Question 1

Ribozymes are enzymes which are made of protein but only work on RNA molecules as substrates.

Accepted Answer

A) True 
 B)False

Question 2

Describe two factors which may increase enzyme activity and two factors which may decrease enzyme activity. Explain how each factor works to increase or decrease enzyme activity, and identify whether that factor is used internally by the cell (i.e. for regulation of a chemical reaction) or acts externally (i.e. is a component of the environment or a human- influenced component).

Accepted Answer

The following factors may influence enzy

Question 3

By the end of the Krebs cycle, every carbon originally in glucose is converted into carbon dioxide.

Accepted Answer

A) True 
 B)False

Question 4

The intermediate(s) needed to synthesize lipids from sugar catabolism is (are)

Accepted Answer

A)  acetyl CoA. 
B)  citric acid and dihydroxyacetone phosphate (DHAP). 
C)  citric acid. 
D)  dihydroxyacetone phosphate (DHAP). 
E)  acetyl CoA and dihydroxyacetone phosphate (DHAP). 
A)  acetyl CoA. 
B)  citric acid and dihydroxyacetone phosphate (DHAP). 
C)  citric acid. 
D)  dihydroxyacetone phosphate (DHAP). 
E)  acetyl CoA and dihydroxyacetone phosphate (DHAP).

Question 5

Anabolic reactions

Accepted Answer

A)  are endergonic. 
B)  involve dehydration synthesis. 
C)  are endergonic and involve breaking down larger molecules into smaller molecules. 
D)  are endergonic and involve dehydration synthesis. 
E)  involve breaking down larger molecules into smaller molecules. 
A)  are endergonic. 
B)  involve dehydration synthesis. 
C)  are endergonic and involve breaking down larger molecules into smaller molecules. 
D)  are endergonic and involve dehydration synthesis. 
E)  involve breaking down larger molecules into smaller molecules.

Question 6

Generally, purines and pyrimidines are not synthesized de novo but rather obtained through salvage pathways to recycle them from food because de novo synthesis has a high energy cost.

Accepted Answer

A) True 
 B)False

Question 7

The figure shows which process?

Accepted Answer

A)  allosteric inhibition 
B)  competitive inhibition 
C)  either allosteric inhibition, competitive inhibition, or non- competitive inhibition 
D)  allosteric activation 
E)  non- competitive inhibition 
A)  allosteric inhibition 
B)  competitive inhibition 
C)  either allosteric inhibition, competitive inhibition, or non- competitive inhibition 
D)  allosteric activation 
E)  non- competitive inhibition

Question 8

Radioactive isotopes of various elements can be used to label molecules for use in studies of metabolic pathways. For example, 14C is a radioactive isotope of carbon and naturally occurs at much lower rates than non- radioactive 12C (i.e. most molecules contain 12C carbon atoms). A cell can be fed a nutrient molecule labeled with the radioactive isotope and scientists can detect where the radioactive isotope ends up. For each of the following scenarios, trace the radioactive isotope to where it ultimately would end up after moving through the cellular respiration, fermentation, or biosynthetic pathways. Only consider these metabolic pathways; do not consider any other cellular processes.
A. E. coli is fed 14C- labeled glucose and grown under aerobic conditions.
B. E. coli is fed 14C- labeled glucose and grown under anaerobic conditions (fermentation).
C. E. coli is fed 14C- labeled fatty acids and grown under aerobic conditions.
D. E. coli is fed 14C- labeled acetyl CoA and grown under conditions that promote biosynthetic pathways.

Accepted Answer

In scenario A, the 14C glucose would ent

Question 9

Oxidation of nutrients by cells results in

Accepted Answer

A)  a requirement for energy which can be used to recharge ADP to ATP. 
B)  a release of energy, which is released by converting ATP to ADP. 
C)  a release of energy, which can be used to recharge ADP to ATP. 
D)  a requirement of energy which can be obtained by converting ATP to ADP. 
E)  either a release or a requirement for energy depending on what type of nutrient is available. 
A)  a requirement for energy which can be used to recharge ADP to ATP. 
B)  a release of energy, which is released by converting ATP to ADP. 
C)  a release of energy, which can be used to recharge ADP to ATP. 
D)  a requirement of energy which can be obtained by converting ATP to ADP. 
E)  either a release or a requirement for energy depending on what type of nutrient is available.

Question 10

Catabolic reactions

Accepted Answer

A)  are endergonic. 
B)  are hydrolytic and involve breaking down larger molecules into smaller molecules. 
C)  are hydrolytic. 
D)  involve breaking down larger molecules into smaller molecules. 
E)  are endergonic and are hydrolytic. 
A)  are endergonic. 
B)  are hydrolytic and involve breaking down larger molecules into smaller molecules. 
C)  are hydrolytic. 
D)  involve breaking down larger molecules into smaller molecules. 
E)  are endergonic and are hydrolytic.

Question 11

Cells harvest energy from nutrients by stripping electrons from them. In other words, the nutrients are oxidized.

