Question 1

In the carbon assimilation ("dark") reactions of photosynthesis, the biosynthesis of 1 mol of hexose from 6 mol of carbon dioxide requires:

Accepted Answer

A)  12 mol of NADPH and 12 mol of ATP. 
B)  12 mol of NADPH and 18 mol of ATP. 
C)  18 mol of NADPH and 12 mol of ATP. 
D)  18 mol of NADPH and 18 mol of ATP. 
E)  no NADPH and 12 mol of ATP. 
A)  12 mol of NADPH and 12 mol of ATP. 
B)  12 mol of NADPH and 18 mol of ATP. 
C)  18 mol of NADPH and 12 mol of ATP. 
D)  18 mol of NADPH and 18 mol of ATP. 
E)  no NADPH and 12 mol of ATP.

Question 2

Which statement about the light reactions in photosynthetic plants is FALSE?

Accepted Answer

A)  A membrane-bound ATPase couples ATP synthesis to electron transfer. 
B)  No CO2 is fixed in the light reactions. 
C)  The ultimate electron acceptor is O2. 
D)  The ultimate source of electrons for the process is H2O. 
E)  There are two distinct photosystems, linked together by an electron transfer chain. 
A)  A membrane-bound ATPase couples ATP synthesis to electron transfer. 
B)  No CO2 is fixed in the light reactions. 
C)  The ultimate electron acceptor is O2. 
D)  The ultimate source of electrons for the process is H2O. 
E)  There are two distinct photosystems, linked together by an electron transfer chain.

Question 3

In photophosphorylation, absorption of light energy in chloroplast "light reactions" leads to:

Accepted Answer

A)  absorption of CO2 and release of O2. 
B)  absorption of O2 and release of CO2. 
C)  hydrolysis of ATP and reduction of NADP+. 
D)  synthesis of ATP and oxidation of NADPH. 
E)  use of iron-sulfur proteins. 
A)  absorption of CO2 and release of O2. 
B)  absorption of O2 and release of CO2. 
C)  hydrolysis of ATP and reduction of NADP+. 
D)  synthesis of ATP and oxidation of NADPH. 
E)  use of iron-sulfur proteins.

Question 4

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

Accepted Answer

Fructose 2,6-bisphosphate plays a crucia

Question 5

The three subcellular organelles involved in the phosphoglycolate salvage pathway are:

Accepted Answer

A)  endoplasmic reticulum, chloroplast, and mitochondrion. 
B)  nucleus, endoplasmic reticulum, and chloroplast. 
C)  golgi apparatus, chloroplast, and mitochondrion. 
D)  mitochondrion, peroxisome, and chloroplast. 
E)  peroxisome, endoplasmic reticulum, and chloroplast. 
A)  endoplasmic reticulum, chloroplast, and mitochondrion. 
B)  nucleus, endoplasmic reticulum, and chloroplast. 
C)  golgi apparatus, chloroplast, and mitochondrion. 
D)  mitochondrion, peroxisome, and chloroplast. 
E)  peroxisome, endoplasmic reticulum, and chloroplast.

Question 6

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

The reaction sequence by which 2-phospho

Question 7

Photosynthetic phosphorylation and oxidative phosphorylation appear to be generally similar processes, both consisting of ATP synthesis coupled to the transfer of electrons along an electron carrier chain. Which statement is NOT true of both processes?

Accepted Answer

A)  Both contain cytochromes and flavins in their electron carrier chains. 
B)  Both processes are associated with membranous elements of the cell. 
C)  Both use oxygen as a terminal electron acceptor. 
D)  Each represents the major route of ATP synthesis in those cells in which it is found. 
E)  Protons are pumped from the inside to the outside of both mitochondria and chloroplast membranes 
A)  Both contain cytochromes and flavins in their electron carrier chains. 
B)  Both processes are associated with membranous elements of the cell. 
C)  Both use oxygen as a terminal electron acceptor. 
D)  Each represents the major route of ATP synthesis in those cells in which it is found. 
E)  Protons are pumped from the inside to the outside of both mitochondria and chloroplast membranes

Question 8

Show the path of electrons from photosystem II to NADPH in the chloroplast. What is the source of the energy that moves electrons through this path? Show where oxygen is involved in this pathway.

Accepted Answer

The path of electrons from photosystem I

Question 9

DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII) to the cytochrome b6f complex. Predict the effect of DCMU on O2 production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Accepted Answer

DCMU, also known as Diuron, is a specifi

Question 10

Give five general classes of electron carriers that function in both mitochondrial electron transfer to O2 and photosynthetic electron transfer.

Accepted Answer

1. Flavoproteins: These are proteins tha

Question 11

Which statement 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.

Question 12

Write out the net balanced chemical reaction catalyzed by rubisco.

Accepted Answer

The net balanced chemical reaction catal

Question 13

In the synthesis of cellulose, UDP glucose in the $\alpha$ configuration is used as a substrate to synthesize $\beta$1$\rightarrow$4 linkages in cellulose. Why does this imply a single-displacement mechanism?

Accepted Answer

In the synthesis of cellulose, UDP-gluco

Question 14

The compound that condenses with CO2 in the first reaction of carbon dioxide assimilation is:

Accepted Answer

A)  3-phosphoglycerate. 
B)  ribose 1,5-bisphosphate. 
C)  ribulose 1,5-bisphosphate. 
D)  ribulose 5-phosphate. 
E)  rubisco. 
A)  3-phosphoglycerate. 
B)  ribose 1,5-bisphosphate. 
C)  ribulose 1,5-bisphosphate. 
D)  ribulose 5-phosphate. 
E)  rubisco.

Exam 20: Carbohydrate Biosynthesis in Plants and Bacteria

In the carbon assimilation ("dark") reactions of photosynthesis, the biosynthesis of 1 mol of hexose from 6 mol of carbon dioxide requires:

Which statement about the light reactions in photosynthetic plants is FALSE?

In photophosphorylation, absorption of light energy in chloroplast "light reactions" leads to:

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

The three subcellular organelles involved in the phosphoglycolate salvage pathway are:

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.

Photosynthetic phosphorylation and oxidative phosphorylation appear to be generally similar processes, both consisting of ATP synthesis coupled to the transfer of electrons along an electron carrier chain. Which statement is NOT true of both processes?

Show the path of electrons from photosystem II to NADPH in the chloroplast. What is the source of the energy that moves electrons through this path? Show where oxygen is involved in this pathway.

DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII) to the cytochrome b6f complex. Predict the effect of DCMU on O2 production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Give five general classes of electron carriers that function in both mitochondrial electron transfer to O2 and photosynthetic electron transfer.

Which statement is NOT true about the biosynthesis of cellulose?

Write out the net balanced chemical reaction catalyzed by rubisco.

In the synthesis of cellulose, UDP glucose in the α\alphaα configuration is used as a substrate to synthesize β\betaβ 1 →\rightarrow→ 4 linkages in cellulose. Why does this imply a single-displacement mechanism?

The compound that condenses with CO2 in the first reaction of carbon dioxide assimilation is:

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

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

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

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

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.

DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII) to the cytochrome b₆f complex. Predict the effect of DCMU on O₂ production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Give five general classes of electron carriers that function in both mitochondrial electron transfer to O₂ and photosynthetic electron transfer.

In the synthesis of cellulose, UDP glucose in the $\alpha$ configuration is used as a substrate to synthesize $\beta$ 1 $\rightarrow$ 4 linkages in cellulose. Why does this imply a single-displacement mechanism?

The compound that condenses with CO₂ in the first reaction of carbon dioxide assimilation is: