Test Bio Unit 3 PDF
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This document contains a collection of biology questions with answers, covering topics like protein functions, the roles of the nucleus, active transport, the structure of cells, and more.
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. Which of the following protein functions is NOT correctly associated with its correct integral 1 protein? A. carrier proteins - passage of molecules through the membrane B. enzymatic proteins - carry out metabolic reactions directly C. channel proteins - block the activity of carrie...
. Which of the following protein functions is NOT correctly associated with its correct integral 1 protein? A. carrier proteins - passage of molecules through the membrane B. enzymatic proteins - carry out metabolic reactions directly C. channel proteins - block the activity of carrier proteins D. cell recognition proteins - recognize pathogens E. receptor proteins - bind to signal molecules Answer: C Explanation: Channel proteins provide a passage for molecules, not block carrier proteins. . The nucleus is NOT important as the site of 2 A. DNA synthesis. B. RNA synthesis. C. synthesis of ribosomal subunits. D. protein synthesis E. All of these take place in the nucleus Answer: D Explanation: Protein synthesis occurs outside the nucleus in the cytoplasm, specifically on ribosomes. . Which is the BEST definition of active transport? 3 A. movement of molecules from an area of their higher concentration to an area of their lower concentration B. movement of water across a semipermeable membrane from an area of high water concentration to an area of lower water concentration C. movement of molecules from an area of their lower concentration to an area of their higher concentration D. movement of water across a semipermeable membrane from an area of low water concentration to an area of higher water concentration E. movement of a substance against its concentration through the release of energy from ATP Answer: E Explanation: Active transport involves moving substances against their concentration gradient using energy from ATP. . Pinocytosis is an example of 4 A. facilitated transport. B. active transport. C. cotransport. D. endocytosis. E. exocytosis. Answer: D Explanation: Pinocytosis is a type of endocytosis where the cell engulfs fluids. . Red blood cells come in many "blood types" including type A, type B, type AB, type O 5 (lacking proteins A and B), Rh positive, and Rh negative (lacking Rh factor) and many others. If blood is transfused, the recipient detects any new or "foreign" proteins. These blood type proteins are A. in the plasma where they have been secreted by the red blood cells. B. inside the red blood cell cytoplasm. C. on the outer surface of the red blood cell membrane. D. evenly distributed throughout the cell contents and plasma. E. in the red blood cell nucleus. Answer: C Explanation: Blood type proteins (antigens) are located on the outer surface of red blood cells. . Which of the following is NOT associated with animal cells? 6 A. an extracellular matrix B. plasmodesmata C. gap junctions D. adhesion junctions (desmosomes) E. tight junctions Answer: B Explanation: Plasmodesmata are channels between plant cells, not animal cells. . Which is NOT a reason for the small size of cells? 7 A. As the linear dimensions of a cell increase, the volume increases twice as fast as the surface area. B. Nutrients and wastes must enter and leave the cell through the plasma membrane. C. The nucleus can only control a certain amount of cytoplasm. D. The increased number of organelles requires that eukaryotic cells be smaller than prokaryotic cells. E. Materials must be able to move quickly and efficiently through the cytoplasm. Answer: D Explanation: Eukaryotic cells can be larger than prokaryotic cells due to their compartmentalized organelles. . Whether a molecule can cross the plasma membrane depends upon 8 A. the size of the molecule. B. the shape of the molecule. C. the chemical properties of the molecule. D. the charge of the molecule. E. All of the choices are correct. Answer: E Explanation: All these factors influence whether a molecule can pass through the plasma membrane. . If a living plant were moved from a freshwater aquarium to a saltwater aquarium, which of the 9 following would occur? A. Nothing. The plant would be fine in either. B. The plant's cells would take on ions. C. The plant's cells would take on water. D. The plant's cells will lose water. E. The plant's cells will lose sodium. Answer: D Explanation: The plant's cells would lose water in the saltwater aquarium due to osmosis (water moving out of the cell). 