ap bio unit 1

If 30%30% of the nucleotides in a single-stranded RNA molecule are adenine, then what percent are expected to be thymine? A 0% B 20% C 30% D 70%

0%

Which of the following best describes the formation of the bond shown in Figure 1 ? A An ionic bond is formed between a carbon atom of one amino acid and the nitrogen atom of the other amino acid. B An ionic bond is formed when the negative charge of an OHOH group is balanced by the positive charge of a hydrogen ion. C A covalent bond is formed between a carbon atom and a nitrogen atom along with the formation of H2OH2O . D A covalent bond is formed that replaces the hydrogen bond between the OHOH group and the HH atom.

A covalent bond is formed between a carbon atom and a nitrogen atom along with the formation of H2OH2O .

Amylase is an enzyme that converts carbohydrate polymers into monomers. Glycogen synthase is one of the enzymes involved in converting carbohydrate monomers into polymers. Which of the following best explains the reactions of these enzymes? A Amylase aids in the removal of a water molecule to break covalent bonds whereas glycogen synthase aids in the addition of a water molecule to form covalent bonds. B Amylase aids in the addition of a water molecule to break covalent bonds whereas glycogen synthase aids in the removal of a water molecule to form covalent bonds. C Amylase aids in the addition of a water molecule to form covalent bonds whereas glycogen synthase aids in the removal of a water molecule to break covalent bonds. D Amylase aids in the removal of a water molecule to form covalent bonds whereas glycogen synthase aids in the addition of a water molecule to break covalent bonds.

Amylase aids in the addition of a water molecule to break covalent bonds whereas glycogen synthase aids in the removal of a water molecule to form covalent bonds.

The amino acid in Figure 1 is found in a region of a polypeptide that folds away from water. Which part of the amino acid most likely contributes to the hydrophobic behavior of this region of the polypeptide? A Amine (NH2NH2) group B Carboxyl (COOHCOOH) group C Methyl (CH3CH3) group D Hydrogen (HH) atom

C Methyl (CH3CH3) group

Which of the following best explains why a cell's plasma membrane is composed of two layers of phospholipids rather than just a single layer? A Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact with water inside and outside of the cell. B Having two oppositely oriented layers of phospholipids allows the hydrophilic heads to repel water both inside and outside of the cells. C Having two identically oriented layers of phospholipids gives cells more protection from the exterior environment than just a single layer would. D Having two identically oriented layers of phospholipids allows for the production of vacuoles while still maintaining a protective barrier.

Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact with water inside and outside of the cell.

Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. Figure 1. Alignment of water molecules at air-water interface Based on Figure 1, which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface? A Covalent bonds between water molecules and the air above provide cohesion, which causes tiny bubbles to form under the feet of the insect. B Ionic bonds between molecules at the surface of the water provide an electric charge, which attracts the feet of the insect, keeping it on the surface. C Polar covalent bonds between molecules at the surface of the water provide adhesion, which supports the weight of the insect. D Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.

Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.

Which of the following is responsible for the cohesive property of water? A Hydrogen bonds between the oxygen atoms of two adjacent water molecules B Covalent bonds between the hydrogen atoms of two adjacent water molecules C Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule D Covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule E Hydrogen bonds between water molecules and other types of molecules

Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule

Which of the following is most directly responsible for water's unique properties? A It contains oxygen atoms. B It contains hydrogen atoms. C It is an ionic compound. D It forms hydrogen bonds. E It is nonpolar.

It forms hydrogen bonds.

Polypeptides are continuously being formed and degraded. One of these processes is shown. Figure 1. Polypeptide reaction Which statement is the most accurate description of the reaction shown in Figure 1? A It represents monomers linked by dehydration synthesis. B It represents a polypeptide chain that folds to form the tertiary structure. C It represents a polypeptide chain that is denatured into the primary structure. D It represents a polypeptide chain that is broken down through a hydrolysis reaction.

It represents a polypeptide chain that is broken down through a hydrolysis reaction.

The CFTRCFTR protein is made up of 1,4801,480 amino acids linked together in a chain. Some humans produce a version of the CFTRCFTR 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 CFTRCFTR protein? A It will have no observable effect on the structure of the CFTRCFTR protein. B It will affect the primary structure of the CFTRCFTR protein, but the other levels of protein structure will not be affected. C It will affect the secondary and tertiary structures of the CFTRCFTR protein, but the primary structure will not be affected. D It will affect the primary, secondary, and tertiary structures of the CFTRCFTR protein.

