Chapter 4 Carbon and the Molecular Diversity of Life

CH4

16.mathane

C2H6

17.Ethane

C2H4

18.Ethene (ethylene)

4

2. How many bonds carbon can form?

the number of covalent bonds it can form.

22• The number of unpaired electrons in the valence shell of an atom is generally equal to its valence,

undergo reactions that release a large amount of energy. Fuel

28• Hydrocarbons can

compounds with the same molecular formula but different structures and properties.

29• Isomers are

have different covalent arrangements of their atoms. - The same amount in all elements arrange in that compound, but they aren't going to be arranged in the same order. The physical difference between them

30.Structural isomers

(also called geometric isomers) have the same covalent bonds but differ in their spatial arrangements. - Carbon-carbon double bound.

31.Cis-trans isomers

are isomers that are mirror images of each other. - Clockwise and the other in a counterclockwise direction if they are right.

32.Enantiomers

the pharmaceutical industry.

33. Enantiomers are important in

• Often only one enantiomer is biologically active. • Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules.

34. Two enantiomers of a drug may have different effects.

depend on the carbon skeleton and the chemical groups attached to it. • These groups help give each molecule its unique properties.

35• Distinctive properties of organic molecules

are the components of organic molecules that are most involved in chemical reactions. • The number and arrangement of functional groups give each molecule its unique properties.

36.• Functional groups

Hydrogen Oxygen Nitrogen

3· Carbon commonly bonds to:

lipids, DNA, carbohydrates.

4.Living organisms consist mostly of carbon-based compounds. Example:

ITS CARBON SKELETON AND CHEMICAL GROUPS.

5· Properties of a carbon containing molecules depend on

studies compounds that contain carbon, regardless of origin.

6. Organic chemistry

are based in "educated intelligence,"

7• Mechanistic techniques

2 phosphates

ADP:

3 phosphates

ATP

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

ATP (adenosine triphosphate)

hydroxyl group (-OH) EX:Ethanol

Alcohol

amino group (NH2) Ex:Glycine ≈ Ionized form -NH2

Amine

- (amino acids)

Amino group (-NH2)

b) single and double bonds Correct! If you had trouble with this question, review the following material: The number of electrons in an atom's valence shell determines its bonding capacity. The type of covalent bond an atom with four valence electrons can form with oxygen will be limited by oxygen. Oxygen has six valence electrons, and can form two covalent bonds (one double bond or two single bonds) to complete its valence shell

An atom has four electrons in its valence shell. What type(s) of covalent bonds is it capable of forming with oxygen? a) double bonds only b) single and double bonds c) it cannot form covalent bonds with oxygen. d) single bonds only

double bound to the O (sugars)structural isomers.

Carbonyl group (C=O) is

alcohols

Hydroxyl (-OH) group

(-OH)

Hydroxyl Group

One of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.

Isomer:

carbonyl group (>C=O) Ex: Acetone≈Propanal

Ketone aldehyde

Methylated compound Ex: methylcytosine

Methyl group (-CH3)

- carbon attach to hydrogen atoms (DNA)

Methyl group (-CH3) group

The study of carbon compounds (organic compounds)

Organic Chemistry:

- Double bound and OH (amino acids)

The Carboxyl group (-COOH) is

sulfhydryl group (-SH) Ex: Cystein

Thiol

(-NH2)

amino group

(>C=O)

carbonyl group

(-COOH)

carboxyl group

carboxyl group (-COOH) Ex:acetic acid≈Ionized form of -COOH

carboxylic acid or organic acid

(-ch3)

methyl group

phosphate group (-OPO3^-2) Ex:Glycerol Phosphate

organic phosphates

-OPO3^2-

phosphate group

(-SH)

sulfhydryl group

-Amino acids (cystine)

sulfhydryl group (-SH)

consists of an organic molecule called adenosine attached to a string of three phosphate groups.

• ATP

a) it has 26 protons and 26 electrons. The atoms of a particular element have a unique number of protons in their nuclei, and this number is called the atomic number. Unless otherwise indicated, an atom is neutral in electrical charge, which means that its protons must be balanced by an equal number of electrons. Therefore, since the atomic number tells us the number of protons, it also tells us the number of electrons in an electrically neutral atom.

