 9.
34) If the pH of a solution is decreased from 9 to 8, it means that the
concentration of OH- is 100 times greater than what it was at pH 5.
35) If the pH of a solution is increased from pH 5 to pH 7, it means that the
They maintain a relatively constant pH when either acids or bases are added to them.
38) Which of the following statements is true about buffer solutions?
both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
39) Buffers are substances that help resist shifts in pH by
the concentration of H+ ions in the water equals the concentration of OH- ions in the water.
45) If a solution has a pH of 7, this means that
53) Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely
54) How many grams would be equal to 1 mol of the compound shown in the figure above?
(carbon = 12, oxygen = 16, hydrogen = 1)
the absorption of heat by the breaking of hydrogen bonds
63) Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
Number of Molecules
66) We can be sure that a mole of table sugar and a mole of vitamin C are equal in their
67) Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?
68) Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?
54) Which drawing in the figure above depicts the electron configuration of an element with chemical properties most similar to Helium (2He)?
55) Which drawing in the figure above depicts the electron configuration of an atom that can form covalent bonds with two hydrogen atoms?
56) Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms?
will form hydrogen bonds with water molecules.
66) The illustration above shows a representation of formic acid. A formic acid molecule
The chemical versatility of carbon atoms.
2) The complexity and variety of organic molecules is due to
living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.
3) The experimental approach taken in current biological investigations presumes that
differences in the types and relative amounts of organic molecules synthesized by each organism.
4) Differences among organisms are caused by
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
14) Why are hydrocarbons insoluble in water?
15) How many structural isomers are possible for a substance having the molecular formula C4H10?
They have variations in arrangement around a double bond.
16) Which of the following statements correctly describes cis-trans isomers?
are mirror images of one another.
17) Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
the presence or absence of double bonds between the carbon atom and other atoms
18) What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?
be more constrained in structure.
19) Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will
20) Organic molecules with only hydrogens and five carbon atoms can have different structures in all of the following ways except
It should dissolve in water.
21) A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
would function as both an acid and a base.
25) A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it
C) Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
28) Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?
C) arrangement of carbon, hydrogen, and oxygen atoms.
31) The figure above shows the structures of glucose and fructose. These two molecules differ in the
D) structural isomers.
32) The figure above shows the structures of glucose and fructose. These two molecules are
35) Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric forms) of the same molecule?
36) Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule?
B) are mirror images of one another.
38) Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that
47) Which of the groups shown above is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules?
49) Which of the groups above is an acidic functional group that can dissociate and release H+ into a solution?
50) Which of the groups above is a basic functional group that can accept H+ and become positively charged?
57) Which molecule shown above can increase the concentration of hydrogen ions in a solution and is therefore an organic acid?
D) All of these molecules except B will form hydrogen bonds with water.
59) Which molecules shown above will form hydrogen bonds with water?
62) Which molecule shown above contains a functional group that cells use to transfer energy between organic molecules?
64) A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?
67) Which chemical group is most likely to be responsible for an organic molecule behaving as a base?
A) structural isomers
69) Choose the term that correctly describes the relationship between these two sugar molecules:
A) the replacement of the OH of a carboxyl group with hydrogen
71) Which action could produce a carbonyl group?
2 H20 moles can shift from one to another
hydrogen atom leaves its e- behind and its transferred as a partial h+
How many mol would you need to make .01M solution a hydrogen atom in a hydrogen bond
A Solution with a pH of 2 compared to a solution with a pH of 4 will differ in its hydrogen ion concentration by a factor of
Determines the kinds and number of bonds an atom will form with other atoms
Organic molecules consisting of only carbon and hydrogen
Can undergo reactions that release a large amount of energy
Carbon skeleton and on the molecular components
Distinctive properties of organic molecules depend on the
The components of organic molecules that are most commonly involved in chemical reactions
Occurs when two monomers bond together through the loss of A water molecule (dehydration synthesis)
Polymers are disassembled to monomers
A reaction that is essentially the reverse of the dehydration reaction (water is added)
An-OH group (hydroxyl group) from one molecule combines with a H atom from an other molecule
Water forms as the two molecules bond covalently
Include sugars and the polymers of sugars
The simplest carbohydrates are monosaccharide, or single sugars
Carbohydrate macromolecules are polysaccharides, polymers composed of many sugar building blocks
Serve as a major fuel for cells and as raw material for building molecules
Glucose (C6H12O6) is the most common
The polymers of sugars
Have storage and structural roles
The structure and function of a polysaccharides and determined by its sugar monomers and the positions of gylcosidic linkages
A storage polysaccharide of plants, consisting of glucose
The simplest form of starch is amylose
A storage polysaccharide in animals, consisting of glucose
Humans and other vertebrates store glycogen mainly in liver and muscle cells
A structural polysaccharide consisting of glucose
Parallel cellulose molecules are grouped into microfibrils, which from strong building materials for plants
A structural polysaccharide found in the exoskeleton of arthropods
Also provides structural support for the cell walls of many fungi
Do not form polymers
Have little or no affinity for water
Lipids are hydrophobic because they consist mostly of hydrocarbons, which form nonpolar covalent bonds
The major function of fats is energy storage
Humans and other mammals store their fat in adipose cells
Adipose tissue also cushions vital organs and insulates the body
Two fatty acids and a phosphate group are attached to glycerol
The two fatty acid tails are hydrophobic
The phosphate group and its attachments form a hydrophilic head
Lipids characterize by a carbon skeleton consisting of four fused rings
Cholesterol, an important steroid, is a component in animal cell membrane
structural support, storage, transport, cellular communications, movement, and defense against foreign substances
Organic molecules with carboxyl and amino groups
Differ in their properties due to differing side chains, call R groups
Determines Protein Structure?
In addition to primary structure, physical and chemical conditions can affect structure
Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel
The loss of a protein's native structure is called denaturation
A denatured protein is biologically inactive
Proteins that assist in the proper folding of other proteins
Diseases such as Alzheimer's, Parkinson's, and mad cow disease are associated with misfolded proteins
Covalent bonds form between the OH group on the 3' carbon of one nucleotide and the phosphate on the 5' carbon on the next
DNA Molecule Double Helix
Two backbones are antiparallel
Run In opposite 5'-3' directions from each other
The nitrogenous base in DNA
Pair up and form hydrogen bonds; adenine (A) to thymine (T), and guanine (G) to cytosine (C)