Bio Final PT 1

When a crystal of table salt (Na+Cl-) dissolves in water, _____ bonds are being broken in the salt, and the salt is forming ____ bonds with water. (A) ionic, hydrogen (B) ionic, ionic (C) hydrogen, ionic (D) hydrogen, hydrogen (E) none of these choices are correct

(A) ionic, hydrogen

A certain ring molecule is made up of only C and H atoms and has no double bonds. If the ring has 6 carbon atoms, then how many H atoms does it have? Recall that one carbon atom can form single covalent bonds with four atoms. - 6 - 10 - 12 - 18 - none of these is correct

12

If the delta G of ATP hydrolysis is -7.3 kcal/mol, then ATP hydrolysis can be energy-coupled with and drive reactions having which of the following values of delta G? A. + 5 kcal/mol B. + 7.3 kcal/mol C. C. + 9 kcal/mol D. A or B but not C E. A or B or C

A. + 5 kcal/mol

Certain cells in the digestive tract transport chloride ions to the inside of the cell and transport bicarbonate ions to the outside the cell, which is done together by same membrane transport protein. Such a transport protein is called a A. antiport. B biport. C. cotransport. D. symport. E. uniport.

A. antiport.

Monomers of this group are polar but never electrically charged. A. carbohydrates B. lipids C. nucleic acids D. proteins

A. carbohydrates

An antibody is a complex protein made by our defense system. The tip of each specific type of antibody binds only to a particular antigen (e.g., specific viral particle). This binding specificity depends on which combination of properties at the tip? A. complementary surface shapes and polarity of antigen and antibody B. similar electrostatic charges on R groups of antigen and R groups of antibody C. ability of antibody to undergo a chemical reaction (e.g., by condensation) to the antigen D. presence of an enzyme binds to both antigen and antibody then joins them to each

A. complementary surface shapes and polarity of antigen and antibody

Competitive inhibitors of enzymes work by A. fitting into the active site B. fitting into a site other than the active site C. altering the shape of the enzyme D. changing the enzyme into an inactive form E. increasing the activation energy of the enzyme-catalyzed reaction.

A. fitting into the active site

A water strider (an insect that can walk on water) has legs that are coated with a hydrophobic substance. What would happen if the substance were more polar? A. it would break the surface tension of the water B. it would dissolve the insect's legs C. the insect would heat up more quickly D. water on the insect's surface would evaporate more quickly

A. it would break the surface tension of the water

Solution A contains 0.2 M glucose and 0.5 M sucrose (both solutes). A membrane separates it from Solution B which contains 0.1 M glucose and 0.1 M sucrose. The membrane is permeable to glucose and water but is not permeable to sucrose. After net movement of sugar stops, which describes the water movement that occurs? A. net movement of water towards side A B. net movement of water towards side B C. no net movement of water

A. net movement of water towards side A

The specific sequence of amino acids in a polypeptide is the __ structure of the protein A. primary B. secondary C. tertiary D. quaternary

A. primary

Which redox statement is true about the overall process of cellular respiration? A. Oxidized carbon compounds enter and become reduced B. Reduced carbon compounds enter and become oxidized C. Coenzyme carriers become oxidized, losing electrons to fuel molecules D. Coenzyme carriers become reduced, gaining electrons from ATP

B. Reduced carbon compounds enter and become oxidized

Hydrogen bonding helps to hold all of these aspects of protein structure, EXCEPT which? A. Secondary structure, but not via hydrogen bonds between R groups B. Secondary structure, via hydrogen bonds between R groups C. Tertiary structure, via hydrogen bonds between R groups D. Quaternary structure, via hydrogen bonds between R groups

B. Secondary structure, via hydrogen bonds between R groups

What chemical property of lipids accounts for their insolubility in water? A. The length of the carbon chain B. The large number of non-polar C-H bonds C. The branching of saturated fatty acids D. The type of carbon-carbon bonds found in unsaturated fatty acids.

