Eukaryotic Cells

Eukaryotic Cell Definition

A eukaryotic cell is one of the cells that contain membrane-bound organelles, including the nucleus, found in all complicated organisms.

What is a Eukaryotic Cell?

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This Story also Contains

1. Eukaryotic Cell Definition
2. What is a Eukaryotic Cell?
3. Characteristics of Eukaryotic Cells
4. Structure of Eukaryotic Cells
5. Eukaryotic Cell Diagram
6. Eukaryotic Cell Cycle
7. Differences Between Eukaryotic and Prokaryotic Cells
8. Examples of Eukaryotic Cells
9. Applications of Eukaryotic Cells
10. Recommended video for Eukaryotic Cells

The eukaryotic cells have a well-defined nucleus in which the cell’s DNA is stored and it also contains other membrane-bound organelles that have specific tasks to perform in the cell.

Eukaryotic cells are the tissue cells of animals, plants, fungi, and protists, which are the more complex multicellular organisms. Such cells are characterised by their polarity and consist of different organelles, making them unique and efficient in their functionality.

Characteristics of Eukaryotic Cells

• Membrane-bound nucleus: Has the cell’s entire genome, which is DNA, together with products that control gene activity and maintain cellular health.

• Organelles: They consist of mitochondria (containing the energy-producing mechanism), endoplasmic reticulum (for the synthesis of protein and lipids), Golgi complex, which modifies and sorts the proteins, and lysosome, which is the digestive and waste disposal unit of the cell, among others.

• Larger and more complex: Eukaryotic cells are usually larger and more complex in terms of composition than prokaryotic cells; the internal structures are elaborate.

• Cytoskeleton: A group of slender protein threads attached to the cell membrane that gives the cell its shape, gives it support, and helps in locomotion.

• Cell division: Eukaryotic cells undergo processes that include mitosis for growth and repair and meiosis for the production of sexual reproductive cells; this aids in genetic variation.

• Plasma membrane: A plasma membrane composed of phospholipids that envelop the cell, determine what goes in and what comes out, and help the cell to interact with other cells.

• Flagella and cilia are the locomotory organs in a eukaryotic cell.

• The cell wall is the outermost layer.

Structure of Eukaryotic Cells

Cell Membrane

In terms of structure, the cell membrane is fluid in a way and is also described as a semi-permeable barrier that is mostly made of phospholipids with proteins, cholesterol, and carbohydrates usually interspersed into a phospholipid double-layer. It works as a shield and acts as a filter or gatekeeper of molecules that are allowed to enter or exit the cell, as well as a mediator in cell-to-cell communications and signalling.

Diagram: Structure of a Cell Membrane

Cell wall

The cell wall is an imperative outer layer to offer protection and support to the cells; it is found in plant cells, fungi, and certain protists. Found mainly in plants, it serves as the mechanical support, and shield and also assists in the formation of the cell’s shape.

Nucleus

The nucleolus which lies in the nucleus enclosed by the nuclear membrane carries out ribosomal RNA synthesis and is embedded with chromatin. The nucleolus located in the nucleus of cells is involved in ribosome formation which has great involvement in protein synthesis.

Diagram: Structure of a Nucleus

Cytoplasm and Cytoskeleton

The cytoplasm is a semi-fluid that occupies the cell and this consists of organelles as well as cytoskeleton framework. Microtubules, microfilaments, and intermediate filaments are the framework structure of the cell that allows it to move and transport substances within the cell.

Diagram: Cytoskeleton Components

Organelles

Mitochondria

Mitochondria is something like the battery producer of the cell through the process called cellular respiration. They are membranous and composed of two layers of membrane; the inner one has cristae for more detail of the area where energy generation takes place.

Endoplasmic Reticulum

The endoplasmic reticulum (ER) is comprised of channels of tubular and sacular membranes. While the rough, containing ribosomes ER is concerned with protein synthesis, the smooth ER is associated with lipid metabolism as well as detoxification functions and storage of calcium ions.

Golgi Apparatus

The organelle generally known as the Golgi apparatus is made up of flattened membranous sacs known as cisternae. It remolds, segregates, and packages protein and lipids for export or transport to other organelles.

