Plants are highly evolved, eukaryotic organisms that contain membrane-bound cell organelles. Even though plants and animals belong to eukaryotes, they differ in certain characteristic features. For example, a plant cell possesses a well-developed cell wall and large vacuoles, while an animal cell lacks such structural parts. Besides these structural differences, a plant cell lacks centrioles and intermediate filaments, which are present in an animal cell.
A typical plant cell is made up of cytoplasm and organelles. In fact, all the organelles (except nucleus) and subcellular structures are present in the cytoplasm, which is enclosed by protective layers (the cell wall and cell membrane). Scientific studies have been done regarding the cell organelles and their functions. Each of the organelles of a plant cell has specific functions, without which the cell cannot operate properly.
The plant cell is protected from the surrounding environment by the cell wall and cell membrane. Note that these two are surface structures and not cell organelles. They not only give shape, support, and strength to the cell, but also aid in transportation. When it comes to the organelles found in a plant cell, they are more or less similar to animal cells, except that the latter lacks chloroplasts, that are responsible for photosynthesis. Following is a list of organelles found in plant cell.
Nucleus (plural nuclei) is a highly specialized cell organelle, which stores the genetic component (chromosomes) of the particular cell. It serves as the main administrative center of the cell by coordinating the metabolic processes like cell growth, cell division, and protein synthesis. Together, the nucleus along with its contents is referred to as nucleoplasm.
Plastids are a collective term for organelles that carry pigments. In a plant cell, chloroplasts are the most prominent forms of plastids that contain the green chlorophyll pigment. Because of these chloroplast plastids, a plant cell has the ability to undergo photosynthesis in the presence of sunlight, water, and carbon dioxide to synthesize its own food.
Ribosomes are plant organelles that comprise proteins (40 percent) and ribonucleic acid or RNA (60 percent). They are responsible for the synthesis of proteins. Inside the cell, a ribosome may occur freely (free ribosome) or it may be attached to another organelle, endoplasmic reticulum (bound ribosome). Each ribosome consists of two parts, a larger subunit and a smaller subunit.
Mitochondria (singular mitochondrion) are large, spherical or rod-shaped organelles present in the cytoplasm of the plant cell. They break down the complex carbohydrates and sugars into usable forms for the plant. A mitochondrion contains certain enzymes that are essential for supply of energy to the plant cell. Hence, these cell organelles also known as the powerhouse of the cell.
A golgi body is also referred to as golgi complex or golgi apparatus. It plays a major role in transporting chemical substances in and out of the cell. After the endoplasmic reticulum synthesizes lipids and proteins, golgi body alters and prepares them for exporting outside the cell. Arranged in a saclike pattern, this organelle is located near the cell nucleus.
Endoplasmic reticulum (ER) is the connecting link between the nucleus and cytoplasm of the plant cell. Basically, it is a network of interconnected, convoluted sacs present in the cytoplasm. Based on the presence or absence of ribosomes, ER can be of smooth or rough types. The former type lacks ribosomes, while the latter is covered with ribosomes. Overall, endoplasmic reticulum serves as a manufacturing, storing, and transporting structure for glycogen, proteins, steroids, and other compounds.
Vacuoles are the membrane-bound, storage organelles that help in regulating turgor pressure of the plant cell. In a plant cell, there can be more than one vacuole. However, the centrally located vacuole is larger than others, which stores all sorts of chemical compounds. Vacuoles also assist in intracellular digestion of complex molecules and excretion of waste products.
Peroxisomes are cytoplasmic organelles of the plant cell, which contains certain oxidative enzymes. These enzymes are used for the metabolic breakdown of fatty acids into simple sugar forms. Another important function of peroxisomes is to help chloroplasts in undergoing photorespiration process.
Well! This was a brief information regarding plant cell organelles, their structure, and specific functions. Other parts of the plant cell include microfilaments (structural component), microtubules (cytoskeleton component), and plasmodesmata (connecting tube between cells). As we have seen above, the coordination of cell organelles is crucial for carrying out the physiological and biochemical functionalities of the plant.