Accepted Answer

A) True 
 B)False

Question 12

Many strains of E. coli are able to grow on minimal media which consists only of a single sugar, usually glucose, and inorganic salts to provide nitrogen, sulfur, phosphorous and trace nutrients. What does this tell you about E. coli's biosynthetic capabilities?

Accepted Answer

A)  E. coli can funnel intermediates from glycolysis, the intermediate step, and the Krebs cycle to synthesize amino acids, fatty acids, glycerol, and nucleotides. 
B)  E. coli will be unable to build the peptidoglycan it needs for its cell wall. 
C)  All amino acids are "essential" to E. coli. 
D)  E. coli will be unable to perform amination. 
E)  E. coli will use salvage pathways to make nucleotides. 
A)  E. coli can funnel intermediates from glycolysis, the intermediate step, and the Krebs cycle to synthesize amino acids, fatty acids, glycerol, and nucleotides. 
B)  E. coli will be unable to build the peptidoglycan it needs for its cell wall. 
C)  All amino acids are "essential" to E. coli. 
D)  E. coli will be unable to perform amination. 
E)  E. coli will use salvage pathways to make nucleotides.

Question 13

In the typical ATP- ADP cycle, which part of the ATP molecule is removed when energy is released and added back when energy is stored?

Accepted Answer

A)  the terminal two phosphate groups 
B)  adenine 
C)  the terminal phosphate group 
D)  ribose 
E)  all three phosphate groups 
A)  the terminal two phosphate groups 
B)  adenine 
C)  the terminal phosphate group 
D)  ribose 
E)  all three phosphate groups

Question 14

Biochemical tests are useful to microbiology because

Accepted Answer

A)  they can be used to identify microbes. 
B)  they can be used to identify microbes and to identify potential pathogens in clinical samples. 
C)  they can be used to detect metabolic end- products, intermediates, or particular enzymes. 
D)  they can be used to identify potential pathogens in clinical samples. 
E)  they can be used to identify microbes and to identify potential pathogens in clinical samples and they can be used to detect metabolic end- products, intermediates, or particular enzymes. 
A)  they can be used to identify microbes. 
B)  they can be used to identify microbes and to identify potential pathogens in clinical samples. 
C)  they can be used to detect metabolic end- products, intermediates, or particular enzymes. 
D)  they can be used to identify potential pathogens in clinical samples. 
E)  they can be used to identify microbes and to identify potential pathogens in clinical samples and they can be used to detect metabolic end- products, intermediates, or particular enzymes.

Question 15

Enzymes are necessary for cells because

Accepted Answer

A)  enzymes slow down chemical reactions that would otherwise occur too quickly to facilitate life. 
B)  enzymes allow chemical reactions to occur under physiological conditions and within a time frame conducive to life. 
C)  enzymes allow chemical reactions to occur under physiological conditions. 
D)  enzymes allow chemical reactions to take place that would otherwise be impossible. 
E)  enzymes allow chemical reactions to occur quickly enough to facilitate life. 
A)  enzymes slow down chemical reactions that would otherwise occur too quickly to facilitate life. 
B)  enzymes allow chemical reactions to occur under physiological conditions and within a time frame conducive to life. 
C)  enzymes allow chemical reactions to occur under physiological conditions. 
D)  enzymes allow chemical reactions to take place that would otherwise be impossible. 
E)  enzymes allow chemical reactions to occur quickly enough to facilitate life.

Question 16

Which molecule is the product of the intermediate step which is a direct input into the Krebs cycle?

Accepted Answer

A)  carbon dioxide 
B)  ATP 
C)  pyruvic acid 
D)  NADH 
E)  acetyl CoA 
A)  carbon dioxide 
B)  ATP 
C)  pyruvic acid 
D)  NADH 
E)  acetyl CoA

Question 17

The main goal of fermentation is to sustain ATP production by glycolysis. This is accomplished by

Accepted Answer

A)  passing the electrons on NADH to pyruvic acid, regenerating NAD+ so glycolysis can continue. 
B)  enables the cell to use its respiratory chain without oxygen being available. 
C)  producing acids and alcohols which the microorganism can use as an alternative nutrient source when glucose is not available. 
D)  producing acids which lower cellular pH to promote more efficient ATP recharge. 
E)  diverting glycolysis intermediates into the pentose phosphate pathway. 
A)  passing the electrons on NADH to pyruvic acid, regenerating NAD+ so glycolysis can continue. 
B)  enables the cell to use its respiratory chain without oxygen being available. 
C)  producing acids and alcohols which the microorganism can use as an alternative nutrient source when glucose is not available. 
D)  producing acids which lower cellular pH to promote more efficient ATP recharge. 
E)  diverting glycolysis intermediates into the pentose phosphate pathway.

Question 18

Which of the following factors may influence an enzyme's activity by altering its three- dimensional structure?

