Deck 3: The Chemistry of Life Organic Compounds

Question 1

What carbohydrate energy storage molecule is found in animal liver and muscle cells?

A) starch
B) cellulose
C) glycogen
D) a fatty acid
E) cholesterol

Answer 1

C

Question 2

Unlike lipids, hydrophilic functional groups typically contain ____ atoms, which make them more soluble in water.

A) carbon
B) oxygen
C) hydrogen
D) nitrogen
E) phosphate

Answer 2

B

Question 3

Which is an example of a disaccharide?

A) ribose
B) glucose
C) maltose
D) fructose
E) tricylglycerol

Answer 3

C

Question 4

What group of molecules is represented in this structure?

A) structural proteins
B) polysaccharides
C) triacylglycerols
D) phospholipids
E) polypeptides

Question 5

What substance is removed during a condensation reaction?

A) water
B) a dimer
C) a polymer
D) a hydrocarbon
E) a carboxyl group

Question 6

Why are hydrocarbons considered hydrophobic?

A) Hydrocarbons exist as isomers.
B) Hydrocarbons contain oxygen atoms.
C) The covalent bonds between carbon atoms are polar.
D) The covalent bonds between hydrogen and carbon are nonpolar.
E) The hydrogen bonds between hydrogen and carbon are nonpolar.

Question 7

Amyloplasts are organelles that store:

A) fat.
B) starch.
C) protein.
D) lipids.
E) DNA.

Question 8

An amino group is weakly basic and includes a(n) ____ atom covalently bonded to two hydrogen atoms.

A) sulfur
B) carbon
C) oxygen
D) nitrogen
E) phosphate

Question 9

Which description illustrates an amphipathic molecule?

A) A phospholipid with two polar ends
B) A phospholipid with two hydrophobic ends
C) A phospholipid with only one hydrophilic end
D) A phospholipid with only one hydrophobic end
E) A phospholipid with both a hydrophobic end and a hydrophilic end

Question 10

A molecule of a saturated triacylglycerol contains:

A) the maximum number of double bonds between carbons in the fatty acid chains.
B) the maximum number of triple bonds between carbons in the fatty acid chains.
C) the maximum number of hydrogen atoms in the fatty acid chains.
D) fatty acid chains with both amino and carboxyl groups.
E) alternating single and double bonds between carbons in the fatty acid chains.

Question 11

Which carbohydrate is the most structurally complex?

A) polymer
B) monomer
C) phospholipid
D) polysaccharide
E) monosaccharide

Question 12

Figure 3-1 What chemical process is represented in the accompanying figure?

A) hydrolysis
B) denaturation
C) condensation
D) protein synthesis
E) dehydration synthesis

Question 13

Figure 3-1 The products of the process in the accompanying figure are:

A) enzymes.
B) amino acids.
C) monosaccharides.
D) molecules of glycerol.
E) representative of a glycoside linkage.

Question 14

How many carbon sugars are there in a pentose sugar?

A) two
B) three
C) five
D) six
E) eight

Question 15

If you partially hydrogenate oleic acid, the resulting molecule most likely would:

A) lose a carbon atom.
B) lose a carboxyl group.
C) become soluble in water.
D) contain more double bonds.
E) have a double bond changed from cis to trans.

Question 16

When we know what kinds of ____ are present in an organic compound, we can predict its chemical behavior.

A) proteins
B) enzymes
C) triacylglycerols
D) macomolecules
E) functional groups

Question 17

Which is a property of unsaturated fats?

A) They are more common in animals.
B) They are generally liquid at room temperature.
C) They have no double bonds in the carbon chains of their fatty acids.
D) They have fewer fatty acids per fat molecule than do saturated fats.
E) They contain more hydrogen than do saturated fats having the same number of carbon atoms.

Question 18

You isolate a compound that is insoluble in water, has alternating single and double bonds, and has a bright orange color. You correctly conclude that this compound is a:

A) protein.
B) nucleic acid.
C) polysaccharide.
D) steroid.
E) carotenoid.

Question 19

Glucose and fructose are ____ because they have identical molecular formulas but their atoms are arranged differently.

