Question

Which of the following statements is correct? a. Some animal cells are prokaryotic. b. Only eukaryotic cells have mitochondria. c. The plasma membrane is the outermost boundary of all cells.

Short answer

Statement b is correct.

Step-by-step solution

Analyze Statement a

Statement a says, 'Some animal cells are prokaryotic.' Prokaryotic cells are a category of cells that do not have a nucleus. All animal cells are eukaryotic, meaning they contain a nucleus among other complex structures. Therefore, this statement is incorrect.

Analyze Statement b

Statement b says, 'Only eukaryotic cells have mitochondria.' Eukaryotic cells are characterized by the presence of membrane-bound organelles, including mitochondria. Prokaryotic cells do not have mitochondria. Consequently, this statement reflects a correct description of eukaryotic and prokaryotic cell characteristics.

Analyze Statement c

Statement c says, 'The plasma membrane is the outermost boundary of all cells.' While the plasma membrane is the outermost boundary for animal cells and many other cells, plant cells and bacterial cells have additional structures outside the plasma membrane, such as the cell wall. Thus, this statement is not universally correct.

Key concepts

Eukaryotic Cells

Eukaryotic cells are distinguished by their complex structure. They have a true nucleus, which is enclosed by a nuclear membrane. This nucleus contains the cell's genetic material organized as DNA. Other organelles within eukaryotic cells include the mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. These organelles each have specific functions that contribute to the overall operation of the cell.
The presence of mitochondria is a hallmark of eukaryotic cells. Mitochondria are known as the powerhouses of the cell because they generate most of the cell's supply of ATP, the energy currency. Without mitochondria, eukaryotic cells would struggle to produce enough energy to sustain complex life processes.

• Have a nucleus and membrane-bound organelles.
• Include animal, plant, fungal, and protist cells.
• Capable of performing complex functions due to compartmentalization.

In essence, eukaryotic cells represent a highly organized and efficient form of cellular life, which allows for the diversity of life forms, from plants to animals.

Prokaryotic Cells

Unlike eukaryotic cells, prokaryotic cells lack a true nucleus. Instead, their genetic material is found in a region called the nucleoid, which is not separated from the rest of the cell by a membrane. Prokaryotes include all bacteria and archaea.
Prokaryotic cells are usually smaller and simpler in structure compared to eukaryotic cells. They do not have membrane-bound organelles like mitochondria or endoplasmic reticulum. Instead, their cellular processes occur in the cytoplasm or at the cell membrane. This simplicity allows prokaryotes to reproduce quickly and adapt to different environments.

• DNA present in the nucleoid, not enclosed by a nuclear membrane.
• Simpler interior structure compared to eukaryotic cells.
• Examples include bacteria and archaea.

Despite their simplicity, prokaryotic cells are incredibly efficient and can survive in a wide range of environments, making them some of the most versatile forms of life.

Cell Structure

The basic cell structure consists of several fundamental components that are common to all cell types, whether eukaryotic or prokaryotic. One of these is the plasma membrane, which forms a protective barrier around the cell, regulating what enters and exits. In animal cells, the plasma membrane is the outermost boundary, while in plant and bacterial cells, it is protected further by a cell wall.
The cytoplasm, another essential part of all cells, is the gel-like substance where cellular components are suspended. Within the cytoplasm of eukaryotic cells, you'll find various organelles, each with unique functions, while in prokaryotic cells, cellular processes are conducted in the cytoplasm without organelles.

• Plasma membrane: the outer protective layer in animal cells.
• Cytoplasm: contains cell organelles or areas for biochemical processes.
• Organelles in eukaryotes vs. simpler structures in prokaryotes.

The diversity in cell structure not only defines the complexity of an organism but also determines its ability to adapt to different environments and perform necessary life functions.