Prokaryotic cells

The vast majority of prokaryotic cells have a single copy of each gene, which is why they are called haploid. The genomes of these cells are compact and have little repetitive DNA.

Unlike eukaryotes where the DNA is located within the nucleus, the DNA of prokaryotes is found in a circular chromosome in the nucleoid within the cytoplasm; which is why transcription and translation occur simultaneously.

The cell cycle of prokaryotic cells consists of a long period of growth, where the cell replicates its DNA, followed by a form of cell division called binary fission.

In binary fission, bacteria perform cell division. It is similar to mitosis, but its purpose is different. It is an asexual reproduction where a prokaryotic organism duplicates its genetic material , DNA, and then divides into two parts (cytokinesis), where each of these has a copy of DNA.

What are ?

Prokaryotic cells are a type of cell that lacks a distinct nucleus and other membrane-bound organelles. Here are some key points about prokaryotic cells:

  1. Structure: Prokaryotic cells are typically smaller and simpler in structure compared to eukaryotic cells. They lack a nucleus, so their DNA is located in a region called the nucleoid, which is not enclosed by a membrane. Prokaryotic cells also lack membrane-bound organelles, such as mitochondria, endoplasmic reticulum, and Golgi apparatus.
  2. Genetic Material: The genetic material of prokaryotic cells consists of a single, circular DNA molecule that contains the cell’s genetic instructions. This DNA is not associated with proteins and is free-floating in the cytoplasm.
  3. Cell Membrane: Prokaryotic cells have a cell membrane composed of a phospholipid bilayer that separates the cell’s internal components from the external environment. The cell membrane regulates the movement of substances into and out of the cell.
  4. Cell Wall: Most prokaryotic cells have a cell wall outside the cell membrane. The cell wall provides support and protection to the cell and helps maintain its shape. The composition of the cell wall varies among different types of prokaryotes, with bacteria having different types of cell walls, such as peptidoglycan in the case of Gram-positive bacteria.
  5. Ribosomes: Prokaryotic cells contain ribosomes, which are responsible for protein synthesis. These ribosomes are smaller and structurally different from the ribosomes found in eukaryotic cells.
  6. Reproduction: Prokaryotic cells reproduce through a process called binary fission, where a single cell divides into two identical daughter cells. This process allows prokaryotic cells to multiply rapidly and adapt to changing environments.
  7. Diversity: Prokaryotic cells are found in two domains of life: Bacteria and Archaea. They exhibit a wide range of shapes, including spherical (cocci), rod-shaped (bacilli), and spiral (spirilla). Prokaryotes have diverse metabolic capabilities and are found in various habitats, including soil, water, and even extreme environments like hot springs and deep-sea hydrothermal vents.

In summary, prokaryotic cells are simple, single-celled organisms that lack a distinct nucleus and membrane-bound organelles. They have a cell membrane, genetic material in the form of circular DNA, and a cell wall in many cases. Prokaryotes are diverse, with various shapes and metabolic capabilities, and they play essential roles in ecosystems and human health. Understanding prokaryotic cells is crucial for studying microbiology and the fundamental processes of life.

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