Origin of Rice Essay Example for Free

Origin of Rice Essay A major component of plants that are starchy in nature, the amyloplast are organelles that store starch. They are classified as plastids, and are also known as starch grains. They are responsible for the conversion of starch into sugar, that gives the starchy plants and tubers energy. Function: Synthesis and storage of starch granules Cell Membrane or Plasma Membrane The cell membrane is a thin layer made up of proteins, lipids, and fats. It forms a protective wall around the organelles contained within the cell. It is selectively permeable and thus, regulates the transportation of materials needed for the survival of the organelles of the cell. Function: Protects the cell from surrounding Cell Wall Unique to plant cells, the cell wall is the fairly rigid, protective wall that resists the strain of physical forces. The cell wall is mainly made up of cellulose fiber and it helps maintain the shape of the cell. Function: Maintain cell pressure and prevent over-expansion of cells Centrosome The centrosome is located close to the nucleus and is a small body made up of radiating tubules. It is responsible for producing and organizing the microtubules. In plant cells, the centrosome is a centriole-free organelle. It is also called the Microtubule-organizing center (MTOC). Function: Regulates cell-cycle progression Chloroplast Found only in plants, chloroplasts are organelles that resemble the structure of the mitochondria. It is a plastid that traps energy from sunlight. It contains chlorophyll molecules, that carry on the process of photosynthesis as well as, give the plants a lush green color. Function: Conducts photosynthesis Cytoplasm The cytoplasm forms the gel-like substance that holds the organelles in the cell. It is a colorless substance that is made up of mainly water, salts and organic molecules. It also contains proteins, that make up the cytoskeleton. We can refer to it as, the stage where all the action in the cell takes place, or as the home of all the organelles of the cell. Function: Site of multiple cell processes including, cell metabolism Golgi Body Known as the golgi complex or the golgi apparatus, it is located near the nucleus. It is a stack of membrane-bound structures that, is involved in the transportation of lipids and modification of proteins. It is crucial in segregating and transporting material within the cell. Function: Sorting, processing and modifying proteins Mitochondrion Known to be the power house or the storehouse of energy of the cell, the mitochondria plays an important role in a cell. They are made up of cristae or finger-like structures, which convert the sugar into Adenosine Triphosphate or ATP, that is energy for the cell. It is responsible for regulating membrane potential, programming the death of the cell and regulating cellular metabolism. Function: Energy production and conversion, regulates cell metabolism Nucleus This is a spherical body that contains various organelles like the nucleolus (where ribosomal RNA is produced) and is surrounded by a nuclear membrane. The nucleus is known to be the control room of the cell. It regulates various cell functions by controlling the protein synthesis of the plant cell. The nucleus contains DNA within the chromosomes. It is a membrane-bound structure that contains the cells hereditary information. Function: Controls expression and transcription of the gene Nucleolus Known to be the heart of the cell, the nucleolus transcribes ribosomal RNA. It is composed of proteins and nucleic acid and is known to be a genetically determined element. Function: Produces ribosomes Peroxisomes Membrane-bound packets of oxidative enzymes, the peroxisomes play a vital role in converting fatty acids to sugar. They also assist the chloroplasts in photo-respiration. Their functions include the glyoxylate cycle that occurs in germinating seeds and photo-respiration in leaves. Function: Breakdown of metabolic hydrogen peroxide Ribosomes They are small packets or granules of RNA that convert amino acids into proteins. It serves as a site of protein synthesis and is therefore termed as the workhorses of protein biosynthesis. Function: Protein builders and synthesizers Rough Endoplasmic Reticulum The rough endoplasmic reticulum or rough ER, is a vast interconnected membrane system located close to the nucleus. The presence of ribosomes on its surface gives it a rough appearance and hence the name. The RER works in accord with the golgi body to send new proteins to their proper destinations. These networks transport materials through the cell and produce proteins in sacs known as cisternae. Function: Manufactures lysosomal enzymes, translating and folding of new proteins Smooth Endoplasmic Reticulum Similar to the structure of the rough ER, the smooth ER is a separate interconnected network membrane structure that is free from ribosomes. The SER transports material through the cell. It is also crucial in producing and digesting lipids and proteins. Function: Manufactures and transports lipids Vacuole Vacuoles are essentially sacs filled with water that help maintain the shape of the cell. It stores nutrients and waste products. Its functions include, isolating materials harmful to the cell, maintaining turgor within the cell and exporting unwanted materials away from the cell.