chapter 4 questions

Amino groups ...

(a), (b), and (c) Proteins contain many of these N-containing groups, which take H+ from water to become ions. a. act as bases in water b. contain nitrogen atoms c. occur in proteins

A straight-chain carbon compound constructed from __________ must contain at least one carbon-carbon double bond.

6 hydrogen atoms and 3 carbon atoms There must be a carbon-carbon double bond for this molecule to exist.

A molecule constructed from _____ must contain at least one carbon-carbon double bond.

6 hydrogen, 3 carbon

How does a carbonyl group differ from a carboxyl group?

A carboxyl group contains H; a carbonyl does not A carbonyl group is just C=O. A carboxyl group is a carbonyl group with an OH group attached.

Which of these is a thiol?

A thiol is a molecule containing a sulfhydryl functional group.

This molecule contains a functional group that has the potential to react with water releasing energy?

ATP or adenosine triphosphate

What is ATP's importance in the cell?

ATP stores the potential to react with water, thereby removing a phosphate group and releasing energy for cellular processes. ATP releases energy during a hydrolysis reaction that removes a phosphate group.

How many asymmetric carbons are present in acetic acid, glycine, and glycerol phosphate?

Acetic acid and glycine have no asymmetric carbons, whereas glycerol phosphate has one.

_____ is formed when a Carboxyl Group is added

Acid

_____ is formed when a Hydroxyl Group is added

Alcohol

_____ is formed when a Carbonyl Group is added

Aldehyde and ketone

How does an aldehyde group differ from a ketone group?

Aldehydes, but not ketones, have H bound to C=O

Which of the following functional groups increases the solubility of organic compounds in water?

All of the listed responses are correct. All of the listed functional groups are hydrophilic and thus increase the solubility of organic molecules in water.

Which of the following groups is capable of hydrogen bonding with an oxygen atom on another functional group?

All of the listed responses are correct. All of the listed functional groups are polar, and thus capable of hydrogen bonding with the oxygen of another molecule. a. carboxyl group b. hydroxyl group c. carbonyl group d. amino group

What is the reason carbon atoms are the most versatile building blocks of the molecules used by living organisms?

Each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions. Carbon has the potential to form molecules that can be straight, branched, or ringed. Along with the ability to form double and triple bonds, this ability permits the formation of an almost infinite number of different molecules.

How do isomers differ from one another?

Isomers differ in the arrangement or bonding of atoms Isomers may differ in the covalent arrangements of their atoms or the position of double bonds within the molecule and thus have different chemical properties.

What does the term amino acid signify about the structure of such a molecule?

It has both an amino group (-NH2), which makes it an amine, and a carboxyl group (-COOH), which makes it a carboxylic acid.

Which type of organic molecule are hydrocarbons associated with in cells?

Lipids (fats)

Which functional group affects the shape of human sex hormones that result is different physical characteristics in the human species.

Methyl group

_____ is formed when a Methyl Group is added

Methylated compound

Can propane (C3H8) form isomers?

No. There is not enough diversity in the atoms. It can form structural isomers because there is only one way for three carbons to attach to each other (in a line). There are no double bonds, so geometric isomers are not possible. Each carbon has at least two hydrogens attached to it so the molecule is symmetrical and cannot have enantiometric isomers.

Pharmaceutical companies are selling billions of dollars' worth of single-enantiomer drugs. Why might it be important to use only one form of an enantiomer?

One enantiomer may provide an effective treatment whereas the other may be ineffective or even toxic. Depending on the body's ability to recognize and use different enantiomers, one version may have dangerous effects, as in the case of methamphetamine.

_____ is formed when a Phosphate Group is added

Organic phosphate-found in ATP

L-dopa is used to treat _____.

Parkinson's disease People with Parkinson's disease lack dopamine.

Which of the following molecules is a weak acid?

R—COOH The carboxyl group (—COOH) of R—COOH can donate a proton (H+).

Which of the following molecules has a carboxyl functional group?

R—COOH The molecule R—COOH contains the carboxyl functional group (—COOH). The presence of this group would make the molecule a weak acid.

Which of the following molecules is a weak base?

R—NH2 The amino group (—NH2) of R—NH2 can function as a base. It can accept a proton (H+).

_____ is formed when a Hydroxyl Group and a Carbonyl Group are added

Sugar

What chemical change occurs to ATP when it reacts with water and releases energy?

The ATP molecule loses a phosphate, becoming an ADP.

Which of the following examples best describes a unique functional property of the carboxyl group?

The covalent bond between oxygen and hydrogen is so polar that hydrogen ions tend to dissociate from oxygen reversibly. This is a property of the carboxyl group.