1. An atom of iron has the atomic number 26. This means that. a) it has 26 protons and 26 electrons. b) it has 13 electrons, 26 protons, and 26 neutrons. c) it has 13 neutrons, 13 protons, and 13 electrons. d) it has 52 protons and 52 electrons.

C)Sulfur Correct! If you had trouble with this question, review the following material: Oxygen (O) has two electrons in its first shell and six electrons in its valence shell. Sulfur (S) has two electrons in its first shell, eight electrons in its second shell, and six electrons in its valence shell. Atoms with the same number of electrons in their valence shells exhibit similar chemical behavior. For example, both oxygen and sulfur can form two single covalent bonds with two hydrogen atoms to complete their valence shells.

1. Based on the electron configuration of the elements in the figure, which would exhibit a chemical behavior most like that of oxygen? 2. a) phosphorus b) nitrogen c) sulfur d) carbon

3 Correct! If you had trouble with this question, review the following material: Each carbon atom can form four bonds. Each hydrogen atom can form one bond. Carbon A has one single bond to the adjacent carbon in the diagram, so it can form three more single bonds with three hydrogen atoms.

1. How many hydrogen atoms can be attached to carbon A? a) 4 b) 1 c) 2 d) 3

c) Identified additional organic compounds that had not been found by Miller.Correct. The reanalysis gives further weight to the hypothesis that volcanic activity could have provided the energy needed for the abiotic synthesis of organic compounds. This comes from the fact that the new analysis used samples from an experiment including hydrogen sulfide gas, which allowed the production of compounds containing sulfur.

1. 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? ( SHOW HINT Hint for Question 2 Consider an outcome that supports a mechanism-based understanding of organic chemistry. (Concept 4.1) a) Contradicted Miller's earlier experimental results and provided more support for an undefined life force as the way organic molecules are made in nature. b) Revealed the formation of the same amino acids that Miller initially observed but in a more purified form. c) Identified additional organic compounds that had not been found by Miller. d) Greatly expanded Miller's earlier findings by uncovering the traces of cell-like entities being formed in the volcano simulation experiments.

d)Carbon, nitrogen, oxygen, hydrogen, phosphate, sulfur Correct. All these elements can form strong covalent bonds, important in building large, complex molecules.

1. What are the six most important chemical elements of life? (Concept 4.0) SHOW HINT Hint for Question 1 Think about the elements that make up the major functional groups. (Concept 4.0) a) Carbon, nitrogen, calcium, oxygen, phosphate, iron b) Carbon, nitrogen, sulfur, hydrogen, iron, magnesium c) Carbon, nitrogen, oxygen, calcium, phosphate, hydrogen d) Carbon, nitrogen, oxygen, hydrogen, phosphate, sulfur

· Carbon can form four bonds. · Carbon can bond other carbons, resulting in carbon skeletons. · Carbon commonly bonds to: Hydrogen Oxygen Nitrogen

1. What makes carbon the basis for all biological molecules?

• Experiments support the idea that abiotic (not alive) synthesis(mixture) of organic compounds, perhaps near volcanoes, could have been a stage in the origin of life.

10• Stanley Miller's

kinds and number of bonds an atom will form with other atoms.

11. Electron configuration determines the

tetrahedral shape.

12• In molecules with multiple carbons, each carbon bonded to four other atoms has a

carbon are hydrogen, oxygen, and nitrogen. HON Hydrogen Oxygen Nitrogen

13• The most frequent bonding partners of

the region(s) surrounding the nucleus where electrons travel Carbon 1st energy level 2 2nd energy levels 4

14.Energy Levels/Electron Shells

the atoms joined to the carbons are in the same plane as the carbons.

15• However, when two carbon atoms are joined by a double bond,

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

23. What is ATP's importance in the cell? (Concept 4.3) SHOW HINT Hint for Question 24 How does the structure of ATP allow it to carry out its function? (Concept 4.3) a) ATP stores energy in carbonyl groups. When a carbonyl group is removed, energy is released to be used in cellular processes. b) ATP stores the potential to react with water, thereby removing a phosphate group and releasing energy for cellular processes. c) ATP contains a long hydrocarbon tail and is important in storing energy. d) ATP can add phosphate groups, thereby releasing energy that can be used in cellular processes.