B. The large number of non-polar C-H bonds

One end of the main chain of any polypeptide ends in an amino group. What functional group must be at the other end of that polypeptide chain? A. amino B. carboxyl C. hydroxyl D. two of these could be possible E. any of these three could be possible

B. carboxyl

Which of the following functional groups when covalently bonded to a carbon atom on molecules in cells often dissociates to donate a H+ ion and become negatively charged? A. amino B. carboxyl C. hydroxyl D. methyl E. two of these

B. carboxyl

The statement "Enzymes are highly specific" means certain A. enzymes are found in certain cells B. enzymes catalyze reactions with certain substrates C. enzymes require certain concentrations of substrates You Answered D. reactions with certain activation energies are catalyzed by certain enzymes E. enzymes can catalyze many different reactions, one at a time

B. enzymes catalyze reactions with certain substrates

In oral rehydration therapy for severely dehydrated patients, the solution includes water, "electrolytes" (ions such as Na+, K+, Cl-), and a little sugar. The function of the electrolytes and sugars in such solutions is to: A. increase the thirst of the patient so they drink more B. increase the overall uptake of water into cells C. decrease the overall loss of water from cells D. increase the energy molecules entering the cells E. increase the use of ATP for membrane transport of water

B. increase the overall uptake of water into cells

Macromolecules in this group are NOT chains of monomers A. carbohydrates B. lipids C. nucleic acids D. proteins

B. lipids

NAD+ is a dinucleotide coenzyme that is important in cellular respiration. It is (becomes) _______ when gaining electrons and then is (becomes) _______ when it A. oxidized . . . reduced B. reduced . . . oxidized C. oxidized . . . energized D. reduced . . . energized

B. reduced . . . oxidized

Cystic fibrosis is a genetic disease caused by lack of functional chloride ion channels of a certain type. In normal lung tissue chloride ions flow out of cells, as part of the flow keeping the external lining of mucus and cilia clear. In cystic fibrosis patients, harmful mucus accumulates on the outside of cells and is not cleared away. This accumulation occurs because the chloride ions are NOT flowing out of the cell normally and as a result - A. excess water flows out of the cell B. water stops flowing out of the cell C. excess chloride ions flow into the cell D. excess mucus flows into the cell

B. water stops flowing out of the cell

Which of the following is considered a non-polar covalent bond in biological molecules? O-H N-H C-H Na-Cl- Na-Cl

C-H

A straight chain molecule (not in a ring, not branched) made up of only C and H atoms has just one double bond between two of the carbon atoms in the chain. If the chain has 5 carbon atoms, then how many H atoms does it have? A. 5 B. 8 C. 10 D. 12 E. none of these is correct

C. 10

Which of the following statements about ion channels is NOT true? A. They form pores in the membrane B. Movement through them is passive, does not require ATP C. Many types of ions pass through the same type of channel D. Movement through a given channel could be either into the cell or out of the cell E. Two of these statements (A-D) are not true.

C. Many types of ions pass through the same type of channel

Two samples of experimental data differ in mean values, but both samples have very large standard errors. Which of these conclusion statements is mostly likely true? A. because their mean values differ, the two populations must differ from one another B. because both have large standard errors, the two populations must differ from one another C. because both have very large standard errors, we cannot say whether the two populations differ D. because the two samples are large and from large populations, they must differ from one another.

C. because both have very large standard errors, we cannot say whether the two populations differ

Which of the following statements about enzymes is FALSE? A. enzymes do not affect equilibrium point of reactions B. enzymes lower the activation energy of a reaction C. enzymes convert endergonic reactions to exergonic reactions D. enzymes are highly specific

C. enzymes convert endergonic reactions to exergonic reactions

During the era of chemical evolution in the early earth, before any living cells, one important step was formation of polymers from monomers. Such synthesis reactions usually require energy. Which of these is a reasonable scenario for this step to have occurred in the early abiotic earth? A. sunlight was trapped during photosynthesis reactions B. enzymes in solutions facilitated binding of monomers into chains C. heating of sediment layers promoted condensation reactions D. excess ultraviolet light trapped to break covalent bonds

C. heating of sediment layers promoted condensation reactions

What type of bonds/interactions occur between the hydrocarbon tails of two adjacent phospholipid molecules in a plasma membrane? A. ionic bonds B. hydrogen bonds C. hydrophobic interactions D. polar covalent bonds E. more than one of these.