A) polar
B) tertiary
C) enantiomers
D) structural isomers
E) geometric isomers

Question 20

How many electron pairs are shared between carbon 2 and 3 in the accompanying figure?

A) one
B) one and a half
C) two
D) three
E) four

Question 21

When a nucleic acid undergoes hydrolysis, the resulting subunits are:

A) fatty acids.
B) amino acids.
C) nucleotides.
D) carotenoids.
E) monosaccharides.

Question 22

Which description illustrates the tertiary structure of a protein molecule?

A) bonding of two amino acids to form a dipeptide
B) folding of a peptide chain to form an alpha helix
C) association of several polypeptide chains by weak bonds
D) order in which amino acids are joined in a peptide chain
E) three-dimensional shape of an individual polypeptide chain

Question 23

Which statement best summarizes the differences between RNA and DNA?

A) RNA is a single-stranded form of DNA.
B) DNA is a polymer and RNA is a monomer.
C) RNA is a protein and DNA is a nucleic acid.
D) DNA is the primary energy currency of all cells.
E) DNA comprises the genes, while RNA is a direct participant in the process of protein synthesis.

Question 24

Figure 3-3 The molecular fragment (the G, U and A's) represented in the accompanying figure is:

A) ATP.
B) RNA.
C) DNA.
D) a nucleotide.
E) a polysaccharide.

Question 25

At which level of protein structure are peptide bonds most important?

A) primary
B) secondary
C) tertiary
D) quaternary
E) globular

Question 26

What is the purpose of molecular chaperones?

A) To transfer an amino acid
B) To attach a carboxyl group
C) To straighten other molecular proteins
D) To strengthen the tertiary structure of a protein
E) To assist the folding of other molecular proteins

Question 27

Figure 3-3 What type of connection exists between the atoms at the point labeled 1 in the accompanying figure?

A) peptide bond
B) disulfide bond
C) hydrogen bond
D) glycoside linkage
E) phosphodiester linkage

Question 28

Figure 3-2 In the accompanying figure, hydrophobic interactions would occur between the R groups of which two amino acids?

A) 1 and 4
B) 2 and 5
C) 3 and 6
D) 2 and 4
E) 3 and 5

Question 29

Which functional group forms bridges to help stabilize a protein's quaternary structure?

A) amino
B) carbonyl
C) hydroxyl
D) phosphate
E) sulfhydryl

Question 30

Which pair matches the correct macromolecule with the bond that joins its subunits?

A) protein − ester linkage
B) steroid − peptide bond
C) polysaccharide − peptide bond
D) triacylglycerol − glycosidic linkage
E) nucleic acid − phosphodiester linkage

Question 31

What is the purpose of regulatory proteins?

A) To store nutrients
B) To defend against foreign invaders
C) To catalyze a specific chemical reaction
D) To control the expression of specific genes
E) To strengthen and protect cells and tissues

Question 32

Which of the following is responsible for the alpha-helical structure of proteins?

A) hydrogen bonds
B) ionic interactions
C) polar covalent bonds
D) hydrophobic interactions
E) nonpolar covalent bonds

Question 33

The primary difference between the amino acids commonly found in proteins is in their:

A) R or variable groups.
B) number of potassium groups.
C) number of phosphate groups.
D) number of carbonyl groups.
E) number of asymmetric carbons.

Question 34

Figure 3-2 In the accompanying figure, ionic bonds would form between the R groups of which amino acids?

A) 1 and 3
B) 2 and 4
C) 3 and 5
D) 4 and 6
E) 3 and 6

Question 35

Assume that the shaded portions of the molecule in the accompanying figure each represent different polypeptide chains. What does this represent?

A) cellulose
B) a carotenoid
C) an amino acid
D) a steroid hormone
E) the quaternary structure of a protein

Question 36

If tyrosine and isoleucine undergo condensation, where does the new bond form?

A) Between carbon of the R group and the nitrogen of the amino group
B) Between oxygen of the R group and the hydrogen of the amino group
C) Between carbon of the carboxyl group and the hydrogen of the R group
D) Between carbon of the carboxyl group and the hydrogen of the amino group
E) Between carbon of the carboxyl group and the nitrogen of the amino group

Question 37

The helical coil shape of an α -helix fibrous protein provides what type of property to that protein?

