Deck 29: Biosynthetic Pathways

Question 1

Examine the following structure.
Which of the following is true when a normal biosynthetic pathway is blocked?

A) The organism can always make the necessary compounds by using the reverse of the blocked synthetic pathway.
B) The organism can never make the necessary compounds by using the reverse of the blocked synthetic pathway.
C) The organism can often make the necessary compounds by using the reverse of the blocked synthetic pathway.
D) The organism will always die.

Answer 1

C

Question 2

The dark reactions of photosynthesis consume which of the following?

A) carbon dioxide
B) water
C) both a and b
D) neither a nor b

Answer 2

A

Question 3

Examine the following structure.
Which of the following refers to the biosynthesis of compounds?

A) anabolism
B) catabolism
C) metabolism
D) none of these

Answer 3

A

Question 4

How many enzymes which are involved in gluconeogenesis make it a distinctly different pathway than glycolysis?

A) 1
B) 2
C) 3
D) 4

Question 5

Examine the following structure.
Which of the following is true of the relationship between anabolic pathways and catabolic pathways?

A) They are always different.
B) They are always the same.
C) They are usually different.
D) They are usually the same.

Question 6

Which of the following is considered to be a waste product of photosynthesis?

A) H₂O
B) CO₂
C) O₂
D) none of these

Question 7

Which of the following correctly describes ATP usage in gluconeogenesis and glycolysis?

A) ATP is consumed by both gluconeogenesis and glycolysis.
B) ATP is produced by both gluconeogenesis and glycolysis.
C) ATP is consumed by gluconeogenesis and produced by glycolysis.
D) ATP is produced by gluconeogenesis and consumed by glycolysis.

Question 8

Which amino acids can serve as starting material for gluconeogenesis?

A) all of them
B) none of them
C) only glucogenic amino acids
D) only ketogenic amino acids

Question 9

Which of the following is the process by which glucose is synthesized in the body?

A) glucolysis
B) glucogenesis
C) gluconeogenesis
D) glucosylation

Question 10

The body contains a large amount of inorganic phosphate, P_i. What is the effect of inorganic phosphate on the cleavage of glucose from glycogen?

A) It favors the cleavage reaction and promotes glycogen degradation.
B) It represses the cleavage reaction and prevents glycogen degradation.
C) It speeds up the conversion of glucose to glycogen.
D) It speeds up the conversion of glycogen to glucose.

Question 11

The light reactions of photosynthesis produce which of the following?

A) glucose
B) molecular oxygen
C) both a and b
D) neither a nor b

Question 12

Which of the following are the starting materials for photosynthesis?

A) CO₂ and H₂O
B) CO₂ and O₂
C) H₂O and O₂
D) none of these combinations

Question 13

Which of the following is the cycle which utilizes lactate as the starting material for gluconeogenesis?

A) the Calvin cycle
B) the citric acid cycle
C) the Cori cycle
D) the Krebs cycle

Question 14

The light reactions of photosynthesis consume which of the following?

A) carbon dioxide
B) water
C) both a and b
D) neither a nor b

Question 15

Which of the following can serve as starting material for gluconeogenesis?

A) leucine
B) lysine
C) tryptophan
D) threonine

Question 16

The dark reactions of photosynthesis produce which of the following?

A) glucose
B) molecular oxygen
C) both a and b
D) neither a nor b

Question 17

During photosynthesis, how many molecules of oxygen are produced for each molecule of glucose which is synthesized?

A) 1
B) 3
C) 6
D) 12

Question 18

Which of the following won a Nobel Prize for studies of photosynthesis?

A) M. Calvin
B) C. Cori
C) H. Krebs
D) L. Pauling

Question 19

Which of the following is involved in one of the mechanisms of glycogen synthesis?

A) ADP-glucose
B) ATP-glucose
C) UDP-glucose
D) UTP-glucose

Question 20

Approximately what percentage of the radiant energy absorbed by plants is converted to carbohydrates?

A) 1%
B) 10%
C) 50%
D) 90%

Question 21

Which of the following is the oxidizing agent in the conversion of a saturated fatty acid to an unsaturated fatty acid?

A) FADH₂
B) FADPH₂
C) NADH
D) NADPH

Question 22

Which of the following are the precursors of phosphatidylcholines?

A) cholinates
B) cholinesterates
C) phosphatidates
D) triphosphates

Question 23

Which of the following are the two essential fatty acids?

