chapter 2

How many electrons are shared by the oxygen atoms in an oxygen molecule? (Module 2.4B) one electron 2 pairs of electrons eight electrons 3 pairs of electrons 1 pair of electrons

2 pairs of electrons

What is a functional group? (Module 2.13B) A functional group is the complex created when an enzymes binds its substrate to complete a reaction. A functional group is the result of dissociation of organic molecules. A functional group is a grouping of atoms that confer specific chemical properties to the rest of the molecule to which it is attached. A functional group is the specific grouping of atoms on a molecule to which enzymes can bind. A functional group is the final energy source in organic catabolism.

A functional group is a grouping of atoms that confer specific chemical properties to the rest of the molecule to which it is attached.

What kind of bond forms during the dehydration synthesis of two amino acids, and which functional groups are involved? (Module 2.17B) A hydrogen bond forms between the hydrogen atom of one amino acid and the oxygen atom of the other amino acid. A lipophilic bond forms between the hydrophobic tail of one amino acid and the hydrophilic head of the other amino acid. A glycosidic bond forms between the amino group of one amino acid and the carboxyl group of the other amino acid. A peptide bond forms between the amino group of one amino acid and the carboxyl group of the other amino acid. An ionic bond forms between the amino ion of one amino acid and the carboxylic acid of the other amino acid.

A peptide bond forms between the amino group of one amino acid and the carboxyl group of the other amino acid.

Describe the functional groups that are considered acidic or basic. (Module 2.13D) A phosphate group acts as a base because it can accept hydrogen ions, and a hydroxyl group acts as an acid because it releases a hydrogen ion. An amino group acts as a base because it can accept hydrogen ions, and a carboxyl group acts as an acid because it releases a hydrogen ion. Phosphate groups can act as an acid or a base depending on the pH of the surrounding solution. An amino group acts as a base because it releases a hydrogen ion, and a carboxyl group acts as an acid because it can accept hydrogen ions. A phosphate group acts as an acid because it can accept hydrogen ions, and a hydroxyl group acts as a base because it releases a hydrogen ion.

An amino group acts as a base because it can accept hydrogen ions, and a carboxyl group acts as an acid because it releases a hydrogen ion.

What is the relationship between an atom and matter? An atom is a chemical substance made up of two or more different elements in a fixed proportion, and matter is a pure substance consisting only of atoms with the same atomic number. An atom is the smallest stable unit of matter, and matter is a pure substance consisting only of atoms with the same atomic number. An atom is the smallest stable unit of matter, and matter is anything that takes up space and has mass. An atom is the largest stable unit of matter, and matter is anything that takes up space and has mass. An atom is a particle with a negative electrical charge, and matter is mass within a gravitational field.

An atom is the smallest stable unit of matter, and matter is anything that takes up space and has mass.

What is an enzyme? (Module 2.9A) An enzyme is a polymer produced by linking monomers together. An enzyme is an inorganic compound. An enzyme is a protein that lowers the activation energy of a reaction. An enzyme provides the activation energy of a reaction. An enzyme is a protein that increases the activation energy so more energy can be generated.

An enzyme is a protein that lowers the activation energy of a reaction.

Explain why the atoms of inert elements do not react with one another or combine with atoms of other elements. (Module 2.3B) Atoms of inert elements are nonreactive because the innermost electron shell contains the maximum number of electrons possible. Atoms of inert elements are nonreactive because the outermost electron shell (valence shell) contains the minimum number of electrons possible. Atoms of inert elements are nonreactive because the outermost electron shell (valence shell) contains the maximum number of electrons possible. Atoms of inert elements are nonreactive because the number of electrons is equal to the number of protons. Atoms of inert elements are nonreactive because the innermost electron shell contains the minimum number of electrons possible.

Atoms of inert elements are nonreactive because the outermost electron shell (valence shell) contains the maximum number of electrons possible.

Using chemical notation, write the molecular formula for glucose, a compound composed of 6 carbon (C) atoms, 12 hydrogen (H) atoms, and 6 oxygen (O) atoms. (Module 2.7D) C6H12O6 C1H2O1 CHO (6-12-6) CH2O CHO

C6H12O6

Which of the following is not a cation? Na+ K+ Cl- Ca2+ Mg2+

Cl-

________ are soluble inorganic compounds whose solutions will conduct an electric current. Proteins Electrolytes Enzymes Lipids Ions

Electrolytes

Describe the subatomic particle not in the nucleus. Neutrons are not in the nucleus. They whirl around the nucleus creating a neutron cloud. Electrons are not in the nucleus. They whirl around the nucleus creating an electron cloud. Protons are not in the nucleus. They whirl around the nucleus creating a proton cloud. Protons and electrons are not in the nucleus. They whirl around the nucleus creating a proton and electron cloud. Protons and neutrons are not in the nucleus. They whirl around the nucleus creating a proton and neutron cloud.

Electrons are not in the nucleus. They whirl around the nucleus creating an electron cloud.

Distinguish between hydrophilic and hydrophobic molecules. (Module 2.11C) Hydrophilic molecules are inorganic, whereas hydrophobic molecules are organic. Hydrophilic molecules do not interact with water molecules, whereas hydrophobic molecules are attracted to water. Hydrophilic molecules are organic, whereas hydrophobic molecules are inorganic. Hydrophilic molecules are attracted to water, whereas hydrophobic molecules do not interact with water molecules. Hydrophilic molecules are monomers, whereas hydrophobic molecules are polymers.

Hydrophilic molecules are attracted to water, whereas hydrophobic molecules do not interact with water molecules.

Compare the role of water in hydrolysis and dehydration synthesis reactions. (Module 2.8A) In hydrolysis and dehydration synthesis, water is a product. In hydrolysis, water is a product; in dehydration synthesis, water is a reactant. In hydrolysis and dehydration synthesis, water is an enzyme. In hydrolysis, water is a reactant; in dehydration synthesis, water is a product. In hydrolysis and dehydration synthesis, water is a reactant.

In hydrolysis, water is a reactant; in dehydration synthesis, water is a product.

Carbon-12 (12C) is the most common form of the element carbon. How is the isotope carbon-13 (13C) similar to and different from 12C? Isotope 13C has the same chemical properties but has one more neutron than 12C. Isotope 13C has the same chemical properties but has one more electron than 12C. Isotope 13C has the same chemical properties but has one more proton than 12C. Isotope 13C has different chemical properties and has one more electron and one more proton than 12C. Isotope 13C has different chemical properties and has one more electron than 12C.

Isotope 13C has the same chemical properties but has one more neutron than 12C.

list the chemical symbols of the six most abundant elements in the human body and their total percentage contribution to total body weight. (Module 2.2E) O, C, H, N, Ca, and P. They account for 99.3% of total body weight. O, C, H, N, Ca, and P. They account for 100% of total body weight. O, C, H, N, Ca, and P. They account for 65% of total body weight. O, C, H, N, K, Na. They account for 99.3% of total body weight. O, C, H, N, K, Na. They account for 65% of total body weight.

O, C, H, N, Ca, and P. They account for 99.3% of total body weight.

The gravitational field of the moon is 17% of Earth's. How would the weight and mass of a 100-pound astronaut change on the moon? On the moon, the astronaut would have the same mass as on Earth but would weigh 588 pounds (100/0.17). On the moon, the astronaut would have more mass than on Earth but would weigh the same. On the moon, the astronaut would have less mass than on Earth and would weigh 17 pounds (100 × 0.17). On the moon, the astronaut would have the same mass as on Earth but would weigh 17 pounds (100 × 0.17). On the moon, the astronaut would have less mass than on Earth but would weigh the same.

On the moon, the astronaut would have the same mass as on Earth but would weigh 17 pounds (100 × 0.17).

________ are short-chain fatty acids in which five of the carbon atoms are joined in a ring. Cholesterol Estrogen Glycolipids Testosterone Prostaglandins

Prostaglandins

How are chemical reactions represented? (Module 2.7B) Reactions are represented by Lewis structural models and the total number of atoms represents the direction of the reaction. Reactions are represented by line plots and the line represents the direction of the reaction. Reactions are represented by superscripts and subscripts and the charge represents the direction of the reaction. Reactions are represented by a sine wave and the slope represents the direction of the reaction. Reactions are represented by chemical equations and the arrow represents the direction of the reaction.

Reactions are represented by chemical equations and the arrow represents the direction of the reaction.

Describe the orientations of phospholipids and glycolipids when they form a micelle. (Module 2.16C) The phospholipids are on the inside, and the glycolipids form the surface of the micelle. The hydrophilic tails are inside, and the hydrophobic heads form the surface of the micelle. The hydrophilic heads are inside, and the hydrophobic tails form the surface of the micelle. The hydrophobic tails are inside, and the hydrophilic heads form the surface of the micelle. The hydrophobic heads are inside, and the hydrophilic tails form the surface of the micelle.

The hydrophobic tails are inside, and the hydrophilic heads form the surface of the micelle.

Explain how the ionic compound sodium chloride dissolves in water. (Module 2.11A) The positive poles of water molecules are attracted to the positively charged chloride ions, and the negative poles of water molecules are attracted to the negatively charged sodium ions. The negative poles of water molecules are attracted to the positively charged chloride ions, and the positive poles of water molecules are attracted to the negatively charged sodium ions. The positive poles of water molecules are attracted to the negatively charged chloride ions, and the negative poles of water molecules are attracted to the positively charged sodium ions. The negative poles of water molecules are attracted to the negatively charged chloride ions, and the positive poles of water molecules are attracted to the positively charged sodium ions. Sodium chloride is hydrophobic so it does not dissolve in water.

The positive poles of water molecules are attracted to the negatively charged chloride ions, and the negative poles of water molecules are attracted to the positively charged sodium ions.

What is the source of energy that converts glucose, a six-carbon molecule, into two three-carbon molecules in cells? (Module 2.8C) The potential energy stored in the covalent bonds of the glucose molecule is released when some of the bonds break. The kinetic energy released as one glucose molecule combines with another glucose molecule. The kinetic energy is converted to potential energy as the glucose molecule forms. The kinetic energy released as ions are formed when glucose is broken down. The potential energy stored in the ionic bonds of the glucose molecule is released when some of the bonds break.

The potential energy stored in the covalent bonds of the glucose molecule is released when some of the bonds break.

Cations are smaller in diameter than their electrically neutral atom. Why? (Module 2.3D) When electrons are lost, the remaining electrons enter the nucleus. When electrons are lost, the remaining electrons are pulled closer toward the nucleus. When electrons are lost, the remaining electrons are pulled further away from the nucleus. When electrons are gained, the electrons are pulled further away from the nucleus. When electrons are gained, the electrons are pulled closer toward the nucleus.

When electrons are lost, the remaining electrons are pulled closer toward the nucleus.

When two monosaccharides undergo a dehydration synthesis, a polysaccharide is formed. a disaccharide is formed. two new monosaccharides are formed. a starch is formed. All of the answers are correct.

a disaccharide is formed.

Every amino acid has a central carbon atom to which all of the followings are attached except a phosphate group. a hydrogen atom. a carboxyl group. an amino group. a variable side group labeled as R.

a phosphate group.

The actual mass of an atom is known as its element number. atomic number. atomic mass unit. atomic weight. mass number.

atomic weight.

A functional group is best described as reoccurring clusters of elements that occur in a salt. atoms that function in the body. elements that form at high pH. atoms that greatly influence the chemical properties of molecules they are part of. amino acids in a globular protein.

atoms that greatly influence the chemical properties of molecules they are part of.

The smallest stable units of matter are neutrons. atoms. protons. electrons. molecules.

atoms.

A(n) ________ removes hydrogen ions, and a(n) ________ releases hydrogen ions. acid; base molecule; acid base; acid element; compound compound; element

base; acid

Which of the following is/are inorganic substance(s)? fructose carbon dioxide water glycerol both water and carbon dioxide

both water and carbon dioxide

By what means are water molecules attracted to each other? (Module 2.5B) by hydrogen bonds by ionic bonds by oxygen bonds by nonpolar covalent bonds by isotopes

by hydrogen bonds

Chemical reactions that yield energy, such as heat, are said to be endergonic. activated. neutral. exergonic. thermonuclear.

exergonic.

A carbohydrate is attached to a diglyceride in which type of lipid? steroids phospholipids leukotrienes prostaglandins glycolipids

glycolipids

List the elements that make up organic compounds. (Module 2.13A) hydrogen, nitrogen, and sodium hydrogen and carbon, and generally oxygen as well hydrogen, oxygen, sodium, chloride hydrogen and oxygen only sodium, chloride, and potassium

hydrogen and carbon, and generally oxygen as well

Which of the following lipids are produced in response to cellular injury or disease? sex steroids glycolipids phospholipids cholesterol leukotrienes

leukotrienes

Predict the reactants and the type of chemical reaction involved when muscle cells make and store glycogen. (Module 2.14D) many glucose monomers; hydrolysis many glucose monomers; dehydration synthesis glucose and fructose; dehydration synthesis many starch monomers; hydrolysis glucose and fructose; hydrolysis

many glucose monomers; dehydration synthesis

Which is larger: an element's atomic number or mass number? atomic number mass number

mass number

Compounds that can be synthesized or broken down by chemical reactions inside the body are called inorganic compounds. organic compounds. metabolites. nutrients. enzymes.

metabolites.

All of the following are correct regarding DNA except the nitrogenous base is made of adenine, guanine, cytosine, and thymine. it stores genetic information. it contains a double helix. molecular shape varies with hydrogen bonding along the length of the strand. it contains deoxyribose sugar.

molecular shape varies with hydrogen bonding along the length of the strand.

The chemical behavior of an atom is determined by the number of neutrons. outermost electron shell. number of protons. mass of the nucleus. size of the atom.

outermost electron shell.

By weight, which element is the most plentiful in the human body? potassium sodium sulfur oxygen carbon

oxygen

The molecule O2 is known as oxygen and organic. organic. oxygen. oxide. oxyous.

oxygen.

The ________ of a solution is the negative logarithm of the hydrogen ion concentration expressed in moles per liter. electropositivity electronegativity electrical current dissociation pH

pH

A hydrogen ion is the same as what subatomic particle? (Module 2.12B) proton quark electron neutron neutrino

proton

The "atomic number" of an atom is determined by the number of ________ it has. neutrons protons + electrons protons protons + neutrons electrons

protons

The mass of an atom is largely determined by the number of ________ it has. protons + electrons protons neutrons electrons protons + neutrons

protons + neutrons

The atomic weight of an atom reflects the average number of protons + neutrons + electrons. protons + neutrons. electrons. protons. neutrons.

protons + neutrons + electrons.

The mass number represents the number of neutrons + electrons. protons in an atom. neutrons in an atom. protons + neutrons. electrons in an ion.

protons + neutrons.

The nucleus of an atom consists of neutrons. protons + neutrons. protons + electrons. protons. electrons.

protons + neutrons.

Which subatomic particles have a positive charge? Which are uncharged? neutrons; electrons protons; neutrons protons; electrons electrons; protons electrons; neutrons

protons; neutrons

Adenine and guanine are nucleotides represented by A and G. purines represented by A and G. pyrimidines represented by T and C. pyrimidines represented by A and G. purines represented by T and C.

purines represented by A and G.

If one pair of electrons is unequally shared between two atoms, a ________ occurs. hydrogen bond double polar covalent bond single polar covalent bond double nonpolar covalent bond single nonpolar covalent bond

single polar covalent bond

The three familiar states of matter listed in order from the least to most thermal energy are solid, gas, liquid. gas, solid, liquid. gas, liquid, solid. solid, liquid, gas. liquid, gas, solid.

solid, liquid, gas.

