UMUC Biology 103

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An atom is converted into an ion by adding or removing ___________________.
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electrons :When electrons are added or removed from an atom, the charge of the atom changes and the atom becomes an ion.
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The positive particle in the atom is the ...
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proton :Protons are positively charged.
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How many electrons does a neon atom have in its second shell?
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8 :This second and third shells can hold up to 8 electrons.
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Which is the biggest? Proton Neutron Atom Electron
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Atom
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The negative particle in the atom is the ...
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electron
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What would be the charge of a beryllium atom that has a full outer shell? +1 no charge -1 +2
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+2
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Fluorine, F, has an atomic number of 9 and an approximate atomic mass of 19. What would be the charge of fluorine that has a full outer shell? +2 +1 -1 no charge
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-1
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Negatively charged particles are found where in an atom? In the nucleus In a single layer outside the nucleus In multiple layers outside the nucleus Both inside and outside the nucleus
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In multiple layers outside the nucleus
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Beryllium, Be, has an atomic number of 4 and an atomic mass of approximately 9. How many neutrons does a beryllium atom have? 9 5 4 13
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5
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Beryllium, Be, has an atomic number of 4 and an atomic mass of approximately 9. How many electrons does a beryllium atom have? 5 13 9 4
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4
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Fluorine, F, has an atomic number of 9 and an approximate atomic mass of 19. How many electrons does a fluorine atom have? 10 28 9 19
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9
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Two atoms that have the same number of protons but different numbers of neutrons are called... isomers isotopes ions
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isotopes
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What would be the charge of a neon atom that has a full outer shell? -1 +2 no charge +1
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no charge
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Zinc is abbreviated Zn. What is the atomic mass of zinc? 35 95 65.39 30
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65.39
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Gold is abbreviated Au. How many protons does gold have? 79 197 118 276
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79
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An element has 43 protons and 50 neutrons. What is the atomic number of this element? 93 43 50
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43
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Neon has an atomic number of 10 and an atomic mass of approximately 20. How many electrons does neon have in its first shell? 2 10 20 8
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2
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Zinc is abbreviated Zn. How many electrons does zinc have in its first shell? 79 2 197 8
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2
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An element has 43 protons and 50 neutrons. What is the ATOMIC MASS of this element? 43 50 93
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93
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Zinc is abbreviated Zn. How many protons does zinc have? 65.39 35 30 95
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30
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What is the correct molecular formula for caffeine (shown here)? C8H9N4O2 C3H9N4O2 C3H10N4O2 C8H10N4O2
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C8H10N4O2
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A covalent chemical bond is one in which: Electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged Outer shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both. Outer shell electrons of one atom are transferred to the inner electron shells of another atom. Protons or neutrons are shared by two atoms so as to satisfy the requirements of both.
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Outer shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both.
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The lines on the above drawing of caffeine indicate: Covalent bonds Hydrogen bonds Ionic bonds Polar bonds
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Covalent bonds
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Which bond is the weakest? Covalent bonds Hydrogen bonds Ionic bonds All 3 of these bonds are approximately the same strength.
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Hydrogen bonds
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A double covalent bond is the sharing of a total of how many electrons? 2 4 6 8
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4
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A shared pair of electrons is called a: _________. covalent bond hydrogen bond ionic bond polar bond
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covalent bond
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The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. This attraction is called: a covalent bond an ionic bond a hydrogen bond
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a hydrogen bond
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What do the four elements most abundant in life - carbon, oxygen, hydrogen and nitrogen - have in common? They are elements produced only in living cells. Each element exists in only one isotopic form. They all have the same number of valence electrons. They all have unpaired electrons in their valence shells.
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They all have unpaired electrons in their valence shells.
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Weak chemical bonds that form BETWEEN polar molecules are Covalent bonds Hydrogen bonds Ionic bonds None of these answers are correct.
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Hydrogen bonds
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What do atoms form when they share electron pairs? molecules isotopes elements
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molecules
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What determines the number of covalent bonds formed by an atom? Orbitals found in the atom Valence shells in the atom Electrons in the outer valence shell of the atom Electrons in each orbital of the atom
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Electrons in the outer valence shell of the atom
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The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. This attraction is called: a covalent bond a hydrogen bond an ionic bond
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a hydrogen bond
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What bond(s) is (are) disrupted in the presence of water? atomic ionic molecular covalent
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ionic
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What do the four elements most abundant in life - carbon, oxygen, hydrogen and nitrogen - have in common? They all have the same number of valence electrons. They all have unpaired electrons in their valence shells. They are elements produced only in living cells. Each element exists in only one isotopic form.