Lysosomes and Peroxisomes

Lysosomes have hydrolytic enzymes that degrade worn-out substances and debris within the cell. However, peroxisomes also have damaging compounds’ detoxifying enzymes and are involved in lipids metabolism.

Plastids

Plastids are double membrane structures that are present in plant cells and are engaged in the process of production of food. Chloroplasts, chromoplasts, and leucoplasts are the subgroups of plastids that have unique functions in plant cells.

Ribosomes

The ribosome is one of the cellular structures with the noble function of focusing on protein synthesis. They can be free in the cytoplasm or attached to the rough endoplasmic reticulum Some of the components of the rough endoplasmic reticulum The rough endoplasmic reticulum about protein synthesis

Vacuoles

A vacuole represents a storage organelle that may contain water, nutrients, or waste products. Plants’ ordinary cells have a considerable quantity of central vacuole which aids in the upkeep of turgidity force and assisting the structure of the cell.

Chloroplasts (in Plant Cells)

Chloroplasts are the organelles that can make food within the cells of plant tissues. These have the chlorophyll pigment and are composed of two membranes; the internal thylakoid membrane in which light-dependent reactions take place.

Diagram: Various Organelles in Eukaryotic Cells

Functions of Eukaryotic Cells

Cell Division

Mitosis and Meiosis: The division that takes place in the eukaryotic cells is known as mitosis and meiosis. Mitosis produces two identical daughter cells but for their sex, and is used in growth and repair. Meiosis, on the other hand, yields four genetically haploid gametes; hence, each is decidedly less than the parent cell.

Diagram: Stages of Mitosis and Meiosis

Metabolism

Cellular Respiration: Cellular respiration is the process through which the energy in food is broken down by the cell into a usable form of energy known as adenosine triphosphate. Glycolysis occurs in the cytoplasm, whereas the Krebs cycle occurs in the mitochondrial matrix and the electron transport chain takes place in the inner mitochondrial membrane. Combined in this manner, these stages are effective in synthesizing ATP, water, and carbon dioxide effectively.

Photosynthesis (in Plant Cells): Photosynthesis is the mechanism through which cells of the plant synthesize light energy into chemical energy that is in glucose. It occurs in chloroplasts and involves two main stages: the reaction of photosynthesis carried out in the thylakoid membranes referred to as the light-dependent reactions and the stroma referred to as the Calvin cycle.

Diagram: Cellular respiration and photosynthesis

Protein Synthesis

Transcription and Translation Processes: Protein synthesis in eukaryotic cells involves two main processes: transcribe and translate In Transcription and Translation, the function of the DNA is to transcribe while the role of the RNA is to translate. In transcription, a specific segment of DNA is transcribed into the mRNA within the nucleus of the cell. The mRNA then gets transported to the ribosome in the cytoplasm to carry out translation where the sequence of mRNA is used to synthesize amino acids into a specific protein.

Cell Signalling

Mechanisms and Importance: Cell signaling is defined as the transfer of signal from the extracellular environment of a cell to its intracellular environment to allow the cells’ interaction and cooperation. It is a vital process of controlling many cellular processes such as diseases, body development, and the immune system among others. This is the initiation of signal reception by altering it to another form that is easily transmitted to the target cell before discharging a final response through the help of receptors and second messengers.

Eukaryotic Cell Diagram

Eukaryotic cells contain a nucleus surrounded by the cell membrane and consist of organelles like the nucleus, mitochondria, smooth and rough endoplasmic reticulum, Golgi apparatus, lysosomes, and chloroplast in plants. At the same time, every organelle has unique tasks necessary for the cell’s life and its normal activity

Eukaryotic Cell Cycle

The process of eukaryotic cell division is a set of micro-events that systematically take place. It comprises the interphase, where the cell prepares for division together with the G1, S, and G2 phases, and the mitotic phase, which includes mitosis and cytokinesis. The cell cycle is therefore important in growth and development as well as the maintenance of the body's organs.

