BIOL1406 LEC Exam 2: Ch. 4-7
Valence
# of covalent bonds an atom can form
How many valence electrons does Carbon have?
4
How many common monomers are there?
40-50
How many electrons does Carbon have?
6
Amino Group (Compound Name: Glycine)
Acts as a base; can pick up an H⁺ from the surrounding solution (water, in living organisms).
Carboxyl Group (Compound Name: Carboxylic Acid or Organic Acid)
Acts as an acid (can donate H⁺) bc the covalent bond between oxygen & hydrogen is so polar.
Macromolecules (huge)
Carbs, Lipids, Proteins, & Nucleic Acids
Phosphate Group (Compound Name: Glycerol Phosphate)
Contributes negative charge (1⁻ when positioned inside a chain of phosphates; 2⁻ when at the end). When attached, confers on a molecule the ability to react w water, releasing energy.
The most common monosaccharide is?
Glucose (C₆H₁₂O₆)
Are hydrocarbons hydrophilic or hydrophobic?
Hydrophobic bc a great majority of their bonds are relatively non-polar
7 chemical groups MOST important in bio processes
Hydroxyl group Carbonyl group Amino group Sulfhydryl group Phosphate group Methyl group
Hydroxyl Group (Compound Name: Alcohol)
Is polar due to electronegative oxygen. Forms hydrogen bonds w water, helping dissolve compounds such as sugars.
What do enantiomers resemble visually
Left vs Right hands
What are the 4 ways that carbon skeletons can vary?
Length Branching Double Bond Positions Presence of Rings
What are the simplest carbohydrates?
Monosaccharides (Simple Sugars)
Sulfhydryl Group (Compound Name: Cysteine)
NOT hydrophilic 2 -SH groups can react, forming a "cross-link" that helps stabilize protein structure. Hair protein cross-links maintain the straightness or curliness of hair; in hair salons, perms break cross-links, then re-form them while the hair is in the desired shape.
Methyl Group (Compound Name: 5-Methylcytosine)
NOT reactive. Affects the expression of genes when on DNA or on proteins bound to DNA. Affects the shape and function of male and female sex hormones.
What are carbon's main bonding partners?
Oxygen, Nitrogen, Hydrogen
What industry are enantiomers important in?
Pharma Ex: Ibrupofen
Polymerization
Repeated Process: when a bond forms between 2 monomers, each monomer contributes part of the water molecule that is released during the reaction: 1 monomer provides hydroxyl group (-OH), while other provides Hydrogen (-H).
Carbonyl Group (Compound Name: Ketone or Aldehyde)
Sugars w ketone groups are called ketoses; those w aldehydes are called aldoses.
True or False: Organic compounds, once thought to arise only w/in living organisms, were finally synthesized in the laboratory.
TRUE
Trans Isomer
The 2 Xs are on opposite sides
Cis Isomer
The 2 Xs are on the same side
True or False: although each class of polymer is made up of a different type of monomer, the chemical mechanisms by which cells make and break down polymers are basically the same in all cases.
True
Can hydrolysis also be involved in the formation and breakdown of molecules that are not polymers?
Yes, such as some lipids.
Are proteins, DNA, & carbs all made up of carbon?
Yes.
Polymer
a long molecule consisting of many similar or identical building blocks linked by covalent bonds
What does a polymer resemble?
a train consisting of a chain of cars
A straight-chain carbon compound constructed from __________ must contain at least one carbon-carbon double bond. a. 6 hydrogen atoms and 3 carbon atoms b. 6 hydrogen atoms, 2 carbon atoms, and 1 oxygen atom c. 8 hydrogen atoms, 3 carbon atoms, and 3 oxygen atoms d. 6 hydrogen atoms and 2 carbon atoms
a. 6 hydrogen atoms and 3 carbon atoms (There must be a carbon-carbon double bond for this molecule to exist.)
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. a. ATP contains a long hydrocarbon tail and is important in storing energy. b. ATP can add phosphate groups, thereby releasing energy that can be used in cellular processes. c. ATP stores energy in carbonyl groups. When a carbonyl group is removed, energy is released to be used in cellular processes. d. ATP is an important component of cell membranes because it is nonpolar and hydrophobic.
a. ATP contains a long hydrocarbon tail and is important in storing energy.