A(n) ________ is a homogeneous mixture containing a solvent and a solute. blend organic molecule inorganic molecule solution concoction

solution

Which of the following is a structural component of hormones? steroids phospholipids lauric acid prostaglandins monoglycerides

steroids

Which of the following substances would be most acidic? lemon juice, pH = 2 stomach secretions, pH = 1 urine, pH = 6 white wine, pH = 3 tomato juice, pH = 4

stomach secretions, pH = 1

When placed in water, an inorganic compound dissociates 99 percent, forming hydrogen ions and anions. This compound would be a weak acid. strong base. strong acid. weak base. salt. Submit

strong acid

AB → A + B is to decomposition as A + B → AB is to combustion. replacement. exchange. synthesis. metabolism.

synthesis.

Which of the following is a result of convoluted coiling and folding that grants protein its final three-dimensional shape? tertiary structure primary structure quaternary structure secondary structure pentagonal

tertiary structure

In hydrolysis reactions, compounds react with hydrogen, causing decomposition. water, causing synthesis. glucose, causing decomposition. water, causing decomposition. carbon, causing decomposition.

water, causing decomposition.

Describe lipids in terms of their elemental composition and solubility in water. (Module 2.15A) water-soluble organic compounds made up of hydrogen and oxygen water-soluble inorganic compounds made up of hydrogen and oxygen water-soluble organic compounds made up of carbon, hydrogen, and oxygen water-insoluble inorganic compounds made up of hydrogen and oxygen water-insoluble organic compounds made up of carbon, hydrogen, and oxygen

water-insoluble organic compounds made up of carbon, hydrogen, and oxygen

Magnesium atoms have two electrons in the outermost shell. As a result, you would expect magnesium to form ions with a charge of -1. -2. +1. +2. either +2 or -2.

+2.

Of the following choices, the pH of the least acidic solution is 6.0. 1.0. 12.0. 2.3. 4.5.

12.0

Indicate the maximum number of electrons that can occupy each of the first three energy levels of an atom. (Module 2.3A) 1, 4, 8 2, 8, 8 2, 4, 8 1, 2, 4 2, 8, 16

2, 8, 8

What are the products of ATP hydrolysis? (Module 2.19D) ribose, adenine, a phosphate group, and energy an adenosine, a phosphate group, and energy AMP, two phosphate groups, and energy ADP, a phosphate group, and energy 3 phosphate groups and energy

ADP, a phosphate group, and energy

AMP + P → adenine. ADP. 2ADP. ATP. DNA.

ADP.

Adding a phosphate group to adenosine forms 2ATP. ribose. ADP. ATP. AMP.

AMP.

Which of the following is both an anion and a compound? K+ Cl- HCO3- NaCl Na+

HCO3-

Which of the following statements about hydrogen bonds is false? Hydrogen bonds are important for holding large molecules together. Hydrogen bonds can occur within a single molecule. Hydrogen bonds can form between neighboring molecules. Hydrogen bonds are responsible for many of the properties of water. Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.

Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.

Which of the following statements about water is not correct? It is responsible for much of the mass of the human body. It is composed of polar molecules. It has a relatively low heat capacity. It contains hydrogen bonds. It can dissolve many substances.

It has a relatively low heat capacity.

Why is cholesterol necessary in the body? (Module 2.16B) It makes up the genetic material. It is important for energy production. It is a building block for proteins. It is a component of plasma membranes and is important for cell growth and division. It is an important enzyme

It is a component of plasma membranes and is important for cell growth and division.

Which of the following is correct regarding fructose? It is a polysaccharide. It is an isomer of glucose. It is a disaccharide. It is the most important metabolic fuel in the body. It is obtained only from food.

It is an isomer of glucose.

In living cells, complex metabolic reactions proceed in a series of steps called enzymes. reactants. a metabolic pathway. products. catalysts.

a metabolic pathway.

In an aqueous solution, sodium ions would move toward an organic terminal. a positive terminal. the bottom. a pH terminal. a negative terminal.

a negative terminal.

All of the following are true concerning enzymes except that they function as biological catalysts. affect only the rate of a chemical reaction. lower the activation energy required for a reaction. are consumed during the reaction. are proteins.

are consumed during the reaction.

Elements that have atoms with full outer shells of electrons frequently form hydrogen bonds. will normally form cations. are inert gases. will normally form anions. will form many compounds.

are inert gases

A high-energy bond in ATP is present between the first and second, and the second and third phosphate groups. adenine and ribose. the second and third phosphate group. the first and second phosphate group. adenine and a phosphate group.

the first and second, and the second and third phosphate groups. adenine and ribose.

Which of the following is the symbol for an amino group? -PO3 -NH2 -OH -AMO -COOH

-NH2

Magnesium atoms have two electrons in their outermost shells, and chlorine atoms have seven. The compound magnesium chloride would contain 1 magnesium and 2 chlorine. 1 magnesium and 1 chlorine. 2 magnesium and 1 chlorine. 2 magnesium and 7 chlorine. It is impossible to determine without more information.

1 magnesium and 2 chlorine.

If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is 12. 18. 26. 8. 16.

18

Calculate the weight of 1 mol of glucose. (The atomic weight of carbon = 12). (Module 2.7E) 12 grams 29 grams 180 grams 120 grams 24 grams

180 grams

The innermost electron shell in an atom holds up to ________ electrons. 2 1 6 4 8

2

In the reaction listed below, what coefficient needs to be added to balance the equation? 6 CO2 + 6 H2O → C6H12O6 + ________ O2. 8 6 2 10 4

6

If an element is composed of atoms with an atomic number of 6 and a mass number of 14, then the nucleus of a neutral atom of this element contains 6 protons and 8 neutrons. 6 protons. 8 neutrons. 6 protons and 8 electrons. 8 electrons.