1-H

23.Hydrogen

2-O

24.Oxygen

3-N

25.Nitrogen

1. Hydroxyl group-alcohols 2.Carbonyl group- double bound to the O (sugars)structural isomers. 3.Carboxyl group- Double bound and OH (amino acids) 4.Amino group- (amino acids) 5.Sulfhydryl group-Amino acids (cystine) 6.Phosphate group- Nucleoid acids ATP, reacts with water and releases energy. 7.Methyl group- carbon attach to hydrogen atoms (DNA)

37• The seven functional groups that are most important in the chemistry of life are the following:

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

74. Stanley Miller's experiments were significant because he demonstrated that __________. Hint for Question 3 Miller's work involved research into the origin of life. (Concept 4.1) a) Lightning discharges could produce the molecules previously presumed to have originated in volcanic outgassing. b) The behavior of any molecule containing a carbon atom was fundamentally the same. c) A variety of simple organic compounds could be spontaneously synthesized from components in earth's primitive atmosphere. d) Organic molecules can be synthesized only by living organisms. .

a) CH4 Correct. Compounds containing carbon are said to be organic

75. Which of the following is an organic molecule? Hint for Question 4 Consider what organic chemists study. a) CH4 b) Ne c) NaCl d) O2

a) A tetrahedron with carbon in the center Correct. 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.

76. What is the three-dimensional shape created by hybrid orbitals that are formed when a carbon atom is covalently bonded with four other atoms? Hint for Question 5 The number 4 is key to the answer. (Concept 4.2) a) A tetrahedron with carbon in the center b) A triangle with carbon in the center c) A flat sheet with carbon in the center d) All the listed responses are possible.

b) The isomers are enantiomers, with one having toxic effects on humans. Correct. 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.

77. 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? Hint for Question 6 Consider which isomers are defined by the presence of an asymmetrical carbon atom. a) The two isomers of the drug contain different functional groups, and the isomer with the aberrant functional group is connected to the fatalities. b) The isomers are enantiomers, with one having toxic effects on humans. c) The asymmetrical carbon causes the solubility of the two drug isomers to vary significantly, thus having different chemical properties and effects on people who take them. d) The double bond involving the asymmetrical carbon can generate cis-trans isomers that typically have different chemical properties, thus accounting for the drug's toxic properties.

rely on "innate intelligence." Disproved in 1953 by Miller

8. whereas vitalist techniques

two Correct. Only two cis-trans isomers exist

82.A molecule has one carbon-carbon double bond and four monovalent atoms or groups. How many different cis-trans isomers exist for this molecule? (Concept 4.2) Hint for Question 11 Draw the possible molecular structures. (Concept 4.2) a) Four b) Six c) Two d) None

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

84. Which of the following functional groups is present in all amino acids? (Concept 4.3) Hint for Question 14 Consider the element that is diagnostic of amino groups. (Concept 4.3) a) —SH b) —COH c) —NH2 d) —OH

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

86. Ethanol, propanol, and methanol are three simple alcohols. They can be grouped together because they __________. (Concept 4.3) Hint for Question 16 Consider the functional group that defines alcohol. (Concept 4.3) a) all contain a carbonyl group. b) are hydrophobic. c) share the same functional group: a hydroxyl. d) are soluble in water.

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

87. Which of the following molecules has a carboxyl functional group? (Concept 4.3) SHOW HINT Hint for Question 17 Review the structures of functional groups. (Concept 4.3) a) R—COH b) R—OPO3-2 c) R—COOH d) R—NH2 d.

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

88. Which of the following functional groups increases the solubility of organic compounds in water? (Concept 4.3) a) —COH b) —OH c) —COOH d) All the listed responses are correct.

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

89. Which of the following examples best describes a unique functional property of the carboxyl group? (Concept 4.3) Hint for Question 19 Review the structures of functional groups and think about relative electronegativity. (Concept 4.3) a) It is polar because of the electronegative oxygen atom drawing electrons toward it. b) Its compounds may be structural isomers with different properties. c) Two carboxyl groups can bond covalently to help stabilize protein structure. d) The covalent bond between oxygen and hydrogen is so polar that hydrogen ions tend to dissociate from oxygen reversibly.