Which of the following are properties of hydrocarbons? a. Hydrophobic, nonpolar, and a good source of stored energy b. Hydrophobic, polar, and charged c. Hydrophilic, a good source of stored energy, and consisting primarily of carbon and hydrogen d. Hydrophilic, containing numerous carboxyl groups, and nonpolar e. Hydrophobic, containing numerous amine groups, and polar
a. Hydrophobic, nonpolar, and a good source of stored energy
Which of the following molecules is a weak acid? a. R-COOH b. R-NH₂ c. R-SH d. R-OH e. None of the listed responses is correct.
a. R-COOH
Which of the following molecules is a weak base? a. R-NH₂ b. R-SH c. R-OH d. R-COOH e. None of the listed responses is correct.
a. R-NH₂
Which of the following molecules has a carboxyl functional group? a. R—COOH b. R—OPO₃⁻² c. R—COH d. R—NH₂
a. 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 functional group would you predict is part of abscisic acid? a. carboxyl group b. carbonyl group c. amino group d. hydroxyl group
a. 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)
The chemical group that is involved in regulating DNA is the __________. a. methyl group (-CH₃) b. carboxyl group (-COOH) c. amine group (-NH₂) d. sulfhydryl group (-SH) e. phosphate group (-PO₃⁻²)
a. methyl group (-CH₃)
Inorganic carbon such as CO2 differs from organic carbon because __________. a. organic carbon always has a hydrogen atom covalently attached to it b. inorganic carbon always has double bonds and organic carbon never has double bonds c. inorganic carbon always has a hydrogen atom covalently attached to it d. CO2 is an example of an organic molecule
a. organic carbon always has a hydrogen atom covalently attached to it
The chemical group that helps stabilize protein structure is the __________. a. sulfhydryl group (-SH) b. amine group (-NH2) c. carboxyl group (-COOH) d. phosphate group (-PO3-2) e. methyl group (-CH3)
a. sulfhydryl group (-SH)
Which action could produce a carbonyl group? a. the replacement of the -OH of a carboxyl group w hydrogen b. the addition of a thiol to a hydroxyl c. the addition of a hydroxyl to a phosphate d. the replacement of the nitrogen of an amine w oxygen
a. the replacement of the -OH of a carboxyl group w hydrogen
Chemical groups are significant because __________. a. they contribute to the molecular shape of a molecule and its unique properties b. they are always the same and do not influence the properties of a molecule c. they can never be substituted d. they stabilize a molecule by preventing chemical reactions
a. they contribute to the molecular shape of a molecule and its unique properties
Which of the following functional groups is present in all amino acids? a. ⁻NH₂ b. ⁻SH c. ⁻COH d. ⁻OH
a. ⁻NH₂ (This is the amino group. This group is present in all amino acids.)
ADP
adenosine diphosphate
ATP
adenosine triphosphate
Depending on location of carbonyl group, a sugar is either an _______ or ________.
aldose or ketose
What did Friedrich Wohler try to make? What happened?
an "inorganic" salt (ammonium cyanate), ended up w urea
What is ATP's importance in the cell? a. ATP can add phosphate groups, thereby releasing energy that can 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 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. (ATP releases energy during a hydrolysis reaction that removes a phosphate group.)
Which of the following molecules is a weak base? a. R—SH b. R—NH₂ c. R—OH d. None of the listed responses is correct.
b. R—NH₂ (The amino group (—NH2) of R—NH₂ can function as a base. It can accept a proton (H⁺).)
