Eukaryotic Cells, Structure, Characteristics, Diagram, Examples

Eukaryotic Cells: Most living things are classified as either unicellular or multicellular organisms.  Unicellular organisms, such as bacteria, are made up of a single cell that performs all of the vital functions. Multicellular organisms, such as plants, animals, and humans, are made up of many cells, some of which specialize to perform specific functions. It is important to note that fungi can be both unicellular and multicellular.

What are Eukaryotic Cells?

Table: Comparison of Animal and Plant Cells

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Eukaryotic Cells Diagram

Cell Envelope

Eukaryotic Cells Characteristics

1. Nucleus Enclosure: One characteristic that sets eukaryotic cells apart is the presence of a nucleus, a specialized chamber surrounded by a membrane for protection. The nucleus functions as the central nervous system of the cell, storing its genetic material and directing all cellular processes.
2. Organelle Complexity: Membrane-bound organelles, each with a distinct function in cellular function, are abundant in eukaryotic cells. These organelles, which include mitochondria, the Golgi apparatus, the endoplasmic reticulum, and lysosomes, add to the cell's complexity and efficiency in performing various functions.
3. Linear DNA Configuration: Eukaryotic cells' genetic material is organized as double-stranded linear DNA molecules, which are neatly packaged within the nucleus.  This configuration enables precise regulation of gene expression and facilitates complex cellular processes.
4. Dimensional Advantage: Eukaryotic cells are typically larger in size than their prokaryotic counterparts.  This increased size allows for the intricate structures and organelles required to carry out various cellular functions efficiently.
5. Multicellular Complexity: While multicellularity is a common feature of eukaryotic organisms, there are some exceptions, such as unicellular organisms. Multicellular eukaryotes have a complex organization of specialized cell types that form tissues, organs, and organ systems, all of which contribute to the organism's survival and function.
6. Taxonomic Diversity: Eukaryotic cells represent a wide range of organisms, including protists, plants, fungi, and animals. Despite their diversity, eukaryotic cells have fundamental similarities that highlight their evolutionary relatedness and common ancestry.

Prokaryotic Cells

Eukaryotic Cells Structure

Cell The Unit of Life

Plasma Membrane

Fluid Mosaic Model of Plasma Membrane

Transport of Molecules Across Cell Membrane

• Passive transport allows molecules to move across the membrane without expending energy. This includes simple diffusion, where molecules move along a concentration gradient, and osmosis, the movement of water across a membrane.

• Diffusion: For polar molecules unable to pass through the lipid bilayer, carrier proteins facilitate their transport via facilitated diffusion.

• Active transport moves ions or molecules against their concentration gradient, requiring energy typically derived from ATP, as seen in the Na+/K+ pump.

Cell Wall

• Primary walls , present in young plant cells, allow for growth and are gradually replaced by secondary walls.
• Secondary walls primarily consist of cellulose, along with other polysaccharides, lignin, and suberin.
• Middle lamella , rich in calcium pectate, acts as a glue, holding adjacent cells together.

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Endomembrane System

Cell The Unit of Life MCQ

Endoplasmic Reticulum (ER) 

Golgi Apparatus

Lysosomes

Vacuoles

Mitochondria

Plastids

Ribosomes

Cytoskeleton

Cilia and Flagella

Centrosome and Centrioles

Nucleus

Chromosomes

Eukaryotic Cells Examples

• Plant Cells: These have cellulose cell walls, a large central vacuole for turgor pressure, and chloroplasts for photosynthesis.
• Fungal Cells: Featuring chitin cell walls, some fungi have septa allowing organelle passage.
• Animal Cells: Lacking cell walls, they have membranes offering diverse shapes and phagocytic abilities.
• Protozoa: Unicellular, they may use cilia for movement and possess a pellicle for support.