Accepted Answer

A)  temperature 
B)  pH 
C)  pH and temperature only 
D)  competitive inhibitor 
E)  pH, temperature, and competitive inhibitor 
A)  temperature 
B)  pH 
C)  pH and temperature only 
D)  competitive inhibitor 
E)  pH, temperature, and competitive inhibitor

Question 19

Refer to the numbered steps in the figure when answering the question. Which step is a redox reaction?

Accepted Answer

A)  step 1 
B)  step 3 
C)  step 4 
D)  step 6 
E)  step 9 
A)  step 1 
B)  step 3 
C)  step 4 
D)  step 6 
E)  step 9

Question 20

Describe or diagram the relationship between catabolic pathways, anabolic pathways and the ATP- ADP cycle. Include in your answer an explanation of the role each of these plays in the metabolism of a cell.

Accepted Answer

All the chemical reactions that take pla

Ribozymes are enzymes which are made of protein but only work on RNA molecules as substrates.

By the end of the Krebs cycle, every carbon originally in glucose is converted into carbon dioxide.

The intermediate(s) needed to synthesize lipids from sugar catabolism is (are)

Anabolic reactions

Generally, purines and pyrimidines are not synthesized de novo but rather obtained through salvage pathways to recycle them from food because de novo synthesis has a high energy cost.

The figure shows which process?

Oxidation of nutrients by cells results in

Catabolic reactions

Cells harvest energy from nutrients by stripping electrons from them. In other words, the nutrients are oxidized.

Many strains of E. coli are able to grow on minimal media which consists only of a single sugar, usually glucose, and inorganic salts to provide nitrogen, sulfur, phosphorous and trace nutrients. What does this tell you about E. coli's biosynthetic capabilities?

In the typical ATP- ADP cycle, which part of the ATP molecule is removed when energy is released and added back when energy is stored?

Biochemical tests are useful to microbiology because

Enzymes are necessary for cells because

Which molecule is the product of the intermediate step which is a direct input into the Krebs cycle?

The main goal of fermentation is to sustain ATP production by glycolysis. This is accomplished by

Which of the following factors may influence an enzyme's activity by altering its three- dimensional structure?

Refer to the numbered steps in the figure when answering the question. Which step is a redox reaction?

Describe or diagram the relationship between catabolic pathways, anabolic pathways and the ATP- ADP cycle. Include in your answer an explanation of the role each of these plays in the metabolism of a cell.

Introduction to Microbiology

Biochemistry Basics

Introduction to Prokaryotic Cells

Introduction to Eukaryotic Cells

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Viruses and Prions

Fundamentals of Microbial Growth

Principles of Infectious Disease and Epidemiology

Host-Microbe Interactions and Pathogenesis

Innate Immunity

Adaptive Immunity

Immune System Disorders

Vaccines and Biotechnology-Based Diagnostics and Therapeutics

Antimicrobial Drugs

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Exam 8: Microbial Metabolism

Ribozymes are enzymes which are made of protein but only work on RNA molecules as substrates.

By the end of the Krebs cycle, every carbon originally in glucose is converted into carbon dioxide.

The intermediate(s) needed to synthesize lipids from sugar catabolism is (are)

Anabolic reactions

Generally, purines and pyrimidines are not synthesized de novo but rather obtained through salvage pathways to recycle them from food because de novo synthesis has a high energy cost.

The figure shows which process?

Oxidation of nutrients by cells results in

Catabolic reactions

Cells harvest energy from nutrients by stripping electrons from them. In other words, the nutrients are oxidized.

Many strains of E. coli are able to grow on minimal media which consists only of a single sugar, usually glucose, and inorganic salts to provide nitrogen, sulfur, phosphorous and trace nutrients. What does this tell you about E. coli's biosynthetic capabilities?

In the typical ATP- ADP cycle, which part of the ATP molecule is removed when energy is released and added back when energy is stored?

Biochemical tests are useful to microbiology because

Enzymes are necessary for cells because

Which molecule is the product of the intermediate step which is a direct input into the Krebs cycle?

The main goal of fermentation is to sustain ATP production by glycolysis. This is accomplished by

Which of the following factors may influence an enzyme's activity by altering its three- dimensional structure?

Refer to the numbered steps in the figure when answering the question. Which step is a redox reaction?

Describe or diagram the relationship between catabolic pathways, anabolic pathways and the ATP- ADP cycle. Include in your answer an explanation of the role each of these plays in the metabolism of a cell.

Introduction to Microbiology

Biochemistry Basics

Introduction to Prokaryotic Cells

Introduction to Eukaryotic Cells

Genetics

Viruses and Prions

Fundamentals of Microbial Growth

Principles of Infectious Disease and Epidemiology

Host-Microbe Interactions and Pathogenesis

Innate Immunity

Adaptive Immunity

Immune System Disorders

Vaccines and Biotechnology-Based Diagnostics and Therapeutics

Antimicrobial Drugs

Respiratory System Infections

Skin and Eye Infections

Nervous System Infections

Digestive System Infections

Urinary and Reproductive System Infections

Cardiovascular and Lymphatic Infections

Filters