Question 1

Discuss how a mutation in DNA could be harmful or beneficial to an organism.

Accepted Answer

Some mutations lead to the synthesis of an inactive or defective enzyme or other protein that can no longer carry out its proper function,which is thus harmful to the organism.However,other mutations may lead to a more stable enzyme or to a protein that is better able to carry out its function in a particular environment,making it beneficial to the organism.

Question 2

The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate,but it will not catalyze the hydration of maleic acid,the cis isomer of fumaric acid.This is an example of:

Accepted Answer

A) biological activity. 
B) chiral activity. 
C) racemization. 
D) stereoisomerization. 
E) stereospecificity. 
A) biological activity. 
B) chiral activity. 
C) racemization. 
D) stereoisomerization. 
E) stereospecificity. E

Question 3

Which one of the following is not among the four most abundant elements in living organisms?

Accepted Answer

A) Carbon 
B) Hydrogen 
C) Nitrogen 
D) Oxygen 
E) Phosphorus 
A) Carbon 
B) Hydrogen 
C) Nitrogen 
D) Oxygen 
E) Phosphorus E

Question 4

When a region of DNA must be repaired by removing and replacing some of the nucleotides,what ensures that the new nucleotides are in the correct sequence?

Accepted Answer

A) DNA cannot be repaired and this explains why mutations occur. 
B) Specific enzymes bind the correct nucleotides. 
C) The new nucleotides base pair accurately with those on the complementary strand. 
D) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it. 
E) The three-dimensional structure determines the order of nucleotides. 
A) DNA cannot be repaired and this explains why mutations occur. 
B) Specific enzymes bind the correct nucleotides. 
C) The new nucleotides base pair accurately with those on the complementary strand. 
D) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it. 
E) The three-dimensional structure determines the order of nucleotides.

Question 5

Instant cold packs get cold when the contents,usually solid urea and liquid water,are mixed,producing an aqueous solution of urea.Although this process is clearly spontaneous,the products are colder than the reactants.Explain how this is possible in terms of the difference between $\Delta$G and $\Delta$H.

Accepted Answer

Since the dissolution reaction is sponta

Question 6

Differentiate between configuration and conformation.

Accepted Answer

Configuration denotes the spatial arrang

Question 7

The three-dimensional structure of a protein is determined primarily by:

Accepted Answer

A) electrostatic guidance from nucleic acid structure. 
B) how many amino acids are in the protein. 
C) hydrophobic interaction with lipids that provide a folding framework. 
D) modification during interactions with ribosomes. 
E) the sequence of amino acids in the protein. 
A) electrostatic guidance from nucleic acid structure. 
B) how many amino acids are in the protein. 
C) hydrophobic interaction with lipids that provide a folding framework. 
D) modification during interactions with ribosomes. 
E) the sequence of amino acids in the protein.

Question 8

The dimensions of living cells are limited,on the lower end by the minimum number of biomolecules necessary for function,and on the upper end by the rate of diffusion of solutes such as oxygen.Except for highly elongated cells,they usually have lengths and diameters in the range of:

Accepted Answer

A) 0)1 $\mu$m to 10 $\mu$m. 
B) 0)3$\mu$m to 30 $\mu$m. 
C) 0)3 $\mu$m to 100 $\mu$m. 
D) 1 $\mu$m to 100 $\mu$m. 
E) 1 $\mu$m to 300 $\mu$m. 
A) 0)1 $\mu$m to 10 $\mu$m. 
B) 0)3$\mu$m to 30 $\mu$m. 
C) 0)3 $\mu$m to 100 $\mu$m. 
D) 1 $\mu$m to 100 $\mu$m. 
E) 1 $\mu$m to 300 $\mu$m.

Question 9

E.coli is known as a gram-negative bacterial species.
(a)How is this determined? 
(b)How do gram-negative bacteria differ structurally from gram-positive bacteria?

Accepted Answer

(a)Gram-negative bacteria have little af

Question 10

Proteins are constantly being synthesized in a living cell.Why doesn't the number of protein molecules become too great for the cell to contain,leading to cell destruction?

Accepted Answer

The proteins in a cell are continuously

Question 11

The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions.Which one of the following is not considered a noncovalent interaction?

Accepted Answer

A) Carbon-carbon bonds 
B) Hydrogen bonds 
C) Hydrophobic interactions 
D) Ionic interactions 
E) van der Waals interactions 
A) Carbon-carbon bonds 
B) Hydrogen bonds 
C) Hydrophobic interactions 
D) Ionic interactions 
E) van der Waals interactions

Question 12

What six characteristics distinguish living organisms from inanimate objects?

Accepted Answer

Living organisms (1)are chemically compl

Question 13

Which is a list of organelles?

