chapter 2 smart book

Name the type of bond that holds amino acids together in a protein molecule.

Peptide bond

Amino acids are the subunits of larger molecules called __________

Peptides

Which of the following molecules are the major component of the plasma membrane?

Phospholipids

Which are examples of lipids?

Phospholipids Fatty acids Triglycerides Steroids

Kinases catalyze which type of reaction?

Phosphorylation

What term is used to describe reactions that can proceed in either direction?

Reversible

Which are classifications of fatty acids?

Saturated and unsaturated

The _________ level of protein structure is determined by the folding of the protein due to hydrogen bonding between amino acids to form alpha helices and beta-pleated sheets.

Secondary

Which best describes the functional role of cyclic adenosine monophosphate (cAMP)?

Serves as a chemical messenger in cells

Which of the following best describes a covalent bond?

Sharing of electrons between two atoms

A peptide bond is formed through ______.

dehydration synthesis

An oxidation-reduction reaction is defined as a chemical reaction that involves the transfer of__________ between molecules.

electrons

the chemical properties of an atom are determined by its

electrons

An input of _________ is required for a system to perform work.

energy

Which type of reaction occurs when two molecules trade atoms or groups of atoms?

exchange

Triglycerides are also called ______.

neutral fats

Isotopes differ from one another by containing different numbers of which subatomic particle?

neutrons

Any enzyme that adds an inorganic phosphate (Pi) group to another organic molecule is known as a(n)

phosphokinase

A(n) __________ is a lipid that consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head.

phospholipids

What term refers to a covalent bond in which the electrons are not equally shared?

polar

A large molecule that consists of many identical or similar subunits, such as protein, DNA, or starch is a(n)

polymer

Molecules like carbohydrates, proteins, and nucleic acids are examples of _____________, because they are made up of many repeating

polymers

Name the level of protein structure that is determined by the amino acid sequence of the protein.

primary

The ________ structure of a protein is its amino acid sequence.

primary

Which of the following always contains an amino functional group?

protein

Estrogen and testosterone are examples of which type of lipid?

steroids

kinetic energy

the energy an object has due to its motion

A lipid composed of three fatty acids joined to a glycerol is a(n)

triacylglycerols

True or false: Formation of adenosine triphosphate from adenosine diphosphate and an inorganic phosphate molecule requires the input of energy.

true

determine the reactive properties of an atom

valence electrons

Which of the following are the monomeric subunits that make up a protein?

amino acids

Which molecule combines with an inorganic phosphate to form ATP?

Adenosine diphosphate

Which term is used to refer to a simple sugar, or sugar monomer?

Monosaccharide

Which term refers to a negatively charged ion?

Anion

Which term means a chemical reaction in which electrons are transferred between molecules?

Oxidation-reduction reaction

Which level of protein structure is due to bending and folding into various globular and fibrous shapes?

Tertiary

True or false: An enzyme will usually catalyze only one step in a metabolic pathway.

True

Which term refers to an attractive force caused by the sharing or transfer of electrons?

Chemical bond

Which are examples of nucleic acids?

DNA and RNA

Which of the following is most likely to decrease the rate of a chemical reaction?

Decrease temperature Decrease concentration of reactants

Sucrose or table sugar is formed when the simple sugars fructose and glucose are covalently bonded. This reaction releases water. What is the name of this type of reaction?

Dehydration synthesis

Which term refers to a change in the three-dimensional conformation of a protein that destroys its functional properties?

Denaturation

are substances that lower the activation energy of a reaction and speed up the rate of reaction

Enzymes

Indicate which statements are true of proteins

-They act as receptors on cells' surfaces -They catalyze chemical reactions -They transport oxygen

Sodium has an atomic number of 11 and an atomic mass of 23. Sodium has

12 neutrons and 11 protons

Which of the following best describes a glycolipid?

A phospholipid molecule covalently bonded to a carbohydrate

Which of the following is a type of connective tissue that provides energy storage, thermal insulation, and protective cushioning?

Adipose tissue

Which is an enzyme?

Amylase

Which of the following is another term for enzyme?

Biological catalyst

Polysaccharides are examples of what type of molecule?

Carbohydrate

Which steroid is a precursor for all other steroids in the body?

Cholesterol

Which of the following statements about enzymes are true?

Enzymes are not consumed in the reactions they catalyze. Enzymes speed up reaction rates by lowering the activation energy of a specific reaction. Enzymes show enzyme-substrate specificity.