0. The major functions of the plasma membrane do NOT include 1 A. separation of the fluid environments inside and outside the cell. B. regulation of molecules and ions that pass into and out of the cell. C. recognition and communication between different cells and tissues. D. maintaining connections between adjacent cells. E. production of proteins used in construction of the cell wall. Answer: E Explanation: The plasma membrane does not produce proteins for the cell wall; this is done by the ribosomes and Golgi apparatus. 1. After being formed by the ribosomes located on the endoplasmic reticulum, what is the next 1 organelle to which a protein could be transported? A. mitochondria B. smooth endoplasmic reticulum C. Golgi apparatus D. nucleus E. chloroplast Answer: C Explanation: Proteins synthesized by ribosomes on the rough ER are transported to the Golgi apparatus for further processing and sorting. 2. In plants, _____ is a shrinking of the cytoplasm due to osmosis. 1 A. Plasmolysis B. Endocytosis C. Crenation D. Diffusion E. Turgor Answer: A Explanation: Plasmolysis is the process where plant cells lose water in a hypertonic solution, causing the cytoplasm to shrink away from the cell wall. 3. Which is NOT true about the cell theory? 1 A. Its various parts were described by Schleiden, Schwann, and Virchow. B. It states that all organisms are composed of cells. C. It states that all cells come from preexisting cells. D. It states that bacteria and other small organisms can arise spontaneously. E. It is accepted today by biologists as applying to virtually all forms of life. Answer: D Explanation: The cell theory does not support spontaneous generation; it asserts that cells come from preexisting cells. 4. The organelle of the endomembrane system associated with the sorting of lipids and 1 proteins for various cellular functions is A. rough endoplasmic reticulum. B. lysosomes. C. vesicles. D. Golgi apparatus. E. None of these Answer: D Explanation: The Golgi apparatus is responsible for modifying, sorting, and packaging lipids and proteins. 5. A eukaryotic organelle that can easily be seen with the light microscope is the 1 A. endoplasmic reticulum. B. nucleus. C. ribosome. D. polyribosome. E. microtubule. Answer: B Explanation: The nucleus is large enough to be seen with a light microscope, unlike smaller organelles such as ribosomes. 6. The cells that line our respiratory tract, and one-celled paramecia both have these short 1 hair-like projections. A. flagella B. microfilaments C. centrioles D. cilia E. pili Answer: D Explanation: Cilia are short, hair-like projections that help move substances over cell surfaces or aid in locomotion. 17. Freshwater protozoans react to a/an _____ environment by removing water through _____ . hypertonic, turgor pressure A B. hypotonic, turgor pressure C. isotonic, a contractile vacuole D. hypertonic, a contractile vacuole E. hypotonic, a contractile vacuole Answer: E Explanation: Freshwater protozoans in a hypotonic environment use a contractile vacuole to expel excess water. 8. Active transport 1 A. requires an input of ATP. B. is involved in diffusion. C. occurs in osmosis and facilitated transport. D. is needed for water to move through cell membranes. E. All of these are true Answer: A Explanation: Active transport requires energy (ATP) to move substances against their concentration gradient. 9. Which of the following is the reason plants wilt on a hot summer day? 1 A. loss of water B. lack of turgor pressure C. heat weakens the plant cell walls D. both loss of water and therefore lack of turgor pressure E. reduced photosynthetic activity Answer: D Explanation: Plants wilt due to the loss of water, which results in reduced turgor pressure. 0. Large membranous sacs that are more prevalent in plant cells and some protozoa than in 2 animal cells are called A. vacuoles. B. vesicles. C. glyoxisomes. D. lysosomes. E. peroxisomes. Answer: A Explanation: Vacuoles are large storage sacs found predominantly in plant cells and some protozoa. 1. Which of the following organelles would only be found within a cell that was both eukaryotic 2 and autotrophic? A. mitochondria B. ribosomes C. rough endoplasmic reticulum D. chloroplast E. vesicle Answer: D Explanation: Chloroplasts are found in autotrophic eukaryotic cells, where they perform photosynthesis. 2. Which of the following are involved with the movement or transport of materials or 2 organelles throughout the cell? A. rough endoplasmic reticulum B. cytoskeleton C. smooth endoplasmic reticulum D. vesicles E. all of the choices are true Answer: E Explanation: All of these structures (RER, cytoskeleton, SER, vesicles) play a role in transporting materials within the cell. 3. Which statement is NOT true about the proteins in the plasma membrane? 