Question 1

Diagram the reaction catalyzed by transketolase when fructose 6-phosphate and glyceraldehyde 3-phosphate are the substrates.

Accepted Answer

Fructose 6-phosphate + glycera

Question 2

Describe briefly how the allosteric effector fructose 2,6-bisphosphate (F2,6BP)regulates starch and sucrose synthesis.

Accepted Answer

In vascular plants,the concentration of

Question 3

Draw the structure of 3-phosphoglycerate.Circle the atom(s)that would be labeled first in plants grown in CO2 labeled with radioactive carbon.

Accepted Answer

Question 4

Which of the following is not true about plastids?

Accepted Answer

A) Most of the proteins in a plastid are encoded in nuclear genes. 
B) Plastids are encoded by a double membrane. 
C) Plastids are self-replicating. 
D) Plastids contain a small circular genome. 
E) The inner membrane of plastids is permeable to polar and charged molecules. 
A) Most of the proteins in a plastid are encoded in nuclear genes. 
B) Plastids are encoded by a double membrane. 
C) Plastids are self-replicating. 
D) Plastids contain a small circular genome. 
E) The inner membrane of plastids is permeable to polar and charged molecules.

Question 5

Describe the reaction sequence by which 2-phosphoglycolate (produced when O2 replaces CO2 as substrate for rubisco)is converted to serine.Name each enzyme and any cofactors required and indicate the subcellular compartment in which the reaction takes place.

Accepted Answer

2-phosphoglycolate is converted to glyco

Question 6

Diagram the pathway by which sucrose is synthesized from glucose 6-phosphate;indicate how any required cofactors are involved.

Accepted Answer

(See Fig. 20-24.)  Glucose 6-phosphate i

Question 7

The precursors for sucrose biosynthesis are:

Accepted Answer

A) glucose and fructose. 
B) UDP-glucose and fructose 6-phosphate. 
C) UDP-fructose and glucose 6-phosphate. 
D) UDP-glucose and fructose. 
E) UDP-glucose and UDP-fructose. 
A) glucose and fructose. 
B) UDP-glucose and fructose 6-phosphate. 
C) UDP-fructose and glucose 6-phosphate. 
D) UDP-glucose and fructose. 
E) UDP-glucose and UDP-fructose.

Question 8

Which of these chloroplast enzymes is not regulated by light?

Accepted Answer

A) Fructose 1,6-bisphosphatase 
B) Glyceraldehyde-phosphate dehydrogenase 
C) Ribulose 5-phosphate kinase 
D) Sedoheptulose 1,7-bisphosphatase 
E) All of the above 
A) Fructose 1,6-bisphosphatase 
B) Glyceraldehyde-phosphate dehydrogenase 
C) Ribulose 5-phosphate kinase 
D) Sedoheptulose 1,7-bisphosphatase 
E) All of the above

Question 9

Which of the following is not required to activate rubisco?

Accepted Answer

A) ATP hydrolysis 
B) Carbamoylation of the active site lysine by rubisco activase 
C) Release of ribulose 1,5-bisphosphate from the active site 
D) Release of 2-carboxyarabinitol from the active site 
E) Binding of Mg2+ 
A) ATP hydrolysis 
B) Carbamoylation of the active site lysine by rubisco activase 
C) Release of ribulose 1,5-bisphosphate from the active site 
D) Release of 2-carboxyarabinitol from the active site 
E) Binding of Mg2+

Question 10

Explain why photorespiration occurs in plant cells carrying out photosynthesis.

Accepted Answer

Because rubisco is not particularly spec

Question 11

Describe the role of fructose 2,6-bisphosphate in the regulation of sucrose biosynthesis in plant cells.

Accepted Answer

In conditions of intense light,3-phospho

Question 12

Transketolase requires the coenzyme:

Accepted Answer

A) cobalamin (vitamin B12). 
B) lipoic acid 
C) pyridoxal phosphate. 
D) tetrahydrofolic acid. 
E) thiamine pyrophosphate. 
A) cobalamin (vitamin B12). 
B) lipoic acid 
C) pyridoxal phosphate. 
D) tetrahydrofolic acid. 
E) thiamine pyrophosphate.

Question 13

The assimilation of CO2 into organic compounds (triose phosphates)in green plants:

Accepted Answer

A) involves condensation of the two-carbon compound acetate with CO2 to form 3-phosphoglycerate. 
B) requires NADPH. 
C) results in the production of ATP. 
D) takes place at equal rates in light and darkness. 
E) takes place in the cytosol. 
A) involves condensation of the two-carbon compound acetate with CO2 to form 3-phosphoglycerate. 
B) requires NADPH. 
C) results in the production of ATP. 
D) takes place at equal rates in light and darkness. 
E) takes place in the cytosol.

Question 14

Describe how plants and some microorganisms can,unlike animals,convert acetyl-CoA derived from fatty acids into glucose or sucrose.