C. hydrophobic interactions

Since most biological enzymes are proteins, which is the best explanation for how an enzyme can work only on specific reactions? A. it has a specific overall size B. it consists of only one specific amino acid. C. its active site has a specific shape and polarity D its active site has a specific volume E. it only works with specific inhibitors

C. its active site has a specific shape and polarity

In a classic molecular genetics experiment, biologists used either radioactive sulfur or radioactive phosphorus atoms to "label" two batches of virus molecules. In this way they were able to distinguish DNA from proteins because A. nucleic acids but not proteins contain sulfur; B. proteins but not nucleic acids contain phosphorus C. proteins but not nucleic acids contain sulfur D. both proteins and nucleic acids contain both phosphorus and sulfur.

C. proteins but not nucleic acids contain sulfur

Which of the following is a hydrophobic material? A. paper B. table salt C. wax D. sugar E. more than one of these

C. wax

Which of the following is NOT a correct match of one of the domains of life and a distinctive trait of members of the group named? A. Eukarya - nuclear envelope present B. Archaea - branched hydrocarbon chains in membrane lipids C. Bacteria - single loop chromosome D. Archaea - presence of peptidoglycan in cell wall E. Bacteria - smaller ribosomes than in Eukarya

D. Archaea - presence of peptidoglycan in cell wall

Solutes that easily dissolve in water are said to be A. hydrophobic B. hydrophilic C. polar molecules D. B and C only E. all of the above

D. B and C only

Which of these is a case of hydrolysis? A. Dissolving sugar in water B. Linking sugars to form a chain C. Splitting water into individual, separate H and O atoms D. Digesting starch into sugars E. Breaking hydrogen bonds between water molecules

D. Digesting starch into sugars

Feedback inhibition works to control the rate of an enzyme-catalyzed reaction sequence in which way? A. The product of the first reaction in the pathway binds to and inhibits the enzyme that produced it B. The product of the first reaction in the pathway binds to and inhibits the last enzyme in the pathway C. The end product of the pathway binds to and inhibits the enzyme that produced it D. The end product of the pathway binds to and inhibits the first enzyme in the pathway E. The last enzyme in the pathway binds to and inhibits the first enzyme in the pathway

D. The end product of the pathway binds to and inhibits the first enzyme in the pathway

If a hypothesis statement were "cells with extra-cellular distilled water added (outside cell) produce more aquaporins", then the null hypothesis would be: A. cells with extracellular isotonic water added produce more aquaporins B. cells with extracellular distilled water added produce fewer aquaporins C. cells with no extracellular distilled water added produce more aquaporins D. adding extracellular distilled water has no effect on production of aquaporins

D. adding extracellular distilled water has no effect on production of aquaporins

Unsaturated fats would be expected to __ A. contain all single bond carbons and be solid at room temperature B. contain double bond carbons and be solid at room temperature C. contain all single bond carbons and be liquid at room temperature D. contain double bond carbons and be liquid at room temperature

D. contain double bond carbons and be liquid at room temperature

According to the second law of thermodynamics, when a reaction occurs (within a closed system) which of these tends to happen? A. energy is destroyed B. energy changes form; C. enthalpy H increases D. entropy S increases E. free energy increases.

D. entropy S increases

Extremely high temperatures can denature proteins, so they no longer function. Which of the following is happening in protein denaturation to explain the loss of function? A. only the disulfide bridges are being broken B. only the bonds holding secondary structure are broken C. peptide bonds between amino acids are being broken D. interactions between R groups are being broken

D. interactions between R groups are being broken

On days when the humidity is very high, it may "feel" hotter to us than on dry days reaching the same temperature. "It's not just the heat, it's the humidity." Which of these describes the reason that our skin feels cooler on dry days? A. because water is polar, it boils at a temperature of 212°F (100°C) B. because water is polar, it has a high surface tension C. when water evaporates, energy is released to break hydrogen bonds D. less water evaporates under conditions of higher humidity

