biology exam 2

Which of the following factors tend to increase membrane fluidity? A) A greater proportion of unsaturated phospholipids B) A greater proportion of saturated phospholipids C) A lower temperature D) A relatively high protein content in the membrane E) A greater proportion of relatively large glycolipids compared with lipids having smaller molecular masses

A) A greater proportion of unsaturated phospholipids

Which of the following crosses lipid bilayers the slowest? A) A sodium ion B) A small, polar molecule like water C) A large, polar molecule like glucose D) A small, nonpolar molecule like oxygen (O2)

A) A sodium ion

Structurally, nucleotides are similar to what energy-rich molecule? A) ATP B) Amino acids C) Glucose D) Lipids E) None—nucleotides are extremely unique

A) ATP

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? A) CO2 B) An amino acid C) Glucose D) K+E) Starch

A) CO2

Which of the following is NOT a polymer? A) Glucose B) Starch C) Cellulose D) Chitin E) DNA

A) Glucose

Which of these best reflects the following relationship: monosaccharide versus polysaccharide? A) Glucose versus glycogen B) Glucose versus fructose C) 1,4-glycosidic linkage versus 1,6-glycosidic linkage D) α-linkage versus β-linkage

A) Glucose versus glycogen

Which of the following contains hydrolytic enzymes? A) Lysosome B) Vacuole C) Mitochondrion D) Golgi apparatus E) Peroxisome

A) Lysosome

Nucleic acids are polymers made up of which of the following monomers? A) Nucleotides B) Ribose sugars C) Amino acids D) Nitrogenous bases E) Phosphates

A) Nucleotides

Which structure is the site of the synthesis of proteins that may be exported from the cell? A) Rough ER B) Lysosomes C) Plasmodesmata D) Golgi vesicles E) Free cytoplasmic ribosomes

A) Rough ER

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? A) Starch B) Cellulose C) Chitin D) Starch and chitin only E) Starch, cellulose, and chitin

A) Starch

Which of the following can vary among monosaccharides? A) The number of carbon atoms B) The presence of a carbonyl group C) The presence of hydroxyl groups D) The presence of sulfur groups

A) The number of carbon atoms

How do the α and β forms of glucose differ?A) Their ring structures differ in the location of a hydroxyl group. B) Their linear structures differ in the location of a hydroxyl group. C) The α form can be involved in 1,4- and 1,6-glycosidic linkages; the β form can participate only in 1,4 linkages. D) The oxygen atom inside the ring is located in a different position.

A) Their ring structures differ in the location of a hydroxyl group.

Which aspect of phospholipids is most important to the formation of bilayers? A) They are amphipathic. B) Their polar heads can interact with water. C) The length of their hydrocarbon tails can be altered to modulate membrane fluidity. D) Their hydrocarbon tails can consist of fatty acids or isoprene subunits.

A) They are amphipathic.

When nucleotides polymerize to form a nucleic acid, ________. A) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second B) a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second C) covalent bonds form between the bases of two nucleotides D) hydrogen bonds form between the bases of two nucleotides

A) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second

A membrane protein that spans the phospholipid bilayer one or more times is ________. A) a transmembrane protein B) an associated protein C) a peripheral protein

A) a transmembrane protein

Both DNA and RNA ________. A) are information-containing molecules B) show primary, secondary, tertiary, and quaternary structure C) are highly reactive catalysts in cells D) naturally occur as a double helix

A) are information-containing molecules

Lipids ________. A) are insoluble in water B) are made from glycerol, fatty acids, and nitrogen C) contain less energy than proteins and carbohydrates D) are made by dehydration reactions E) contain sulfur polymers

A) are insoluble in water

Starch and cellulose ________. A) are polymers of glucose B) are interchangeable C) can be digested by humans D) are used for energy storage in plants E) are structural components of the plant cell wall

A) are polymers of glucose

In some cells, there are many ion electrochemical gradients across the plasma membrane even though there are usually only one or two proton pumps present in the membrane. The gradients of the other ions are most likely accounted for by ________. A) cotransport proteins B) ion channels C) pores in the plasma membrane D) passive diffusion across the plasma membrane E) cellular metabolic reactions that create or destroy ions

A) cotransport proteins

Cooking oil and gasoline (a hydrocarbon) are NOT amphipathic molecules because they ________. A) do not have a polar or charged region B) do not have a nonpolar region C) have hydrophobic and hydrophilic regions D) are highly reduced molecules

A) do not have a polar or charged region

The evolution of eukaryotic cells most likely involved ________. A) endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria B) anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen—the anaerobic bacterium evolved into chloroplasts C) an endosymbiotic fungal cell evolving into the nucleus D) acquisition of an endomembrane system and subsequent evolution of mitochondria from a portion of the Golgi apparatus

A) endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria

All of the following are polysaccharides EXCEPT ________. A) lactose B) glycogen C) chitin D) cellulose E) amylopectin

A) lactose

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of ________. A) 120 adenine and 120 uracil molecules B) 120 thymine and 120 adenine molecules C) 120 cytosine and 120 thymine molecules D) 120 adenine and 120 cytosine molecules E) 120 guanine and 120 thymine molecules

B) 120 thymine and 120 adenine molecules

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence ________. A) 5'TAACGT3' B) 5'TGCAAT3' C) 5'UAACGU3' D) 3'UAACGU5' E) 5'UGCAAU3'

B) 5'TGCAAT3'

A glycosidic linkage is analogous to which of the following in proteins? A) An amino group B) A peptide bond C) A disulfide bond D) A β-pleated sheet

B) A peptide bond

What is the structural feature that allows DNA to replicate? A) Sugar-phosphate backbone B) Complementary pairing of the nitrogenous bases C) Disulfide bonding (bridging) of the two helixes D) Twisting of the molecule to form an α-helix E) Three-component structure of the nucleotides

B) Complementary pairing of the nitrogenous bases

Which of the following are pyrimidine nitrogenous bases? A) Guanine and adenine B) Cytosine and uracil C) Thymine and guanine D) Ribose and deoxyribose E) Adenine and thymine

B) Cytosine and uracil

Which of the following is a major difference between prokaryotic cells and eukaryotic cells? A) Prokaryotes have cells but eukaryotes do not. B) Eukaryotic cells have more intracellular organelles than prokaryotes. C) Prokaryotes are not able to carry out aerobic respiration, relying instead on anaerobic metabolism. D) Prokaryotes are generally larger than eukaryotes.

B) Eukaryotic cells have more intracellular organelles than prokaryotes.

Which of the following are purine nitrogenous bases? A) Cytosine and guanine B) Guanine and adenine C) Adenine and thymine D) Thymine and uracil E) Uracil and cytosine

B) Guanine and adenine

Which of the following is a characteristic feature of a carrier protein in a plasma membrane? A) It is a peripheral membrane protein. B) It exhibits a specificity for a particular type of molecule. C) It requires the expenditure of cellular energy to function. D) It works against diffusion. E) It has no hydrophobic regions.

B) It exhibits a specificity for a particular type of molecule.

What is the difference between a ribonucleotide and a deoxyribonucleotide? A) Ribonucleotides contain a phosphate group. B) Ribonucleotides have a hydroxyl group on the 2 carbons of their sugar subunit. C) Ribonucleotides contain a sugar with five carbon atoms. D) Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit.

B) Ribonucleotides have a hydroxyl group on the 2 carbons of their sugar subunit.

Which of the following is present in a prokaryotic cell? A) Mitochondrion B) Ribosome C) Nuclear envelope D) Chloroplast E) ER

B) Ribosome

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells? A) Rough ER B) Smooth ER C) Golgi apparatus D) Nuclear envelope E) Transport vesicles

B) Smooth ER

Which of the following statements about the 5' end of a polynucleotide strand of RNA is correct? A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose. B) The 5' end has a phosphate group attached to the number 5 carbon of ribose. C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base. D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose. E) The 5' end is the fifth position on one of the nitrogenous bases.

B) The 5' end has a phosphate group attached to the number 5 carbon of ribose.

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? A) The two strands of the double helix would separate. B) The phosphodiester linkages of the polynucleotide backbone would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.

B) The phosphodiester linkages of the polynucleotide backbone would be broken.

Which organelle often takes up much of the volume of a plant cell? A) Lysosome B) Vacuole C) Mitochondrion D) Golgi apparatus E) Peroxisome

B) Vacuole

Under what circumstances does membrane transport require energy? A) Wherever large molecules are moved within a cell B) Whenever a solute is moved against its electrochemical gradient C) Whenever an ion moves through a phospholipid bilayer membrane D) Whenever oxygen moves through a phospholipid bilayer membrane

B) Whenever a solute is moved against its electrochemical gradient

A phospholipid is a ________. A) nonpolar lipid molecule that is made polar by the addition of a phosphate B) nonpolar lipid molecule that is made amphipathic by the addition of a phosphate C) polar lipid molecule that fully interacts with water D) polar lipid molecule that fully repels water

B) nonpolar lipid molecule that is made amphipathic by the addition of a phosphate

A cell with an extensive area of smooth endoplasmic reticulum is specialized to ________. A) play a role in storage B) synthesize large quantities of lipids C) actively export protein molecules D) import and export protein molecules

B) synthesize large quantities of lipids

If a double-stranded DNA sample was composed of 10 percent thymine, what would be the percentage of guanine? A) 10 B) 20 C) 40 D) 80 E) It is impossible to tell from the information given.