It will affect the primary, secondary, and tertiary structures of the CFTRCFTR protein.

A typical bag of fertilizer contains high levels of nitrogen, phosphorus, and potassium but trace amounts of magnesium and calcium. Which of the following best matches the fertilizer component with the molecule in which it will be incorporated by organisms in the area? A Nitrogen will be incorporated into nucleic acids. B Phosphorus will be incorporated into amino acids. C Potassium will be incorporated into lipids. D Magnesium will be incorporated into carbohydrates.

Nitrogen will be incorporated into nucleic acids.

Which of the following conclusions is most clearly supported by the representations of nucleic acid #1#1 and nucleic acid #2#2 ? A Nucleic acid #1#1 contains only purines, whereas nucleic acid #2#2 contains only pyrimidines. B Nucleic acid #1#1 contains the sugar ribose, whereas nucleic acid #2#2 contains the sugar deoxyribose. C Nucleic acid #1#1 contains positively charged phosphate groups, whereas nucleic acid #2#2 does not. D Nucleic acid #1#1 contains adenine-thymine base pairs, whereas nucleic acid #2#2 does not.

Nucleic acid #1 contains adenine-thymine base pairs, whereas nucleic acid #2#2 does not.

Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules? A Rabbits eat plants and use energy absorbed from the plants to make carbon atoms from electrons, protons, and neutrons in the air. B Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules. C Rabbits eat plants and use water absorbed from the plants to hydrolyze CO2CO2, which the rabbits breathe in from the air and use as a carbon source. D Rabbits eat plants and make carbon-containing molecules by using carbon atoms that the plants absorbed from the soil and stored in the cells of their leaves.

Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules.

A student analyzed a viral genome and found that the genome had the following nucleotide composition. • 28% adenine • 20% thymine • 35% cytosine • 17% guanine Which of the following best describes the structure of the viral genome? A Double-stranded DNA B Single-stranded DNA C Double-stranded RNA D Single-stranded RNA

Single-stranded DNA

Which of the following best describes the hydrolysis of carbohydrates? A The removal of a water molecule breaks a covalent bond between sugar monomers. B The removal of a water molecule forms a covalent bond between sugar monomers. C The addition of a water molecule breaks a covalent bond between sugar monomers. D The addition of a water molecule forms a covalent bond between sugar monomers.

The addition of a water molecule breaks a covalent bond between sugar monomers.

The figure shows a model of the exchange of matter between the organisms that live together in an aquarium. The model includes matter exchange between plants, fish, and bacteria. The bacteria are represented as rod-shaped organisms living in the gravel at the bottom of the aquarium. Which of the following statements best describes how molecules released by the fish become nutrients for the plants? A The carbon dioxide molecules released by the fish are converted by the bacteria to oxygen atoms, which are used by the plants to make water molecules. B The oxygen molecules released by the fish are converted by the bacteria to ammonia molecules, which are used by the plants to make lipids and fatty acids. C The nitrites released by the fish are converted by the bacteria to carbon dioxide molecules, which are used by the plants to make carbohydrates. D The ammonia molecules released by the fish are converted by the bacteria to nitrates, which are used by the plants to make proteins and nucleic acids.

The ammonia molecules released by the fish are converted by the bacteria to nitrates, which are used by the plants to make proteins and nucleic acids.

DNADNA and RNARNA 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 DNADNA and RNARNA? A DNADNA contains four types of nitrogenous bases, whereas RNARNA contains only two types of nitrogenous bases. B The backbone of DNADNA contains deoxyribose, whereas the backbone of RNARNA contains ribose. C A DNADNA molecule is composed of two parallel strands with the same 5′5′ to 3′3′ directionality, whereas an RNARNA molecule is composed of only one 5′5′ to 3′3′ strand. D Phosphate groups provide rigidity to DNADNA, but RNARNA is flexible and contains no phosphate groups.

The backbone of DNADNA contains deoxyribose, whereas the backbone of RNARNA contains ribose.

The carbohydrates glucose, galactose, and fructose have the same chemical formula (C6H12O6)(C6H12O6) but different structural formulas, as represented in the figure. Which of the following statements about glucose, galactose, and fructose is most likely true? A The carbohydrates have the same properties because they have the same number of carbon, hydrogen, and oxygen atoms. B The carbohydrates have the same properties because they each have a single carbon-oxygen double bond. C The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms. D The carbohydrates have different properties because they have different numbers of carbon-carbon bonds.