A) rigidity
B) strength
C) elasticity
D) heat tolerance
E) water retention

Question 38

The following amino acid would be characterized as ____ based on the chemical properties of its side chain.

A) basic
B) acidic
C) nonpolar
D) hydrophilic
E) electrically charged

Question 39

Analysis of a certain polymer shows that it contains phosphate groups, ribose groups, and pyrimidines. Based on this information, what statement best describes this compound?

A) It is RNA.
B) It is DNA.
C) It is cylic AMP.
D) It is a polypeptide.
E) It is an inorganic compound.

Question 40

What type of protein accelerates the thousands of different chemical reactions that take place in an organism?

A) enzyme
B) amino acid
C) transport protein
D) regulatory protein
E) protective protein

Question 41

Carotenoids are composed of isoprene subunits.
__________________

Question 42

What organic molecules is the primary structural component of cell membranes?

A) cellulose
B) glycogen
C) disaccharides
D) phospholipids
E) adenine triphosphate

Question 43

A phosphate group is weakly acidic .
__________________

Question 44

Why is ATP important in living organisms?

A) It is easily converted to starch for long-term storage.
B) It can transfer some of its energy to other chemicals.
C) It is an important structural component of cell membranes.
D) Like all other nucleic acids, it stores hereditary information.
E) Like RNA, it acts as a source code for the formation of proteins.

Question 45

Identify the levels of organization for protein molecules, and list the type(s) of bond(s) involved in establishing each structural level.

Question 46

Fats high in unsaturated fatty acids tend to be solid at room temperature.
__________________

Question 47

A disaccharide is composed of two monosaccharides joined by a(n) glycosidic linkage .
__________________

Question 48

Identify three functions of proteins other than enzymes and briefly discuss or describe each.

Question 49

Which organic compound is not only responsible for energy storage, but also can provide thermal insulation?

A) lipids
B) proteins
C) nucleic acids
D) carbohydrates
E) monosaccharides

Question 50

Which of the following is a purine base found in nucleotides?

A) uricil
B) steroid
C) guanine
D) cytosine
E) thymine

Question 51

What does the term "functional group" mean in reference to the structure of organic molecules? Identify two types of functional groups and describe their chemical properties.

Question 52

Which lipid can be identified by its isoprene units?

A) fats
B) steroids
C) carotenoids
D) amino acids
E) phospholipids

Question 53

Since a carbon atom has 4 valence electrons, it can complete its valence shell by forming a total of 4 hydrogen bonds.
__________________

Question 54

Chitin is a polymer composed of N-acetyl glucosamine monomers.
__________________

Question 55

Compare and contrast the structure, physical characteristics, and biological functions of two of the following: fats, steroids, and phospholipids.

Question 56

A(n) essential amino acid is one that the body cannot synthesize in sufficient amounts.
__________________

Question 57

When glucose and fructose undergo condensation, maltose is produced as a product.
__________________

Question 58

The carboxyl group can exist in an ionized form and also in a nonionized form.
__________________

Question 59

Condensation and hydrolysis reactions are catalyzed by the same enzymes..
__________________

Question 60

By definition, geometric isomers are mirror images of each other.
__________________

Question 61

A beta-pleated sheet is an example of a protein's tertiary structure.
__________________

Question 62

Why is carbon ideally suited to be the "backbone" in molecules produced by living organisms?

Question 63

Methane, which is composed of carbon and hydrogen, lacks functional groups and is a gas at room temperature. Upon replacing one of the hydrogen atoms with a hydroxyl group, methane is converted to methanol, which is a liquid at room temperature. Explain the reason behind this difference in physical properties.

Question 65

Cyclic AMP is a type of nucleotide .
__________________

Question 66

A pyrimidine is a double -ring molecule.
__________________

Question 67

Molecular chaperones mediate the folding of other protein molecules.
__________________

Question 68

Sickle cell anemia is a genetic disease caused by the replacement of one amino acid in the hemoglobin molecule. This replacement changes the shape and function of the hemoglobin protein in dramatic ways, which can sometimes be lethal. How can the substitution of one amino acid lead to such drastic results?