Exam 1

Question 1

Which of the following characteristics is NOT a basic property of cells?

A. Cells carry out a variety of emotional reaction.
B. Cells engage in numerous mechanical activities.
C. Cells generally respond to stimuli.
D. Cells are capable of self-regulation.
E. Cells evolve.

Answer 1

A. Cells carry out a variety of emotional reaction.

Question 2

The central dogma provides a framework for thinking about how genetic information is copied and used to produce structural and catalytic compounds??? CHECK AGAIN From the choices below, select the order of biochemical processes that best correlates with the tenets of the central dogma.

A. Transcription - Translation - Replication
B. Replication - Translation - Transcription
C. Replication - Transcription - Translation
D. Translation - Transcription - Replication
E. Translation - Replication - Transcription

Answer 2

C. Replication - Transcription - Translation

Question 3

! The ________ __________ is made up of two concentric membranes and is continuous with the membrane of the endoplasmic reticulum.

A. plasma membrane
B. Golgi network
C. mitochondrial membrane
D. nuclear envelope
E. lipid bilayer

Answer 3

D. nuclear envelope

Question 4

Which of the following choices BEST describes the role of the lysosome?

A. transport of material to the Golgi apparatus
B. clean-up, recycling, and disposal of macromolecules
C. sorting of transport vesicles
D. the storage of excess macromolecules
E. lysing DNA & RNA

Answer 4

B. clean-up, recycling, and disposal of macromolecules

Question 5

Photosynthesis enables plants to capture the energy from sunlight. In this essential process, plants incorporate the carbon from CO2 into high-energy ________ molecules, which the plant cell mitochondria use to produce ATP.

A. fat
B. protein
C. fiber
D. sugar
E. CO2

Answer 5

D. sugar

Question 6

! Which 3 characteristics best support the rapid evolution of prokaryotic populations?

A. microscopic, motile, anaerobic
B. aerobic, motile, rapid growth
C. no organelles, cell wall, can exchange DNA
D. large population, rapid growth, can exchange DNA
E. only God knows….

Answer 6

D. large population, rapid growth, can exchange DNA

Question 7

Biologists cannot possible study all living species. Instead, they try to understand cell behavior by studying a select subset of species. Which of the following characteristics are useful in an organism chosen for use as a model in laboratory studies?

A. amenability to genetic manipulation
B. ability to grow under controlled conditions
C. rapid rate of reproduction
D. all of the above
E. none of the above

Answer 7

D. all of the above

Question 8

Which of the following is NOT evidence to support the endosymbiosis theory?

A. Mitochondria and chloroplasts have their own DNA.
B. Mitochondria & chloroplasts have their own cell membranes.
C. Mitochondria & chloroplasts replicate independently of the nucleus by binary fission.
D. Cells are able to recreate mitochondria & chloroplast when lost due to incorporation of DNA.
E. all of the above

Answer 8

D. Cells are able to recreate mitochondria & chloroplast when lost due to incorporation of their DNA.

Question 9

! The world of prokaryotes is divided into two domains (bacteria & archaea), each as different from each other as from eukaryotes. Select the observable characteristic that BEST separates archaea from bacteria.

A. can metabolize inorganic substances
B. are found in extremely harsh environments
C. thrive in anaerobic conditions
D. are photosynthetic organisms
E. none of the above

Answer 9

B. are found in extremely harsh environments

Question 10

If the isotope 32-S has 16 protons and 16 neutrons, how many protons, neutrons and electrons will the isotope 35-S have, respectively?

A. 16; 20; 15
B. 16; 19; 15
C. 16; 19; 17
D. 16; 19; 16
E. 16; 16; 16

Answer 10

D. 16; 19; 16

Question 11

! (EC) Although covalent bonds are 10-100 times stronger than noncovalent interactions, many biological processes depend upon the number and type of noncovalent interactions between molecules. Which of the noncovalent interactions below will contribute most to the strong and specific binding of two molecules, such as a park of proteins?

A. electrostatic attractions
B. hydrogen bonds
C. hydrophobic interactions
D. van dear Waals interactions
E. all of the above

Answer 11

A. electrostatic attractions

NOT hydrogen bonds

Question 12

How do protein, nucleic acid, and polysaccharide molecules polymerize (grow in length)?

A. by hydrolysis reactions
B. by oxidation reactions
C. by condensation reactions
D. by phosphorylation
E. by a random mutation

Answer 12

C. by condensation reactions

Question 13

! There is incredible chemical diversity even in the simplest of cells. A typical bacterial cell contains more than 6000 different types of molecules. From the list below, select the class of molecules with the largest number of different types.

A. nucleotides & precursors
B. sugars & precursors
C. amino acids & precursors
D. fatty acids & precursors
E. phospholipids & lipid bilayer

Answer 13

B. sugars & precursors

NOT nucleotides & precursors

Question 14

! There are 20^100 different possible sequence combinations for a protein chain with 100 amino acids. In addition to the amino acid sequence of the protein, what other factors INCREASE the potential for diversity in these macromolecules?

A. free rotation around single bonds during synthesis
B. noncovalent interactions sampled as protein folds
C. the directionality of amino acids being added
D. the planar nature of the peptide bond
E. enzyme diversity

Answer 14

B. noncovalent interactions sampled as protein folds

NOT the directionality of amino acids being added

Question 15

One of the weakest molecular interactions that is usually defined as the simple attractions & repulsions of atoms is:

A. James Bonds 
B. hydrogen bonds
C. pi bonds
D. disulfide bridges
E. van der Waals

Answer 15

D. van der Waals

Question 16

The major difference between a saturated fat and an unsaturated fat is that:

A. saturated fats have at least one C=C bond
B. unsaturated fats have very high melting points
C. unsaturated fats have at least one C=C bond
D. saturated fats are usually liquid at room temperature
E. none of the above

Answer 16

C. unsaturated fats have at least one C=C bond

Question 17

Which of the following is NOT a major use of cholesterol?

A. Cholesterol can be used in the plasma membrane of animal cells.
B. Cholesterol can be derived into testosterone.
C. Cholesterol can be derived into estrogen.
D. Cholesterol can be used by plants to help their cell walls from being too stiff.
E. all of the above

Answer 17

D. Cholesterol can be used by plants to help their cell walls from being too stiff.

Question 18

All lipids

A. are made from glycerol & fatty acids
B. contain nitrogen
C. have low energy content
D. are acidic when mixed with water
E. do not dissolve well in water

Answer 18

E. do not dissolve well in water

Question 19

Unlike other macromolecules such as proteins and nucleic acids, lipids cannot be generally considered polymers because

A. they contain polar covalent bonds
B. their structure includes carbon rings
C. they can be artificially created
D. their monomers are connected via ionic bonds
E. they are not composed of monomer subunits

Answer 19

E. they are not composed of monomer subunits

Question 20

What type of bond links nucleotides in a nucleic acid chain?

A. phosphoanhydride
B. glycosidic
C. peptide
D. hydrogen
E. phosphodiester

Answer 20

E. phosphodiester

Question 21

! Which of the following statements is NOT true?

A. When a sugar molecule is oxidized to CO2 and H2O, the O2 molecules involved in forming the H2O are reduced.
B. When a carbon atom in a C-H bond has somewhat more than its share of electrons, it is said to be reduced.
C. Oxidation and reduction reactions always occur simultaneously.
D. Hydrogenation reactions are oxidations, and dehydrogenation reactions are reductions.
E. None of the above.

Answer 21

D. Hydrogenation reactions are oxidations, and dehydrogenation reactions are reductions.

NOT When a sugar molecule is oxidized to CO2 & H2O, the O2 molecules involved in forming the H2O are reduced.

Question 22

Dad-Sung tells you that his precious fruit flies have reached equilibrium. What would be your appropriate response (- this is a biology question)?

A. send a sympathy card since his flies are dead
B. congratulate him on teaching his flies the laws of thermodynamics
C. say that his flies must produce lots of ATP & GTP
D. say that his flies are generating proper amount of energy to survive at the moment
E. say that his flies are at their maximum enzymatic speed at the moment

Answer 22

A. send a sympathy card since his flies are dead

Question 23

Do you happen to know how Dae-Sung creates macromolecules, organelles, cells, tissues, and complex higher-order structures in his body?