The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.

Which of the following best describes the effect of a greater number of cysteine amino acids on the stability of the proteins? A The change has no effect on the stability of the protein because only one type of amino acid is involved. B The change leads to increased protein stability because of an increased number of S-SS-S bonds in the tertiary structure of the proteins. C The change leads to decreased protein stability because of an increased number of S-SS-S bonds in the tertiary structure of the proteins. D The change leads to increased protein stability only when the added cysteine amino acids are next to other cysteine amino acids in the primary structure.

The change leads to increased protein stability because of an increased number of S-SS-S bonds in the tertiary structure of the proteins.

Which of the following is an accurate description of the process shown in Figure 1 ? A The linking of amino acids with an ionic bond as an initial step in the protein synthesis process B The formation of a more complex carbohydrate with the covalent bonding of two simple sugars C The hydrolysis of amino acids with the breaking of covalent bonds with the release of water D The formation of a covalent peptide bond in a dehydration synthesis reactionThe formation of a covalent peptide bond in a dehydration synthesis reaction

The formation of a covalent peptide bond in a dehydration synthesis reaction

Humans produce sweat as a cooling mechanism to maintain a stable internal temperature. Which of the following best explains how the properties of water contribute to this physiological process? A The high specific heat capacity of water allows the body to absorb a large amount of excess heat energy. B The high heat of vaporization of water allows the body to remove excess heat through a phase change of water from liquid to gas. C The high surface tension of water contributes to the physical process by which water leaves the body. D The high melting temperature of water allows the body to remove excess heat through a phase change of water from solid to liquid.

The high heat of vaporization of water allows the body to remove excess heat through a phase change of water from liquid to gas.

Which of the following best describes how amino acids affect the tertiary structure of a protein? A The number of amino acids determines the tertiary structure of the protein. B The interactions of the different RR-groups with other RR-groups and with their environment determine the tertiary structure of the protein. C The RR-group of the last amino acid that is added to a growing polypeptide chain determines the next amino acid that is added to the chain. D The sequence of the amino acids in the polypeptide chain determines the protein's primary structure but has no effect on its tertiary structure.

The interactions of the different RR-groups with other RR-groups and with their environment determine the tertiary structure of the protein.

Water and ammonia interact to form hydrogen bonds, as represented in the figure. Which statement best helps explain the formation of the hydrogen bond represented in the figure? A The oxygen has a partial positive charge, and the nitrogen has a partial negative charge. B The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge. C The hydrogen attached to the oxygen has a partial negative charge, and the nitrogen also has a partial negative charge. D The nitrogen has a partial positive charge, and the hydrogen attached to the oxygen also has a partial positive charge.

The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge.

Which of the following best describes the structures of carbohydrates? A They only occur as disaccharides. B They occur as monomers, chains of monomers, and branched structures. C They only occur as long and branched structures. D They occur as chains of monomers that hydrogen bond with complementary chains of monomers.

They occur as monomers, chains of monomers, and branched structures.

Ultraviolet (UVUV) radiation can damage DNADNA by breaking weak bonds. Which of the following best explains how this occurs? A UVUV radiation disrupts the double helix structure by breaking the covalent bonds between the nitrogenous base pairs. B UVUV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs. C UVUV radiation is able to break DNADNA strands in two by breaking covalent bonds between the sugar-phosphate backbone molecules. D UVUV radiation is able to break DNADNA strands in two by breaking hydrogen bonds between the sugar-phosphate backbone molecules.

UVUV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs.

The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct? A ATP B Oxygen C Carbon dioxide D Urea E Water

Water

The diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. Which of the following best explains how water is able to move upward from the roots of a plant, through its xylem in the stem, and out to the leaves? A Water is polar, and the walls of the xylem are nonpolar. Water molecules have the ability to form hydrogen bonds with one another but not with the xylem walls. B Water is nonpolar, and the walls of the xylem are polar. Water molecules are able to form hydrogen bonds with the xylem walls, and they are pulled up the xylem. C Water and the xylem are both nonpolar. Water molecules have the ability to form hydrogen bonds with one another but not with the xylem walls. D Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem.

Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem.

A feature of organic compounds NOT found in inorganic compounds is the presence of A ionizing chemical groups B electrons C carbon atoms covalently bonded to each other D oxygen E hydrogen bonds

carbon atoms covalently bonded to each other