2 A. Proteins may be attached to the inner surface of the plasma membrane. B. The hydrophobic portion of a protein is embedded within the membrane. C. Some peripheral proteins are connected to cytoskeletal filaments. D. Integral proteins are responsible for membrane functions. E. Glycoproteins contain carbohydrate chains that are oriented toward the inner surface of the membrane. Answer: E Explanation: Glycoproteins’ carbohydrate chains are oriented toward the outside of the plasma membrane, not the inside. 4. Which of these is NOT part of the endomembrane system of the cell? 2 A. mitochondria B. endoplasmic reticulum C. lysosomes D. Golgi complex E. vesicles Answer: A Explanation: Mitochondria are not part of the endomembrane system, which is involved in transporting and processing materials within the cell. 5. Which phrase does NOT describe one of the functions of proteins of the plasma membrane? 2 A. forming a channel through the membrane B. initiating the replication of the genetic material C. binding to a substance to carry it through the membrane D. acting as a receptor for substances external to the cell E. increasing the rate of a chemical reaction Answer: B Explanation: Proteins in the plasma membrane do not initiate the replication of genetic material, a function carried out in the nucleus. 6. If a cell is placed in a hypertonic solution, which will occur? 2 A. Salts will move into the cell from the surrounding solution. B. Water will move into the cell from the surrounding solution. C. Salts will move out of the cell into the surrounding solution. D. Water will move out of the cell into the surrounding solution. E. None of the choices will occur. Answer: D Explanation: In a hypertonic solution, water will leave the cell, causing it to shrink. 7. In a phospholipid bilayer, the 2 A. phosphate groups are hydrophobic. B. fatty acid tails are ionized. C. fatty acid tails are hydrophilic. D. proteins are located only between the two layers. E. phosphate heads are oriented toward the exterior of the cell or toward the cytoplasm. Answer: E Explanation: The phosphate heads of phospholipids are hydrophilic and face outward toward the exterior of the cell and the cytoplasm. 8. Which statement is NOT true about bacteria? 2 A. Their cell wall is made of a slime layer that is the same as in plant cell walls. B. Some are photosynthetic. C. Some are motile due to flagella. D. They are all prokaryotes. E. They have a cell wall that contains peptidoglycan. Answer: A Explanation: Bacterial cell walls contain peptidoglycan, not a slime layer like in plant cell walls. 9. Lysosomes are produced by the 2 A. vacuoles. B. nucleus. C. mitochondria. D. Golgi apparatus. E. ribosomes. nswer: D A Explanation: Lysosomes are formed by the Golgi apparatus and contain digestive enzymes. 0. The current theory of the structure of the plasma membrane is best described by the 3 A. sandwich B. fluid-mosaic C. unit membrane D. electrochemical E. unipermeable Answer: B Explanation: The fluid-mosaic model describes the plasma membrane as a flexible structure with a variety of proteins embedded in or attached to a bilayer of phospholipids. 1. Sugars and amino acids are carried into the cell by means of 3 A. facilitated transport. B. active transport. C. simple diffusion. D. endocytosis. E. exocytosis. Answer: A Explanation: Sugars and amino acids enter the cell through facilitated transport, where carrier proteins help move molecules down their concentration gradient. 2. Which of the following is NOT true concerning cytoskeletal elements? 3 A. Cilia are small extensions of membrane-surrounded microtubules. B. Microtubules are made up of a globular protein called tubulin. C. Intermediate filaments compose flagella. D. Flagella have a 9+2 pattern of microtubule structure. E. Basal bodies are located at the base of cilia and flagella. Answer: C Explanation: Flagella are not composed of intermediate filaments; they are made of microtubules arranged in a 9+2 structure. 3. Of the following, which is NOT associated with the mitochondria? 3 A. ATP production B. cristae C. stroma D. matrix . All of these are associated with the mitochondria E Answer: C Explanation: Stroma is part of the chloroplast, not the mitochondria. The mitochondria contain cristae and a matrix where ATP is produced. 4. Turgor pressure in plants results when 3 A. cells lose water from their water vacuoles. B. cells contain water vacuoles that are full of water. C. water is being used up in photosynthesis. D. water is being evaporated from the leaves. E. All of these create turgor pressure. Answer: B Explanation: Turgor pressure occurs when the vacuoles are full of water, pressing the plasma membrane against the cell wall. 5. All of the following are parts of plant cells EXCEPT 3 A. centrioles. B. mitochondria. C. chloroplasts. D. cell walls. E. vacuoles. Answer: A Explanation: Plant cells do not have centrioles, which are found in animal cells. 