What is the three-dimensional shape created by hybrid orbitals that are formed when a carbon atom is covalently bonded with four other atoms?

a tetrahedron with carbon in the center The pairs of bonding electrons are oriented as distantly as possible from one another in a tetrahedron with the carbon atom at the center and the other four atoms at the vertices of the tetrahedron.

Stanley Miller's experiments were significant because he demonstrated that __________.

a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere By discharging an electrode in a mixture similar to Earth's primitive atmosphere, Miller was able to synthesize a variety of simple organic molecules.

Which of these is found in all amino acids?

both —COOH and —NH2 For a compound to be an amino acid, it must contain at least one carboxyl functional group and one amino functional group. In addition, it may contain one or more of the other functional groups.

Which element is always associated with organic chemistry?

carbon Compounds containing carbon are said to be organic.

The large diversity of shapes of biological molecules is possible because of the extensive presence of _____ in the molecules.

carbon With four electrons to share, carbon-based molecules can be multibranching and three-dimensionally variable.

What are the six most important chemical elements of life?

carbon, nitrogen, oxygen, hydrogen, phosphate, sulfur All of these elements are capable of forming strong covalent bonds, important in building large, complex molecules.

From your knowledge of organic chemistry, which functional group would you predict is part of abscisic acid (ABA)?

carboxyl

Citric acid makes lemons taste sour. Which of the following is a functional group that would cause a molecule such as citric acid to be acidic?

carboxyl The carboxyl group can release a hydrogen ion when in solution.

Which functional group would you predict is part of abscisic acid?

carboxyl group Compounds containing the carboxyl functional group (—COOH) are known as carboxylic acids or organic acids. They can donate a hydrogen ion (proton) to a solution due to a highly polar oxygen atom of the functional group.

A carbon atom is most likely to form what kind of bond(s) with other atoms?

covalent

Geometric isomers are molecules that _____.

differ in the arrangement of their atoms about a double bond

Non-ionized carboxyl groups cause a molecule to act as an acid because they ... a.

donate H+ ions to water Any molecule that donates H+ to water is an acid.

Carbon atoms are the most versatile building blocks of the molecules used by living organisms because _____.

each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions

Molecules that have the same chemical formula (same numbers of each atom) but different three-dimensional shapes are called _____.

isomers Isomers of carbon compounds can arise in several different ways.

What functional group is commonly used in cells to transfer energy from one organic molecule to another?

phosphate The addition and release of phosphate groups to and from ADP and ATP is how cells store chemical energy and expend it to accomplish work.

Which of the following functional groups is associated with a release of energy when removed from the carbon skeleton with water?

phosphate group Cleaving a phosphate group from ATP releases energy that is used to perform many cellular functions.

Vitalism gave way to mechanism, the view that _____.

physical and chemical laws govern living systems Living things are subject to physical and chemical laws. They do not exist outside of them.

Ethanol, propanol, and methanol are three simple alcohols. They can be grouped together because they __________.

share the same functional group: a hydroxyl Alcohols are distinguished by the presence of the hydroxyl (-—OH) functional group.

Choose the term that correctly describes the relationship between these two sugar molecules: a

structural isomers

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?

sulfhydryl

Which functional group is not present in this molecule?

sulfhydryl

Which of the following functional groups is associated with the amino acid cysteine which maintains the curliness or straightness of hair?

sulfhydryl group ( - SH)

Variations in the reactive properties of different organic molecules are most closely associated with _____.

the presence or absence of functional groups Functional groups are the most common participants in chemical reactions.

What action could produce a carbonyl group?

the replacement of the -OH of a carboxyl group with hydrogen

Which action could produce a carbonyl group?

the replacement of the -OH of a carboxyl group with hydrogen

Organic chemistry is currently defined as

the study of carbon compounds

A molecule has one carbon-carbon double bond and four monovalent atoms or groups. How many different cis-trans isomers exist for this molecule?

two Only two cis-trans isomers exist.

The first organic molecule to be synthesized from inorganic substances that could be prepared directly from inorganic substances was _____.

urea

At the beginning of the 19th century, it was thought that the substances that made up living things were special and could not be synthesized by ordinary chemical methods. This now-discarded theory was called the theory of _____.

vitalism

Which of the following functional groups is present in all amino acids?

—NH2 This is the amino group. This group is present in all amino acids.