What effect do enzymes have on the activation energy of a chemical reaction in the body?

Enzymes lower the activation energy.

Which of the following terms refers to common arrangements of atoms that give organic molecules their unique properties?

Functional groups

Which term is used to describe a series of reactions, where each step is catalyzed by a specific enzyme?

Metabolic pathway

Fats have an abundance of which functional group?

Methyl

Nucleotides are the subunits of the macromolecule type called ______ acids.

Nucleic

Which term refers to the substance upon which an enzyme acts?

Substrate

Which of the following best describes very weak, brief attractions between neutral atoms?

Van der Waals forces

What is the active site of an enzyme?

Where it binds its substrate

Which of the following is a molecule that is produced from ATP and which often serves as a second messenger?

cAMP

Potassium, sodium and chlorine are considered trace elements?

false

True or false: An enzyme is consumed by the reaction it catalyzes.

false

True or false: Saturated fatty acids contain one or more double bonds.

false

Polypeptides over 100 amino acids long are generally classified as which of the following?

proteins

consider oxygen, which has an atomic number of 8 an an atomic mass of 16. how many valence electrons does it have?

6

Which of the following best describes the chemical reaction called hydrolysis?

A covalent bond is broken by adding an OH to one side of the molecule, and an H to the other side.

Which best describes what occurs in a condensation reaction?

A water molecule is removed from a molecule when it creates a covalent bond.

The body's most important energy-transfer molecule is ______.

ATP

Which is an example of a nucleotide?

ATP

Which term refers to the energy needed to get a chemical reaction started?

Activation energy

Which molecule, composed of adenine, ribose, and three phosphate groups, functions as an energy-transfer molecule?

Adenosine triphosphate

Which secondary structure of proteins has a spiral shape?

Alpha helix

indicate how pH and temperature affect the activity of an enzyme.

Altering the shape of the substrate binding site Causing a conformational change in the enzyme

The monomer subunits of proteins always have which of the following functional groups?

Amino

Peptide bonds are used to join two of these together.

Amino acids

Which of the following is most likely to contain a carboxyl functional group?

Amino acids

Molecules described as ____________ , such as phospholipids, contain both a hydrophobic and a hydrophilic region.

Amphipathic

Which term refers to the dual nature of phospholipids, which contain both hydrophilic and hydrophobic groups?

Amphipathic

Which type of reaction is endergonic?

Anabolic

Name the secondary structure of proteins that has a pleated, ribbon-like shape.

Beta sheet

The term anabolism specifically applies to metabolic reactions that do which of the following?

Build large molecules from small molecules

Monosaccharides, disaccharides, and polysaccharides are all examples of which type of macromolecule?

Carbohydrates

Fatty acids contain ______ groups.

Carboxyl Methyl

Which three functional groups are part of the basic structure of every amino acid?

Carboxyl group Amino group Radical (R group)

Which of the following is a type of plant saccharide that is commonly found in our diet, even though we do not have the enzymes to digest it?

Cellulose

Which steroid molecule are all of the other steroids derived from?

Cholesterol

Which term refers to an organic cofactor that is required for an enzyme to function?

Coenzyme

Which term refers to a nonprotein, such as a metal ion or a coenzyme, that is needed for some enzymes to function?

Cofactor

Which important properties of water allow it to support life?

Cohesion Solvency Chemical reactivity

What are the functions of adipose tissue?

Cushioning Energy storage Insulation

In many biochemical reactions, individual subunits are joined to form larger macromolecules with the release of water molecules. How are these reactions classified?

Dehydration synthesis reactions

A carbohydrate composed of two covalently-bonded simple sugars (monosaccharides) is called a(n)

Disaccharide

A compound that dissociates in water, producing a solution that conducts electricity, is known as a(n)

Electrolyte

Which term applies to anabolic reactions?

Endergonic

Each enzyme catalyzes one particular chemical reaction. Which term describes this property of enzymes?

Enzyme-substrate specificity

Reversible reactions exist in a state of chemical _____________, in which the ratio of products to reactants is stable.

Equilibrium

Which term specifically refers to fatty acids that must be eaten since the human body is unable to synthesize them?

Essential fatty acids

Catabolic reactions release energy. Because of this, they can be classified as which of the following?

Exergonic

A molecule consisting of a carbon chain, with 4 to 24 carbons, with a methyl group on one end and a carboxyl group on the opposite end is which of the following?

Fatty acid

Choose the lipids in the list below.