Accepted Answer

A) Mitochondria,chromatin,endoplasmic reticulum 
B) Peroxisomes,lysosomes,plasma membrane 
C) Proteasomes,peroxisomes,lysosomes 
D) Mitochondria,endoplasmic reticulum,peroxisomes 
E) All of the above 
A) Mitochondria,chromatin,endoplasmic reticulum 
B) Peroxisomes,lysosomes,plasma membrane 
C) Proteasomes,peroxisomes,lysosomes 
D) Mitochondria,endoplasmic reticulum,peroxisomes 
E) All of the above

Question 14

Use the terms a)chemoautotrophs,b)chemoheterotrophs,c)photoautotrophs,and d)photoheterotrophs and identify the answer that correctly finishes the statement:
Carnivores are and herbivores are .

Accepted Answer

A) b,c 
B) b,d 
C) b,b 
D) a,b 
E) a,a 
A) b,c 
B) b,d 
C) b,b 
D) a,b 
E) a,a

Question 15

In eukaryotes,the nucleus is enclosed by a double membrane called the:

Accepted Answer

A) cell membrane. 
B) nuclear envelope. 
C) nucleolus. 
D) nucleoplasm. 
E) nucleosome. 
A) cell membrane. 
B) nuclear envelope. 
C) nucleolus. 
D) nucleoplasm. 
E) nucleosome.

Question 16

All cells are surrounded by a plasma membrane composed of lipid and protein molecules.What is the function of the plasma membrane?

Accepted Answer

The plasma membrane acts as a barrier to

Question 17

(a)List the types of noncovalent interactions that are important in providing stability to the three-dimensional structures of macromolecules.
(b)Why is it important that these interactions be noncovalent,rather than covalent,bonds?

Accepted Answer

(a)Noncovalent interactions include hydr

Question 18

If the free energy change $\Delta$G for a reaction is -46.11 kJ/mol,the reaction is:

Accepted Answer

A) at equilibrium. 
B) endergonic. 
C) endothermic. 
D) exergonic. 
E) exothermic. 
A) at equilibrium. 
B) endergonic. 
C) endothermic. 
D) exergonic. 
E) exothermic.

Question 19

The major carrier of chemical energy in all cells is:

Accepted Answer

A) acetyl triphosphate. 
B) adenosine monophosphate. 
C) adenosine triphosphate. 
D) cytosine tetraphosphate. 
E) uridine diphosphate. 
A) acetyl triphosphate. 
B) adenosine monophosphate. 
C) adenosine triphosphate. 
D) cytosine tetraphosphate. 
E) uridine diphosphate.

Question 20

The free-energy change for the formation of a protein from the individual amino acids is positive and is thus an endergonic reaction.How,then,do cells accomplish this process?

Accepted Answer

The endergonic (thermodynamically unfavo

Exam 1: The Foundations of Biochemistry

Discuss how a mutation in DNA could be harmful or beneficial to an organism.

The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate,but it will not catalyze the hydration of maleic acid,the cis isomer of fumaric acid.This is an example of:

Which one of the following is not among the four most abundant elements in living organisms?

When a region of DNA must be repaired by removing and replacing some of the nucleotides,what ensures that the new nucleotides are in the correct sequence?

Differentiate between configuration and conformation.

The three-dimensional structure of a protein is determined primarily by:

The dimensions of living cells are limited,on the lower end by the minimum number of biomolecules necessary for function,and on the upper end by the rate of diffusion of solutes such as oxygen.Except for highly elongated cells,they usually have lengths and diameters in the range of:

E.coli is known as a gram-negative bacterial species. (a)How is this determined? (b)How do gram-negative bacteria differ structurally from gram-positive bacteria?

Proteins are constantly being synthesized in a living cell.Why doesn't the number of protein molecules become too great for the cell to contain,leading to cell destruction?

The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions.Which one of the following is not considered a noncovalent interaction?

What six characteristics distinguish living organisms from inanimate objects?

Which is a list of organelles?

Use the terms a)chemoautotrophs,b)chemoheterotrophs,c)photoautotrophs,and d)photoheterotrophs and identify the answer that correctly finishes the statement: Carnivores are and herbivores are .

In eukaryotes,the nucleus is enclosed by a double membrane called the:

All cells are surrounded by a plasma membrane composed of lipid and protein molecules.What is the function of the plasma membrane?

(a)List the types of noncovalent interactions that are important in providing stability to the three-dimensional structures of macromolecules. (b)Why is it important that these interactions be noncovalent,rather than covalent,bonds?

If the free energy change Δ\DeltaΔ G for a reaction is -46.11 kJ/mol,the reaction is:

The major carrier of chemical energy in all cells is:

The free-energy change for the formation of a protein from the individual amino acids is positive and is thus an endergonic reaction.How,then,do cells accomplish this process?

Water

Amino Acids, peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

Glycolysis, gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

If the free energy change $\Delta$ G for a reaction is -46.11 kJ/mol,the reaction is: