Prokaryotic (Bacteria) Cell Structure & Function | Cell Biology

Summary

This video explores the structure and function of prokaryotic cells, including their simple design without a nucleus and lack of organelles. Prokaryotes, such as E. coli, may have a protective capsule, a rigid cell wall made of peptidoglycan, and a semi-permeable cell membrane. Key features like flagella for locomotion, pili for attachment and conjugation, and the nucleoid containing circular DNA are also discussed. The video highlights the cytoplasm, cytosol, and ribosomes, which play vital roles in metabolism and protein synthesis. It provides a comprehensive look at the unique characteristics of prokaryotic cells.

Takeaways

• 😀 Prokaryotes include organisms from the domains Archaea and Bacteria.
• 😀 Prokaryotic cells do not have a nucleus and lack compartmentalization into organelles.
• 😀 E. coli is an example of a prokaryotic organism and cell.
• 😀 Prokaryotic cells may have a capsule, which helps protect them from drying out and aids in attachment to surfaces.
• 😀 The cell wall of prokaryotes is rigid, made of peptidoglycan, and provides structural support to prevent bursting.
• 😀 The cell membrane is semi-permeable and regulates the movement of materials in and out of the cell.
• 😀 Flagella are long extensions on prokaryotes that function in locomotion.
• 😀 Pili are small hair-like structures on prokaryotes that help with attachment to surfaces and bacterial conjugation.
• 😀 The nucleoid is where the DNA is located in prokaryotes, consisting of the genophore (circular DNA).
• 😀 Prokaryotes may have plasmids, which are small, circular pieces of DNA that can be transferred between bacteria through horizontal gene transfer.

Q & A

What is a prokaryotic cell?

A prokaryotic cell is a simple type of cell that lacks a nucleus and does not have compartmentalized organelles. It is found in organisms like bacteria and archaea.

What is the capsule in prokaryotic cells and what does it do?

The capsule, or slime capsule, is a thick layer made of polysaccharides that surrounds the prokaryotic cell. It protects the cell from drying out and helps it attach to surfaces.

What is the function of the cell wall in prokaryotic cells?

The cell wall in prokaryotic cells provides structural support, helps maintain the shape of the cell, and prevents the cell from bursting due to turgor pressure.

How does the cell membrane of a prokaryote function?

The cell membrane of a prokaryote is semi-permeable, meaning it regulates the movement of materials in and out of the cell.

What is the role of the flagellum in prokaryotic cells?

The flagellum is a long extension on the surface of some prokaryotic cells that aids in locomotion, helping the cell move.

What are pili in prokaryotic cells, and what are their functions?

Pili are small, hair-like extensions on the surface of prokaryotic cells. There are two types: attachment pili, which help bacteria adhere to surfaces, and sex pili, which are involved in bacterial conjugation for DNA exchange.

What is the nucleoid in a prokaryotic cell?

The nucleoid is the region within a prokaryotic cell where the genetic material (DNA) is located. It consists of the genophore, a circular strand of DNA.

What are plasmids, and why are they important in prokaryotic cells?

Plasmids are small, circular pieces of DNA found in some prokaryotic cells. They can exist independently from the chromosomal DNA and can be transferred between bacteria through horizontal gene transfer.

What is the cytosol and what role does it play in prokaryotic cells?

The cytosol is a gel-like liquid within the cytoplasm of prokaryotic cells. It serves as the site for most of the cell's metabolic activities.

How do the ribosomes in prokaryotic cells differ from those in eukaryotic cells?

The ribosomes in prokaryotic cells are smaller (70s) compared to those in eukaryotic cells, which are larger (80s). Both types of ribosomes are responsible for protein synthesis.