Fatty acids Eicosanoids Triglycerides Phospholipids Steroids

A starch molecule may contain thousands of smaller glucose subunits. Which of the following statements is true?

Glucose is a monomer of starch.

Identify the polysaccharide used for energy storage in animals.

Glycogen

A __________ is a protein molecule with a smaller carbohydrate covalently bonded to it.

Glycoprotein

Name the chemical reaction that breaks a covalent bond in a molecule by adding an OH group to one side of the bond and H to the other side, thus consuming a water molecule.

Hydrolysis

Which term refers to polar molecules that dissolve in water?

Hydrophilic

What term can be used to describe any molecule that is non-polar and does not dissolve in water?

Hydrophobic

Which of the following will, in general, increase the rate of a reaction?

Increasing temperature Increasing concentration of reactants

What does the quaternary structure of a protein depend upon?

Interactions between multiple polypeptide chains

Which of the following statements about the molecular weight of a molecule are true?

It is equal to the sum of the atomic weights. It is useful for calculating concentrations. It is measured in atomic mass units.

Which of the following would give you the molarity of a solution?

Moles/liter

In a carbon dioxide molecule, electrons are shared equally among the atoms. What type of bond do they form?

Nonpolar covalent

Which of the following is an acidic polymer of nucleotides, found or produced in the nucleus, that functions in heredity and protein synthesis?

Nucleic acid

Which organic molecules are composed of a nitrogenous base, a monosaccharide, and a phosphate group?

Nucleotides

Which term specifically applies to a reaction that involves the removal of electrons from a molecule?

Oxidation

Which term is used specifically to describe the addition of an inorganic phosphate to an organic molecule?

Phosphorylation

Which type of fatty acid has two or more double bonds within its carbon chain?

Polyunsaturated

How is chemical energy defined?

Potential energy stored in the bonds of molecules

chemical energy

Potential energy stored in the bonds of molecules

Which term refers to a molecule composed predominantly of a carbohydrate covalently bonded to a smaller protein component?

Proteoglycan

Which term below refers to large molecules composed of covalently-bonded carbohydrate and protein groups? Hint: They usually serve as lubricants at joints or as a structural component of cartilage.

Proteoglycans

The ________ level of protein structure is determined by the interactions between two or more polypeptide chains within a protein.

Quaternary

In a solution, the more abundant substance that dissolves another substance is known as what?

Solvent

The lock and key model describes the property of enzyme-substrate ____________

Specificity

A _________ is the substance that an enzyme acts upon

Substrates

A chemical reaction in which two or more smaller molecules combine to form a larger molecule is what type of reaction?

Synthesis

The folding of proteins into various globular and fibrous shapes is referred to as the ___________ structure of the proteins.

Tertiary

Which of the following best describes denaturation?

The unfolding of a protein's three-dimensional shape

How do catalysts affect reaction rates?

They increase reaction rates.

Which of the following statements apply to catalysts?

They may bind to reactants and bring them into proximity. They may position reactants in such as way as to favor their reaction. They are not consumed by the reaction.

Identify the components of a triglyceride below.

Three fatty acids Glycerol

How many double covalent bonds are in the carbon chain of a polyunsaturated fatty acid?

Two or more

Which type of bond listed below is the weakest?

Van der Waals forces

Which of the following are used to express concentration?

Weight per volume Molarity Percentages

What is the toxic end product of anaerobic fermentation?

What is the toxic end product of anaerobic fermentation?

A base is a compound that acts as a proton ______.

acceptor

A proton (H+) donor, or a chemical that releases protons into solution, is a(n

acid

NaOH is a compound that releases hydroxide ions in water. Therefore, it is a(n) ______.

base

Which term refers to a chemical that binds protons in a solution and functions as a proton acceptor?

base

Phosphorylation of an enzyme ______.

can turn off a metabolic pathway can activate a metabolic pathway

The ______ family of macromolecules are composed of carbon, hydrogen and oxygen in a 1:2:1 ratio and includes sugars, starches, glycogen, and cellulose.

carbohydrate

The element that is the foundation of biological molecules is ___________. This element has four valence electrons and can form a wide variety of bonds.

carbon

In nature, sodium atoms lose electrons; therefore, they become ______.

cation

The structural polysaccharide found in plant cells is ____________

cellulose

Some fatty acids must be obtained from the diet because the body cannot synthesize them. The term given to this group of compounds is _________ ,fatty acids.

