Cell and Molec Test 1B

Which of the following statements is false?

A. All organisms consist of one or more cells

B. All cells arise from preexisting cells

C. The cell is the basic unit of structure for all organisms

D. All cells have a membrane bound organelles

E. Cells come in a wide variety of sizes and shapes

D. All cells have a membrane bound nucleus

What is the relation between the wavelength of illumination, lens quality, magnification, and the limit of resolution for light microscopy?

As a shorter wavelength illumination and better quality lenses are used, magnification will stay about the same and the limit of resolution will decrease.

Which of the following is a basic principle of a macromolecular assembly?

A. A monomer need not be activated before being added to the polymer

B. Addition of monomers to the polymer involves the addition of molecules

C. Monomers are added to both ends of a polymer

D. Monomers activated by ATP are added to only one end of a polymer by condensation

D. Monomers activated by ATP are added to only one end of a polymer by condensation

Many biochemical reactions that occur in the cell are nonspontaneous when measured at the biochemical standard state but are spontaneous inside of the cell. What is the most likely explanation for this difference in spontaneity for the same reaction measured under different conditions?

The concentrations of reactions and products inside the cell favor the products

How did Wohler revolutionized biology in the 1800’s through his demostraation that bio molecules are governed by the ordinary laws of physics and chemistry. He demonstrated this by:

synthesizing urea in the lab from ammonium cyanate

Which of the following is the smallest?

A. ribosome

B. virus

C. polypeptide

D. mitochondrion

E. prokaryote

C. polypeptide

List the steps of the scientific method

Observation, hypothesis, design experiments, collect data, interpret results, draw conclusions

How are monomers removed from polymers?

Hydrolysis reactions

Hydrogen bonding is most important in stabilizing what structure of proteins?

Secondary

What is the function of triglycerides?

To store energy

What are fatty acids and what are their function in the cell?

Long, unbranched hydrocarbon chains with a carboxyl group at one end; the building blocks of phospholipids

What is bioenergetics?

Applied thermodynamics

What processes occur in the Golgi complex?

The production and packaging of lipids

In which of the following properties are the archaea more like eukaryotes than bacteria?

A. Synthesis of steroids

B. Production and packaging of lipids

C. Glycosylation of proteins

D. Synthesis of DNA

E. Detoxification of drugs

B. Production and packaging of lipids

In which ways are archaea more like eukaryotes than the bacteria?

The mode of cell division

In a reversable chemical reaction at equilibrium, the concentration of X (the reactant) is 0.75 mol/L, and the concentration of Y (the product) is 2.25 mol/L. At 25 C, what would be the K_eq?

3.0

What does a large negative change in Gibbs free energy in a cell indicate?

Energy must be added to the reaction before it can proceed

What is the site on an enzyme that binds to a substrate?

The active site

Which of the following is an example of a prosthetic group?

A. a heme group containing iron in hemoglobin

B. A zinc ion

C. A polypeptide chain

D. a hydrogen ion

E. A and B

E. A and B

Prosthetic

a non-peptide molecule that binds to a protein and affects it’s function

The active site for many enzymes:

A. contains amino acids that are contiguous to one another along the primary sequence of the protien

B. Usually depends on only one amino acid

C. Involves amino acids that are brought into close proximity by extensive protein folding

D. May require a prosthetic group such as a metal ion

C and D

A spontaneous reaction:

A. Has to occur immediately

B. Will never occur

C. Has an overall positive free energy change

D. Could occur but might take a long time

E. Is associated exclusively with warm blooded animals

D. Could occur but might take a long time +

In a biochemical reaction, reactants may be converted into products. The extent to which this occurs spontaneously is expresses as which of the following?