A) linoleic acid and oleic acid
B) linoleic acid and linolenic acid
C) linolenic acid and oleic acid
D) oleic acid and stearic acid

Question 24

Glycerol 3-phosphate reacts with how many molecules of acyl CoA to form the precursor of phosphatidylcholines?

A) 1
B) 2
C) 3
D) 4

Question 25

Which of the following activates choline to complete the synthesis of phosphatidylcholines?

A) ATP
B) CTP
C) GTP
D) UTP

Question 26

UTP has how many high-energy phosphate anhydride bonds?

A) 1
B) 2
C) 3
D) 4

Question 27

How many of the fatty acids which the body needs is it unable to synthesize?

A) 1
B) 2
C) 3
D) 4

Question 28

Which of the following reacts with acetyl fatty acid synthase to elongate the growing fatty acid?

A) acetyl-ACP
B) formyl-ACP
C) fumaryl-ACP
D) malonyl-ACP

Question 29

Why is dietary cholesterol and cholesterol synthesized in the liver not available for synapse formation?

A) There is a subtle between these cholesterols and the cholesterol synthesized in the nerve cells of the brain.
B) LDL cannot cross the blood-brain barrier.
C) both a and b
D) neither a nor b

Question 30

The synthesis of cholesterol begins with the sequential condensation of how many molecules of acetyl CoA.

A) 1
B) 2
C) 3
D) 4

Question 31

Which of the following is present in ACP?

A) a disulfide
B) a thioether
C) a thioester
D) a thiol

Question 32

Which of the following enzymes controls the rate of cholesterol synthesis?

A) cholesterase
B) HMG oxidase
C) HMG CoA reductase
D) mevalonate decarboxylase

Question 33

The synthesis of unsaturated fatty acids from fatty acids is which type of reaction?

A) condensation
B) hydrolysis
C) oxidation
D) reduction

Question 34

In which organ does gluconeogenesis using the Cori cycle take place?

A) the intestine
B) the liver
C) the muscles
D) the spleen

Question 35

Which of the following is the starting material for the Cori cycle?

A) lactate
B) malate
C) oxaloacetate
D) pyruvate

Question 36

Which of the following is the process by which glucose is converted to glycogen?

A) glucolysis
B) gluconeogenesis
C) glycogenesis
D) glycogenolysis

Question 37

Which of the following is the largest saturated fatty acid which can be synthesized by the ACP merry-go-round mechanism?

A) arachidonic acid
B) lauric acid
C) palmitic acid
D) stearic acid

Question 38

Which of the following is true of fatty acid degradation and fatty acid synthesis?

A) They both take place in the cytoplasm.
B) They both take place in the mitochondria.
C) Degradation takes place in the cytoplasm and synthesis takes place in the mitochondria.
D) Degradation takes place in the mitochondria and synthesis takes place in the cytoplasm.

Question 39

Why are fatty acids built up two carbon atoms at a time?

A) the starting material is acetate
B) the starting material is acetyl CoA
C) the starting is malate
D) the starting material is oxaloacetate

Question 40

Which of the following is present in acetyl ACP?

A) a disulfide
B) a thioether
C) a thioester
D) a thiol

Question 41

Of the 20 amino acids found in human proteins, how many are essential amino acids?

A) 5
B) 10
C) 15
D) 20

Question 42

Prenylation of a protein results in which of the following?

A) the protein becomes more hydrophilic
B) the protein becomes more hydrophobic
C) protein synthesis is accelerated
D) protein synthesis ceases

Question 43

Glutamate plays an essential role in the synthesis of how many nonessential amino acids?

A) 3
B) 5
C) 10
D) 20

Question 44

Of the 20 amino acids found in human proteins, how many are nonessential amino acids?

A) 5
B) 10
C) 15
D) 20

Question 45

Prenylation is which of the following?

A) a step in the synthesis of cholesterol
B) the binding of farnesyl pyrophosphate or geranyl pyrophosphate to a protein
C) both a and b
D) neither a nor b

Question 46

Farnesyl pyrophosphate and geranyl pyrophosphate are related to which of the following?

A) alkaloids
B) alkanes
C) isoprenes
D) none of these

Question 47

Which of the following amino acids can be synthesized from glutamate?

A) asparagine
B) cysteine
C) tyrosine
D) valine

Question 48

Which of the following amino acids cannot be synthesized from glutamate?

