Ap bio Unit one Mcq
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?
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.
Which of the following best depicts the tertiary structures of the two proteins in water? The diagrams in the options are not drawn to the same scale as those in Figure 1 and Figure 2.
Answer A (the protein would fold so that the hydrophobic portions would be toward the center of the tertiary structure both look pretty bunched together)
Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water () from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups and ). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups and ). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups and ). After exposing the samples to light or dark for one hour, the students recorded the of the water in each beaker. Carbon dioxide dissolved in water will lower the of an aqueous solution. In the experim
B (it's a bar graph)
Students conducted a controlled experiment to investigate whether sawdust provides enough nutrients to support plant growth. The students separated ten nearly identical sunflower seedlings into two groups. They grew the seedlings in the first group in potting soil and the seedlings in the second group in sawdust composed mostly of cellulose. After twenty days, the students recorded observations about the seedlings in each group. The students' observations are presented in the table The observed differences between the groups most likely resulted from differences in the ability of the seedlings to produce which of the following monomers?
C (the answer is literally a photo I can't put on it sorry)
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?
Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact with water inside and outside of the cell.
Which of the following types of bonds is most likely responsible for the unusual base pairing shown in Figure 3 that results in the formation of a triplex DNA structure?
Hydrogen
Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. 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?
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.
Polypeptides are continuously being formed and degraded. One of these processes is shown. Which statement is the most accurate description of the reaction shown in Figure 1?
It represents a polypeptide chain that is broken down through a hydrolysis reaction.
The CFTR protein is made up of 1,480 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 protein.
Figure 1. An amino acid 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?
Methyl (CH3) group
Based on Figure 1, the amino acids in region are most likely to have which of the following characteristics?
Most amino acids will be hydrophobic because they interact most favorably with the phospholipid tails.
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?
Nitrogen will be incorporated into nucleic acids.
Scientists examined the folded structure of a purified protein resuspended in water and found that amino acids with nonpolar R groups were primarily buried in the middle of the protein, whereas amino acids with polar R groups were primarily on the surface of the protein. Which of the following best explains the location of the amino acids in the folded protein?
Nonpolar R groups that cannot form hydrogen bonds with water are pushed into the middle of the protein.
Which of the following conclusions is most clearly supported by the representations of nucleic acid #1 and nucleic acid #2 ?
Nucleic acid #1 contains adenine-thymine base pairs, whereas nucleic acid #2 does not.
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 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?
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.
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 ?
The backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose.
The carbohydrates glucose, galactose, and fructose have the same chemical formula but different structural formulas, as represented in the figure. Which of the following statements about glucose, galactose, and fructose is most likely true?
The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.
Figure 1 represents a common process that occurs in organisms. Which of the following is an accurate description of the process shown in Figure 1 ?
The formation of a covalent peptide bond in a dehydration synthesis reaction
Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?
The identity of each nitrogenous base
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?
The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge.
A mutation in the gene coding for a single-polypeptide enzyme results in the substitution of the amino acid serine, which has a polar R group, by the amino acid phenylalanine, which has a nonpolar R group. When researchers test the catalysis of the normal enzyme and the mutated enzyme, they find that the mutated enzyme has much lower activity than the normal enzyme does.
The substitution altered the secondary and tertiary structure of the enzyme so that the mutated enzyme folds into a different shape than the normal enzyme does.
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?
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.
