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1 Name: Marcie Joseph Module: Cells & chemistry Test topic/animation: My animations/all animations Test type: Multiple choice Score: 48/50 Percent correct: 96% The following question(s) were incorrectly answered. Question: Glycolysis is... Answer: A series of steps during which glucose is oxidized to pyruvate Explanation: Glycolysis is the oxidation of glucose to pyruvate. Question: Atoms are most stable when?... Answer: Their outermost (valence) shells are full of electrons Explanation: Atoms are extremely stable and non-reactive when they have full electron shells. The following question(s) were correctly answered. Question: Diffusion continues until... Answer: Equilibrium is reached Explanation: Diffusion continues until equilibrium is reached and the substance is equally distributed. Question: Diffusion is the.. Answer: Tendency of substances to move from areas of high concentration to low concentration Explanation: Diffusion is the tendency for substance to move down their concentration gradient from high to low concentration. Question: The rate of diffusion is affected by... Answer: Temperature, size of molecules, and the incline of the concentration gradient Explanation: The rate of diffusion is affected by all three parameters. Question: Molecules that are dissolved in a solution are in constant random motions due to... Answer: Kinetic energy

2 Explanation: Kinetic energy is responsible for the constant random motion of substances. Question: Diffusion is not used to move substances through cell membranes. Explanation: Certain substance do diffuse through membranes to either enter or leave a cell. Question: Under aerobic conditions, pyruvate is... Answer: Oxidized to yield more ATP Explanation: In the presence of oxygen, pyruvate is further oxidized for yield more ATP. Question: The initial steps of glycolysis cost the cell energy (ATP). Explanation: The initial steps of glycolysis use two ATP molecules from the cell. Question: During glycolysis, a 6-carbon glucose molecule is split to form... Answer: Two 3-carbon pyruvate molecules Explanation: During glycolysis, a 6-carbon glucose molecule is eventually split to for two 3-carbon pyruvate molecules. Question: What is the net effect of glycolysis? Answer: Production of two molecules of ATP Explanation: Glycolysis produces two net ATP molecules. Question: Which of the following can be viewed as cellular "drinking"? Answer: Pinocytosis Explanation: Pinocytosis can be thought of as cellular "drinking" because it involves moving quantities of fluid into the cell via endocytosis. Question: Endocytosis is a process by which the surrounds and engulfs large particles. Answer: Plasma membrane Explanation: Endocytosis is a process by which the plasma membrane surrounds and engulfs large particles.

3 Question: All of the following are ways in which cells bring material to the inside of the plasma membrane except... Answer: Exocytosis Explanation: Exocytosis describes the way in which cells move material to the outside of the plasma membrane. Question: Phagocytosis can be thought of as cellular "eating" because the cell is bringing in solid material too large to pass through the cell membrane. Explanation: Phagocytosis can be thought of as cellular "eating" because the cell is bringing in solid material too large to pass through the cellular membrane. Question: Which of the following is characterized by the binding of molecules to an extracellular protein, deepening of a coated pit, and eventual creation of a coated vesicle? Answer: Receptor-mediated endocytosis Explanation: Receptor-mediated endocytosis involves the binding of molecules to extracellular receptors, deepening of a coated pit, and the eventual pinching off into a coated vesicle inside the cell. Question: Each element is uniquely defined by the number of in an atom of that element. Answer: Protons Explanation: Each element is uniquely defined by the number of protons in an atom of that element. Question: Which statement is false? Answer: Atomic number refers to the number of electrons in an atom Explanation: Atomic number refers to the number of protons in an atom. Atomic mass is the combined number of protons and neutrons while isotopes are atoms with the same atomic number but differ in their atomic mass due to a differing number of neutrons. Question: Which subatomic particle and charge assignment is correctly paired? Answer: Electrons, -1 Explanation: Each proton exhibits a charge of positive one and each electron a charge of negative one. Neutrons exhibit no charge and are considered neutral.

4 Question: Which of the following are included in the nucleus of an atom? Answer: Protons Explanation: A centrally located cluster of protons and neutrons forms the nucleus of an atom. Electrons reside outside the nucleus in electron shells or energy levels. Question: Osmosis deals specifically with the diffusion of... Answer: Water molecules Explanation: The diffusion of water molecules down a concentration gradient is osmosis. Question: When the osmotic concentrations of two solutions are equal, the solutions are said to be... Answer: Isotonic Explanation: Isotonic solutions have equal osmotic pressures. Question: The net movement of molecules down a concentration gradient is known as... Answer: Diffusion Explanation: Diffusion is the net movement of molecules down a concentration gradient. Question: Sugars can freely pass through the lipid bilayer of a cell. Explanation: Sugars are polar and cannot pass freely through the cell's lipid bilayer. Question: A hypotonic solution has a higher concentration of solutes than does a hypertonic solution. Explanation: Hypertonic solutions have higher concentrations of solutes than do hypotonic solutions. Question: Active transport requires the breakdown of to move substances against their concentration gradients. Answer: ATP Explanation: Active transport requires the harnessing of energy released from ATP hydrolysis to move substances against their concentration gradients. Question: In the example shown in this animation...

5 Answer: Sodium is more highly concentrated in the extracellular fluid Explanation: Sodium is more highly concentrated in the extracellular fluid. Question: What specifically occurs when the phosphate is released from the inner surface of the membrane? Answer: Potassium moves to the inside of the cell Explanation: Phosphate release from the inner portion of the carrier protein allows potassium ions to move to the inside of the cell. Question: The sodium-potassium pump is responsible for moving... Answer: Sodium to the outside of the cell Explanation: The sodium-potassium pump moves sodium to the outside of the cell and potassium to the inside of the cell. Question: The change in shape of the carrier protein that results from the sodium moving through the membrane allows... Answer: Potassium to bind to the carrier protein Explanation: The conformational change resulting from sodium binding moves three sodium molecules to the extracellular fluid and causes potassium to the bind to the carrier protein. Animation: Bonds Question: When forming compounds, atoms tend to alter their number of electrons in order to achieve a stable number of electrons. Answer: Valence Explanation: Atoms achieve stability when their valence shells are full. This is achieved through the borrowing, donating, or sharing or electrons. Animation: Bonds Question: Sodium can achieve greater stability in its valence shell by chlorine. Answer: Donating one electron to Explanation: Sodium can achieve greater stability in its valence shell by donating one electron to chlorine. Animation: Bonds Question: A polar covalent bond occurs because shared electrons have a greater attraction to one of the atoms than the other. Explanation: A polar covalent bond occurs because shared electrons have a greater attraction to one of the atoms than the other.

6 Animation: Bonds Question: A(n) bond exhibits an unequal sharing of electrons between two or more molecules. Answer: Polar covalent Explanation: Polar covalent bonds refer to an unequal sharing of electrons resulting in a net relative charge throughout the molecule. Animation: Bonds Question: If an atom like hydrogen gives an electron to another atom like chlorine, the resulting charge of hydrogen will be?... Answer: Plus one Explanation: Gaining electrons results in a net negative charge, while losing electrons results in a net positive charge. Animation: Electrolytes Question: Why does glucose dissolve in water? Answer: Because the polar regions of the water molecules are attracted to the polar regions of the glucose molecules, resulting in weakened attractions between individual glucose molecules. Explanation: Glucose dissolves in water because the polar regions of the water molecule are attracted to the polar regions of the glucose molecule. This weakens the intermolecular attractions of the glucose molecules. Animation: Electrolytes Question: NaCl is an electrolyte because when dissolved in water it will?... Answer: Conduct electricity Explanation: While NaCl will dissolve in water, NaCl is an electrolyte because when dissolved in water it will conduct electricity. Animation: Electrolytes Question: Which statement is false? Answer: NaCl is a weak electrolyte because when placed in water it will completely dissociate Explanation: NaCl is a strong electrolyte because when placed in water it will completely dissociate. Carbonic acid is a weak acid because when it is when placed in water, it only partially dissociates into H+ and bicarbonate. Animation: Electrolytes Question: Which of the following is not an electrolyte? Answer: Glucose Explanation: Na+, Cl-, H+, and bicarbonate are considered electrolytes because when placed water they will conduct electricity.

7 Animation: Electrolytes Question: When NaCl is placed in water, the negative regions of polar water molecules are attracted to... Answer: Na+ Explanation: When placed in water, NaCl dissociates because the electrically polar regions of water are attracted to their oppositely charged ion. Question: A given carrier protein can bind to and transport several different types of molecules. Explanation: A carrier protein can bind and move only a specific type of molecule, such as a certain sugar or amino acid. Question: In facilitated diffusion, a given carrier protein can move a substance either into or out of the cell depending on its concentration gradient. Explanation: A carrier protein is able to move a substance in either direction, depending on its concentration. Question: Facilitated diffusion is similar to simple diffusion in that both processes... Answer: Involve the movement of substances down their concentration gradients Explanation: Both facilitated and simple diffusion allow the movement of substances down their concentration gradient without energy input from the cell. Question: Special carrier molecules are composed of... Answer: Protein Explanation: The special carrier molecules are made of protein. Question: In facilitated diffusion, molecules are transported across a membrane by... Answer: Special carrier molecules Explanation: Facilitated diffusion requires the use of special carrier proteins to move substances down their concentration gradients. Animation: Enzymes Question: The released compound resulting from the action of an enzyme is known as a(n)? Answer: Product Explanation: Products are the released result of enzyme reactions.

8 Animation: Enzymes Question: Following a reaction, an enzyme is irreversibly altered and cannot perform the same reaction a second time. Explanation: The release of products allows the enzyme to return to its original shape in order to perform the reaction again. Animation: Enzymes Question: An enzyme might be able to produce two products from one substrate while another enzyme might be able to produce one product from two substrates. Explanation: Enzymes are capable of synthesis and degradation reactions. Animation: Enzymes Question: The formation of a(n) alters some of the chemical bonds of the substrates. Answer: Enzyme-substrate complex Explanation: Enzyme-substrate complexes create stress or weakening of chemical bonds in the substrates. Animation: Enzymes Question: Which statement does not correctly describe an enzyme? Answer: Active sites can often bind a wide variety of different substrates Explanation: Active sites are only capable of binding specific substrates.