Bio Test 2

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

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

Amoebae move by crawling over a surface (cell crawling), which involves ________. A) growth of actin filaments to form bulges in the plasma membrane B) setting up microtubule extensions that vesicles can follow in the movement of cytoplasm C) cytoplasmic streaming D) reinforcing the pseudopod with intermediate filaments

A) growth of actin filaments to form bulges in the plasma membrane

A primary function of carbohydrates attached to the glycoproteins and glycolipids of animal cell membranes is to ________. A) mediate cell cell recognition B) facilitate diffusion of molecules down their concentration gradients C) maintain membrane fluidity at low temperatures D) actively transport molecules against their concentration gradients E) maintain the integrity of a fluid mosaic membrane

A) mediate cell; cell recognition

Movement of vesicles within the cell depends on what cellular structures? A) microtubules and motor proteins B) actin filaments and microtubules C) actin filaments and motor proteins D) centrioles and motor proteins E) actin filaments and ribosomes

A) microtubules and motor proteins

Which structure is common to plant and animal cells? A) mitochondrion B) centriole C) chloroplast D) central vacuole E) wall made of cellulose

A) mitochondrion

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

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

Which of the following processes includes all others? A) passive transport B) diffusion of a solute across a membrane C) transport of an ion down its electrochemical gradient D) facilitated diffusion E) osmosis

A) passive transport

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

A) the sugar and base

Some bacteria are metabolically active in hot springs because ________. A) their enzymes have high optimal temperatures B) they are able to maintain a lower internal temperature C) they use molecules other than proteins or RNAs as their main catalysts D) high temperatures make catalysis unnecessary E) their enzymes are completely insensitive to temperature

A) their enzymes have high optimal temperatures

Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin? A) -1,4-glycosidic linkage B) -1,6-glycosidic linkage C) -1,4-glycosidic linkage D) -1,6-glycosidic linkage

B) 1-6-glycosidic linkage

Nucleic acids are polymers made up of which of the following monomers? A) amino acids B) nucleotides c) phosphates D) ribose sugars E) nitrogenous bases

B) Nucleotides

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

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

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

B) a peptide bond

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

B) cytosine, uracil, and thymine

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

B) glucose versus glycogen

What is the function of the nuclear pore complex found in eukaryotes? A) It assembles ribosomes from raw materials that are synthesized in the nucleus. B) It regulates the movement of proteins and RNAs into and out of the nucleus. C) It selectively transports molecules out of the nucleus but prevents all inbound molecules from entering the nucleus. D) It synthesizes the proteins required to copy DNA and make mRNA.

B) it regulates the movement of proteins and RNAs into and out of the nucleus

Which plant cell organelle contains its own DNA and ribosomes? A) Golgi apparatus B) mitochondrion C) vacuole D) glyoxysome E) peroxisome

B) mitichondrion

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? A) cellulose B) proteins C) lipids D) nucleic acids E) glycogen

B) proteins

Which of the following is present in a prokaryotic cell? A) nuclear envelope B) ribosome C) ER D) mitochondrion E) chloroplast

B) ribosome

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

B) the presence of carbon atoms

Which of the following statements is TRUE about enzyme-catalyzed reactions? A) The free-energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme. B) The reaction is faster than the same reaction in the absence of the enzyme. C) An enzyme catalyzes a reaction by raising the activation energy. D) Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions. E) Enzyme-catalyzed reactions require energy to activate the enzyme.

B) the reaction is faster than the same reaction in the absence of the enzyme

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed? A) their sugar groups B) their phosphate groups C) their methyl groups D) their nitrogenous bases

B) their phosphate groups

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

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

C) Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.

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

C) Ribonucleotides have a hydroxyl group on the 2 carbon on their sugar subunit

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

C) are insoluble in water

A noncompetitive inhibitor decreases the rate of an enzyme reaction by ________. A) decreasing the activation energy of the reaction B) acting as a coenzyme for the reaction C) changing the shape of the enzyme's active site D) binding at the active site of the enzyme E) changing the overall free-energy of the reaction

C) changing the shape of an enzymes active site

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

C) chitin

7) What is the structural feature that allows DNA to replicate? A) disulfide bonding (bridging) of the two helixes B) three-component structure of the nucleotides C) complementary pairing of the nitrogenous bases D) sugar-phosphate backbone E) twisting of the molecule to form an -helix

C) complimentary pairing of nitrogenous bases

5) Which of the following are purine nitrogenous bases? A) thymine and uracil B) uracil and cytosine C) guanine and adenine D) adenine and thymine E) cytosine and guanine

C) guanine and adenine

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

C) have a glycerol backbone

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

D) a greater proportion of saturated phospholipids

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

D) a sodium ion

Which structure function pair is mismatched? A) ribosome protein synthesis B) nucleolus production of ribosomal subunits C) lysosome intracellular digestion D) microtubule muscle contraction E) Golgi protein trafficking

D) microtubule muscle contraction

Which of the following molecules contains at LEAST one peptide bond? A) chitin B) glycogen C) cellulose D) peptidoglycan

D) peptidoglycan

An organism with a cell wall would most likely be unable to take in materials through ________. A) osmosis B) diffusion C) active transport D) phagocytosis E) facilitated diffusion

D) phagocytosis

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) polar heads and nonpolar tails; the nonpolar tails interact with water C) completely polar, which allows them to dissolve in 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

According to the induced fit hypothesis of enzyme catalysis, ________. A) some enzymes change their structure when activators bind to the enzyme B) a competitive inhibitor can outcompete the substrate for the active site C) the binding of the substrate depends on the shape of the active site D) the binding of the substrate changes the shape of the enzyme's active site E) the active site creates a microenvironment ideal for the reaction

D) the binding of the substrate changes the shape of an enzyme's active site

Nucleic acids have a 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 has a hydrogen atom on the 2 carbon. B) one end contains a nitrogenous base; the other end lacks it. C) one ned has one phosphate group; the other end has two phosphate groups D) one end has an unlinked 3' carbon; the other end has an unlinked 5 carbon.

D)one end has an unlinked 3' carbon; the other end has an unlinked 5 carbon.

Which of the following correctly matches a component of the cytoskeleton to one of its functions? A) Microfilaments form the nuclear lamina. B) Microfilaments cause ciliary bending. C) Microtubules help animal cells divide in two. D) Intermediate filaments contribute to cytoplasmic streaming. E) Microtubules move chromosomes.

E) Microtubules move chromosomes

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

E) a major structural component of plant cell walls

Thylakoids, DNA, and ribosomes are all components found in ________. A) nuclei B) lysosomes C) mitochondria D) vacuoles E) chloroplasts

E) chloroplasts

When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are ________. A) carbohydrates B) cholesterol molecules C) phospholipids D) peripheral proteins E) integral proteins

E) integral proteins

The Golgi apparatus has a polarity, or sidedness, to its structure and function. Which of the following statements correctly describes this polarity? A) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. B) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. C) Transport vesicles fuse with one side of the Golgi and leave from the opposite side. D) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. E) All of the listed responses correctly describe polarity characteristics of the Golgi function.

E)All of the listed responses correctly describe polarity characteristics of the Golgi function.