A. The laws of thermodynamics do not apply to him.
B. He creates order by recycling and reusing energy from the sun.
C. He creates order locally, but the energy transformation generates heat waste that increases the entropy of the universe.
D. Through photosynthesis.
E. His kids increase local entropy, that I know for sure.

Answer 23

C. He creates order locally, but the energy transformation generates heat waste that increases the entropy of the universe.

Question 24

Chemical reactions carried out by living systems depend on the ability of some organisms to capture and use atoms from non living sources in the environment. The specific subset of these reactions that break down nutrients in food can be described as (_______). When there is an excess of nutrients available in the human body, insulin is released to stimulate the synthesis of glycogen from glucose. This is a specific example of a/an (________) process, a general process in which larger molecules are made from smaller molecules.

A. metabolic; enzymatic
B. anabolic; catabolic
C. catabolic; anabolic
D. biosynthetic; unfavorable
E. spontaneous rxn; spontaneous

Answer 24

C. catabolic; anabolic

Question 25

! Your company has developed an organic molecule with commercial potential and you know how to produce it in the lab. You want to increase production and make as much of the molecule as possible, but the reaction has a positive ΔG°. What can you do to try to drive reaction toward your desired product? A. increase the concentration of reactants B. add an enzyme that does not couple to another reaction C. add some products initially to get the reaction primed D. continually remove products E. none of the above

Answer 25

A. increase the concentration of reactants AND D. continually remove products

Question 26

ΔG° indicates the change int he’s tankard free energy as a reactant is converted to product. Given what you know about these values, which reaction below is the most favorable? A. ADP + Pi —> ATP ΔG° = + 7.3 kcal/mole B. glucose 1-phosphate —> glucose 6-phosphate ΔG° = -1.7 kcal/mole C. glucose + fructose —> sucrose ΔG° = +5.5 kcal/mole D. glucose —> CO2 + H2O ΔG° = -686 kcal/mole E. both a & c

Answer 26

D. glucose —> CO2 + H2O ΔG° = -686 kcal/mole

Question 27

! You are a researcher trying to design an enzyme inhibitor for a particular enzyme. Which molecule should your inhibitor most closely resemble for the most effective inhibition to take place? A. the enzyme’s final product B. the enzyme’s initial substrate C. the transition state intermediate produced during enzyme-product release D. the enzyme’s precursor molecule E. the transition state intermediate produced during enzyme-substrate interaction

Answer 27

E. the transition state intermediate produced during enzyme-substrate interaction NOT the enzyme’s initial substrate

Question 28

When NADH or NADPH transfers electrons to a recipient molecule, the recipient becomes reduced and the activated carriers are oxidized (to NAD+ or NADP+, respectively). What else happens during this reaction? A. A proton is taken up by the recipient molecule. B. A phosphate group is transferred to the recipient molecule. C. A proton is released into the solution. D. A molecule of water is released into the solution. E. A proton is taken up by the carrier.

Answer 28

A. A proton is taken up by the recipient molecule.

Question 29

! Which of the following statements is FALSE for a favorable binding reaction? A. The free-energy change is negative for the system. B. The concentration of the complex remains lower than the concentration of the unbound components. C. The complex dissociation rate is slower than the rate for component association. D. The binding energy for the association is large and negative. E. all of the above

Answer 29

B. The concentration of the complex remains lower than the concentration of the unbound components.

Question 30

The variations in the physical characteristics between different proteins are influenced by the overall amino acid compositions, but even more important is the unique amino acid _____ ``` A. number B. sequence C. bond D. orientation E. charge ```

Answer 30

B. sequence

Question 31

Proteins bind selectively to small-molecule targets called ligands. The selection of one ligand out of a mixture of possible ligands depends on the number of weak, noncovalent interactions in the protein’s ligand-binding site. Where is the binding site typically located in the protein structure? A. on the surface of the protein B. inside a cavity of the protein surface C. buried deep in the interior of the protein forming hydrophobic interactions D. forms on the surface of the protein in the presence of ligand E. anywhere they can form covalent bond

Answer 31

B. inside a cavity of the protein surface

Question 32

Fully folded proteins typically have polar side chains on their surfaces, where electrostatic attractions and hydrogen bonds can form between the polar group on the amino acid and the polar molecules in the solvent. IN consternation, some proteins have a polar side chain in their hydrophobic interior. Which of the following would NOT occur to help accommodate an internal, polar side chain? A. A hydrogen bond forms between 2 polar side chains. B. A hydrogen bond forms between a polar side chain & the protein backbone. C. A hydrogen bond forms between a polar side chain and an aromatic side chain. D. Hydrogen bonds form between polar side chains and a buried water molecule. E. all of the above

