GRE Subject Test: Biology : Understanding Mitochondria and Chloroplasts

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #1 : Understanding Mitochondria And Chloroplasts

The inner mitochondrial membrane is organized into cristae, which essentially results in a series of folds within the mitochondria. Which of the following best describes the primary advantage to having cristae in inner compartments of mitochondria?

Possible Answers:

Decreased requirement for input to the mitochondrion due to increased presence of glucose on the cristae membrane. 

Increased surface area for the biochemical reactions to produce ATP, thus increasing metabolic output of each mitochondrion. 

Increased spacing of cytochromes to increase metabolic output.

Protection of integral membrane proteins from the extremely basic intracristal space of the mitochondria. 

ATP synthase is sequestered from the outer membrane, thus increasing its potential energy. 

Correct answer:

Increased surface area for the biochemical reactions to produce ATP, thus increasing metabolic output of each mitochondrion. 

Explanation:

ATP synthase and cytochromes stud the inner membrane, and more surface area means that more of them can be present in each mitochondrion. This increases the capacity to generate ATP. 

Example Question #2 : Understanding Mitochondria And Chloroplasts

Chloroplasts are found primarily in which cell type?

Possible Answers:

Mesophyll

None of these

Collenchyma

Parenchyma

Sclerenchyma

Correct answer:

Mesophyll

Explanation:

Chloroplasts are found primarily in the mesophyll cells. Mesophyll cells are the green colored tissue that is found within the leaf. It is the abundance of chloroplasts containing chlorophyll that give the mesophyll cells their green coloring. Parenchyma, sclerenchyma, and collenchyma cells are all found within the shoot and root of the plant, not in the leaves. These cell types have little to no chloroplasts within their membranes.

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