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

90. Which of the following functional groups is associated with a release of energy when removed from the carbon skeleton with water? (Concept 4.3) Hint for Question 20 Review the functional groups. Think about a molecule that can release energy to be used in the cell. (Concept 4.3) a) Hydroxyl group b) Sulfhydryl group c) Phosphate group d) Amino group

c) Carboxyl group Correct. 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.

91. Which functional group would you predict is part of abscisic acid? (Concept 4.3) SHOW HINT Hint for Question 21 Consider which of these groups is a proton donor. (Concept 4.3) a) Hydroxyl group b) Carbonyl group c) Carboxyl group d) Amino group

d) All of the listed responses are correct. Correct. All the listed functional groups are polar and thus capable of hydrogen bonding with the oxygen of another molecule.

92. Which of the following groups is capable of hydrogen bonding with an oxygen atom on another functional group? (Concept 4.3) SHOW HINT Hint for Question 22 Recall that hydrogen bonds form between polar molecules. (Concept 4.3) a) Hydroxyl group b) Carboxyl group c) Amino group d) All of the listed responses are correct.

d) None of the listed responses is correct.Correct. A thiol is a molecule containing a sulfhydryl functional group

93. Which of these is a thiol? (Concept 4.3) SHOW HINT Hint for Question 23 Consider the functional group that is diagnostic of a thiol. (Concept 4.3) a) —OH b) —SH c) —COH d) None of the listed responses is correct.

to the versatility of carbon.

9• The great diversity of organisms on the planet is due

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

A straight-chain carbon compound constructed from __________ must contain at least one carbon-carbon double bond. SHOW HINT Draw the structures of the molecules. a) 8 hydrogen atoms, 3 carbon atoms, and 3 oxygen atoms b) 6 hydrogen atoms and 3 carbon atoms c) 6 hydrogen atoms and 2 carbon atoms d) 6 hydrogen atoms, 2 carbon atoms, and 1 oxygen atom

An organic molecule consisting only of carbon and hydrogen.

Hydrocarbon:

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

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? (Concept 4.2) Hint for Question 13 Consider the importance of the relationship of form to function in the interaction of biological molecules. (Concept 4.2) a) It is not important. Both enantiomers will be equally effective. b) The left-handed version of the enantiomer is always the effective one. c) It is cheaper to manufacture only one of the enantiomers. d) One enantiomer may provide an effective treatment whereas the other may be ineffective or even toxic.

- Nucleoid acids ATP, reacts with water and releases energy.

Phosphate (OPO₃²⁻) group

b)4 Yes. Carbon's four valence electrons allow it to form four covalent bonds.

The carbon atom possesses __________ valence electron(s). (Concept 4.2) Consider the meaning of the prefix "tetra-." (Concept 4.2) a) 2 b) 4 c) 1 d) 3

The bonding capacity of a given atom; the number of covalent bonds that an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell.

Valence:

c) Each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions. Correct. 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.

What is the reason carbon atoms are the most versatile building blocks of the molecules used by living organisms? Hint for Question 8 Consider the tetravalence of carbon. (Concept 4.2) a) Carbon is the central atom of carbon dioxide, a necessary molecule for photosynthesis. b) Carbon is the central atom in urea, a molecule used by many living organisms to transport wastes from the body. c) Each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions. d) All the listed responses are correct.

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

Which of the following are properties of hydrocarbons? (Concept 4.2) Hint for Question 10 What are some hydrocarbons you are familiar with? How do they behave? (Concept 4.2) a) Hydrophilic, containing numerous carboxyl groups, nonpolar. b) Hydrophobic, nonpolar, good source of stored energy. c) Hydrophilic, a good source of stored energy, consisting primarily of carbon and hydrogen. d) Hydrophobic, polar, charged.

a) both —COOH and —NH2 Correct. 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 of these is found in all amino acids? (Concept 4.3) Hint for Question 15 Consider the functional group or groups present in all amino acids. (Concept 4.3) a) both —COOH and —NH2 b) —COOH c) —OH d) —COH

hydrophilic (water loving) Hydroxyl group b) Carboxyl group c) Amino group

polar molecules are

• This reaction releases energy that can be used by the cell. •

• ATP stores the potential energy to react with water.