6 protons and 8 neutrons.

Which has the greater concentration of hydrogen ions, a substance with a pH of 5 or a substance with a pH of 4? A pH of 5 is greater. They are both equal; 4 and 5 are relative values. pH 9, if you mixed the solutions. Neither; pH has nothing to do with hydrogen ion concentration. A pH of 4 is greater

A pH of 4 is greater

Compare AMP with ADP. (Module 2.19B) AMP has one sugar molecule and ADP has two sugar molecules. AMP has one binding site and ADP has two binding sites. AMP has one potassium ion and ADP has two potassium ions. AMP has one fatty acid and ADP has two fatty acids. AMP has one phosphate group and ADP has two phosphate groups.

AMP has one phosphate group and ADP has two phosphate groups.

Describe ATP. (Module 2.19A) ATP consists of an adenosine molecule with three phosphate groups attached. ATP consists of an adenosine with three potassium ions attached. ATP consists of an adenosine, a thymine, and a pyrimidine molecule linked together. ATP consists of an adenine molecule with three potassium ions attached. ATP consists of an adenine molecule with three phosphate groups attached.

ATP consists of an adenosine molecule with three phosphate groups attached.

An excess of hydrogen ions in the body fluids can have fatal results because this can change the shape of large complex molecules, rendering them nonfunctional. block ion movements. disrupt tissue functions. All of the answers are correct. None of the answers is correct.

All of the answers are correct.

Define electrolytes. (Module 2.11B) Define electrolytes. (Module 2.11B) Electrolytes are sugar polymers used to rehydrate by increasing plasma volume. Electrolytes are hydrophobic and will create an electrical barrier between the hydrophobic substances and the hydrophilic substances in a solution. Electrolytes are ions that will conduct an electrical current in a solution. Electrolytes are enzymes that create energy in a solution. Electrolytes are enzymes that lower the activation energy for a solution.

Electrolytes are ions that will conduct an electrical current in a solution.

Where do cells obtain the energy needed for their vital functions? (Module 2.19C) Energy comes from the type of sugar molecule bound to the structure. Energy comes from breaking high energy bonds in a compound. Energy comes from the number of enzymes that are present in the cell. Energy depends on the number of rings in their structure. Energy comes from the type of nitrogenous base in the structure.

Energy comes from breaking high energy bonds in a compound.

________ accelerate chemical reactions that occur in the human body. Nutrients Reactants Products Metabolites Enzymes

Enzymes

Why do our cells need enzymes? (Module 2.9B) Enzymes are important inorganic compounds used by cells. Enzymes lower the activation energy of a reaction so it can occur. Enzymes increase the activation energy of a reaction so it can occur. Enzymes provide the activation energy of a reaction so it can occur. Enzymes are important sources of nutrients.

Enzymes lower the activation energy of a reaction so it can occur.

________ compounds do not usually contain carbon as a primary structural atom. Complex Organic Exergonic Endergonic Inorganic

Inorganic

What is an important characteristic of amino acid uracil? It is not found in DNA or RNA. It is found only in RNA. It is an essential part of quaternary proteins. It is found only in DNA. It is found both in DNA and RNA.

It is found only in RNA.

An important buffer in body fluids is An important buffer in body fluids is NaCl. NaOH. NaHCO3. HCl. H2O.

NaHCO3.

________ molecules are compounds that contain carbon as the primary structural atom. Endergonic Complex Exergonic Inorganic Organic

Organic

Describe the different states of matter in terms of shape and volume. (Module 2.5A) Solids have a constant volume but not fixed shape, liquids have neither a constant volume nor a fixed shape, and gases have a fixed volume and shape. Solids have neither a constant volume nor a fixed shape, liquids have a constant volume but no fixed shape, and gases have a fixed volume and shape. Solids have a fixed volume and shape, liquids have neither a constant volume nor a fixed shape, and gases have a constant volume but no fixed shape. Solids have a constant volume but not fixed shape, liquids have a fixed volume and shape, and gases have neither a constant volume nor a fixed shape. Solids have a fixed volume and shape, liquids have a constant volume but no fixed shape, and gases have neither a constant volume nor a fixed shape.

Solids have a fixed volume and shape, liquids have a constant volume but no fixed shape, and gases have neither a constant volume nor a fixed shape.

________ are large lipid molecules with distinctive carbon-ring frameworks. Steroids Micelles Eicosanoids Glycolipids Phospholipids

Steroids

Describe why table salt is a compound. (Module 2.4A) Table salt is a compound because it is made up of more than one element in different proportions. Table salt is a compound because it is made up of only one element with different isotopes. Table salt is a compound because it is made up of only one element bound with more than one type of chemical bond. Table salt is a compound because it is made up of more than one isotope in different proportions. Table salt is a compound because it is made up of more than one element in a fixed proportion.

Table salt is a compound because it is made up of more than one element in a fixed proportion.

Explain why small insects can walk on the surface of a pond and why tears protect the surface of the eye from dust particles. (Module 2.5C) The attraction of the water molecules disrupts the ionic bonds preventing small objects from penetrating the water. The attraction of water molecules creates an ice layer that prevents small objects from penetrating the water. The attraction of water molecules creates a gas layer that prevents small objects from penetrating the water. The attraction of water molecules creates a surface tension barrier that prevents small objects from penetrating the water. The attraction of water molecules forms ionic bonds creating a barrier that prevents small objects from penetrating the water.