The carbon atom is tetravalent, which means that __________. a. the bond angle between each bond is 90°, forming an arrangement like the points on a compass b. a carbon atom can complete its valence shell by forming four covalent bonds c. carbon's first electron shell holds four electrons d. carbon readily forms ionic bonds
b. 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. a. acid; carbonyl b. acid; amino c. hydroxyl; amino d. ketone; phosphate
b. acid; amino
What are the six most important chemical elements of life? a. carbon, nitrogen, calcium, oxygen, phosphate, iron b. carbon, nitrogen, oxygen, hydrogen, phosphate, sulfur c. carbon, nitrogen, sulfur, hydrogen, iron, magnesium d. carbon, nitrogen, oxygen, calcium, phosphate, hydrogen
b. carbon, nitrogen, oxygen, hydrogen, phosphate, sulfur
Ethanol, propanol, and methanol are three simple alcohols. They can be grouped together because they __________. a. are hydrophobic b. share the same functional group: a hydroxyl c. all contain a carbonyl group d. are soluble in water
b. share the same functional group: a hydroxyl (Alcohols are distinguished by the presence of the hydroxyl (-—OH) functional group.)
Structural isomers have __________. a. left- and right-handed forms b. the same molecular formula but different covalent arrangements of their carbon skeletons c. different functional groups d. a different molecular formula and the same covalent arrangement of their carbon skeletons
b. the same molecular formula but different covalent arrangements of their carbon skeletons
A molecule has one carbon-carbon double bond and four monovalent atoms or groups. How many different cis-trans isomers exist for this molecule? a. none b. two c. four d. six
b. two
Hydrolysis
breaking down a polymer (water breakage) a process that is essentially the reverse of the dehydration reaction
Which chemical group is most likely to be responsible for an organic molecule behaving as a base? a. Carboxyl b. Phosphate c. Amino d. Hydroxyl
c. Amino
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
c. C₂H₄
Stanley Miller's experiments were significant because he demonstrated that __________. a. the behavior of any molecule containing a carbon atom was fundamentally the same b. lightning discharges could produce the molecules previously presumed to have originated in volcanic outgassings c. a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere d. urea could be synthesized from entirely naturally occurring salts
c. a variety of simple organic compounds could be spontaneously synthesized from components in Earth's primitive atmosphere
In Miller's 1953 laboratory experiment, __________. a. the atmosphere in the experiment contained O₂ b. the experiment was not useful in supporting evolution c. abiotic compounds cycled through the apparatus and were sampled for organic compounds d. organic compounds were added to the seawater and decomposed
c. abiotic compounds cycled through the apparatus and were sampled for organic compounds
Although the structures of the functional groups that are most important to life vary, they share one thing in common: They __________. a. all contain oxygen b. all have at least one double bond c. all help give each biological molecule its unique properties d. force straight chains of carbons into closed rings of carbon
c. all help give each biological molecule its unique properties
Which chemical group is most likely to be responsible for an organic molecule behaving as a base? a. hydroxyl b. carbonyl c. amino d. phosphate
c. amino
When a double bond joins two carbon atoms, __________ can form. a. enantiomers b. chemical groups c. cis-trans isomers d. saturated fats
c. cis-trans isomers
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? a. greatly expanded Miller's earlier findings by uncovering the traces of cell-like entities being formed in the volcano simulation experiments 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. contradicted Miller's earlier experimental results and provided more support for an undefined life force as the way organic molecules are made in nature
c. identified additional organic compounds that had not been found by Miller
The carbon skeleton can vary in all of the following except __________. a. length b. branching c. lacking hydrogen atoms d. presence of rings e. double bond position
c. lacking hydrogen atoms
Organic chemistry is the study of ____________
carbon compounds
Cis-trans isomers
carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds
Functional Groups
chemical groups are directly involved in chemical reactions
Isomers
compounds that have the same numbers of atoms of the same elements but diff. structures & hence diff. properties
Disaccharides (double sugars)
consisting of 2 monosaccharides joined by a covalent bond
Carbon's atomic number is 6. This means that it has __________ electrons. After completing the first energy level, carbon has __________ valence electrons and can form __________ bonds. a. 12; 6; 6 b. 12; 4; 4 c. 4; 4; 4 d. 6; 4; 4
d. 6; 4; 4
Which of the following functional groups increases the solubility of organic compounds in water? a. —COH b. —OH c. —COOH d. All of the listed responses are correct.
d. 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? a. carboxyl group b. hydroxyl group c. amino group d. All of the listed responses are correct.
d. 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.)