D. less water evaporates under conditions of higher humidity

The Miller-Urey laboratory experiments (closed container with heat and electricity) demonstrated that: A. living cells could be formed in a test-tube environment B. living cells, once formed, could survive under early earth conditions C. membrane-like structures could form from phospholipids in water D. organic molecules could form from simple inorganic molecules E. polymers could form from monomers in chemical evolution

D. organic molecules could form from simple inorganic molecules

Which of the following describes the action of the sodium-potassium pump with respect to concentration gradients? A. transports Na+ ions against their gradient and K+ ions down their gradient B. transports K+ ions against their gradient and Na+ ions down their gradient C. transports both Na+ ions and K+ ions down their gradients D. transports both Na+ ions and K+ ions against their gradients

D. transports both Na+ ions and K+ ions against their gradients

The versatility of carbon to serve as the backbone for a variety of different molecules is due to A. the ability of carbon atoms to form four covalent bonds B. the ability of carbon to form covalent bonds with many different types of atoms. C. the fact that carbon usually forms ionic bonds with many different atoms D. the abundance of carbon in the environment E. A and B are correct F. A, B, and C are correct G. A, B, and D are correct

E. A and B are correct

Which of the following statements contributes LEAST support to the argument that mitochondria and chloroplasts evolved from prokaryotic endo-symbionts? A. Mitochondria and chloroplasts have double membranes. B. Mitochondria and chloroplasts have their own ribosomes. C. Mitochondria and chloroplasts have their own DNA. D. The mitochondrial and chloroplast genomes are circular. E. Mitochondria and chloroplasts have internal membranes containing many types of proteins.

E. Mitochondria and chloroplasts have internal membranes containing many types of proteins.

When an enzyme's function is to catalyze two reactions at once, one an exergonic reaction and one an endergonic reaction, the two reactions are said to be A. substrates B. non-spontaneous C. kinetic D. activated E. coupled

E. coupled

Three 5-carbon monosaccharide molecules (simple sugars, like ribose) react by condensation to form a short chain (a tri-saccharide). How many oxygen atoms will be in the resulting tri-saccharide? A. 5 B. 10 C. 12 D. 15 E. none of these (some other number is correct)

E. none of these (some other number is correct)

One glycerol (an alcohol with 3 carbon atoms each bonded to an OH group) and 3 fatty acid molecules react to form a triglyceride fat or oil (= a triacylglyceride) by condensation. How many water molecules are formed? A. none, water molecules are used up, not formed B. none; water does not form hydrogen bonds with fats C. one D. two E. three

E. three

Which of the following can move through the phospholipid bilayer portion of a membrane without requiring a transport protein? A. potassium ion B. glucose C . O2 D. a small amino acid with a non-polar R group E. a fatty acid molecule F. C and E D. A, C and E

F. C and E

The pH scale indicates the relative concentration of H+ ions in a solution. When the pH increases by 1 unit (e.g., from 4 to 5), which of these changes is occurring? A. the H+ ion concentration is increasing by a factor of 2 (doubling), and the solution is becoming more acidic B. the H+ ion concentration is increasing by a factor of 10, and the solution is becoming more acidic C. the H+ ion concentration is decreasing by a factor of 2 (halving), and the solution is becoming more acidic D. the H+ ion concentration is decreasing by a factor of 10, and the solution is becoming more acidic E. the H+ ion concentration is increasing by a factor of 2 (doubling), and the solution is becoming more basic F. the H+ ion concentration is increasing by a factor of 10, and the solution is becoming more basic G. the H+ ion concentration is decreasing by a factor of 2 (halving), and the solution is becoming more basic H. the H+ ion concentration is decreasing by a factor of 10, and the solution is becoming more basic

H. the H+ ion concentration is decreasing by a factor of 10, and the solution is becoming more basic

Which of the following characteristics does NOT apply to water? - All three atoms in water readily form hydrogen bonds with other molecules - The covalent bonds in water are highly polarized. - The water molecule readily joins hydrophobic interactions. - The water molecule is asymmetric. - Electrons in the covalent bonds are shared unequally.

The water molecule readily joins hydrophobic interactions.