The attraction of water molecules creates a surface tension barrier that prevents small objects from penetrating the water.

In the hydrolysis of a triglyceride, what are the reactants and the products? (Module 2.15D) The reactants are a triglyceride and three water molecules; the products are a glycerol molecule and three fatty acids. The reactants are a glycerol molecule and three fatty acids; the products are a triglyceride and three water molecules. The reactants are a glycine molecule and three water molecules; the products are a glyceride molecule and three fatty acids. The reactants are a glycogen molecule and three water molecules; the products are a glucose monomer and three fatty acids. The reactants are a glucose monomer and three water molecules; the products are a glycogen molecule and three fatty acids.

The reactants are a triglyceride and three water molecules; the products are a glycerol molecule and three fatty acids.

Relate an enzyme's structure to its reaction specificity. (Module 2.18B) The reaction specificity relates to the size of the enzyme. The reaction specificity relates to how many active sites are present on the enzyme. The reaction specificity relates to how much energy is created when the enzyme-substrate complex forms. The reaction specificity relates to the unique shape of the active site to which only a complementary shape can bind. The reaction specificity relates to the number of enzymes with the same structure.

The reaction specificity relates to the unique shape of the active site to which only a complementary shape can bind.

Describe the structure and role of prostaglandins. (Module 2.16A) They are a type of eicosanoid released by cells to coordinate local cellular activities and produce pain sensations. They are a type of steroid used to maintain the plasma membrane and for cell growth and division. They have a carbon-ring structure and are used for producing many steroid hormones. They have a carbohydrate attached to a diglyceride and are used to maintain the plasma membrane. They are a type of leukotrienes released by cells to coordinate local cellular activities and produce pain sensations.

They are a type of eicosanoid released by cells to coordinate local cellular activities and produce pain sensations.

What do cholesterol, phospholipids, and glycolipids have in common? (Module 2.16D) They all have carbohydrate groups attached. They are all soluble in water. They are all structural lipids that form membranes of cells. They all form ring structures. They are all linear structures.

They are all structural lipids that form membranes of cells

Explain how the complementary strands of DNA are held together. (Module 2.20B) They are held by complementary base pairing; adenine to cytosine and thymine to guanine. They are held by complementary base pairing; adenine to guanine and thymine to cytosine. They are held by complementary base pairing; adenine to thymine and guanine to cytosine. They are held by complementary base pairing; adenine to adenine, thymine to thymine, guanine to guanine, and cytosine to cytosine. They are held by ionic bonds.

They are held by complementary base pairing; adenine to thymine and guanine to cytosine.

Which of the following is correct regarding enzymes? They slow down cellular reactions. They are released during cellular injury. They bind to the active site of substrates. They are organic catalysts and are made of proteins. They are made of lipids.

They are organic catalysts and are made of proteins.

Describe trace elements. Trace elements are abundant in the atmosphere and also abundant in the human body. Trace elements are present in small amounts in the body and are required for normal growth and maintenance. Trace elements are present in small amounts in the body and are not necessary for normal growth and maintenance. Trace elements are the elements produced by nuclear reactions in research laboratories. Trace elements are present in small amounts in the atmosphere but accumulate in the body at high levels.

Trace elements are present in small amounts in the body and are required for normal growth and maintenance.

Describe the kind of bonds that hold the atoms in a water molecule together. (Module 2.4C) Water molecule bonds are oxygen bonds, in which oxygen atoms form bonds together. Water molecule bonds are polar covalent bonds, in which unequal sharing of electrons occurs. Water molecule bonds are ionic bonds, in which electrons are gained and lost to create the bond. Water molecule bonds are nonpolar covalent bonds, in which equal sharing of electrons occurs. Water molecules bonds are nonpolar ionic bonds, in which equal movement of electrons occurs.

Water molecule bonds are polar covalent bonds, in which unequal sharing of electrons occurs.

In chemical notation, the symbol Ca2+ means a calcium ion that has lost two protons. two calcium atoms. a calcium ion that has gained two protons. a calcium ion that has gained two electrons. a calcium ion that has lost two electrons.

a calcium ion that has lost two electrons.

Substrate molecules bind to enzymes at the ________ sites. neutral amino reactant active carboxyl

active

Adenosine is formed by combining adenine and ribose. adenine and phosphate group. adenine, ribose, and a phosphate group. ribose and a phosphate group. adenine, ribose, and 3 phosphate groups.

adenine and ribose.

The purines found in DNA are ________ and ________. adenine; guanine adenine; cytosine thymine; cytosine cytosine; guanine thymine; guanine

adenine; guanine

What product is formed from the addition of a phosphate group to ADP? adenine adenosine diphosphate adenosine triphosphate ribose deoxyribonucleic acid

adenosine triphosphate

The most abundant high-energy compound in cells is RNA. DNA. adenosine triphosphate. adenosine monophosphate. adenosine diphosphate.

adenosine triphosphate.

If a substance has a pH that is greater than 7, it is acidic. a salt. alkaline. neutral. a buffer.

alkaline.

When electrons are transferred from one atom to another, and the two atoms unite as a result of the opposite charges, an ion is formed. a hydrogen bond is formed. a free electron is formed. a covalent bond is formed. an ionic bond is formed.

an ionic bond is formed.