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They all have unpaired electrons in their valence shells.
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Table salt is composed of Na+ and Cl- to form NaCl. This type of bond is called: _____________. Polar Ionic Hydrogen Covalent
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Ionic
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Compare the liquid and solid states of water. Which statement is true? Liquid water is more dense Solid water is more dense
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Liquid water is more dense
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Polar molecules are hydrophilic. True False
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true
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Which of the following statements is true concerning hydrogen bonding and the liquid and solid states of water? Only liquid water forms hydrogen bonds. Only solid water forms hydrogen bonds. Both liquid and solid states of water form hydrogen bonds.
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Both liquid and solid states of water form hydrogen bonds.
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Which characteristic of water protects fish when a lake freezes? water is less dense as a solid cohesion water as a solvent All of the these characteristics.
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water is less dense as a solid
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Detergents are neither polar nor nonpolar nonpolar amphipathic polar
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amphipathic
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Which of the following statements is true? Water moves up a tree in tubes. These tubes must be polar. Water moves through a tree mainly using the force of gravity. Non-polar molecules would move up trees in the same way water does. All of these are true
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Water moves up a tree in tubes. These tubes must be polar.
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Which of the following molecules is hydrophilic? butter olive oil table salt
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table salt
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You are able to fill a glass with water so that the water goes above the rim of the glass. What property of water have you observed? moderates temperature density cohesiveness
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cohesiveness
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You make a cup of tea. What is the solute? the tea leaves the tea leaves and water together the water
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the tea leaves
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What is the pH of bleach? very acidic slightly acidic slightly basic very basic
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very basic
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Solution A has a lower concentration of H+ than solution B. Solution A is more acidic more basic more neutral
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more basic
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You test soda (pH 2.5) with blue litmus paper. What color would you expect to see? Yellow Green Red Blue
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Red
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You test bleach (pH 13) with red litmus paper. What color would you expect to see? Blue Yellow Red Green
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Blue
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A small amount of acid is added to a buffered solution. What will happen? The pH will change very little, if at all. The buffer will accept the hydrogen ions from the added acid, keeping pH constant. The pH will increase rapidly after acid is added. The pH will decrease rapidly after acid is added. The pH will change very little, if at all. The buffer will donate extra hydrogen ions to the solution to keep the pH constan
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The pH will decrease rapidly after acid is added.
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Which of the following is the strongest base? baking soda, pH 8.5 stomach acid, pH 1 ammonia, pH 12 black coffee, pH 5 water, pH 7
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ammonia, pH 12
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What is the pH of lemon juice? very acidic slightly acidic slightly basic very basic
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very acidic
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You have a solution that has a pH of 5 and need it to be pH 8. What do you do? Add a base Add water Add an acid
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Add a base
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The pH of a substance is determined by measuring the ____________ of the substance. electrical charge toxicity hydrogen ions chemical reactivity
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hydrogen ions
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A strong base is dripped into a buffered solution. What will happen as a large amount of base is added to the solution? At first, the pH will not respond much. Then, when the buffering capacity is \"used up,\" pH will increase rapidly as more base is added until some limit is reached. At first, the pH will not respond much. Then, when the buffering capacity is \"used up,\" pH will decrease rapidly as more base is added. The pH will start to increase as soon as base is added, and will continue to increase until it reaches 14. The pH will start to decrease as soon as base is added, and will continue to decrease until it reaches 0.
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At first, the pH will not respond much. Then, when the buffering capacity is \"used up,\" pH will increase rapidly as more base is added until some limit is reached.
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Buffers do all of the following EXCEPT: Help organisms maintain homeostasis. Donate (provide) hydrogen ions to the solution when an base is added to the solution. Make a solution strongly acidic Absorb excess hydrogen ions when an acid is added to a solution. Maintain a stable pH within a solution.
