BIOB 160 test 2

This H7N9 Influenza A virus is being called a bird flu, and it is probably so deadly since it: 48) ______ A) Evolved different surface molecules in chickens that are different from those that were most common in recent human influenza outbreaks. B) The immune systems of birds and humans are so different. C) Chickens and humans should not share the same diseases. D) These are the first cases of a virus jumping from a bird to a human. E) Birds are not mammals.

evolved different surface molecules in chickens that are different from those that were most common in recent human influenza outbreaks

Prion diseases are caused by: 49) ______ A) Mis-folded proteins that cause others to change their shape too. B) Viruses with unique combinations of surface proteins. C) Viruses that jump into humans from other animals such as cows and deer. D) Bacteria that jump into humans from other animals such as cows and deer.. E) Genetic mutations in enzymes.

mis-folded proteins that cause others to change their shape too

Which of the following statements correctly describes cis-trans isomers? 11) ______ A) Their atoms and bonds are arranged in different sequences. B) They have the same chemical properties. C) They have different molecular formulas. D) They have an asymmetric carbon that makes them mirror images. E) They have variations in arrangement around a double bond.

they have variations in arrangement around a double bond

In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are then used for the synthesis of new macromolecules. The net result is that: 22) ______ A) water is consumed during homeostasis, but water is generated during periods of growth. B) water is generated by animal metabolism. C) water is generated during homeostasis, but water is consumed during periods of growth. D) water is consumed by animal metabolism. E) the water consumed is exactly balanced by the water generated, to maintain homeostasis. 23)

water is consumed by animal metabolism

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? 24) ______ A) 11 B) 8 C) 9 D) 10 E) 12

10

) How many electron pairs does carbon share in order to complete its valence shell? 9) ______ A) 2 B) 8 C) 4 D) 3 E) 1

4

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A) a van der Waals interaction B) an ionic bond C) a covalent bond D) a hydrogen bond E) a hydrophilic bond

a hydrogen bond

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement? 27) ______ A) a steroid B) a contractile protein C) an enzyme D) cellulose E) DNA

a steroid

Which of the following effects is produced by the high surface tension of water? A) Lakes don't freeze solid in winter, despite low temperatures. B) Evaporation of sweat from the skin helps to keep people from overheating. C) Organisms resist temperature changes, although they give off heat due to chemical reactions. D) A water strider can walk across the surface of a small pond. E) Water flows upward from the roots to the leaves in plants.

a water strider can walk across the surface of a small pond

Liquid water's high specific heat is mainly a consequence of the A) small size of the water molecules. B) high specific heat of oxygen and hydrogen atoms. C) absorption and release of heat when hydrogen bonds break and form. D) higher density of liquid water than solid water (ice). E) fact that water is a poor heat conductor.

absorption and release of heat when hydrogen bonds break and form

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that 12) ______ A) exist in either linear chain or ring forms. B) differ in the arrangement of atoms around their double bonds. C) are mirror images of one another. D) have identical chemical formulas but differ in the branching of their carbon skeletons. E) differ in the location of their double bonds.

are mirror images of one another

What aspects of protein structure are stabilized or assisted by hydrogen bonds? 30) ______ A) primary structure B) secondary, tertiary, and quaternary structures, but not primary structure C) quaternary structure D) secondary structure E) tertiary structure

b or c

The element present in all organic molecules is A) carbon. B) nitrogen. C) oxygen. D) hydrogen. E) phosphorus.

carbon

Which two functional groups are always found in amino acids? 14) ______ A) carbonyl and amino B) carboxyl and amino C) hydroxyl and carboxyl D) amino and sulfhydryl E) ketone and methyl

carboxyl and amino

What is the structural feature that allows DNA to replicate? 37) ______ A) sugar-phosphate backbone B) disulfide bonding (bridging) of the two helixes C) complementary pairing of the nitrogenous bases D) three-component structure of the nucleotides E) twisting of the molecule to form an α helix

complementary pairing of the nitrogenous bases

What is the chemical reaction mechanism by which cells make polymers from monomers? 23) ______ A) phosphodiester linkages B) the formation of disulfide bridges between monomers C) ionic bonding of monomers D) hydrolysis E) dehydration reactions

dehydration reactions

There are 20 different amino acids. What makes one amino acid different from another? 29) ______ A) different side chains (R groups) attached to the amino groups B) different side chains (R groups) attached to an α carbon C) different structural and optical isomers D) different asymmetric carbons E) different side chains (R groups) attached to a carboxyl carbon

different side chains (R-groups) attached to an alpha carbon

A species of archaea lives in near-boiling water in hot springs in Yellowstone. The fatty acids found in its cell membranes are most likely 50) ______ A) Non-existant, since Prokaryotes don't have cell membranes. B) fully saturated. C) Unsaturated. D) Trans fats. E) Omega three fatty acids.