essential

True or false: Some catalysts speed up reactions, while other catalysts slow down reactions.

false

True or false: Unsaturated fatty acids do not have double bonds

false

ionic bonds are very strong and will not easily dissociate in water

false

the high heat capacity of water makes it a very ineffective coolant

false

Which molecule is most likely to contain methyl groups?

fats

Which term can be used to describe any potential energy available in a system to do work?

free energy

Groups of atoms that are added to carbon backbones and that give organic molecules a variety of unique properties are generally known as ____________ groups.

functional

Which is a monosaccharide that provides energy to most body cells?

glucose

Which monosaccharide is the monomer that forms glycogen and starch?

glucose

A glucose polymer synthesized by liver, muscle, uterine, and vaginal cells that serves as an energy-storage polysaccharide is a _________ molecule.

glycogen

A ______________ is a phospholipid molecule with a carbohydrate covalently bonded to it. It can be found in the plasma membranes of cells.

glycolipid

A protein molecule bonded to a smaller carbohydrate molecule is called a ______

glycoprotein

A protein molecule bonded to a smaller carbohydrate molecule is called a ______.

glycoprotein

Which type of bond can be described as a weak attraction between a slightly positive region in one molecule and a slightly negative region in a different molecule?

hydrogen

what type of bond attracts one water molecule to the other?

hydrogen bond

pH is a measurement of the concentration of what?

hydrogen ions

To a certain point, increasing the concentration of reactants in a solution will ______ the rate of the reaction.

increase

Where is a neutron located?

inside the nucleus

When a sodium atom loses an electron, it becomes a sodium ______.

ion

Molecules with the same molecular formula but different arrangements of their atoms are known as

isomers

Atoms of the same element that differ only in the number of neutrons are known as

isotopes

Varieties of elements called ________ differ from one another only in number of neutrons and therefore in atomic mass.

isotopes

Hydrophobic organic molecules, such as fatty acids, fats, steroids, and prostaglandins, are classified as what type of molecule?

lipid

A hydrophobic organic compound composed mainly of carbon and a high ratio of hydrogen to oxygen is a ______. Examples include fatty acids, fats, phospholipids, steroids, and prostaglandins.

lipids

Identify the term used to name one of the identical or similar subunits of a larger molecule.

monomer

Disaccharides can be broken down into ______.

monosaccharides

In a(n) _______ reaction a molecule loses one or more electrons.

oxidation

Colloids are chemical mixtures that contain ______.

particles smaller than 100 nm suspended particles that scatter light

Proteins are macromolecules composed of numerous amino acids. Based on this, which term describes proteins?

polymers

Polymers formed of many simple sugars are classified as ______

polysaccharides complex carbohydrates

Name the family of macromolecules that plays a role in cell structure, communication (hormones and neurotransmitters), membrane transport, catalysis (enzymes), recognition and protection (immune factors), movement (contractile molecules), and cell adhesion.

proteins

In general, a process that involves the formation or breakdown of molecules is called a chemical __________

reaction

Name the type of chemical reaction in which one or more electrons are added to a molecule.

reduction

Which term refers specifically to a type of reaction in which a molecule gains one or more electrons?

reduction

A fatty acid contains the maximum number of hydrogens possible. It is ______.

saturated

An alpha helix is an example of _____________ structure found in proteins.

secondary

Name the level of protein structure that is determined by the folding of the protein into alpha helices and beta sheets due to hydrogen bonding between amino acids.

secondary

Which term defines a substance that consists of a solute dissolved in a more abundant substance called the solvent?

solution

an is defined as a substance consisting of a solute mixed with a more abundant substance called the solvent.

solution

Which of the following is the only plant polysaccharide that humans can digest?

starch

_______ is an energy-storage polysaccharide in plants.

starch

______________ is an energy-storage polysaccharide in plants

starch

Potential energy

stored energy that results from the position or shape of an object

Keratin and collagen are types of ______ proteins.

structural

List the factors that affect enzyme conformation.

temperature and pH

Which of the following terms refers specifically to an element that plays a physiological role in the body, but which accounts for less than 0.02% of the body weight?

trace element

Amino acids and other organic acids contain a carboxyl group, which can act as an acid.

true

Ionic bonds break apart in water more easily than covalent bonds do.

true

True or false: Cellular respiration is more efficient under aerobic conditions.

true

True or false: Formation of adenosine triphosphate from adenosine diphosphate and an inorganic phosphate molecule requires the input of energy

true

neurons are uncharged particles found In the nucleus of an atom

true

Disaccharides are composed of how many covalently-bonded simple sugars?

two

A fatty acid has a double bond in its carbon chain. It is a(n) ______ fatty acid.

unsaturated

In a solution, the solute ______, when the solution is allowed to stand.

will not separate from the solvent

Which of the following best describes what occurs in an exchange reaction?

