Q: Which of the following equations correctly represents the overall process of photosynthesis?

$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + \text{light energy} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2$$

Question 1

Which of the following best describes the relationship between photosynthesis and respiration in plants?

Accepted Answer

Photosynthesis produces sugars and oxygen, which are used in respiration to generate energy, carbon dioxide, and water.

Question 2

Which metabolic intermediate is a key precursor for the synthesis of aromatic amino acids and many secondary metabolites in plants?

Accepted Answer

Shikimic acid

Question 3

Which pathway is responsible for the biosynthesis of terpenoids in plants?

Accepted Answer

Mevalonate pathway

Question 4

A plant is exposed to a herbivore attack. Which class of secondary metabolites is most likely to increase in response, and what is their primary function?

Accepted Answer

Phenolic compounds; they deter herbivores by making tissues less palatable or digestible.

Question 5

Which of the following is NOT a direct product of the citric acid cycle in plant metabolism?

Accepted Answer

Glucose

Question 6

Which secondary metabolite is used as an antimalarial drug and is derived from the bark of Cinchona trees?

Accepted Answer

Quinine

Question 7

Which of the following equations correctly represents the overall process of photosynthesis?

Accepted Answer

$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{light energy} ightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2$$

Question 8

Which of the following statements about secondary metabolites is TRUE?

Accepted Answer

They often serve ecological functions such as defense against herbivores or attraction of pollinators.

Question 9

Which compound is a nitrogen-containing secondary metabolite and is used as a narcotic painkiller?

Accepted Answer

Morphine

Question 10

A mutation blocks the shikimate pathway in a plant. Which of the following would most likely be affected?

Accepted Answer

Synthesis of aromatic amino acids and phenolic compounds

Question 11

Which of the following is the basic five-carbon unit used in the synthesis of terpenoids?

Accepted Answer

Isoprene

Question 12

Which of the following best explains why plants produce secondary metabolites such as alkaloids and terpenoids?

Accepted Answer

To deter herbivores and protect against pathogens

Question 13

Which of the following is a correct description of the fate of glucose in plant cells?

Accepted Answer

Glucose can be used for energy via respiration, stored as starch, or serve as a precursor for biosynthesis of amino acids, nucleotides, and secondary metabolites.

Question 14

Which of the following secondary metabolites is used as an anticancer drug and is derived from the Pacific yew tree?

Accepted Answer

Paclitaxel (Taxol)

Question 15

Which of the following best describes the role of acetyl-CoA in plant metabolism?

Accepted Answer

It is a central intermediate that can enter the citric acid cycle or serve as a precursor for fatty acid and terpenoid biosynthesis.

Question 16

Which of the following is a phenolic compound that contributes to the structural integrity of plant cell walls?

Accepted Answer

Lignin

Question 17

A plant cell is unable to synthesize phosphoenolpyruvate (PEP). Which biosynthetic pathway would be directly affected?

Accepted Answer

Shikimate pathway

Question 18

Which of the following best explains why some secondary metabolites are toxic to humans but beneficial to plants?

Accepted Answer

They evolved as chemical defenses against herbivores and pathogens, but can interfere with animal physiology.

Question 19

Which of the following is a correct equation for aerobic respiration in plants?

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2 ightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{energy}$$

Question 20

Which of the following is a real-world example of a plant secondary metabolite used in medicine, and what is its effect?

Accepted Answer

Morphine from opium poppy; used as a narcotic painkiller

Plant Metabolism: Synthesis of Organic Molecules and Secondary Metabolites

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