A. Delta G

Oxidation:

A. involves the removal of oxygen atoms from a molecule

B. is endothermic

C. occurs when an atom accepts electrons

D. occurs when oxygen atoms are added to a molecule and energy is released

E. Is rare in biological reactions

D. Occurs when oxygen atoms are added to a molecule and energy is released

Substrate activation may involve:

A. a change in enzyme conformation induced by substrate binding

B. accepting protons from the enzyme

C. formation of temporary covalent bonds

D. donation of protons to the enzyme

TRICK QUESTION ALL OF THE ABOVE

the induced fit model:

A. was proposed by Hans Buchner

B. distorts the shape of the enzyme and substrate

C. is also called the lock-and-key model

D. states that enzyme-substrate interactions are rigid

E. proposes that very strong covalent bonds are formed upon substrate binding

B. Distorts the shape of the enzyme and substrate

What part of an enzymatic reaction does a competitive inhibitor affect?

The K_m

Saturation can be defined as:

A. Denaturation of an enzyme

B. the ability to increase reaction velocity beyond a finite upper limit

C. inhibition of enzyme function by blocking the active side

D. the substrate concertation at which velocity reaches one half max velocity

E. a characteristic of all uncatalyzed rxns

B. the ability to increase reaction velocity beyond a finite upper limit

Enzyme regulation may occur by several methods. Which of the following is NOT a means of enzyme regulation?

A. Substrate-level phosphorylation

B. feedback inhibition

C. allosteric regulation

D. covalent modification

E. Saturation

E. Saturation

the enzyme carbonic anhydrase catalyzes the formation of carbonic acid from carbon dioxide and water. Imagine that you have two sealed tubes with carbon dioxide gas above a buffer containing water and carbon dioxide. One tube has carbonic anhydrase and the other does not. After 24 hours, both tubes are at equilibrium. Which of the following accurately describes the conditions in the tubes?

A. The tube with carbonic anhydrase will have a lower concentration of carbon dioxide and a higher concentration of carbonic acid than the tube without any enzyme

B. the tube with carbonic anhydrase will have a higher concentration of carbon dioxide and a lower concentration of carbonic acid than the tube with any enzyme

C. the tubes will have equal concentrations of carbon dioxide and carbonic acid

D. The tube with carbonic anhydrase will have a higher concentration of carbonic acid than the tube without any enzyme, but the concentration of carbon dioxide will be the same in both tubes

E. It is not possible to determine the relative concentrations of the products and reactants without more info about carbonic anhydrase, such as the Km

E. It is not possible to determine the relative concentrations of the products and reactants without more information about carbonic anhydrase, such as the Km

What atom forms the backbone of almost all biological molecules?

Carbon

Which one of the following biological polymers is mismatches with its monomer?

A. DNA - nucleotide

B. enzyme - amino acid

C. chitin - monosaccharide

D. Protein - amino acid

E. cellulose - amino acid

Which of the following statements about the polymerization of macromolecules is FALSE?

A. Often the energy needed for polymerization is supplied by ATP

B. The polymer chain usually has two different ends

C. Water is added to join the monomers of the macromolecules

D. A monomer is usually activated by the coupling of the monomer to a charrier

E. Macromolecules are synthesized by the stepwise addition of monomers

C. Water is added to join the monomers of the macromolecules

An enzyme synthesized in the lab is found to have little activity when compared to the enzyme extracted from cell culture. Both enzymes were examined and have identical amino acid composition. What is the best explanation for the lack of activity of the synthesized enzyme?

A. the van der Waals radius was altered during lab synthesis

B. the synthetic enzyme was not made of amino acids

C. the ATP required for self assembly was present in the cell extract but not in the lab synthesis

D. denaturation of the synthesized enzyme was not complete

E. the synthesized enzyme was not folded bc chaperone proteins were not present

E. the synthesized enzyme was not folded bc chaperone proteins were not present

Ionic bonds are important in biological structures. Which of the following pairs of molecules would form an ionic bond?

A. two water molecules

B. two amino acids w opp charged func groups

C. two different stereoisomers of the same sugar

D. two fatty acids

E. a water molecule and a lipid

B. Two amino acids w opp charged functional groups