Cell Biology: Mitochondria, Plastids, and Vacuoles

A set of practice questions covering the morphology, structure, and classification of mitochondria, various plastids, and vacuoles based on the lecture notes.

What is the typical shape and size of a mitochondrion?

The shape is a sausage or cylinder, with a diameter of $0.2-1.0\,m$.

What is the basic structure of the mitochondrial membrane?

It is a double membrane structure where each has its own respiratory enzymes, and the membranes divide the lumen into an outer and inner chamber.

What are the unfoldings of the inner mitochondrial membrane called, and what is their purpose?

They are called cristae, and they increase the surface area for aerobic respiration.

What components are found in the mitochondrial matrix?

The matrix contains specific enzymes, single circular DNA, and $70S$ ribosomes.

Why is the mitochondrion referred to as the "powerhouse" of the cell?

It is the site where ATP is synthesized.

What does it mean for mitochondria to be "semiautonomous"?

They are controlled partly by the nucleus and partly by themselves.

What are the three specific types of leukoplasts and what do they store?

Amyloplasts store starch, elaioplasts store fats and oils, and aleuroblasts store proteins.

Which pigments are found in chromoplasts to give different colors to plant parts?

Fat-soluble carotenoid pigments such as carotene and xanthophyll.

What is the name of the membrane that bounds the vacuole in a cell?

Tonoplast.

What is one role of the tonoplast in plant cells?

It facilitates the transport of materials against concentration gradients into the vacuole.

What specialized organisms are mentioned in relation to vacuoles?

Plant cells and euglenoids.