The 7 functional groups:

• Hydroxyl (--OH) • Carbonyl (ketone, aldehyde) (>C=O) • Carboxyl (--COOH) • Amino Group (--NH2) • Sulfhydryl (--SH) • Phosphate (--OPO32-) • Methyl (--CH3)

Four Ways that Carbon Skeletons Can Vary:

• Length • Branching • Double Bond Position • Presence of Rings

Functional Groups:

• Perform chemical reactions • A group of atoms responsible for the characteristic behavior of the class of compounds in which the group occurs, as the hydroxyl group in alcohols • Give organic compounds unique properties • Affect shape and non-covalent interaction • Most contain polar bonds and interaction with H bonding

The ionized or dissociated carboxyl group may be written as _____.

-COO-

How many electron pairs does carbon share in order to complete its valence shell?

2

Glycine's molecular formula is C2H5NO2. How many moles of each element would be needed to make 1.0 mole of glycine? a

2 moles carbon, 5 moles hydrogen, 1 mole nitrogen, and 2 moles oxygen

A phosphate group contains _________ oxygen atoms.

4

____ is formed when an Amino Group is added

Amine

Identify the functional groups.

Amino and carboxyl are functional groups

How are gasoline and fat chemically similar?

Both consist largely of hydrocarbon chains.

What are the major elements found in living organisms?

C, H, N, O, P, S

Which of the following hydrocarbons has a double bond in its carbon skeleton?

C2H4

Which of the following is an organic molecule?

CH4 Compounds containing carbon are said to be organic.

Water is the universal medium of life on Earth, but living organisms are made up of chemicals based mostly on what elements? a.

Carbon

Can acetic acid, glycine, and glycerol phosphate exist as forms that are enantiomers?

Glycerol phosphate can exist as forms that are enantiomers, but acetic acid and glycine cannot.

A pharmaceutical company was forced to recall a pain reliever medication that had been linked to the fatalities of several hundred people. Analysis of the recalled drug revealed the presence of two isomers due to an asymmetrical carbon atom in the drug molecule. What can be hypothesized from this observation?

The isomers are enantiomers, with one having toxic effects on humans. Enantiomers are isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon. The remarkable sensitivity of organisms means that subtle differences in molecular structure can translate to different and unintended effects on organism function.

In what ways does the methyl group differ chemically from the other six important chemical groups?

The methyl group is nonpolar and not reactive. The other six groups are called functional groups. They are each hydrophilic, increasing the solubility of organic compounds in water, and can participate in chemical reactions.

Which of the following is a false statement concerning amino groups?

They are basic in pH.

Carbon is unparalleled in its ability to form molecules that are large, complex, and varied.

True

Hydrocarbons are major chemical components of the substance used to fuel most of today's vehicles.

True

The carbon atom is tetravalent, which means that __________.

a carbon atom can complete its valence shell by forming four covalent bonds With four valence electrons, carbon usually shares its four electrons in covalent bonds to complete its outer shell.

Choose the pair of terms that completes this sentence about functional groups in organic chemistry: Carboxyl is to _____ as _____ is to base.

acid ... amino

Choose the pair of terms that correctly completes this sentence about functional groups in organic chemistry: Carboxyl is to __________ as __________ is to base.

acid ... amino A carboxyl group has acidic properties because it can donate a proton (hydrogen ion) to a solution. The amino group acts as a base because it can pick up or accept a proton (hydrogen ion) from a solution.

Although the structures of the functional groups that are most important to life vary, they share one thing in common: They _____.

all are hydrophilic and increase the organic compound's water solubility

Which chemical group is most likely to be responsible for an organic molecule behaving as a base (see Concept 3.3, p. 53)?

amino

A functional group on a molecule in solution carries two H atoms at pH 9 and three H atoms at pH 3. The functional group is probably. . .

amino Amino groups take on H+ in acidic solutions.

Enantiomers are molecules that _____.

are mirror images

Glucose and hexanoic acid each contain six carbon atoms, but they have completely different properties. Glucose is a nutrient found in food; hexanoic acid is poisonous. Their differences must be due to different _____.

functional groups

The two compounds are related to each other by being __________.

hydrocarbons, isomers, organic compounds, and double-bonded compounds All of the listed responses are true characteristics of the two compounds.

Most organic compounds contain carbon and _____.

hydrogen

Which of the following are properties of hydrocarbons?

hydrophobic, nonpolar, good source of stored energy Because they are nonpolar, hydrocarbons are hydrophobic. They also provide energy in the forms of things such as fossil fuels and fats.

The functional group most closely resembling sulfhydryl is the _____ group.

hydroxyl

Using modern equipment, a former graduate student of Stanley Miller recently reanalyzed the sample results of volcano simulation experiments that Miller conducted along with his classic experiment described in the text. This reanalysis did which of the following?

identified additional organic compounds that had not been found by Miller The reanalysis gives further weight to the hypothesis that volcanic activity could have provided the energy needed for the abiotic synthesis of organic compounds.