C) 40

Which of the following is NOT found in a prokaryote? A) DNA B) A cell wall C) A mitochondrion D) A plasma membrane

C) A mitochondrion

Which of the following descriptions best fits the class of molecules known as nucleotides? A) A nitrogenous base and a phosphate group B) A nitrogenous base and a sugar C) A nitrogenous base, a phosphate group, and a sugar D) A phosphate group and an adenine or uracil E) A sugar and a purine or pyrimidine

C) A nitrogenous base, a phosphate group, and a sugar

Which of the following includes all of the pyrimidines found in RNA and DNA? A) Cytosine and uracil B) Cytosine and thymine C) Cytosine, uracil, and thymine D) Cytosine, uracil, and guanine

C) Cytosine, uracil, and thymine

Which of the following is TRUE of osmosis? A) Osmosis only takes place in red blood cells. B) Osmosis is an energy-demanding or "active" process. C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. D) In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration.

C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.

Which organelle is the primary site of ATP synthesis in eukaryotic cells? A) Lysosome B) Vacuole C) Mitochondrion D) Golgi apparatus E) Peroxisome

C) Mitochondrion

Which plant cell organelle contains its own DNA and ribosomes? A) Glyoxysome B) Vacuole C) Mitochondrion D) Golgi apparatus

C) Mitochondrion

Which of the following membrane activities requires energy from ATP? A) Facilitated diffusion of chloride ions across the membrane through a chloride channel B) Movement of water into a cell C) Movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid D) Movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than that inside the cell E) Movement of carbon dioxide out of a paramecium

C) Movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Nucleic acids have definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described? A) One end has a hydroxyl group on the 2 carbon; the other end has a hydrogen atom on the 2 carbons. B) One end contains a nitrogenous base; the other end lacks it. C) One end has an unlinked 3' hydroxyl; the other end has an unlinked 5' phosphate. D) One end has one phosphate group; the other end has two phosphate groups.

C) One end has an unlinked 3' hydroxyl; the other end has an unlinked 5' phosphate.

Which of the following types of molecules are the major structural components of the cell membrane? A) Phospholipids and cellulose B) Nucleic acids and proteins C) Phospholipids and proteins D) Proteins and cellulose

C) Phospholipids and proteins

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? A) Lipids B) Glycogen C) Proteins D) Cellulose E) Nucleic acids

C) Proteins

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids? A) Ribosome B) Lysosome C) Smooth endoplasmic reticulum D) Mitochondrion E) Contractile vacuole

C) Smooth endoplasmic reticulum

For a protein to be an integral membrane protein, it would have to be ________. A) hydrophilic B) hydrophobic C) amphipathic, with at least one hydrophobic region D) completely covered with phospholipids E) exposed on only one surface of the membrane

C) amphipathic, with at least one hydrophobic region

Chitin is a major component of the ________. A) cell walls of bacteria B) hydrostatic skeletons of earthworms C) exoskeleton of insects D) body hairs of mammals E) skeleton in birds

C) exoskeleton of insects

Phospholipids and triglycerides both ________. A) contain serine or some other organic compound B) have three fatty acids C) have a glycerol backbone D) have a phosphate

C) have a glycerol backbone

Celery stalks that are immersed in freshwater for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this, we can deduce that the freshwater ________. A) and the salt solution are both hypertonic to the cells of the celery stalks B) and the salt solution are both hypotonic to the cells of the celery stalks C) is hypotonic and the salt solution is hypertonic to the cells of the celery stalks D) is hypertonic and the salt solution is hypotonic to the cells of the celery stalks E) is isotonic and the salt solution is hypertonic to the cells of the celery stalks

C) is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

A major feature of phospholipids that causes a portion of their structure to be hydrophilic is ________. A) the glycerol backbone B) the unsaturated fatty acid tails C) the phosphate group D) the ester linkages E) the saturated fatty acid tails

C) the phosphate group

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? A) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5' B) 5'-AGCT-3' with 5'-TCGA-3' C) 5'-GCGC-3' with 5'-TATA-3' D) 5'-ATGC-3' with 5'-GCAT-3' E) All of these pairs are correct.

