4. Biomolecules

Carbon

Why is the Carbon Atom said to be unique?

 Carbon is the central atom of carbon dioxide, a necessary molecule for photosynthesis. 

 No. It is true that carbon is the central atom in carbon dioxide, but this does not make carbon versatile. 

 Carbon is the central atom in urea, a molecule used by many living organisms to transport wastes from the body. 

 No. It is true that carbon is the central atom in urea, but this does not make carbon versatile. 

 All of the listed responses are correct. 

 No. All of the listed responses are true statements, but not all of them answer the question. Carbon is a versatile building block for only one of the listed reasons. 

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

Consider the tetravalence of carbon.

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

 No. Try drawing possible configurations on a piece of scrap paper. 

Draw the possible molecular structures.

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

Carbon is an Excellent Building Block

 No. This is a typical hydrocarbon with single bonds, in which the number of hydrogen atoms is equal to two times the number of carbon atoms plus two. 

 6 hydrogen atoms, 2 carbon atoms, and 1 oxygen atom 

 No. If the carbons were double-bonded, only four additional bonds could be formed. 

 8 hydrogen atoms, 3 carbon atoms, and 3 oxygen atoms 

 No. If two carbons were double-bonded, there would not be enough bonds for the rest of the atoms, even if 3 hydrogen atoms bind to the 3 oxygen atoms to form hydroxyl groups. 

Draw the structures of the molecules.

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

 the behavior of any molecule containing a carbon atom was fundamentally the same 

 No. The behavior of molecules containing carbon can be quite different and is influenced primarily by the construction of the carbon skeleton and the presence and variety of functional groups. 

 organic molecules can be synthesized only by living organisms 

 No. Miller's experiments demonstrated that organic molecules could be produced spontaneously under the conditions of the early Earth. 

 lightning discharges could produce the molecules previously presumed to have originated in volcanic outgassings 

 No. Using volcanic gases, Miller showed that these gas molecules, with the energy from lightning, could become a variety of simple organic molecules. 

 a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere 

Miller's work involved research into the origin of life.

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

 No. Carbon has a different number of valence electrons. 

Consider the meaning of the prefix "tetra-."

The carbon atom possesses __________ valence electron(s).

 No. Bonding electrons are positioned as distantly from one another as possible. A flat sheet does not provide the greatest possible distance between electron pairs. 

 No. A triangle has three vertices; the carbon atom in the question is bonded to four other atoms. 

 All of the listed responses are possible. 

 No. Only one of the listed responses is correct. 

 A tetrahedron with carbon in the center 

The number 4 is key to the answer.

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

Bonds formed by Carbon | Don't Memorise

Carbon: The Element of Life

 Contradicted Miller's earlier experimental results and provided more support for an undefined life force as the way organic molecules are made in nature  

 No. At the very least, the reanalysis added additional support for the view that physical and chemical laws govern all natural phenomena, including the processes of life. 

 Revealed the formation of the same amino acids that Miller initially observed but in a more purified form 

 No. The reanalysis indeed corroborated Miller's initial findings, but it revealed the presence of something more that served to extend Miller's interpretation of the original data. 

 Greatly expanded Miller's earlier findings by uncovering the traces of cell-like entities being formed in the volcano simulation experiments 

 No. The new findings indeed expanded Miller's earlier findings, but they did not reveal the formation of cell-like entities in the samples. 

 Identified additional organic compounds that had not been found by Miller 

Consider an outcome that supports a mechanism-based understanding of organic chemistry.

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?

VISUAL SKILLS Visualize the structural formula of each of the following hydrocarbons. Which hydrocarbon has a double bond in its carbon skeleton?
a. C3H8
b. C2H6
c. C2H4
d. C2H2

 No. Hydrocarbons are hydrophobic but not polar and not charged. 

 Hydrophilic, good source of stored energy, consisting primarily of carbon and hydrogen 

 No. Hydrocarbons are definitely not hydrophilic. 

 Hydrophilic, containing numerous carboxyl groups, nonpolar 

 No. Hydrocarbons are hydrophobic and do not contain carboxyl groups. 

 Hydrophobic, nonpolar, good source of stored energy 

What are some hydrocarbons you are familiar with? How do they behave?

Which of the following are properties of hydrocarbons?

Organic chemistry is currently defined as
a. the study of compounds made only by living cells.
b. the study of carbon compounds.
c. the study of natural (as opposed to synthetic) compounds.
d. the study of hydrocarbons.

 No. Neon is not an organic molecule. Neon is an element. 

No. Oxygen is not an organic molecule. Compounds containing carbon are said to be organic. O2 is a molecule of oxygen gas.

 No. NaCl (salt) is not an organic molecule. Compounds containing carbon are said to be organic. 

Consider what organic chemists study.

Which of the following is an organic molecule?

Why is Carbon the Key to Life? (On Earth, Anyway)

Organic molecules are defined as chemical compounds that contain:a) Carbon.b) Carbon &amp; Oxygen.c) Carbon &amp; Nitrogen.d) Carbon &amp; Hydrogen.

Carbon... SO SIMPLE: Crash Course Biology #1

 No. It is true that both compounds are hydrocarbons, but there is a better answer. 

 No. It is true that both compounds are organic compounds, but there is a better answer. 

 No. It is true that the compounds are isomers of each other, but there is a better answer. 

 hydrocarbons, isomers, organic compounds, and double-bonded compounds 

Consider and compare the molecular structures of these compounds.

The two compounds <img src=" /bc/bc_campbell_biology_9/img_quiz/ptch04q15a.gif" alt="Question #15 image" BORDER="0"> <img src=" /bc/bc_campbell_biology_9/img_quiz/ptch04q15b.gif" alt="Question #15 image" BORDER="0"> are related to each other by being __________.

 The two isomers of the drug contain different functional groups, and the isomer with the aberrant functional group is connected to the fatalities. 

 No. Isomers contain the same functional groups. 

 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. 

 No. An asymmetrical carbon in an organic molecule is one that is attached to four different atoms or groups of atoms, but it does not affect the chemical properties of those atoms or groups. 

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.

 No. An asymmetrical carbon in an organic molecule is one that is attached to four different atoms or groups of atoms and does not involve a double bond. 

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

Consider which isomers are defined by the presence of an asymmetrical carbon atom.

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?

 No. The water molecule is shaped roughly like a V. 

 No. A molecule consisting of two atoms is always linear. 

How many atoms does it take to define a tetrahedron?

Which molecule has the shape of a completed tetrahedron?

Carbon Compounds - Introduction | Don't Memorise

Animation: Isomers

Animation: Diversity of Carbon-Based Molecules

 It is cheaper to manufacture only one of the enantiomers. 

 No. In most cases, it is more expensive to separate the left-handed version from the right-handed one. 

 It is not important. Both enantiomers will be equally effective. 

 No. In some cases, both enantiomers can be effective, but in many drugs, only one enantiomer is safe and effective. 

 The left-handed version of the enantiomer is always the effective one. 

 No. Depending on the molecule, either enantiomer may be the effective one, and in some cases, both are effective. 

 One enantiomer may provide an effective treatment whereas the other may be ineffective or even toxic. 

Consider the importance of the relationship of form to function in the interaction of biological molecules.

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?

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