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Make a solution strongly acidic
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Solution A has a lower concentration of H+ than solution B. Solution A is more neutral more acidic more basic
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more basic
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The pH of a substance is determined by measuring the ____________ of the substance. chemical reactivity toxicity electrical charge hydrogen ions
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hydrogen ions
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You test soda (pH 2.5) with blue litmus paper. What color would you expect to see? Green Yellow Red Blue
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Red
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A solution with a pH of 4 has how many H+ ions compared to a solution with a pH of 6? 1000 times less 100 times more two thirds as many 1000 times more 100 times less
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not 1000 times more or 100 times less
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You have a solution that has a pH of 5 and need it to be pH 8. What do you do? Add water Add an acid Add a base
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Add a base
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Solution A has a higher concentration of H+ than solution B. Solution A is more acidic more basic more neutral
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more acidic
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pH is a measure of toxicity hydrogen ions chemical reactivity electrical charge
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hydrogen ions
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You have a solution that has a pH of 8 and need it to be pH 5. What do you do? Add a base Add an acid Add water
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Add an acid
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Fluorine, F, has an atomic number of 9 and an approximate atomic mass of 19. How many neutrons does a fluorine atom have? 9 28 10 19
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10
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Neon has an atomic number of 10 and an atomic mass of approximately 20. How many protons does an atom of neon have? 30 5 10 20
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10
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What is the monomer that is used to build proteins? Amino acids Monosaccharides Fatty acids Nucleotides
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Amino acids
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Complete the sentence: All organic molecules contain ____________. carbon oxygen nitrogen all of these are true
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carbon
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Which of these molecules is not organic? Select all that apply. Water Fatty acid Caffeine Silica dioxide: quartz Styrene
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Silica dioxide: quartz
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Which of the following are functions of carbohydrates? Select all that apply. Energy storage Structure Cell recognition Cell signaling None of these choices
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Energy storage Structure Cell recognition Cell signaling
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What do starch and cellulose have in common? Select all that apply. They both have the same linear structure. They both have the same function They are both made of glucose subunits. They are both made by plants.
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They are both made of glucose subunits. They both have the same linear structure.
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Which of the following is the smallest? Ribose Lactose Starch Sucrose
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Ribose
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What type of molecule is shown here? Amino acid Carbohydrate Nucleotide Lipid
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Carbohydrate
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This carbohydrate is produced by animals for energy storage Cellulose Glycogen Chitin Starch
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Glycogen
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Which polysaccharide is most similar to chitin? Glycogen Starch Cellulose Glucose
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Cellulose
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What characteristic of carbon makes it a good backbone for creating diverse and durable molecules? Carbon is a large atom. Carbon forms four covalent bonds. Carbon forms hydrogen bonds. All of these are true.
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Carbon forms four covalent bonds
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Which of the following is characterized as dietary fiber? Sucrose Cellulose Glycogen Starch
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Cellulose
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Which of the following is characteristic of carbohydrates? Carbohydrates are hydrophobic and have the general formula CH2O. Carbohydrates are hydrophilic and have the general formula CH2O. Carbohydrates are hydrophobic and have the general formula CHO. Carbohydrates are hydrophilic and have the general formula CHO.
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Carbohydrates are hydrophilic and have the general formula CH2O.
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What is this structure? cholesterol saturated fatty acid unsaturated fatty acid phospholipid triglyceride
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triglyceride
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What is the name of this structure? unsaturated fatty acid phospholipid cholesterol triglyceride saturated fatty acid
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cholesterol
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Which of the following are functions of steroids? Select all that apply. communication maintain membrane fluidity precursors to vitamins enzymes
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communication maintain membrane fluidity
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How many glycerols in a triglyceride? 1 2 3 4
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1
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What type of lipid is shown here? Steroid Fatty acid Triglyceride Phospholipid
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Steroid
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Which lipid is mainly used for energy storage? phospholipids steroids triglycerides waxes
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triglycerides
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Which characteristic of trans fats has been linked to an increased risk of heart diseases? They increase the levels of both HDL and LDL They increase the levels of LDL They increase the levels of HDL
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They increase the levels of LDL
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Which type of lipoprotein is carried to the liver for processing? LDL HDL Both of these
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HDL
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Which part of the lipid shown is hydrophilic? The red circle The entire phospholipid is hydrophobic The entire phospholipid is hydrophilic The blue lines
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The red circle
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Which molecule makes up the bulk of a cell's membrane? Polysachharides Proteins Phospholipid Monosaccharides
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Phospholipid
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Which lipids have fused carbon rings? Phospholipids Triglycerides Steroids Waxes
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Steroids
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What type of molecule is shown here? Carbohydrate Nucleic Acid Protein Lipid
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Lipid
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Which lipids have 2 long hydrocarbon chains linked by an ester group? Phospholipids Triglycerides Waxes Steroids
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Waxes
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Which lipid provides a water protective layer on the surface of some animals and plants? triglycerides waxes phospholipids steroids
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waxes
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Which molecule makes up the bulk of a cell's membrane? Polysachharides Monosaccharides Proteins Phospholipid
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Phospholipid
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Where do peptide bonds form? Between amino acids of two different protein chains. Between adjacent amino groups on amino acids. Between adjacent carboxyl groups on amino acids. Between the carboxyl group of one amino acid and the amino group of another amino acid.