Atoms are traded between molecules

Which term applies to metabolic decomposition reactions that release energy?

Catabolism

Saltwater is a solution made out of NaCl (salt) dissolved in water. In this case, water is the solvent and NaCl is the

Solute

a chemical that neutralizes free radicals.

antioxidant

Where is an electron of an atom located?

around the nucleus

NaOH is a compound that releases hydroxide ions in water. Therefore, it is a(n

base

Van der Waals forces are important in ______.

binding proteins to each other protein folding the association of lipid molecules within cell membranes

Substances that resist changes in pH are known as

buffers

Ionizing radiation produces ______ in humans.

free radicals

Which type of particle has an unpaired electron, making it highly reactive and destructive to cells?

free radicals

In a solution, the solute can be a ______.

gas, solid, or liquid

A chemical bond that involves the attraction of a cation to an anion is called a(n) ________ bond

ionic

The sodium ion (Na+) and the chloride ion (Cl-) are attracted to each other and form a(n) ______ bond.

ionic

High-energy radiation that can cause damage to human tissues by removing electrons from other atoms and destroying molecules is called ____________ radiation

ionizing

general term for radiation capable of converting atoms to ions or free radicals

ionizing

Glucose and fructose both have the chemical formula C6H12O6. Which term below describes the relationship between glucose and fructose?

isomers

A reversible reaction continues as long as its products do not accumulate in the system. This is an example of the law of _____________ action.

mass

Salt on a watermelon is an example of a ______.

mixture

an consists of substances that are physically blended but not chemically bound.

mixture

The measure of chemical concentration, expressed as moles of solute per liter of solution, is known as

molarity

Which reflects the weight of a solute in a solution and the number or molecules per volume?

molarity

The number of molecules of a chemical that is equal to its molecular weight in grams, is a(n

mole

composed of two or more atoms that are held together by chemical bonds.

molecule

Unstable isotopes are called

radioisotopes

Saltwater is a solution of NaCl dissolved in water. In this example, NaCl is the solute and water is the

solvent

Which of the following best describes what occurs in a decomposition reaction?

A molecule is broken down into smaller parts.

free energy

All potential energy available in a system

What is an ion?

An atom that has gained or lost electrons

Metabolic reactions that use energy and build more complex molecules from less complex molecules are considered which type of reaction?

Anabolic

What is the term for an ion with a net negative charge (more electrons than protons)?

Anion

Which term refers to the time required for 50% of a radioactive element to be cleared from the body?

Biological half-life

Which type of reaction is always exergonic?

Catabolic

a chemical mixture containing particles that are too large to pass through most selectively permeable membranes, but small enough to remain evenly dispersed through the solvent

Colloid

A chemical reaction in which a larger molecule is broken down into smaller ones is which type of reaction?

Decomposition

Which of the following best describes a polar covalent bond?

Electrons are shared unequally between two atoms.

A suspension of liquid fat in water is an example of which of the following?

Emulsion

What term is used to describe a suspension of one liquid in another?

Emulsion

Which are true regarding metabolism?

It includes reactions where molecules are broken down. It includes reactions where new molecules are synthesized. It can be defined as the sum of all of the chemical reactions in the body.

Which of the following describes a catabolic reaction?

Large protein molecules are broken down into smaller amino acids during digestion.

Which law specifically states that reactions proceed from the side of the reaction with the greater quantity to the side with the lesser quantity?

Law of mass action

The term __________ refers to the sum of all the chemical reactions in the body.

Metabolism

Which of the following best defines an acid?

Proton donor

What does the breakdown of unstable atomic isotopes generate?

Radioactivity

an is the amount of energy required to raise 1 g of water by 1oC.

calorie

The concentration of an electrolyte in a body fluid is expressed as milliequivalents per liter. This is equal to the millimolar concentration of the electrolyte multiplied by the_____________ of the ion.

charge

____________ energy is the potential energy stored in bonds of molecules.

chemical

Which type of bond is formed by the sharing of a pair of electrons between two atoms?

covalent

Which subatomic particle has a negative charge?

electron