In an aqueous solution, cations are attracted toward water. salt. hydrogen ions. buffers. anions.

anions.

Ions with a negative charge are called polar molecules. cations. anions. positrons. protons.

anions.

Carbohydrate molecules are composed of C, H, O, and N atoms. contain the genetic information found in cells. form the regulatory molecules known as enzymes. are the building blocks of cellular membranes. are the body's most readily available source of energy.

are the body's most readily available source of energy.

In the body, inorganic compounds are structural components of cells. can make up proteins. can make up lipids. can serve as buffers. are all very large.

can serve as buffers.

The group of organic compounds containing carbon, hydrogen, and oxygen in a near 1:2:1 ratio is defined as a protein. carbohydrate. nucleic acid. cholesterol. lipid.

carbohydrate.

By weight, which element is the second most abundant in the human body? oxygen carbon calcium hydrogen nitrogen

carbon

The molecule CO2 is known as carbonated oxygen. carbon dioxide. carbon monoxide. carbon oxide. carbonized oxygen.

carbon dioxide.

All amino acid molecules contain carbon, nitrogen, oxygen, phosphate and sulfate. carbon, hydrogen, oxygen and phosphate. carbon, nitrogen, hydrogen and oxygen. carbon, oxygen and nitrogen. carbon, nitrogen and hydrogen.

carbon, nitrogen, hydrogen and oxygen.

All fatty acids contain a functional group at one end called the ________ group. hydroxyl carboxyl amino phosphate nitroxyl

carboxyl

Ions with a + charge are called isotopes. cations. radicals. anions. positrons.

cations.

Oxygen is required in biological systems for cellular respiration. serving as a structural component of bone. serving as a catalyst. storage of energy. chemical messengers.

cellular respiration.

Which of the following is a structural component of cell membranes? cholesterol lauric acid glycogen prostaglandins diglycerides

cholesterol

When atoms complete their outer electron shell by sharing electrons, they form cations. anions. ionic bonds. hydrogen bonds. covalent bonds.

covalent bonds.

In a molecule of oxygen gas, two pairs of electrons are shared equally by two oxygen atoms. The type of bond that is formed is an example of a triple nonpolar covalent bond. single trivalent bond. double nonpolar covalent bond. double polar covalent bond. hydrogen bond.

double nonpolar covalent bond.

During ionization, water molecules disrupt the ionic bonds of a salt to produce a mixture of ions. These ions can carry a current and so are called counter ions. cations. electrolytes. anions. acids.

electrolytes.

Ionic bonds are formed when atoms share electrons. electrons are completely transferred from one atom to another. hydrogen forms bonds with negatively charged atoms. two or more atoms lose electrons at the same time. a pair of electrons is shared unequally by two atoms.

electrons are completely transferred from one atom to another.

A(n) ________ is a pure substance composed of atoms. neutron molecule electron compound element

element

The reaction A + B + energy → AB is an example of a(n) exergonic reaction. exchange reaction. endergonic reaction. equilibrium reaction. decomposition reaction.

endergonic reaction.

Chemical reactions that absorb energy are called metabolic. endergonic. exergonic. enzymatic. energetic.

endergonic.

The hydrolysis of ATP yields ADP, a phosphate ion, and ribose sugar. adenine. a second phosphate ion. energy. a hydrogen ion.

energy.

Chemical reactions that release energy are called enzymatic. endergonic. metabolic. exergonic. energetic.

exergonic.

The most important metabolic fuel molecule in the body is sucrose. glucose. caffeine. vitamins. protein.

glucose.

A polysaccharide that is formed in muscle cells to store glucose is glycogen. cellulose. sucrose. lactose. fructose.

glycogen.

What is an important by-product of exergonic reactions? (Module 2.9C) water polymers oxygen heat carbon dioxide

heat

Oppositely charged ions in solution are prevented from combining by heat capacity of water. hydration spheres. free radicals. water's nonpolar nature. hydrogen bonding.

hydration spheres.

The weakest bond between two atoms is the ________ bond. nonpolar polar ionic hydrogen covalent Submit

hydrogen

Which element commonly has only a proton as its nucleus? argon helium hydrogen neon None of the answers is correct.

hydrogen

The molecule H2 is known as helium. hydroxide. hydrogen. semi-water. hydrohydrogen.

hydrogen.

Nonpolar organic molecules are good examples of molecules that will dissociate when placed into water. hydrophobic compounds. electrolytes. solutes. hydrophilic compounds.

hydrophobic compounds.

Molecules that do not readily dissolve in water are called hydrophilic. electrolytes. isophilic. isophobic. hydrophobic.

hydrophobic.

Which of the following functional groups of organic compounds link molecules through dehydration synthesis? amino group phosphate group hydroxyl group carboxyl group none of the above

hydroxyl group

Atoms of the same element whose nuclei contain the same number of protons, but different numbers of neutrons, are called isotopes. principal elements. trace elements. ions. isomers.

isotopes.

All of the following are correct regarding RNA except it makes protein as directed by DNA. it contains a double helix. molecular shape varies with hydrogen bonding along the length of the strand. it contains ribose sugar. the nitrogenous base is made of adenine, guanine, cytosine, and uracil.

it contains a double helix.

Which of the following is a chemical messenger coordinating local cellular activities? lecithin lauric acid leukotrienes diglycerides vholesterol

leukotrienes

In dehydration reactions, compounds gain electrons. lose water molecules. gain water molecules. convert hydrogen and oxygen to water. convert water molecules to hydrogen and oxygen.

lose water molecules.

