Question 1

A reaction in which the substrate glucose binds to the enzyme hexokinase and the configuration of both molecules changes is an example of

Accepted Answer

A)  a lock-and-key mechanism. 
B)  an induced fit mechanism. 
C)  competitive inhibition. 
D)  allosteric inhibition. 
A)  a lock-and-key mechanism. 
B)  an induced fit mechanism. 
C)  competitive inhibition. 
D)  allosteric inhibition.

Question 2

How is the information in DNA or RNA conveyed?

Accepted Answer

By the order of the

Question 3

Which of the following are involved in forming the tertiary structure of proteins?

Accepted Answer

A)  H bonds 
B)  Hydrophobic interactions 
C)  Ionic bonds 
D)  All of the above 
A)  H bonds 
B)  Hydrophobic interactions 
C)  Ionic bonds 
D)  All of the above

Question 4

Like other catalysts, enzymes

Accepted Answer

A)  increase the rate of reactions without being consumed in reactions. 
B)  shift the chemical equilibrium from more reactants to more products. 
C)  do not alter the chemical equilibrium between reactants and products. 
D)  Both a and c 
A)  increase the rate of reactions without being consumed in reactions. 
B)  shift the chemical equilibrium from more reactants to more products. 
C)  do not alter the chemical equilibrium between reactants and products. 
D)  Both a and c

Question 5

In DNA,

Accepted Answer

A)  G pairs with T and A pairs with C. 
B)  G pairs with A and C pairs with T. 
C)  G pairs with C and A pairs with T. 
D)  G pairs with C and U pairs with A. 
A)  G pairs with T and A pairs with C. 
B)  G pairs with A and C pairs with T. 
C)  G pairs with C and A pairs with T. 
D)  G pairs with C and U pairs with A.

Question 6

Serine, threonine, asparagine, and glutamine are all _______ amino acids.

Accepted Answer

A)  basic 
B)  acidic 
C)  polar 
D)  nonpolar 
A)  basic 
B)  acidic 
C)  polar 
D)  nonpolar

Question 7

Cholesterol is an amphipathic molecule.

Accepted Answer

A) True 
 B)False

Question 8

Which class of molecule accelerates transport across biological membranes?

Accepted Answer

A)  Carbohydrates 
B)  Lipids 
C)  Nucleic acids 
D)  Proteins 
A)  Carbohydrates 
B)  Lipids 
C)  Nucleic acids 
D)  Proteins

Question 9

Cholesterol, a membrane lipid in animals, has a chemical structure similar to

Accepted Answer

A)  estradiol. 
B)  phosphatidylinositol. 
C)  thymine. 
D)  triacylglycerol. 
A)  estradiol. 
B)  phosphatidylinositol. 
C)  thymine. 
D)  triacylglycerol.

Question 10

About 50% of the mass of most biological membranes consists of lipids and about 50% consists of proteins. Therefore,

Accepted Answer

A)  the membranes contain fewer molecules of lipid than of protein. 
B)  the membranes contain equal numbers of lipid and protein molecules. 
C)  the membranes contain more molecules of lipid than of protein. 
D)  only a few membrane proteins are exposed at the cell surface. 
A)  the membranes contain fewer molecules of lipid than of protein. 
B)  the membranes contain equal numbers of lipid and protein molecules. 
C)  the membranes contain more molecules of lipid than of protein. 
D)  only a few membrane proteins are exposed at the cell surface.

Question 11

Which of the following is not a way in which DNA differs from RNA?

Accepted Answer

A)  DNA contains deoxyribose sugars. 
B)  DNA is usually a double-stranded molecule. 
C)  DNA contains thymine as one of its bases. 
D)  DNA can form hydrogen bonds with complementary sequences. 
A)  DNA contains deoxyribose sugars. 
B)  DNA is usually a double-stranded molecule. 
C)  DNA contains thymine as one of its bases. 
D)  DNA can form hydrogen bonds with complementary sequences.

Question 12

In the primary structure of a protein, amino acids are joined together by _______ bonds.

Accepted Answer

A)  peptide 
B)  phosphodiester 
C)  glycosidic 
D)  hydrophobic 
A)  peptide 
B)  phosphodiester 
C)  glycosidic 
D)  hydrophobic

Question 13

Nucleotides function in cells as all of the following except

Accepted Answer

A)  building blocks of nucleic acids. 
B)  carriers of chemical energy. 
C)  intracellular signal molecules. 
D)  defenders against infection. 
A)  building blocks of nucleic acids. 
B)  carriers of chemical energy. 
C)  intracellular signal molecules. 
D)  defenders against infection.

Question 14

The only protein structure known to span a biological membrane, other than $\beta$ helix, is the $\beta$barrel, formed by the folding of $\beta$ sheets into a barrel-like structure. Why does the presence of $\beta$ barrel proteins in the outer membrane of chloroplasts and mitochondria make lipid bilayers permeable to small molecules and ions?

Accepted Answer

A @#LAT-DLM&-barrel structure in a membrane create

Question 15

Suppose you have completed a series of polyacrylamide gel electrophoresis experiments and found that under both denaturing and non-denaturing conditions, purified hemoglobin migrates as one molecular species. However, the apparent mass of the observed species under denaturing conditions is approximately one-quarter of that observed under non-denaturing conditions. What is the most likely explanation for these results?

