Cell Biology: Cell Structure and Composition

Cell Structure and Composition

• The plasma membrane forms the outer boundary of animal cells, whereas plant cells have a cell wall.
• Both prokaryotes and eukaryotes share ribosomes and a plasma membrane as similar components.
• Plant cells possess unique structures, including cell walls, plastids, and a large central vacuole, distinguishing them from animal cells.

Cell Wall Characteristics

• Fungal cell walls are composed of chitin.
• Primary cell walls are present in young plant cells; secondary walls develop later in mature cells, situated inner to the primary wall.
• The mature plant cell wall consists of the primary cell wall, secondary cell wall, and possibly a tertiary wall.

Functions and Properties of the Cell Wall

• The cell wall provides shape, protection, and facilitates cell-to-cell interactions, but does not fully protect against infections.
• Plasmodesmata are microscopic channels that allow for communication and transport between neighboring plant cells.

Components and Comparisons

• The cell wall and middle lamellae can be traversed by plasmodesmata.
• Eukaryotic and prokaryotic flagella share similarities in their motion and structure, although their protein composition may differ.

Different Cell Types

• Not all cells have a cell wall; animal cells are devoid of it while plant and some bacterial cells have cell walls.
• Plant cell walls are primarily made of cellulose, while algal cell walls contain galactan, mannan, and cellulose, but not peptidoglycan.

Genetic Material

• Prokaryotic cells lack a defined nucleus and their genetic material consists of a single circular DNA molecule, which lacks histones and is not surrounded by a nuclear membrane.

Miscellaneous Facts

• Secondary cell walls develop between the primary cell wall and the plasma membrane in mature plant cells.
• Characteristics distinguishing primary and secondary walls include the stage of cell maturity and structural composition.
• Eukaryotic cells have membrane-bound organelles, a trait that distinguishes them from prokaryotic cells.

Conclusion

• Understanding the structures and functions of various cellular elements is crucial for comprehending the complex nature and functionality of different types of cells in biological systems.

This quiz covers the basics of cell biology, including the outer boundary of animal cells and the composition of plant cell walls. Test your knowledge of cell structure and function!