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Between the carboxyl group of one amino acid and the amino group of another amino acid.
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The amino acid valine is shown with its sidechain atoms highlighted in yellow. Do you think this amino acid is hydrophilic or hydrophobic?
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hydrophobic (non-polar)
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The following shows the dipeptide alanine-serine. Four atoms are labeled. Which atom is part of the peptide bond that joins the two amino acids? Atom A Atom B Atom C Atom D
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Atom B between the o and the n right in the middle
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The sequence and folded form of three different proteins are shown below. Although the sequences are different, the folded structures are the same (S shaped). Which of the following three structures will be the least stable (white=polar sidechains, black=non-polar sidechains). protein A protein B protein C
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protein C wwwwbwbbwwww
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Which of the following diagrams represents the correct structure of a protein? Each blue-gray-red box represents an amino acid.
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a bgr bgr bgr bgr bgr bgr * * *
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Which of the following changes when a protein denatures? Length of the entire protein Amino acid sequence Three dimensional structure
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Three dimensional structure
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Which of the following four proteins would bind best to the antibody? The portion of the antibody the binds the protein is shown on the left, the proteins (A, B, C, D) on the right. Protein A Protein B Protein C Protein D
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c :same as diagram
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Where do competitive inhibitors bind on an enzyme? substrate allosteric site competitive site active site
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active site
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A ligand cannot bind to the active site of an enzyme. True False
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False
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Two enzymes catalyze the same reaction. Enzyme A converts substrate to product twice as fast as enzyme B. Which enzyme has the lower activation energy or energy barrier: A or B? Enzyme A Enzyme B
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Enzyme A
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Amino acids in a protein chain are attached by bonds called
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peptide bonds
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This amino acid is ______________. hydrophobic hydrophilic
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hydrophilic
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The peptide bond that forms between two amino acids is an example of a(n): hydrogen bond ionic bond covalent bond
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covalent bond
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Which of the following curves best represents the activity of an enzyme isolated from a bacteria that lives in the hot springs in Yellowstone (water temperature 120 degrees C)? curve A curve B curve C
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curve B curves up then down and goes past 120
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Which of the following plots more correctly shows the activity of pepsin as a function of pH? plot A plot B plot C plot D
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plot A goes up then down like a volcano starts at 0
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An enzyme binds the indicated substrate and converts it to product by removing two hydrogen atoms and forming a double bond between the two middle carbons. Compounds A and B are inhibitors of this enzyme. Which of the two inhibitors is a non-competitive inhibitor? Compound A Compound B
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Compound B
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This is an image of Deoxyribose pyrimidines Ribose pyrimidine Ribose purine Deoxyribose purine
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Deoxyribose pyrimidines
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Which nucleotide is at the 3' end of this nucleic acid? G A T C
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t
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Does the DNA in the skin cell have the same backbone as DNA in the brain cell of the same organism? Yes, all backbones of ALL DNA molecules are the same. Yes, the backbones of DNA are different for each person, but within the organism - they are the same in all cells. No, the backbones will be different in each cell type. No, the backbones will be different because of mutations.
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Yes, all backbones of ALL DNA molecules are the same.
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Which labeled region is the base? Blue Green Red
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Green
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How many phosphate groups does ATP have? 1 2 3 4
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3
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Which of these is NOT a difference between DNA and RNA? DNA tends to be double stranded, while RNA tends to be single stranded RNA uses the base thymine while DNA uses the base uracil. DNA uses the sugar deoxyribose while RNA uses the sugar ribose. All of these are differences between DNA and RNA.
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RNA uses the base thymine while DNA uses the base uracil.
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The molecule shown here is: _________________ an amino acid a carbohydrate a nucleotide a lipid
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an amino acid
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The cells of your body are surrounded by water. The outer layer of these cells is made of many nonpolar molecules. What would happen if the outer layer of these cells was made of mainly polar molecules? The cells would dissolve. The cells could not interact with their environment. The cells would be too heavy to float in the water. Water could not get in to the cell.
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The cells would dissolve.
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Which of the following is used for long term energy storage? Proteins Nucleic Acids Carbohydrates Lipids
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Lipids
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What type of molecule is shown here: Carbohydrate Lipid Nucleotide Amino acid
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Lipid
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Which of these functional groups is hydrophilic? Alcohols Carboxyl Phosphate All of the other selections.