Answer 32

C. A hydrogen bond forms between a polar side chain & an aromatic side chain.

Question 33

! Which of the following statements is TRUE? A. Peptide bonds are the only covalent bonds that can link together 2 amino acids in proteins B. There is free rotation around all covalent bonds in the polypeptide backbone. C. Nonpolar amino acids tend to be found in the interior of proteins. D. The sequence of the atoms in teh polypeptide backbone varies between different proteins. E. all of the above

Answer 33

C. Nonpolar amino acids tend to be found in the interior of proteins NOT all of the above

Question 34

! To study how proteins fold, scientists must be able to purify the protein of interest, use solvents to denature the folded protein, and observe the process of refolding at successive time points. What is the effect of the solvents used in the denaturation process? A. The solvents break all covalent interactions. B. The solvents break all noncovalent interactions. C. The solvents break some of the noncovalent interactions, resulting in a misfolded protein. D. The solvents create a new protein conformation. E. none of the above

Answer 34

B. The solvents break all noncovalent interactions NOT none of the above

Question 35

! Beta sheets can participate in the formation of amyloid fibers, which are insoluble protein aggregates. What drives the formation of amyloid fibers? A. denaturation of proteins containing B sheets B. extension of beta sheets into much longer B strands C. formation of biofilms by infectious bacteria D. B-sheets stabilization of abnormally folded proteins E. B-sheets destruction of abnormally folded proteins

Answer 35

D. B-sheets stabilization of abnormally folded proteins NOT extension of B sheets into much longer B sheets

Question 36

The correct folding or proteins is necessary to maintain a healthy cells and tissues. The presence of unfolded proteins are associated with some neurodegenerative disorders such as Alzheimer’s disease, Huntington’s diseases, and Creutzfeldt Jakob disease (the specific faulty protein is different for each disease). What happens to these disease-causing, unfolded proteins? ``` A. They are degraded. B. They bind a different target protein. C. They form structured filaments. D. They form protein aggregates. E. They form misregulated a-helix. ```

Answer 36

D. They form protein aggregates.

Question 37

Which of the following statements about allostery is TRUE? A. Allosteric regulators are often products of other chemical reactions in the same biochemical pathway. B. Allosteric regulation is always used for negative regulation of enzyme activity. C. Enzymes are the only types of proteins that are subject to allosteric regulation. D. Binding of allosteric molecules usually locks an enzyme in its current conformation, such that the enzyme cannot adopt a different conformation. E. none of the above

Answer 37

A. Allosteric regulators are often products of other chemical reactions int he same biochemical pathway.

Question 38

! Energy required by the cell is generated in the form of ATP. ATP is hydrolysis to power many of the cellular processes, increasing the pool of ADP. As the relative amount of ADP molecules increases, they can bind to glycolysis enzymes, which will lead to the production of more ATP. The best way to describe this mechanism of regulation is ? ``` A. feedback inhibition B. oxidative phosphorylation C. allosteric activation D. substrate-level phosphorylation E. negative inhibition ```

Answer 38

C. allosteric activation NOT substrate-level phosphorylation

Question 39

(EC) NADPH and NADH are interconvertible but have different metabolic roles in cells. Briefly compare and contrast NADH and NADPH for their roles and structure.

Answer 39

NADPH - used most in anabolic reactions (build up), such as photosynthesis; aka used in many biosynthetic pathways - carries an additional phosphate group in comparison to NADH - in cells, NADPH exists more in NADP+ form than the reduced NADPH form NADH - used most in catabolic reactions, especially in the oxidation of food molecules/cellular respiration (breakdown of food molecules) - does not have any phosphate groups in comparison to NADPH - in cells, NADH exists more in teh NADH form than its oxidized form of NAD+

Question 40

! (EC) Briefly explain the cellular and genetic causes of Hutchinson-Gilford progeria syndrome and Adrenoleukodystrophy (ALD). Focus on the information covered in class.

Answer 40

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