Quiescence (G0)

The G0 phase is an interim phase in which the cell becomes non-dividing which in other words can be referred to as quiescence. In this phase, the cell is alive and is often involved in metabolism but does not go through the process of cell division. The G0 phase is a resting phase of a cell or it can be a state of how the cell waits before it will enter the cell cycle again.

Interphase

Interphase is the phase of the cell cycle in which the cell and nucleus increase, DNA replication occurs and the cell prepares for division. It consists of three stages: G1 which is also called inter-phase, DNA synthesis or S phase, and G2 which is referred to as preparation for mitosis. Interphase is the longest phase of the cell cycle that makes the organism prepared for division.

Mitosis

Mitosis is the kind of nuclear division that leads to the formation of two daughter cells with the same genetic makeup. It consists of the following stages: It consists of the following stages:

- Prophase

- Metaphase

- Anaphase

- Telophase

Differences Between Eukaryotic and Prokaryotic Cells

Structural Differences

Unlike the prokaryotic cells, eukaryotic cells contain a membrane-bound true nucleus and organelles like the mitochondria and endoplasmic reticulum. It is commonly found to be bigger and more structured in manner compared to its counterpart, the prokaryotic cell which does not contain a true nucleus or organelles and is relatively small in size.

Diagram: Comparison of Prokaryotic and Eukaryotic Cells

Reproductive Differences

Mitosis and meiosis are the two methods of reproduction or cell division in eukaryotic cells that prevent genetic variation and the proper distribution of chromosomes. Prokaryotic cells reproduce either asexually by binary fission or through the process of budding where the parent cell divides into two similar daughter cells. There is no mitosis in prokaryotic cells because these cells do not undergo DNA replication followed by division, unlike eukaryotic cells.

Genetic Differences

In eukaryotes, there exists a straight chain of DNA that is arranged in a chromosome located in the nucleus with histone proteins. While prokaryotic cells are simpler, they consist of only one circular DNA molecule within the nucleoid area, no histones, and additional genetic material located in plasmids.

Examples of Eukaryotic Cells

Plant Cells

Plant cells possess a hard cell wall that is made of cellulose and contains chloroplast, a large central vacuole that is used to store substances and regulate turgidity.

Fungal Cells

Cells of fungi possess a rigid chitinous cell wall and the source of nutrition is absorbed from the environment. They provide vital duties in both decomposition and nutrient cycling.

Animal Cells

Unlike plant cells, animal cells do not possess a cell wall, instead, they have a more pliable cell membrane. They are filled with several organelles for instance lysosomes and are also involved in movement as well as sensory response as well as complex behaviours.

Protozoa

These are single-celled eukaryotic organisms that can move on their own and mostly have cilia or flagella for movement or food intake mode. They are also inhabitants of a variety of, marine as well as land habitats.

Applications of Eukaryotic Cells

The applications are listed below-

Medical Research

Knowledge of the eukaryotic cells assists in the identification of the disease’s molecular cause; and eradication of disease through treatment. Biomedical research, for example, with stem cells holds the prospect of regenerative medicine, and for diseases such as Parkinson’s and diabetes.

Diagram: Medical Applications of Eukaryotic Cells

Biotechnology

Genetic Engineering

Genetic engineering entails the use of genetic manipulation in eukaryotic cells with a view of getting certain characteristics or products. It is applied to genetic engineering the synthesis of GMOs and the production of biopharmaceutical products including insulin, and monoclonal antibodies.

Production of Biopharmaceuticals

Eukaryotic cells are applied in biotechnology to synthesize biopharmaceuticals; which are medical drugs made through biotechnology. Some of them are hormones vaccines, and antibodies that are used to cure different diseases.

Environmental Applications

Bioremediation

Bioremediation applies eukaryotic cells of fungi and algae and all eukaryotic structures to remove and decompose pollutants from the environment. It is applied in oil wash up, heavy metals, and other pollutants in the water bodies

Bioenergy Production

Eukaryotic yeast cells are applied to produce bioenergy products such as ethanol and biodiesel. Eukaryotic microorganisms such as algae are harvested for their organismal capacity to fix the sun’s energy and CO2 into high-energy molecules.

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