AP Bio Unit 2 Test Prep | BHS
water repelling. Example: lipids, oils which are ___________________.
Hydrophobic
These have an excess of OH- Ions and a pH above 7.
Bases
At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acids?
Between Carbon and Nitrogen
Bacteriophages are viruses that infect bacteria. In an experiment, bacteriophages were labeled with either radioactive phosphorus or radioactive sulfur. The labeled bacteriophages were incubated with bacteria for a brief amount of time and then removed. The infected bacteria cells were found to contain significant amounts of radioactive phosphorus but not radioactive sulfur. Based on the results of the experiment, which of the following types of molecules did the bacteriophages most likely inject into the bacteria cells?
DNA
Which of the following statements best summarizes the differences between DNA and RNA?
DNA nucleotides contain a different sugar than RNA nucleotides.
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
10
The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used once, more than once, or not at all. Which of the following molecules is the pentose sugar found in RNA?
12
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
20^12
How many electron pairs does carbon share in order to complete its valence shell?
4
The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used once, more than once, or not at all. Which molecule has both hydrophilic and hydrophobic properties and would be found in plasma membranes?
5
The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used once, more than once, or not at all. Which of the following molecules consists of a hydrophilic "head" region and a hydrophobic "tail" region?
5
The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used once, more than once, or not at all. Which molecule is a saturated fatty acid?
9
If nine molecules of a monosaccharide with the formula C6H12O6 are assembled to produce a complex carbohydrate, how many atoms of hydrogen will be in the final polymer?
92
Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
99
DNA and RNA are nucleic acids that can store biological information based on the sequence of their nucleotide monomers. Figure 1 shows a short segment of each of the two types of nucleic acids. Which of the following best describes a structural difference between DNA and RNA?
A DNA molecule is composed of two parallel strands with the same 5′ to 3′ directionality, whereas an RNA molecule is composed of only one 5′ to 3′ strand.
The partial negative charge at one end of a water molecule is attracted to a partial positive charge of another water molecule. What is this type of attraction called?
A hydrogen bond
Which of the following effects is produced by the high surface tension of water?
A water strider can walk across the surface of a small pond.
Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules?
Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules.
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
The hydrogenated vegetable oil stays solid at room temperature.
Water is an excellent solvent. Select the property that justifies this statement
As a polar molecule, it can surround and dissolve ionic and polar molecules
Which of the following best describes the structures of carbohydrates?
They occur as monomers, chains of monomers, and branched structures.
Which of the following statements best describes the carbon atoms present in a seed-eating bird?
They were incorporated into organic molecules by plants, they were processed into sugars through photosynthesis, and they are ultimately derived from carbon dioxide.
The linking of like molecules. Example: Water molecules use hydrogen bonds to connect with other water molecules. This creates the surface tension. Think drinking straw.
cohesion
Polymers of carbohydrates and proteins are all synthesized from monomers by which of the following processes?
dehydration reactions
What is the chemical reaction mechanism by which cells make polymers from monomers?
dehydration synthesis reactions
Amino acids are acids because they always possess which functional group?
carboxyl
These have an excess of H+ ions and a pH below 7.
Acids
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
C18H32O16
If three molecules of a fatty acid that has the formula of C16H22O2 are joined to a molecule of glycerol (C3H8O3), then the resulting molecule would have the formula
C51H68O6
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
C60H102O51
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
water-soluble. Examples: solutions which dissolve in water. Example: many salts, sugars, polar molecules, some proteins.
Hydrophilic
Which of the following is most directly responsible for water's unique properties?
It forms hydrogen bonds.
The (cystic fibrosis transmembrane conductance regulator) protein is made up of amino acids linked together in a chain. Some humans produce a version of the CFTR protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. Which of the following best predicts how the amino acid deletion will affect the structure of the CFTR protein?
It will affect the primary, secondary, and tertiary structures of the CFTR protein.
You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.
NaCl crystals will dissolve readily in water but will not dissolve in methanol.
The molecular structures of linoleic acid and palmitic acid, two naturally occurring substances, are shown in the figure. Based on the molecular structures shown in the figure, which molecule is likely to be solid at room temperature?
Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.
The substance being dissolved
Solute
The solvent mixed with the solute
Solution
is the amount of heat required to raise or lower the temperature of a substance by 1oC.
Specific Heat
Enzymes are characterized as this type of protein?
Tertiary (globular) Structure
Why are hydrocarbons insoluble in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
Which of the following best describes how amino acids affect the tertiary structure of a protein?
The interactions of the different R -groups with other R -groups and with their environment determine the tertiary structure of the protein.
Why does evaporation of water from a surface cause cooling of the surface?
The water molecules with the most heat energy evaporate more readily.
Which of the following statements is true for the class of biological molecules known as lipids?
They are insoluble in water.
Which of the following is true regarding saturated fatty acids?
They are the principal molecules in lard and butter.
Which of the following statements concerning saturated fats is not true?
They have multiple double bonds in the carbon chains of their fatty acids.
The movement of water molecules up the very tiny xylem tubes and their evaporation from the stomata in plants.
Transpiration
The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?
Water
A feature of organic compounds NOT found in inorganic compounds is the presence of
carbon atoms covalently bonded to each other
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
a hydrogen bond
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a pentose sugar
Liquid water's high specific heat is mainly a consequence of the
absorption and release of heat when hydrogen bonds break and form.
The clinging of one substance to another _____________________. Example: Water attached to a car windshield. Water climbs up paper tower or cloth.
adhesion
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
as a disaccharide
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. It will be more solid at room temperature.
Buffers are substances that help resist shifts in pH by
both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
An organic compound that is composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio is known as a
carbohydrate
A molecule with the chemical formula C6H12O6 is probably a
carbohydrate and monosaccharide only.
The element present in all organic molecules is
carbon
Because of the unique properties of water associated with hydrogen bonding, water evaporates from pores on the leaves of plants and draws up water molecules in a continuous chains from the roots up through the vascular tissues of plants. Which of the these groups of terms describes the process and properties of water that explain this?
cohesion, adhesion, and transpiration
What is the structural feature that allows DNA to replicate?
complementary pairing of the nitrogenous bases
Water molecules are able to form hydrogen bonds with
compounds that have polar covalent bonds.
A carbon atom is most likely to form what kind of bond(s) with other atoms?
covalent
A molecule with the formula C18H36O2 is probably a
fatty acid
Which of the following is not a polymer?
glucose
Which type of bond must be broken for water to vaporize?
hydrogen bonds
Which type of interaction stabilizes the a helix and the b pleated sheet structures of proteins?
hydrogen bonds
The bonds that are broken when water vaporizes are
hydrogen bonds between water molecules.
The process by which large proteins are broken down into monomers
hydrolysis
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
ionic bonds.
All of the following are polysaccharides except
lactose
Hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules.
Which bonds are created during the formation of the primary structure of a protein?
peptide bonds
The plasma membrane is composed of several different macromolecules. Which macromolecule serves as the fluid interface between the intracellular and extracellular environments?
phospholipids
Which of the macromolecules below could be structural parts of the cell, enzymes, or involved in cell movement or communication
proteins
Which level of protein structure do the a helix and the b pleated sheet represent?
secondary
What aspects of protein structure are stabilized or assisted by hydrogen bonds?
secondary, tertiary, and quaternary structures, but not primary structure
The substance something is dissolved in
solvent
Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
the absorption of heat by the breaking of hydrogen bonds
The complexity and variety of organic molecules is due to
the chemical versatility of carbon atoms.
Hydrolysis is involved in which of the following?
the digestion of sucrose, a disaccaride to its monomers of glucose and fructose
The partial negative charge in a molecule of water occurs because
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
The bonding of two amino acid molecules to form a larger molecule requires
the release of a water molecule.
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
the release of heat by the formation of hydrogen bonds
The tremendous variation and unique properties of proteins are most likely a result of
the sequence of amino acids in the primary structure of the protein
If a solution has a pH of 7, this means that
this is a solution of pure water
The tertiary structure of a protein is the
unique three-dimensional shape of the fully folded polypeptide