Accepted Answer

If native hemoglobin had a quaternary st

Question 16

Common factors affecting membrane fluidity include

Accepted Answer

A)  length of phospholipid fatty acid chains. 
B)  temperature. 
C)  number of double bonds in the fatty acid chains. 
D)  All of the above 
A)  length of phospholipid fatty acid chains. 
B)  temperature. 
C)  number of double bonds in the fatty acid chains. 
D)  All of the above

Question 17

Phospholipids in a membrane commonly

Accepted Answer

A)  move laterally in the plane of the bilayer. 
B)  rotate within the bilayer. 
C)  move from one bilayer to the other. 
D)  Both a and b 
A)  move laterally in the plane of the bilayer. 
B)  rotate within the bilayer. 
C)  move from one bilayer to the other. 
D)  Both a and b

Question 18

Which statement describes the most common relationship of the inhibitor molecule to the allosteric enzyme in feedback inhibition of enzyme activity?

Accepted Answer

A)  The inhibitor is the substrate of the enzyme. 
B)  The inhibitor is the final product of the metabolic pathway. 
C)  The inhibitor is the product of the enzyme-catalyzed reaction. 
D)  The inhibitor is a metabolically unrelated signal molecule. 
A)  The inhibitor is the substrate of the enzyme. 
B)  The inhibitor is the final product of the metabolic pathway. 
C)  The inhibitor is the product of the enzyme-catalyzed reaction. 
D)  The inhibitor is a metabolically unrelated signal molecule.

Question 19

Cholesterol affects membrane fluidity by

Accepted Answer

A)  increasing membrane fluidity at all temperatures. 
B)  decreasing membrane fluidity at all temperatures. 
C)  decreasing membrane fluidity at high temperatures and increasing membrane fluidity at low temperatures. 
D)  increasing membrane fluidity at high temperatures and decreasing membrane fluidity at low temperatures. 
A)  increasing membrane fluidity at all temperatures. 
B)  decreasing membrane fluidity at all temperatures. 
C)  decreasing membrane fluidity at high temperatures and increasing membrane fluidity at low temperatures. 
D)  increasing membrane fluidity at high temperatures and decreasing membrane fluidity at low temperatures.

Question 20

Approximately 50% of the chemical reactions in cells are catalyzed by enzymes.

Accepted Answer

A) True 
 B)False

A reaction in which the substrate glucose binds to the enzyme hexokinase and the configuration of both molecules changes is an example of

How is the information in DNA or RNA conveyed?

Which of the following are involved in forming the tertiary structure of proteins?

Like other catalysts, enzymes

In DNA,

Serine, threonine, asparagine, and glutamine are all _______ amino acids.

Cholesterol is an amphipathic molecule.

Which class of molecule accelerates transport across biological membranes?

Cholesterol, a membrane lipid in animals, has a chemical structure similar to

About 50% of the mass of most biological membranes consists of lipids and about 50% consists of proteins. Therefore,

Which of the following is not a way in which DNA differs from RNA?

In the primary structure of a protein, amino acids are joined together by _______ bonds.

Nucleotides function in cells as all of the following except

Common factors affecting membrane fluidity include

Phospholipids in a membrane commonly

Which statement describes the most common relationship of the inhibitor molecule to the allosteric enzyme in feedback inhibition of enzyme activity?

Cholesterol affects membrane fluidity by

Approximately 50% of the chemical reactions in cells are catalyzed by enzymes.

An Overview of Cells and Cell Research

Bioenergetics and Metabolism

Fundamentals of Molecular Biology

Genomics, Proteomics, and Systems Biology

Genes and Genomes

Replication, Maintenance, and Rearrangements of Genomic Dna

RNA Synthesis and Processing

Transcriptional Regulation and Epigenetics

Protein Synthesis, Processing, and Regulation

The Nucleus

Protein Sorting and Transport

Mitochondria, Chloroplasts, and Peroxisomes

The Cytoskeleton and Cell Movement

The Plasma Membrane

Cell Walls, the Extracellular Matrix, and Cell Interactions

Cell Signaling

The Cell Cycle

Cell Death and Cell Renewal

Cancer

Filters

Exam 2: Molecules and Membranes

A reaction in which the substrate glucose binds to the enzyme hexokinase and the configuration of both molecules changes is an example of

How is the information in DNA or RNA conveyed?

Which of the following are involved in forming the tertiary structure of proteins?

Like other catalysts, enzymes

In DNA,

Serine, threonine, asparagine, and glutamine are all _______ amino acids.

Cholesterol is an amphipathic molecule.

Which class of molecule accelerates transport across biological membranes?

Cholesterol, a membrane lipid in animals, has a chemical structure similar to

About 50% of the mass of most biological membranes consists of lipids and about 50% consists of proteins. Therefore,

Which of the following is not a way in which DNA differs from RNA?

In the primary structure of a protein, amino acids are joined together by _______ bonds.

Nucleotides function in cells as all of the following except

Common factors affecting membrane fluidity include

Phospholipids in a membrane commonly

Which statement describes the most common relationship of the inhibitor molecule to the allosteric enzyme in feedback inhibition of enzyme activity?

Cholesterol affects membrane fluidity by

Approximately 50% of the chemical reactions in cells are catalyzed by enzymes.

An Overview of Cells and Cell Research

Bioenergetics and Metabolism

Fundamentals of Molecular Biology

Genomics, Proteomics, and Systems Biology

Genes and Genomes

Replication, Maintenance, and Rearrangements of Genomic Dna

RNA Synthesis and Processing

Transcriptional Regulation and Epigenetics

Protein Synthesis, Processing, and Regulation

The Nucleus

Protein Sorting and Transport

Mitochondria, Chloroplasts, and Peroxisomes

The Cytoskeleton and Cell Movement

The Plasma Membrane

Cell Walls, the Extracellular Matrix, and Cell Interactions

Cell Signaling

The Cell Cycle

Cell Death and Cell Renewal

Cancer

Filters