Chapter 5 Test – Flashcards
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Osmosis can be defined as____.
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the diffusion of water
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Which of the following statements regarding membrane protein function is false?
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membrane proteins transfer genetic information to the cytoplasm
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A cell that neither gains nor loses water when it is immersed in a solution must be____.
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isotonic to its environment
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The molecules responsible for membrane transport are___.
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proteins
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White blood cells are more resistant to lysis than red blood cells. When looking at a sample of blood of white blood cells, what could you do to reduce interference from red blood cells?
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mix the blood in an isotonic solution and allow the white blood cells to float to the top
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How does inhibition of an enzyme-catalyzed reaction by a competitive inibior differ from inhibition by a noncompetitive inhibitor?
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competitive inhibitors bind to the active site of the enzyme;noncompetitive inhibitors bind to a different site
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Inhibition of an enzyme is irreversible when____.
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covalent bonds form between inhibitor and enzyme
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Most of a cell's enzymes are___.
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proteins
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The process of a white blood cell engulfing a bacterium is_____.
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phagocytosis
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Plasma membranes are selectively permeable. This means that______.
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the plasma membrane allows some substances to enter or leave a cell more easily than others
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Oxygen crosses a plasma membrane by_____.
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passive transport
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Which of the following statements regarding enzyme function is false?
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enzymes are used up when the catalyze a chemical reaction, so must be synthesized for each new chemical reaction
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When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will____.
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exhibit a net movement to the side with lower free water concentration
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Which of the following substances could be a cofactor?
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a zinc atom
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Facilitated diffusion across biological membrane requires ___(1)____ and moves a substance ___(2) its concentration gradient.
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1. energy and transport proteins
2. down
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Most of the functions of a cell membrane, including transport and enzymatic functions, are performed by____.
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proteins
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Phagocytosis is to drinking as pinocytosis is to_____.
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eating
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When an enzyme catalyze a reaction_____.
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it lowers the activation energy of the reactant
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The active site of an enzyme is_____.
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the region of a product that attaches to a substrate
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Which of the following statements regarding enzymes is true?
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enzymes are inorgainc
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All cells are enclosed by a plasma membrane that is similar in ____ and _____.
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structure and function
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Which of the following statements regarding membrane is false?
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the plasma membrane id the control center of the cell
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A child is brought to the hospital with a fever of 107 degrees F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offer the most logical explanation for this action?
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Elevated body temperatures may denature proteins. This would interfere with the cell's abilities to catalyze various reactions
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You are adrift in the Atlantic ocean, and, being thirsty, drink the surrounding seawater. As a result ____.
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you dehydrate yourself
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The fluid mosaic model describes the plasma membrane as consisting of_____.
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diverse proteins embedded in a phospholipid bilayer
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Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of ____.
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passive transport
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After the reverse osmosis system has been operating for 30 minutes, the solution in Tank A would ___.
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by hypertonic to tank B
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Which of the following processes can move a solute against its concentration gradient?
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active transport
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Which of the following statements regarding active transport is false?
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Active transport is driven by the concentration gradient
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A plant cell in a hypertonic solution___.
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becomes turgid because of an inflow of water
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Which of the following statements regarding diffusion is false?
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diffusion occurs when particles spread from areas where they are less concentrate to areas where they are more concentrated
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Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion?
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exocytosis
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Substrate binds to an enzyme's ____ site?
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active
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In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an artificial cell. The balloon is filled with a solution of 20% sucrose and 80% water and immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
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Water will leave the balloon
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Which of the following statements regarding is a typical feature of an ATP-driven active transport mechanism?
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the solute moves against the concentrated gradient
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In a hypertonic solution, an animal cell will_____.
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lyse
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In the lab, you use a special balloon that is permeable to water to make an artificial cell. The balloon is filled with a solution of 20% sucrose and 80% water and immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ______ relative to the solution in the beaker.
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hypertonic
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Heating inactivated enzymes by_____.
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changing the enzyme's three dimensional shape
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Which of the following statements is true among all types of passive transport?
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the concentration gradient is the driving force
