The element present in all organic molecules is _____. |
carbon |
The complexity and variety of organic molecules is due to _____. |
the chemical versatility of carbon atoms |
The experimental approach taken in current biological investigations presumes that _____. |
living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena |
Differences among organisms are caused by differences in the _____. |
types and relative amounts of organic molecules synthesized by each organism |
Stanley Miller's 1953 experiments supported the hypothesis that _____. |
organic molecules can be synthesized abiotically under conditions that may have existed on early Earth |
When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced? |
simple organic compounds, amino acids, and hydrocarbons |
Which of the following is true of carbon? |
It can form both polar and nonpolar bonds. |
Why is carbon so important in biology? |
It can form a variety of carbon skeletons and host functional groups. |
How many electron pairs does carbon share to complete its valence shell? |
4 |
A carbon atom is most likely to form what kind of bond(s) with other atoms? |
covalent |
Why are hydrocarbons insoluble in water? |
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. |
Which of the following statements correctly describes cis-trans isomers? |
They have variations in arrangement around a double bond. |
Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that _____. |
are mirror images of each other |
What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration? |
the presence or absence of double bonds between the carbon atom and other atoms |
Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will _____. |
be more constrained in structure |
Organic molecules with only hydrogens and five carbon atoms cannot _____. |
form enantiomers |
The two molecules shown in the figure below are best described as _____. |
structural isomers |
The figure above shows the structures of glucose and fructose. These two molecules differ in the _____. |
arrangement of carbon, hydrogen, and oxygen atoms |
The figure above shows the structures of glucose and fructose. These two molecules are _____. |
structural isomers |
The two molecules shown in the figure below are best described as _____. |
cis-trans isomers |
Which of the following illustrations is NOT a structural isomer of an organic compound with the molecular formula C6H14? For clarity, only the carbon skeletons are shown; hydrogen atoms |
picture with a double bond |
Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric forms) of the same molecule? |
C |
Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule? |
B |
Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that _____. |
are mirror images of one another |
Which of the following molecules is polar? C3H7OH C2H5COOH |
C3H7OH and C2H5COOH are both polar molecules. |
Which of the functional groups below acts most like an acid in water? |
carboxyl |
A compound contains hydroxyl groups as its predominant functional group. Therefore, this compound _____. |
should dissolve in water |
Which two functional groups are always found in amino acids? |
carboxyl and amino groups |
Amino acids are acids because they always possess which functional group? |
carboxyl |
A hydrocarbon skeleton is covalently bonded to an amino group at one end and a carboxyl group at the other end. When placed in water this molecule would function _____. |
as an acid and a base |
Which chemical group can act as an acid? |
carboxyl |
Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? Testosterone and estradiol _____. |
have different functional groups attached to the same carbon skeleton |
What is the name of the functional group shown in the figure below? |
carboxyl |
Which of the structures illustrated above is an impossible covalently bonded molecule? |
B |
In which of the structures illustrated above are the atoms bonded by ionic bonds? |
none of the structures |
Which functional group shown above is characteristic of alcohols? |
OH |
Which functional group(s) shown above is (are) present in all amino acids? |
B and C |
Which of the groups shown above is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules? |
D |
Which of the groups above is a carboxyl functional group? |
B |
Which of the groups above is an acidic functional group that can dissociate and release H+ into a solution? |
B |
Which of the groups above is a basic functional group that can accept H+ and become positively charged? |
C |
Which molecule shown above would have a positive charge in a cell? |
D |
Which molecule(s) shown above is (are) ionized in a cell? |
C and D |
Which molecules shown above contain a carbonyl group? |
A and B |
Which molecule shown above has a carbonyl functional group in the form of a ketone? |
B |
Which molecule shown above has a carbonyl functional group in the form of an aldehyde? |
A |
Which molecule shown above contains a carboxyl group? |
A |
Which molecule shown above can increase the concentration of hydrogen ions in a solution and is, therefore, an organic acid? |
C |
Which molecule shown above can form a cross linkage? |
B |
Which molecule shown above contains an amino functional group, but is NOT an amino acid? |
A |
Which molecule shown above is a thiol? |
B |
Which molecule shown above contains a functional group that cells use to transfer energy between organic molecules? |
D |
Which molecule shown above can function as a base? |
A |
Which of the following is a FALSE statement concerning amino groups? Amino groups _____. |
are nonpolar |