6. The plant cell's central vacuole 3 A. provides the plant cell with support. B. stores nutrients and cellular waste products. C. is a reservoir for water. D. occupies a large area of the cell. E. All choices are correct. Answer: E Explanation: The central vacuole in plant cells serves all these functions, including support, storage, and water retention. 7. Which is the best definition of diffusion? 3 A. movement of molecules from an area of their higher concentration to an area of their lower concentration B. movement of water across a semipermeable membrane from an area of high water concentration to an area of lower water concentration C. movement of molecules from an area of their lower concentration to an area of their higher concentration D. movement of water across a semipermeable membrane from an area of low water concentration to an area of higher water concentration E. movement of a substance against its concentration through the release of energy from ATP nswer: A A Explanation: Diffusion is the passive movement of molecules from an area of high concentration to an area of lower concentration. 8. Which is NOT a characteristic of mitochondria? 3 A. A mitochondrion has two membranes. B. Mitochondria are the site of cellular respiration. C. Mitochondria are found in prokaryotic and eukaryotic cells. D. Mitochondria contain DNA and ribosomes. E. The inner space of the mitochondrion contains a fluid matrix. Answer: C Explanation: Mitochondria are only found in eukaryotic cells, not in prokaryotes. 9. Cell products are secreted from the cell through 3 A. facilitated transport. B. active transport. C. cotransport. D. endocytosis. E. exocytosis. Answer: E Explanation: Exocytosis is the process by which cells secrete materials through vesicles that fuse with the plasma membrane. 0. Which is the best definition of osmosis? 4 A. movement of molecules from an area of their higher concentration to an area of their lower concentration B. movement of water across a semipermeable membrane from an area of high water concentration to an area of lower water concentration C. movement of molecules from an area of their lower concentration to an area of their higher concentration D. movement of water across a semipermeable membrane from an area of low water concentration to an area of higher water concentration E. movement of a substance against its concentration through the release of energy from ATP Answer: B Explanation: Osmosis is the movement of water molecules through a semipermeable membrane from a region of high water concentration to low water concentration. 1. Prokaryotes are characterized by all of the following structures EXCEPT 4 A. a nucleoid. B. inclusion bodies. C. mitochondria. D. mesosomes. E. ribosomes. nswer: C A Explanation: Prokaryotes lack mitochondria, which are only found in eukaryotic cells. 2. Which is NOT true of eukaryotic cells? 4 A. A true nucleus contains the chromosomes. B. Eukaryotic cells contain membrane-bounded compartments. C. They contain ribosomes that are smaller than those of prokaryotic cells. D. They all contain mitochondria. E. They contain many organelles in the cytoplasm. Answer: C Explanation: Eukaryotic cells contain larger ribosomes than prokaryotic cells, not smaller. 3. If a cell is placed in an isotonic solution, which will occur? 4 A. Salts will move into the cell from the surrounding solution. B. Water will move into the cell from the surrounding solution. C. Salts will move out of the cell into the surrounding solution. D. Water will move out of the cell into the surrounding solution. E. Water will move into and out of the cell at equal rates. Answer: E Explanation: In an isotonic solution, water moves in and out of the cell at equal rates, maintaining balance. 4. The sodium-potassium pump moves sodium and potassium ions across the plasma 4 membrane by A. facilitated transport. B. active transport. C. cotransport. D. endocytosis. E. exocytosis. Answer: B Explanation: The sodium-potassium pump uses active transport to move ions against their concentration gradients using ATP. 5. If a cell is placed in a hypotonic solution, which will occur? 4 A. Salts will move into the cell from the surrounding solution. B. Water will move into the cell from the surrounding solution. C. Salts will move out of the cell into the surrounding solution. D. Water will move out of the cell into the surrounding solution. E. None of the choices will occur. Answer: B Explanation: In a hypotonic solution, water moves into the cell, which can cause it to swell due to osmotic pressure.