fully saturated

One of the primary functions of RNA molecules is to 36) ______ A) make a copy of itself, thus ensuring genetic continuity. B) form the genes of higher organisms. C) function in the synthesis of proteins. D) act as a pattern or blueprint to form DNA. E) transmit genetic information to offspring.

function in the synthesis of proteins

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins? 31) ______ A) peptide bonds B) disulfide bonds C) hydrogen bonds D) hydrophobic interactions E) ionic bonds

hydrogen bonds

) In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine? 34) ______ A) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains B) on the exterior surface of the protein, interacting with water C) anywhere in the protein, with equal probability D) in the interior of the folded protein, away from water E) in the transmembrane portion interacting with lipid fatty acid chains

in the interior of the folded protein, away from water, or in a transmembrane portion interaction with the lipid fatty acid chains

) A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound? 13) ______ A) It lacks an asymmetric carbon, and it is probably a fat or lipid. B) It won't form hydrogen bonds with water. C) It should dissolve in a nonpolar solvent. D) It is hydrophobic. E) It should dissolve in water.

it should dissolve in water

) An extremely virulent Influenza virus is now sweeping China, and about 20% of people who become infected die. The virus is classified as a H7N9 Influenza A. This indicates that 47) ______ A) There are between 7 and 9 different forms of the virus that infect people. B) The virus likely only infects humans and seals. C) Its surface capsule is covered with the glycoprotein hamagglutinin 7 and the neuraminidase 9. D) The epidemic will probably not last long since it is mutating so rapidly. E) The flu season in North America next winter will most likely be very mild.

its surface capsule is covered with the glycoprotein hamagglutinin 7 and the neuraminidase 9

Hydrophobic substances such as vegetable oil are A) polar substances that repel water molecules. B) nonpolar substances that repel water molecules. C) charged molecules that hydrogen-bond with water molecules. D) nonpolar substances that have an attraction for water molecules. E) polar substances that have an affinity for water.

nonpolar substances that repel water molecules

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by A) nonpolar covalent bonds. B) ionic bonds. C) polar covalent bonds. D) hydrogen bonds. E) van der Waals interactions.

polar covalent bonds

Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely A) hydrophobic. B) without charge. C) negatively charged. D) positively charged. E) nonpolar.

positively charged

If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled? 35) ______ A) proteins B) both proteins and nucleic acids C) nucleic acids D) phospholipids E) amylose

proteins

Which level of protein structure do the α helix and the β pleated sheet represent? 32) ______ A) quaternary B) primary C) primary, secondary, tertiary, and quaternary D) secondary E) tertiary

secondary

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? 15) ______ A) Testosterone and estradiol are cis-trans isomers but have the same molecular formula. B) Testosterone and estradiol are enantiomers of the same organic molecule. C) Testosterone and estradiol are structural isomers but have the same molecular formula. D) Testosterone and estradiol have different functional groups attached to the same carbon skeleton. E) Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, while the other has three rings.

testosterone and estradiol have different functional groups attached to the same carbon skeleton

The complexity and variety of organic molecules is due to 8) ______ A) their interaction with water. B) the chemical versatility of carbon atoms. C) their tremendously large sizes. D) the variety of rare elements in organic molecules. E) the fact that they can be synthesized only in living organisms.

the chemical versatility of carbon atoms

The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil? 26) ______ A) The hydrogenated vegetable oil has fewer trans fatty acids. B) The hydrogenated vegetable oil is less likely to clog arteries. C) The hydrogenated vegetable oil has a lower melting point. D) The hydrogenated vegetable oil has more "kinks" in the fatty acid chains. E) The hydrogenated vegetable oil stays solid at room temperature.

the hydrogenated vegetable oil stays solid at room temperature

) Why are hydrocarbons insoluble in water? 10) ______ A) They exhibit considerable molecular complexity and diversity. B) The majority of their bonds are polar covalent carbon-to-hydrogen linkages. C) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. D) They are hydrophilic. E) They are lighter than water.

the majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.

Which of the following statements is true for the class of biological molecules known as lipids? 25) ______ A) They contain less energy than proteins and carbohydrates. B) They contain nitrogen. C) They are made from glycerol, fatty acids, and phosphate. D) They are insoluble in water. E) They are made by dehydration reactions.

they are insoluble in water

Why are human sex hormones considered to be lipids? 28) ______ A) They are essential components of cell membranes. B) They are not soluble in water. C) They are hydrophilic compounds. D) They contribute to atherosclerosis. E) They are made of fatty acids.

they are not soluble in water