Question 1

The main difference between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) is that

Accepted Answer

A)  dsDNA has bases that include thymine (T), while ssDNA has bases including uracil (U). 
B)  dsDNA has strands oriented in an antiparallel fashion, while ssDNA does not. 
C)  dsDNA cannot undergo translation while ssDNA can leave the nucleus to undergo translation. 
D)  dsDNA has 5' to 3' polarity while ssDNA does not. 
A)  dsDNA has bases that include thymine (T), while ssDNA has bases including uracil (U). 
B)  dsDNA has strands oriented in an antiparallel fashion, while ssDNA does not. 
C)  dsDNA cannot undergo translation while ssDNA can leave the nucleus to undergo translation. 
D)  dsDNA has 5' to 3' polarity while ssDNA does not.

Question 2

An amphipathic molecule is

Accepted Answer

A)  water-soluble. 
B)  water-insoluble. 
C)  part water-soluble and part water-insoluble. 
D)  hydrophilic. 
A)  water-soluble. 
B)  water-insoluble. 
C)  part water-soluble and part water-insoluble. 
D)  hydrophilic.

Question 3

In allosteric regulation, binding of a small regulatory molecule to an enzyme _______ enzyme activity.

Accepted Answer

A)  inhibits 
B)  stimulates 
C)  may stimulate or inhibit 
D)  neither stimulates nor inhibits 
A)  inhibits 
B)  stimulates 
C)  may stimulate or inhibit 
D)  neither stimulates nor inhibits

Question 4

The interaction of two α and two β subunits to form a functional hemoglobin molecule is an example of _______ structure.

Accepted Answer

A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary

Question 5

Water is an ideal solvent in cells because it

Accepted Answer

A)  has low heat of vaporization. 
B)  is a polar molecule that can form hydrogen bonds with itself and with other polar molecules. 
C)  dissolves nonpolar molecules. 
D)  contracts when it freezes. 
A)  has low heat of vaporization. 
B)  is a polar molecule that can form hydrogen bonds with itself and with other polar molecules. 
C)  dissolves nonpolar molecules. 
D)  contracts when it freezes.

Question 6

Proteins must have more than one _______ to have a quaternary structure.

Accepted Answer

A)  $\alpha$helix 
B)  $\beta$sheet 
C)  polypeptide chain 
D)  transmembrane segment 
A)  $\alpha$helix 
B)  $\beta$sheet 
C)  polypeptide chain 
D)  transmembrane segment

Question 7

Enzymes act by

Accepted Answer

A)  lowering the overall free energy change of a reaction. 
B)  decreasing the distance reactants must diffuse to find each other. 
C)  increasing activation energy. 
D)  decreasing activation energy. 
A)  lowering the overall free energy change of a reaction. 
B)  decreasing the distance reactants must diffuse to find each other. 
C)  increasing activation energy. 
D)  decreasing activation energy.

Question 8

While small, uncharged molecules can diffuse through the hydrophobic core of a phospholipid bilayer, larger polar molecules such as glucose must enter cells by binding to

Accepted Answer

A)  a nonphospholipid such as cholesterol. 
B)  the carbohydrate portion of glycolipids. 
C)  peripheral membrane proteins located on the inner side of the membrane. 
D)  carrier proteins that facilitate the passage of specific molecules across membranes. 
A)  a nonphospholipid such as cholesterol. 
B)  the carbohydrate portion of glycolipids. 
C)  peripheral membrane proteins located on the inner side of the membrane. 
D)  carrier proteins that facilitate the passage of specific molecules across membranes.

Question 9

The purine base adenine is found in DNA and in the principal form of chemical energy in cells, _______.

Accepted Answer

adenosine

Question 10

The unique functions of different membranes are primarily due to their

Accepted Answer

A)  proteins. 
B)  phospholipids. 
C)  cholesterol molecules. 
D)  glycolipids. 
A)  proteins. 
B)  phospholipids. 
C)  cholesterol molecules. 
D)  glycolipids.

Question 11

Why is phosphatidylethanolamine considered a neutral phospholipid, while phosphatidylinositol is considered an acidic phospholipid?

Accepted Answer

Both phosphatidylethanolamine and phosph

Question 12

Passive transport molecules

Accepted Answer

A)  allow small molecules across membranes. 
B)  are peripheral proteins. 
C)  can transport against a concentration gradient. 
D)  use the energy of ATP to transport molecules. 
A)  allow small molecules across membranes. 
B)  are peripheral proteins. 
C)  can transport against a concentration gradient. 
D)  use the energy of ATP to transport molecules.

Question 13

The mitochondrial inner membrane is about _______ protein.

Accepted Answer

A)  0% 
B)  10% 
C)  42% 
D)  75% 
A)  0% 
B)  10% 
C)  42% 
D)  75%

Question 14

The glucose molecules in cellulose are joined by β(1→4) bonds.

Accepted Answer

A) True 
 B)False

Question 15

Coenzymes are

Accepted Answer

A)  enzymes in the same pathway. 
B)  proteins that form dimeric enzymes. 
C)  small molecules that work with an enzyme to enhance reaction rate. 
D)  small molecules that allosterically regulate enzymes. 
A)  enzymes in the same pathway. 
B)  proteins that form dimeric enzymes. 
C)  small molecules that work with an enzyme to enhance reaction rate. 
D)  small molecules that allosterically regulate enzymes.

Question 16

Sphingomyelin contains two hydrocarbon chains linked to

Accepted Answer

A)  glycerol. 
B)  choline. 
C)  serine. 
D)  glycine. 
A)  glycerol. 
B)  choline. 
C)  serine. 
D)  glycine.

Question 17

Enzymes accelerate reactions and affect the end equilibrium concentration of reactants and products.

Accepted Answer

A) True 
 B)False

Question 18

Suppose you are studying the transport of glucose into red blood cells and find that as you increase the concentration of glucose outside of the cells, a concentration is reached at which there is no further increase in the rate of accumulation of glucose in the cells. What is the explanation for this?

Accepted Answer

Glucose is too polar a molecule to diffu

Question 19

Chymotrypsin, trypsin, elastase, and thrombin are all members of the serine protease family because each

Accepted Answer

A)  has similar charge and shape properties in its substrate insertion pockets. 
B)  can form a heptahedral complex with its substrate. 
C)  uses the same catalytic mechanism involving the same key amino acids. 
D)  can be modified by the cell-wall degrading enzyme chitinase. 
A)  has similar charge and shape properties in its substrate insertion pockets. 
B)  can form a heptahedral complex with its substrate. 
C)  uses the same catalytic mechanism involving the same key amino acids. 
D)  can be modified by the cell-wall degrading enzyme chitinase.

Question 20

In the fluid mosaic model of biological membrane structure, transmembrane proteins are

Accepted Answer

A)  embedded nearly randomly in the lipid bilayer. 
B)  almost completely surrounded by membrane lipid. 
C)  segregated into large protein clusters or rafts. 
D)  weakly held in place on the surface of the lipid bilayer. 
A)  embedded nearly randomly in the lipid bilayer. 
B)  almost completely surrounded by membrane lipid. 
C)  segregated into large protein clusters or rafts. 
D)  weakly held in place on the surface of the lipid bilayer.

The main difference between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) is that

An amphipathic molecule is

In allosteric regulation, binding of a small regulatory molecule to an enzyme _______ enzyme activity.

The interaction of two α and two β subunits to form a functional hemoglobin molecule is an example of _______ structure.

Water is an ideal solvent in cells because it

Proteins must have more than one _______ to have a quaternary structure.

Enzymes act by

While small, uncharged molecules can diffuse through the hydrophobic core of a phospholipid bilayer, larger polar molecules such as glucose must enter cells by binding to

The purine base adenine is found in DNA and in the principal form of chemical energy in cells, _______.

The unique functions of different membranes are primarily due to their

Why is phosphatidylethanolamine considered a neutral phospholipid, while phosphatidylinositol is considered an acidic phospholipid?

Passive transport molecules

The mitochondrial inner membrane is about _______ protein.

The glucose molecules in cellulose are joined by β(1→4) bonds.

Coenzymes are

Sphingomyelin contains two hydrocarbon chains linked to

Enzymes accelerate reactions and affect the end equilibrium concentration of reactants and products.

Chymotrypsin, trypsin, elastase, and thrombin are all members of the serine protease family because each

In the fluid mosaic model of biological membrane structure, transmembrane proteins are

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

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Exam 2: Molecules and Membranes

The main difference between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) is that

An amphipathic molecule is

In allosteric regulation, binding of a small regulatory molecule to an enzyme _______ enzyme activity.

The interaction of two α and two β subunits to form a functional hemoglobin molecule is an example of _______ structure.

Water is an ideal solvent in cells because it

Proteins must have more than one _______ to have a quaternary structure.

Enzymes act by

While small, uncharged molecules can diffuse through the hydrophobic core of a phospholipid bilayer, larger polar molecules such as glucose must enter cells by binding to

The purine base adenine is found in DNA and in the principal form of chemical energy in cells, _______.

The unique functions of different membranes are primarily due to their

Why is phosphatidylethanolamine considered a neutral phospholipid, while phosphatidylinositol is considered an acidic phospholipid?

Passive transport molecules

The mitochondrial inner membrane is about _______ protein.

The glucose molecules in cellulose are joined by β(1→4) bonds.

Coenzymes are

Sphingomyelin contains two hydrocarbon chains linked to

Enzymes accelerate reactions and affect the end equilibrium concentration of reactants and products.

Chymotrypsin, trypsin, elastase, and thrombin are all members of the serine protease family because each

In the fluid mosaic model of biological membrane structure, transmembrane proteins are

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