D) 5'-ATGC-3' with 5'-GCAT-3'

Which of the following crosses lipid bilayers the fastest? A) A sodium ion B) A small, polar molecule like water C) A large, polar molecule like glucose D) A small, nonpolar molecule like oxygen (O2)

D) A small, nonpolar molecule like oxygen (O2)

Which of the following polymers contain nitrogen? A) Starch B) Glycogen C) Cellulose D) Chitin E) Glucose

D) Chitin

Which of the following produces and modifies polysaccharides that will be secreted? A) Lysosome B) Vacuole C) Mitochondrion D) Golgi apparatus E) Peroxisome

D) Golgi apparatus

Which of the following increases the strength of the hydrophobic interactions in lipid bilayers and thus makes them less permeable to polar molecules? A) The presence of double bonds B) Increasing temperature C) Removing cholesterol D) Increasing length of the hydrocarbon chains

D) Increasing length of the hydrocarbon chains

Which structure is common to plant and animal cells? A) Chloroplast B) Wall made of cellulose C) Central vacuole D) Mitochondrion E) Centriole

D) Mitochondrion

Lipids that form membranes have what kind of structure? A) Polar heads and polar tails, which allows them to interact with water on both sides of the membrane. B) Completely polar, which allows them to dissolve in water. C) Polar heads and nonpolar tails; the nonpolar tails interact with water. D) Polar heads and nonpolar tails; the polar heads interact with water.

D) Polar heads and nonpolar tails; the polar heads interact with water.

Where would you most likely find an integral membrane protein? A) On the inside surface of the cell membrane B) On the outside surface of the cell membrane C) Floating freely in the cytoplasm D) Spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell

D) Spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell

What is/are the variable structure(s) of a nucleotide? A) The phosphate group B) The sugar C) The base D) The sugar and the base

D) The sugar and the base

Why are lipids and proteins free to move laterally in membranes? A) The interior of the membrane is filled with liquid water. B) Lipids and proteins repulse each other in the membrane. C) Hydrophilic portions of the lipids are in the interior of the membrane. D) There are only weak hydrophobic interactions in the interior of the membrane. E) Molecules such as cellulose can pull them in various directions.

D) There are only weak hydrophobic interactions in the interior of the membrane.

Refer to the figure. If you examine side A after three days, you should find ________. A) a decrease in the concentration of NaCl and glucose and an increase in the water level B) a decrease in the concentration of NaCl, an increase in the water level, and no change in the concentration of glucose C) no net change in the system D) a decrease in the concentration of NaCl and a decrease in the water level E) no change in the concentration of NaCl and glucose and an increase in the water level

D) a decrease in the concentration of NaCl and a decrease in the water level

Cellulose is ________. A) a polymer composed of fructose monomers B) a storage polysaccharide for energy in plant cells C) used by plants to make glycogen D) a major structural component of plant cell walls E) a monomer of starch

D) a major structural component of plant cell walls

In a plant cell, DNA may be found ________. A) only in the nucleus B) only in the nucleus and mitochondria C) only in the nucleus and chloroplasts D) in the nucleus, mitochondria, and chloroplasts E) in the nucleus, mitochondria, chloroplasts, and peroxisomes

D) in the nucleus, mitochondria, and chloroplasts

In a bacterium, we will find DNA in ________. A) a membrane-enclosed nucleus B) mitochondria C) the endoplasmic reticulum D) the nucleoid E) ribosomes

D) the nucleoid

Ions diffuse across membranes through specific ion channels down ________. A) their chemical gradients B) their concentration gradients C) their electrical gradients D) their electrochemical gradients E) the osmotic potential gradients

D) their electrochemical gradients

Which of the following allows water to move much faster across cell membranes? A) The hydrophobic interior of a cell membrane B) The sodium-potassium pump C) ATP D) Peripheral proteins E) Aquaporins

E) Aquaporins

Which structure—function pair is mismatched? A) Nucleolus—production of ribosomal subunits B) Lysosome—intracellular digestion C) Ribosome—protein synthesis D) Golgi—protein trafficking E) Microtubule—muscle contraction

E) Microtubule—muscle contraction

All of the following are part of a prokaryotic cell EXCEPT ________. A) DNA B) a cell wall C) a plasma membrane D) ribosomes E) an endoplasmic reticulum

E) an endoplasmic reticulum

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA ________. A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar B) can form a double-stranded molecule C) is an aldehyde sugar and the sugar in RNA is a keto sugar D) is in the α configuration and the sugar in RNA is in the β configuration E) contains one less oxygen atom

E) contains one less oxygen atom

A molecule with the chemical formula C6H12O6 is probably a ________. A) fatty acid B) polysaccharide C) phospholipid D) nucleic acid E) monosaccharide

E) monosaccharide

A) a hexose

The molecule shown in the accompanying figure is ________. A) a hexose B) a pentose C) a phosphate D) a fructose E) a maltose

B) side A is hypotonic to side B.

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Refer to the figure. At the beginning of the experiment, A) side A is hypertonic to side B. B) side A is hypotonic to side B. C) side A is isotonic to side B. D) side A is hypertonic to side B with respect to glucose. E) side A is hypotonic to side B with respect to NaCl.