H2O is an example of a(n) glucose molecule. ionic formula. molecular formula. covalent formula.

molecular formula.

List the three structural classes of carbohydrates, and give an example of each. (Module 2.14C) monosaccharides (glucose), disaccharides (sucrose), and polysaccharides (starch) monosaccharides (sucrose), disaccharides (starch), and polysaccharides (glucose) monosaccharides (glucose), disaccharides (starch), and polysaccharides (sucrose) monosaccharides (starch), disaccharides (glucose), and polysaccharides (sucrose) monosaccharides (sucrose), disaccharides (glucose), and polysaccharides (starch)

monosaccharides (glucose), disaccharides (sucrose), and polysaccharides (starch)

A solution containing equal numbers of hydrogen ions and hydroxide ions is in equilibrium. alkaline. acidic. neutral. basic.

neutral.

Isotopes of an element differ in the number of protons in the nucleus. electrons in the nucleus. electrons in energy shells. neutrons in the nucleus. electron clouds.

neutrons in the nucleus.

Molecules that store and process genetic information are steroids. nucleic acids. lipids. proteins. carbohydrates.

nucleic acids.

What is the individual subunit of nucleic acid called? deoxyribonucleic acid pyrimidine ribonucleic acid nucleotide purine

nucleotide

The center of an atom is called the electron cloud. molecule. element. nucleus. proton.

nucleus.

Carbohydrates, lipids, and proteins are classified as inorganic molecules. salts. acids. organic molecules. bases.

organic molecules.

Of the list below, which has the highest concentration of hydroxide ions? pH 7 pH 1 pH 10 pH 14 pH 2

pH 14

Which pH is closest to normal blood pH? pH 7 pH 2 pH 4 pH 3 pH 8

pH 7

Define pH. (Module 2.12A) pH is a measure of the oxygen concentration in a solution. pH is a measure of the temperature in a solution. pH is a measure of the pressure of all the dissolved gases in a solution. pH is a measure of the hydrogen ion concentration in a solution. pH is a measure of blood pressure.

pH is a measure of the hydrogen ion concentration in a solution.

Kinetic energy is stored as ________ energy when a spring is stretched. motion work chemical potential thermal

potential

A sequence of amino acids bonded together in a linear chain is called a primary structure. tripeptide. secondary structure. tertiary structure. quaternary structure.

primary structure.

Each of the following is an example of an inorganic compound except water. salts. bases. proteins. acids.

proteins.

Name the participants in a chemical reaction. (Module 2.7A) cofactors vitamins reactants products enzymes

reactants

hich of the structural representations of glucose shown below is more common in the body? (Module 2.14B) saturated form ionic form linear form ring form unsaturated form

ring form

The maximum rate of an enzyme reaction occurs at saturation limit. hydrolysis. reversible. synthesis. dehydration.

saturation limit.

A shortage of cholesterol in the body could interfere with the formation of proteins. cytoplasm. sex hormones. nucleic acids. glycogen.

sex hormones.

Which of the following lists contains only trace elements? boron, oxygen, carbon selenium, hydrogen, calcium cobalt, calcium, sodium sulfur, chlorine, oxygen silicon, fluorine,

silicon, fluorine,

Which of the following are large polysaccharides and major dietary source of energy? fructose starch lactose maltose sucrose

starch

Which of the following is a structural component of digestive secretions in bile? fatty acids glycerides glycolipids eicosanoids steroids

steroids

What are the reactants in an enzymatic reaction called? (Module 2.18A) substrates energy products ATP inhibitors

substrates

A dust particle floating on a water surface illustrates hydrophilic attraction. surface tension. static electricity. chemical tension. heat capacity.

surface tension.

The reaction N2 + 3 H2 → 2 NH3 is an example of a(n) synthesis reaction. metabolic reaction. decomposition reaction. exchange reaction. enzyme reaction.

synthesis reaction.

The structure of RNA differs from DNA in that DNA contains purines but not pyrimidines. RNA contains pyrimidines but not purines. RNA contains purines but not pyrimidines. the backbone of RNA contains ribose. DNA contains pyrimidines but not purines.

the backbone of RNA contains ribose.

What is formula weight? (Module 2.7C) the sum of the atomic weights of the elements making up an ionic compound the average weight of an element's different atomic masses and proportions of its different isotopes the weight in grams equal to the element's atomic weight the sum of the atomic weights of its component atoms the total weight of an element including the isotopes

the sum of the atomic weights of the elements making up an ionic compound

Which property of water helps keep body temperature stabilized? lubrication reactivity kinetic energy thermal inertia surface tension

thermal inertia

What is the most important function of carbohydrates? (Module 2.14A) to provide the basic structure for all steroid hormones to be derived they are the building blocks of proteins they act as enzymes they are the primary energy source to form and maintain the cell membrane

they are the primary energy source

The pyrimidine bases found in DNA are ________ and ________. cytosine; guanine thymine; cytosine adenine; cytosine adenine; guanine thymine; guanine

thymine; cytosine

Which one of the following must be broken down to fatty acids and glycerol for use as an energy source? lauric acid prostaglandins lecithin triglycerides cholesterol

triglycerides

Hydrophilic molecules readily associate with cholesterol. both lipid molecules and hydrophobic molecules. hydrophobic molecules. lipid molecules. water molecules.

water molecules.