A) alanine
B) asparagine
C) serine
D) tyrosine

Question 49

In addition to a carboxylate group, mevalonate contains two hydroxyl groups. Which of the following is true of these groups?

A) They are both primary.
B) One is primary and one is secondary.
C) One is primary and one is tertiary.
D) They are both secondary.

Question 50

In which of the following diseases does the body break down its own proteins?

A) kwashiorkor
B) multiple sclerosis
C) rickets
D) none of these

Question 51

Children have the ability to synthesize each of the following amino acids, but for which of these are they unable to synthesize a sufficient amount for their needs?

A) alanine
B) arginine
C) proline
D) serine

Question 52

The synthesis of glutamate from α-ketoglutarate is an example of which of the following?

A) reductive amination
B) reductive deamination
C) oxidative amination
D) oxidative deamination

Question 53

Which of the following is the reducing agent in the synthesis of glutamate from α-ketoglutarate?

A) FAD
B) FADH₂
C) NADH
D) NAD⁺

Question 54

Consider the following reaction sequence.
Which of the following characterizes this process?

A) a step in gluconeogenesis
B) consumes energy
C) anabolic
D) all of these

Question 55

Which of the following is true of farnesyl pyrophosphate and geranyl pyrophosphate?

A) They both contain two cis double bonds.
B) They both contain two trans double bonds.
C) They both contain one cis double bond and one trans double bond.
D) None of the above is correct.

Question 56

Children have the ability to synthesize each of the following amino acids, but for which of these are they unable to synthesize a sufficient amount for their needs?

A) histidine
B) proline
C) serine
D) tyrosine

Question 57

Which of the following is the meaning of "essential" in the phrase essential amino acid?

A) An essential amino acid is one which is included in the primary structure of all proteins.
B) An essential amino acid is one which is necessary for a protein to adopt the proper secondary or tertiary structure.
C) An essential amino acid is one which cannot be synthesized by the human body or which can be synthesized but not in sufficient quantities for the body's needs.
D) None of the above is correct.

Question 58

The reaction of glutamate to form α-ketoglutarate is an example of which of the following?

A) reductive amination
B) reductive deamination
C) oxidative amination
D) oxidative deamination

Question 59

Which of the following amino acids is needed in the synthesis of membrane lipids?

A) cysteine
B) glycine
C) serine
D) threonine

Question 60

The synthesis of cholesterol is completed by the condensation of which of the following?

A) two farnesyl pyrophosphates
B) two geranyl pyrophosphates
C) a farnesyl pyrophosphate with a geranyl pyrophosphate
D) none of the above

Question 61

Consider the following reaction sequence.
Examine the following reactants. Which of the following characterizes this reaction?

A) Alanine is a product.
B) The reaction is classified as a deamination.
C) It produces an essential amino acid.
D) All of the above are correct.

Question 62

Consider the following reaction sequence.
Which of the following correctly states the relationship among anabolic pathways?

A) They begin with the citric acid cycle.
B) They use ATP as an energy source.
C) They use the reducing power of NADH and FADH₂.
D) All of these are correct statements.

Question 63

Consider the following reaction sequence.
Consider the following diagram of a chloroplast. Chloroplasts are similar to mitochondria in all but which of the following respects?

A) Both are highly membranous.
B) Both contain iron-sulfur complexes.
C) Both contain translocating ATP-ase.
D) Both utilize a proton gradient.
E) They are similar in all of these respects.

Question 64

Consider the following reaction sequence.
Which of the following is correct about this sequence?

A) The first step is analogous to amino acid activation in protein synthesis.
B) It probably occurs within the mitochonrial matrix.
C) UDP is similar in structure and function to ATP.
D) All of these are correct.

Question 65

Consider the following reaction sequence.
Which of the following describes the sources for the production of carbohydrates during photosynthesis?

A) C - carbon dioxide, H - molecular hydrogen, energy - ATP
B) C - carbon dioxide, H - molecular hydrogen, energy - sunlight
C) C - glucose, H - water, energy - sunlight
D) C - carbon dioxide, H - water, energy - sunlight

Question 66

Consider the following reaction sequence.
Which of the following is associated with obesity?

A) genetics
B) metabolism
C) brain function
D) all of these

Question 67

Consider the following reaction sequence.
Which of the following characterizes the product of this reaction sequence?

A) It is called glycogen.
B) It is an example of a polysaccharide.
C) It can be broken down by the same enzyme used in its synthesis.
D) All of these are correct.