I. THE EUKARYOTIC CELL

A. COMPOSITION AND FUNCTIONS OF EUKARYOTIC CELLULAR STRUCTURES

4. Other Internal Membrane-Bound Organelles

a. Mitochondria

Fundamental Statements for this Learning Object:

1. Mitochondria are rod-shaped structures ranging from 2 to 8 micrometers in length surrounded by two membranes.
2. Mitochondria are located throughout the cytoplasm.
3. Mitochondria function during aerobic respiration to produce ATP through oxidative phosphorylation.
4. The respiratory enzymes and electron carriers for the electron transport system are located within the inner mitochondria membrane. The enzymes for the citric acid cycle (Krebs cycle) are located in the matrix.
5. Mitochondria replicate giving rise to new mitochondria as they grow and divide. They also have their own DNA and ribosomes.

 

LEARNING OBJECTIVES FOR THIS SECTION

The cell is the basic unit of life. Based on the organization of their cellular structures, all living cells can be divided into two groups: prokaryotic and eukaryotic (also spelled procaryotic and eucaryotic). Animals, plants, fungi, protozoans, and algae all possess eukaryotic cell types. Only bacteria have prokaryotic cell types.

Eukaryotic cells are generally much larger and more complex than prokaryotic. Because of their larger size, they require a variety of specialized internal membrane-bound organelles to carry out metabolism, provide energy, and transport chemicals throughout the cell.

Eukaryotic cells contain a variety of internal membrane-bound organelles that are not a part of the endomembrane system. These include mitochondria, chloroplasts, lysosomes, peroxisomes, vacuoles, and vesicles.

We will now look at the mitochondria.

Mitochondria (def) (see Fig. 30A, Fig. 37, and Fig. 38)

Mitochondria are rod-shaped structures ranging from 2 to 8 micrometers in length. They are found throughout the cytoplasm and may account for up to 20% of the cell's volume. Mitochondria are surrounded by two membranes. The outer membrane forms the exterior of the organelle while the inner membrane is arranged in a series of folds called cristae to provide an enormous surface area for chemical reactions. The space between the inner and outer mitochondrial membranes is called the intermembrane space while the compartment enclosed by the inner mitochondrial membrane is called the matrix. Mitochondria replicate giving rise to new mitochondria as they grow and divide. They also have their own DNA and ribosomes.

Mitochondria function during aerobic respiration to produce ATP through oxidative phosphorylation (def). The respiratory enzymes and electron carriers for the electron transport system are located within the inner mitochondria membrane. The enzymes for the citric acid cycle (Krebs cycle) are located in the matrix.

For More Information: Aerobic Respiration from Unit 7

For More Information: Glycolysis from Unit 7

For More Information: Citric Acid (Krebs) Cycle from Unit7

For More Information: Chemiosmosis from Unit7

 

Concept map for Eukaryotic Cell Structure

 

• QUIZ YOURSELF ON THIS SECTION

Gary E. Kaiser, Ph.D.
Professor of Microbiology
The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work The Grapes of Staph at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.