Accepted Answer

The integration of reaction sequences in

Question 15

When transketolase acts on fructose 6-phosphate and glyceraldehyde 3-phosphate,the products are:

Accepted Answer

A) 3-phosphoglycerate and glyceraldehyde 3-phosphate. 
B) 3-phosphoglycerate and two molecules of glyceraldehyde 3-phosphate. 
C) dihydroxyacetone phosphate and glucose 6-phosphate. 
D) xylulose 5-phosphate and erythrose 4-phosphate. 
E) xylulose 5-phosphate and ribose 5-phosphate. 
A) 3-phosphoglycerate and glyceraldehyde 3-phosphate. 
B) 3-phosphoglycerate and two molecules of glyceraldehyde 3-phosphate. 
C) dihydroxyacetone phosphate and glucose 6-phosphate. 
D) xylulose 5-phosphate and erythrose 4-phosphate. 
E) xylulose 5-phosphate and ribose 5-phosphate.

Question 16

The final product that is formed by the enzyme rubisco is:

Accepted Answer

A) 3-phosphoglycerate. 
B) ATP. 
C) ribulose 1,5-bisphosphate. 
D) glyceraldehyde-3-phosphate. 
E) CO2. 
A) 3-phosphoglycerate. 
B) ATP. 
C) ribulose 1,5-bisphosphate. 
D) glyceraldehyde-3-phosphate. 
E) CO2.

Question 17

A precursor in the synthesis of the peptidoglycan of bacterial cell walls is UDP-:

Accepted Answer

A) galactose. 
B) glucose. 
C) glucuronic acid. 
D) N-acetylglucosamine. 
E) penicillin. 
A) galactose. 
B) glucose. 
C) glucuronic acid. 
D) N-acetylglucosamine. 
E) penicillin.

Question 18

Which one of the following sugar phosphates is not part of the pool of readily interconvertible metabolites used by the plant cell?

Accepted Answer

A) Dihydroxyacetone phosphate 
B) Fructose 2,6-bisphosphate 
C) Glucose 1-phosphate 
D) 6-phosphogluconate 
E) Xylulose 5-phosphate 
A) Dihydroxyacetone phosphate 
B) Fructose 2,6-bisphosphate 
C) Glucose 1-phosphate 
D) 6-phosphogluconate 
E) Xylulose 5-phosphate

Question 19

How does glyceraldehyde 3-phosphate formed in the chloroplast stroma by the Calvin cycle reactions enter the cytosol?

Accepted Answer

It is converted to dihydroxyacetone phos

Question 20

Which of the following is not true about the biosynthesis of cellulose?

Accepted Answer

A) UDP-glucose is used as a substrate. 
B) Glucose is transported across the membrane via a lipid-linked oligosaccharide intermediate. 
C) The extracellular form of cellulose synthase adds up to 15,000 glucose units to one chain. 
D) Cellulose polymers line up in an anti-parallel fashion. 
E) The reaction catalyzed by cellulose synthase proceeds via inversion of configuration. 
A) UDP-glucose is used as a substrate. 
B) Glucose is transported across the membrane via a lipid-linked oligosaccharide intermediate. 
C) The extracellular form of cellulose synthase adds up to 15,000 glucose units to one chain. 
D) Cellulose polymers line up in an anti-parallel fashion. 
E) The reaction catalyzed by cellulose synthase proceeds via inversion of configuration.

Exam 20: Carbohydrate Biosynthesis in Plants and Bacteria

Diagram the reaction catalyzed by transketolase when fructose 6-phosphate and glyceraldehyde 3-phosphate are the substrates.

Describe briefly how the allosteric effector fructose 2,6-bisphosphate (F2,6BP)regulates starch and sucrose synthesis.

Draw the structure of 3-phosphoglycerate.Circle the atom(s)that would be labeled first in plants grown in CO2 labeled with radioactive carbon.

Which of the following is not true about plastids?

Describe the reaction sequence by which 2-phosphoglycolate (produced when O2 replaces CO2 as substrate for rubisco)is converted to serine.Name each enzyme and any cofactors required and indicate the subcellular compartment in which the reaction takes place.

Diagram the pathway by which sucrose is synthesized from glucose 6-phosphate;indicate how any required cofactors are involved.

The precursors for sucrose biosynthesis are:

Which of these chloroplast enzymes is not regulated by light?

Which of the following is not required to activate rubisco?

Explain why photorespiration occurs in plant cells carrying out photosynthesis.

Describe the role of fructose 2,6-bisphosphate in the regulation of sucrose biosynthesis in plant cells.

Transketolase requires the coenzyme:

The assimilation of CO2 into organic compounds (triose phosphates)in green plants:

Describe how plants and some microorganisms can,unlike animals,convert acetyl-CoA derived from fatty acids into glucose or sucrose.

When transketolase acts on fructose 6-phosphate and glyceraldehyde 3-phosphate,the products are:

The final product that is formed by the enzyme rubisco is:

A precursor in the synthesis of the peptidoglycan of bacterial cell walls is UDP-:

Which one of the following sugar phosphates is not part of the pool of readily interconvertible metabolites used by the plant cell?

How does glyceraldehyde 3-phosphate formed in the chloroplast stroma by the Calvin cycle reactions enter the cytosol?

Which of the following is not true about the biosynthesis of cellulose?

The Foundations of Biochemistry

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

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

Draw the structure of 3-phosphoglycerate.Circle the atom(s)that would be labeled first in plants grown in CO₂ labeled with radioactive carbon.

Describe the reaction sequence by which 2-phosphoglycolate (produced when O₂ replaces CO₂ as substrate for rubisco)is converted to serine.Name each enzyme and any cofactors required and indicate the subcellular compartment in which the reaction takes place.

The assimilation of CO₂ into organic compounds (triose phosphates)in green plants: