AP Biology Unit 1 & 2 Finals Study Guide

A. Bile salts decrease the surface tension of the urine sample.

A common test for liver function involves sprinkling sulfur powder onto a sample of urine (mostly water with dissolved bodily waste). Sulfur powder sprinkled on a sample from an individual with impaired liver function will sink because the urine contains a high level of bile salts, while the sulfur powder sprinkled on normal urine samples will float. Which of the following best explains why bile salts cause the sulfur powder to sink? A. Bile salts decrease the surface tension of the urine sample. B. Bile salts increase the water potential of the urine. C. Bile salts decrease the density of the urine sample. D. Bile salts decrease the strength of the covalent bonds within a water molecule.

C. View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells.

A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). This type of solution is often used intravenously to quickly rehydrate patients. A drop of the blood from the test tube was placed on a slide and red blood cells (RBCs) were observed under a microscope. Three possible outcomes are diagrammed below: View 1 shows shrunken RBCs, View 2 shows normal RBCs, and View 3 shows swollen and bursting RBCs Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why? A. View 1 because RBC membranes are freely permeable to water. B. View 2 because RBC's use energy to allow sodium entry and to pump water out. C. View 2 because the rate of water movement into the RBC's equals the rate of water movement out of the cells. D. View 3 because the sodium potassium pumps in RBC membranes use energy to keep the sodium out but allow water to freely flow into the cells.

D. The bacterial cell, because it has the largest surface-to-volume ratio.

A spherical bacterial cell has a radius of 3μm. The human egg cell has a radius of 100μm. Which statement correctly indicates the cell that is able to more efficiently exchange materials with the external environment and provides a correct explanation? A. The egg cell, because it has the smallest surface-to-volume ratio. B. The egg cell, because it has the largest surface-to-volume ratio. C. The bacterial cell, because it has the smallest surface-to-volume ratio. D. The bacterial cell, because it has the largest surface-to-volume ratio.

A. Enzymatic modification of newly synthesized integral membrane proteins

All eukaryotic cells contain at least one Golgi complex, typically located in the cytoplasm and near the endoplasmic reticulum. Which of the following best describes a process that occurs within the Golgi complex? A. Enzymatic modification of newly synthesized integral membrane proteins B. Synthesis of cytosolic proteins based on the nucleotide sequences of mRNAs C. Degradation of proteins by hydrolytic enzymes contained within the complex D. synthesis of various types of lipids

D. Rough ER can synthesize and package proteins for export, and smooth ER cannot.

Cells contain smaller components called organelles that are necessary for a cell's survival. Organelle functions have often been compared to components of larger systems. Which of the following functional differences between the rough and smooth endoplasmic reticulum (ER) is explained by the structural differences between them? A. Rough ER breaks down toxic substances, and smooth ER only transports them out of the cell. B. Rough ER can synthesize and package lipids for export, and smooth ER cannot. C. Rough ER can produce ATP, and smooth ER cannot. D. Rough ER can synthesize and package proteins for export, and smooth ER cannot.

D. The ratio decreases as the cube becomes larger.

How does the surface area-to-volume ratio of a 1 mm cube compare to the surface area-to-volume ratio of a 3 mm cube? A. The 3 mm cube has a higher ratio. B. The ratio increases as the cube becomes larger. C. Increasing the volume increases the ratio. D. The ratio decreases as the cube becomes larger.

C. passage of a solute against its concentration gradient

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited? A. movement of oxygen into a cell B. movement of water through aquaporins C. passage of a solute against its concentration gradient D. facilitated diffusion of a permeable substance

B. They have highly folded membranes.

Organelles such as mitochondria and the endoplasmic reticulum have membranes that compartmentalize reactions and other metabolic processes. To function properly, the organelles must move substances across their membranes. Which of the following statements describes a feature shared by mitochondria and the endoplasmic reticulum that increases the efficiency of their basic functions? A. They have rigid, nonfluid, membranes. B. They have highly folded membranes. C. They have membranes composed of many carbohydrates. D. They have double membranes, with one membrane enclosed within the other.

C. The organelle has a double membrane.

Researchers claimed that a particular organelle originated from a free-living prokaryotic cell that was engulfed by a larger cell. Which of the following provides evidence to best support the researchers' claim? A. The organelle has a phospholipid membrane. B. The organelle has a protein in the membrane. C. The organelle has a double membrane. D. The organelle has an internal aqueous environment that is similar to the cytosol of the larger cell.

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.

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.

A. facilitated diffusion

When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as _____ A. facilitated diffusion B. osmosis C. active transport D. pinocytosis

B. phospholipids

When planting crops, farmers rotate the types of plants that are planted for harvest in order to prevent the soil from being leached of essential minerals. If a farmer plants a crop that leaches the soil of phosphorus, which of the following biomolecules will subsequent plants be unable to synthesize? A. cellulose B. phospholipids C. proteins D. fatty acids

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.

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.

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

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.

A. 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 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.

B. protein

Which of the following components of the cell membrane is responsible for active transport? A. phospholipid B. protein C. lipid D. phosphate

C. triglyceride/cellulose

Which of the following does NOT represent a correct monomer/polymer pairing? A. monosaccharide/ polysaccharide B. amino acid/protein C. triglyceride/ celluose D. nucleotide/nucleic acid

D. It forms hydrogen bonds.

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.

A. Hydrogen bonds between the oxygen atoms of two adjacent water molecules

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. Covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule D. Hydrogen bonds between water molecules and other types of molecules

B. Water molecules will still be able to move across the cell membrane but at a slower rate.

Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function? A. Water molecules will no longer be able to move across the cell membrane. B. Water molecules will still be able to move across the cell membrane but at a slower rate. C. Water molecules will only be able to enter the cell by active transport. D. Water molecules will move across the cell membrane but at a faster rate without the aquaporin regulating the flow.