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All of the other selections.
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This is an image of Deoxyribose purine Deoxyribose pyrimidines Ribose purine Ribose pyrimidine
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Deoxyribose purine
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Enzymes are usually ______________? carbohydrates nucleotides lipids proteins
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proteins
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Detergents are ______________. polar nonpolar both polar and nonpolar neither polar nor nonpolar
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both polar and nonpolar
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How will lipids respond when immersed in water? The phospholipids will form crystals at the bottom of the solution The phospholipid will dissolve evenly in the water The heads will orient away from the water The tails will orient away from the water
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The tails will orient away from the water
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Proteins begin with an amino group and end with a carboxyl group. In the case of nucleic acids: They begin at the 3' end and end at the 5' end. They begin at the 5' end and end at the 3'. It is the same in nucleic acids. They begin at the 5' end and end at the 2' end
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They begin at the 5' end and end at the 3'.
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Which of the following is mostly hydrophobic? Carbohydrates Proteins Nucleic acids Lipids
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Lipids
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Which is NOT a function of proteins? Maintains structure of animal cells Move substances in and out of the cell. Form the bulk of cellular membranes. Recognition of specific particles.
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Form the bulk of cellular membranes.
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Which of the following structures can be found together in eukaryotic cells? DNA and ribosomes ribosomes and endoplasmic reticulum cytoplasm and ribosomes cytoplasm and plasma membrane
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ribosomes and endoplasmic reticulum
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Which of the following statements about prokaryotes is incorrect?
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Prokaryotes have circular pieces of DNA within their nuclei.
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A forensic examination reveals cells containing ribosomes, DNA, a plasma membrane, and a cell wall. What type of cell it is?
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bacterium
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Which is NOT a difference between prokaryotic and eukaryotic cells?
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Eukaryotes are larger than prokaryotes.
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Which of these is also called an antibiotic in a medical setting?
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Antibacterial
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Which is a plausible effect of taking oral antibiotics?
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The antibiotics could unintentionally kill good bacteria living in your intestines, leaving you more susceptible to infection by pathogenic bacteria.
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What is the concern with overuse of antibiotics?
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Bacteria will become antibiotic resistant.
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All living things are made of one or more cells: true or false?
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True
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All cells have ______________?
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plasma membrane
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An ideal antibiotic damages only bacterial cells but not human cells. Which of the following cellular structures would be a good target for antibiotics?
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cell wall
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How does the selective permeability of the membrane help the cell.
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This allows the cell to regulate what enters and exits
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Which substance would be most likely to pass through a lipid bilayer/plasma membrane without embedded proteins?
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a steroid hormone
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Biological Membranes are:
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dynamic.
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Which component of the plasma membrane has the widest variety of functions?
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proteins
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What is the role of carbohydrates in the plasma membrane?
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cellular identification
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A set of erythrocytes is placed in a beaker of 0.9% NaCl. Nothing appears to happen to the cells. Why?
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0.9% NaCl is iostonic to the cells.
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All of the following have an effect on the fluidity of a membrane except:
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the presence of integral proteins in the membrane
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Which of the following can cross the cell's plasma membrane without the assistance of protein transporters? Select all that apply.
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small hydrophobic molecules gasses
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An animal cell placed in a hypotonic solution will __________.
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burst
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A substance, such as glucose, will enter a cell following its concentration gradient, from the blood and tissues, through the membrane, and into the cytoplasm. Such movement of glucose has a maximal capacity, does not require energy, and is specific only for glucose. How is the entry of glucose into the cell occurring?
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By facilitated diffusion
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The secretion of materials, such as hormones and neurotransmitters, from inside of a cell to the outside is ___________.
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exocytosis
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An immune cell would engulf a pathogenic cell using the process of: ________________ ?
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endocytosis
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A substance, such as glucose, will enter a cell following its concentration gradient, from the blood and tissues, through the membrane, and into the cytoplasm. Such movement of glucose has a maximal capacity, does not require energy, and is specific only for glucose. How is the entry of glucose into the cell occurring?
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By facilitated diffusion
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Increasing the concentration gradient:
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Increases the rate of diffusion
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Sodium ions are more highly concentrated outside the cell, in the extracellular fluid. Which process would be used to return any sodium ions that leaked into the cell back to the extracellular fluid?
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active transport
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Protein transporters that move materials against a concentration gradient are active transport proteins.
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True
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Active transport could also be called facilitated diffusion.
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False
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A cell will uptake large molecules from the extracellular fluid by the process of __________.
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endocytosis
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