Which of the following is found in all amino acids? a. -NH₂ b. -OH c. -COH d. Both -COOH and -NH₂ e. -COOH
d. Both -COOH and -NH₂
What are the six most important chemical elements of life? a. Carbon, nitrogen, oxygen, calcium, phosphate, and hydrogen b. Carbon, nitrogen, sulfur, hydrogen, iron, and magnesium c. Carbon, nitrogen, calcium, zinc, iron, and hydrogen d. Carbon, nitrogen, oxygen, hydrogen, phosphate, and sulfur
d. Carbon, nitrogen, oxygen, hydrogen, phosphate, and sulfur
Which of these is a thiol? a. —SH b. —COH c. —OH d. None of the listed responses is correct.
d. None of the listed responses is correct. (A thiol is a molecule containing a sulfhydryl functional group.)
Which of the following molecules is a weak acid? a. R—SH b. R—OH c. R—NH₂ d. R—COOH
d. R—COOH (The carboxyl group (—COOH) of R—COOH can donate a proton (H⁺).)
Which of the following examples best describes a unique functional property of the carboxyl group? a. Its compounds may be structural isomers with different properties. b. It is polar as a result of the electronegative oxygen atom drawing electrons toward it. 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.
d. The covalent bond between oxygen and hydrogen is so polar that hydrogen ions tend to dissociate from oxygen reversibly.
Which of these is found in all amino acids? a. ⁻COH b. ⁻OH c. ⁻COOH d. both ⁻COOH and ⁻NH₂
d. 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.)
The chemical group that acts as an acid is the __________. a. amine group (-NH₂) b. methyl group (-CH₃) c. phosphate group (-PO₃⁻²) d. carboxyl group (-COOH)
d. carboxyl group (-COOH)
Which of the following are properties of hydrocarbons? a. hydrophilic, containing numerous carboxyl groups, nonpolar b. hydrophobic, polar, charged c. hydrophilic, good source of stored energy, consisting primarily of carbon and hydrogen d. hydrophobic, nonpolar, good source of stored energy
d. 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.)
Which of the following functional groups is associated with a release of energy when removed from the carbon skeleton with water? a. hydroxyl group b. amino group c. sulfhydryl group d. phosphate group
d. phosphate group Cleaving a phosphate group from ATP releases energy that is used to perform many cellular functions.
Structural isomers
differ in covalent arrangements of their atoms
What is a example of hydrolysis?
digestion in our bodies
What are the main component of petroleum?
hydrocarbons
Carbohydrates
include sugars & polymers of sugars
Enantiomers
isomers that mirror images of each other & that differ in shape due to the presence of an asymmetric carbon, one that is attached to 4 diff. atoms or groups of atoms
What is the key to an atom's characteristics?
its electron configuration
What is a hydrocabron?
organic molecules consisting of only carbon & hydrogen
Carbohydrate molecules are _______, composed of ___________.
polymers called polysaccharides; many sugar building blocks
Macromolecules are _________, built from _________.
polymers; monomers
Monomer
repeating units that serve as the building blocks of a polymer (form polymers)
What can single bonds do that double bonds cannot?
rotate freely about the bond axis w/out changing the compound
A fat molecule consists of _____________
small, non-hydrocarbon component joined to 3 hydrocarbon tails that account for the hydrophobic behavior of fats. The tails can be broken down to provide energy.
Enzymes
specialized macromolecules that speed up chemical reactions
Dehydration Reaction
synthesizing a polymer (making) a reaction in which 2 molecules are covalently bonded to each other w the loss of a water molecule
What is generally equal to an atom's valence?
the # of unpaired electrons in the valence shell of an atom
Carbon
the backbone of life
What does an atom's electron configuration determine?
the kinds and numbers of bonds an atom will form with other atoms
How does carbon enter the biosphere?
through the actions of producers - plants, etc. that use solar energy to transform CO₂ into the carbon-based molecules of life
What is an example of a cis-trans isomer?
trans-fats
