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Eukaryotes are organisms that contain a nucleus, organelles, and membrane-bound cytoplasm enclosed by a cell membrane. Eukaryotic cells are the vast majority of all life forms on Earth and are the basis for all known life. The structure and functions of a eukaryotic cell are unique. Eukaryotic cells have a mitochondrial genome. They do not have a typical nucleus; instead, they have an almost circular membrane-bound organelle called the nucleus, which contains their genes. The DNA is contained in chromatin, embedded in proteins called histones. Mitochondria are found only in eukaryotes and serve as the cell’s energy factories.
About Cells
The term cell is used for all living things’ fundamental structural and functional unit. Cells are microscopic. The smallest known occurs in the amoeba and measures about 0.2 micrometres in diameter. The largest occur in some oceanic algae, such as sargassum, and reach a diameter of about 70 meters. They are called cells because they resemble a cube or a bottle from the top view.
About Eukaryotic cell:
Eukaryotic cells are common to all multicellular (more than one cell) organisms. Eukaryotes have DNA in a centralised nucleus and membrane-bound organelles, such as mitochondria and chloroplasts, carrying specialised functions. Specialised structure and functions of a eukaryotic cell aid in regulating proper tissues and body functioning
Structure and Functions of a Eukaryotic Cell:
1) Structure of a Eukaryotic Cell
A thin, flexible membrane encloses every living cell. The structure of a group of cells is called a tissue, and the group of tissues constitutes an organ.
Cell membrane: The cell membrane is composed of lipids, a greasy organic compound. The membrane also contains proteins that act as a channel for materials to pass in and out of the cell.
Cytoplasm: Below the membrane is a jelly-like substance called cytoplasm. The cytoplasm has many functions and consists of water containing dissolved ions and large molecules such as proteins and nucleic acids (DNA or RNA).
Cell wall: The cytoplasm is surrounded by a fibrous cell wall layer. Cell walls are rigid and provide structural support to cells. They also protect the cell from drying out and attacks by harmful microorganisms. The cell wall is only present in plant cells.
Cell nucleus: The nucleus is the control centre of a eukaryotic cell. It contains DNA used to code for different proteins that perform many functions within a eukaryotic cell. It has all the cell’s genetic information, including hereditary traits and the blueprint for growth and development.
Mitochondria: Mitochondria are tiny membrane-bound organelles found in almost all eukaryotic cells. Mitochondria produce energy in the form of ATP and contain their DNA, separate from the DNA contained within the nucleus.
Chloroplasts: Chloroplasts are tiny membrane-bound organelles found in plant cells. Chloroplasts are involved in photosynthesis and thus, give plants colour and make them grow.
Vacuoles: Vacuoles are membrane-bound sacs present in plant cells and some animal cells. They can store food or waste products.
Golgi bodies: These are tiny membrane-bound organelles present in animal cells. They work in the transport of proteins made by the ribosomes of the rough endoplasmic reticulum.
Ribosome: Ribosomes are large, complex structures in both plant and animal cells. Ribosomes translate messenger RNA (mRNA) into proteins by reading three-letter codes called codons on mRNA and adding amino acids to growing protein chains at precise positions according to these codons.
2) Functions of a Eukaryotic Cell
The functions of a eukaryotic cell are responsible for the healthy shape and functioning of all living things.
Production of food and energy: Eukaryotic cells are heterotrophs, meaning they use external energy sources to produce cellular material such as food and water. The most common energy source is the sun’s light, which helps plants make food from sugars.
Growth: Growth is the increase in the size of an organism. It is driven by cell division, which produces identical copies of cells. Growth is also driven by hormones made in endocrine cells and travel around the body through blood vessels and to target tissues where they bind to receptors on other cells and produce different responses.
Development: Development is creating a new individual from a single cell. It involves the growth and the production of various types of specialised cells.
Reproduction: Sexual reproduction is when two genetically different sets of genes combine in an organism to create a new individual with all the genetic information from both groups. Sexual reproduction is essential for evolution because it introduces variation into populations, allowing new combinations of genes to evolve during survival in different environments.
Regulation of cell growth and death: Cell growth and cell death are controlled by hormones made by the body. When a hormone binds to its receptor on a target cell, it triggers its specific response.
Conclusion
Eukaryotic cells are common to all multicellular (more than one cell) organisms. The structure and functions of a Eukaryotic cell are different from that of a prokaryotic cell. Eukaryotes have DNA in a centralised nucleus and membrane-bound organelles such as mitochondria, which carry out specialised functions. Eukaryotic cells are heterotrophs, meaning they use external energy sources to produce cellular material such as food and water. The most common energy source is the sun’s light, which helps plants make food from sugars. Other organisms may obtain their energy by eating other organisms for photosynthesis using sunlight.
