Question

Which organelles are surrounded by a double membrane?

Short answer

Nucleus, mitochondria, and chloroplasts have a double membrane.

Step-by-step solution

Identify the organelles in eukaryotic cells

Eukaryotic cells contain several types of organelles, each with specific functions. Identify the major organelles, including the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes.

Determine the membrane structure of organelles

Check each identified organelle to see whether it is surrounded by a single or double membrane. For example, the endoplasmic reticulum and Golgi apparatus have a single membrane, while others may have a double membrane.

List organelles with a double membrane

Found through examination: the nucleus, mitochondria, and chloroplasts are surrounded by a double membrane. These organelles are unique compared to others due to their enveloping double layers.

Key concepts

Eukaryotic Cells

Eukaryotic cells are complex cells that are characterized by the presence of various organelles, making them distinct from prokaryotic cells. These organelles each perform specialized roles essential for the cell's survival and function. One key aspect of eukaryotic cells is that they have a nucleus, which houses the cell's genetic material.
They also contain other membrane-bound structures like mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes. The existence of these organelles allows eukaryotic cells to perform a wide range of metabolic processes efficiently.

Cell Organelles

Organelles are specialized subunits within a eukaryotic cell that have specific functions. Think of them as the 'organs' of the cell. These structures are usually membrane-bound, allowing them to maintain environments that are biochemically different from the rest of the cell.
Examples of organelles include the nucleus (which stores genetic information), mitochondria (which produce energy), and chloroplasts (which are involved in photosynthesis). Each organelle plays a crucial role in the cell's overall function and health.

Biology Education

Understanding the structure and function of eukaryotic cells and their organelles is a fundamental part of biology education. It helps students grasp how cells operate and how they contribute to larger biological systems.
Learning about the specific roles of different organelles, like the energy production in mitochondria or the genetic storage in the nucleus, provides a solid foundation for more advanced studies in cell biology, genetics, and biochemistry. Clear, step-by-step solutions for identifying double membrane organelles help students better comprehend these complex topics.

Nucleus

The nucleus is often considered the control center of the cell. It is surrounded by a double membrane known as the nuclear envelope, which protects the cell's DNA. This double membrane structure distinguishes the nucleus from other organelles.
Inside the nucleus, you find chromatin (the material that makes up chromosomes), and the nucleolus, which is involved in ribosome production. The nuclear envelope has pores that regulate the exchange of materials (like RNA and proteins) between the nucleus and the cytoplasm.

Mitochondria

Mitochondria are known as the powerhouses of the cell because they produce ATP (adenosine triphosphate), the cell's main energy currency. These organelles have a unique double membrane structure, which is vital for their function.
The inner membrane folds into structures called cristae, increasing the surface area for energy production. The mitochondria also contain their own DNA, which is separate from the cell's nuclear DNA, highlighting their endosymbiotic origin. This allows them to produce some of the proteins required for their function.

Chloroplasts

Chloroplasts are found in plant cells and some protists, and they are responsible for photosynthesis. Like the nucleus and mitochondria, chloroplasts are also surrounded by a double membrane. This allows them to effectively capture light energy and convert it into chemical energy.
Inside the chloroplasts, thylakoid membranes form stacks known as grana, where the light-dependent reactions of photosynthesis take place. They also contain their own DNA and ribosomes, similar to mitochondria, supporting the theory that they originated from endosymbiotic events.