THE CELL Cell Organelle 1 Plasma membrane plasmalemma

THE CELL

Cell Organelle 1. Plasma membrane/ plasmalemma • It is a membrane that completely covers the surface of the protoplasm. Because it is the outermost membrane of the protoplast, it is selectively impermeable. It is impermeable to harmful materials and permeable to beneficial ones. • There are molecular pumps in the plasma membrane that actively transport needed molecules inward and pumps outward for secretion.

2. Nucleus • It is a permanent storage place for the organisms genetic information. It is stored in the DNA of every cell. The nucleus carries out information retrieval by making copies of specific part of the DNA whenever the information is needed. • It is surrounded by a nuclear envelop which separates the nuclear material (inner membrane) from the rest of the cell (outer membrane).

• The nuclear envelop contains numerous holes, called nuclear pores that are involved in the transport of material between the nucleus and the rest of the protoplasm. • Nuclear DNA is always associated with histones, this complex of the two is known as chromatin. • Inside every nucleus is one, two or several bodies called nucleoli, areas where components of ribosomes are synthesized and partially assembled.

3. Cytoplasm • the space out side the nucleus and the vacuole is the cytoplasm which contain the many organelle. 4. Mitochondria • This is the organelle that store highly energetic but fairly unreactive compounds such as sugars and starches; to utilize the energy, such compounds must be broken down into ATP. This is the organelle that carry out cell respiration.

• Mitochondria are rod-shaped organelles that can be considered the power generators of the cell, converting oxygen and nutrients into adenosine triphosphate (ATP). • ATP is the chemical energy "currency" of the cell that powers the cell's metabolic activities.

5. Ribosomes • Composed of proteins and ribosomal RNA. • There are two main types of ribosomes: free ribosomes and attached ribosomes. • Attached ribosomes are attached to the endoplasmic reticulum and serve as sites for protein synthesis. Proteins synthesized on these ribosomes will be exported from the cell, moved into other organelles of the endomembrane system, or incorporated into membranes.

Golgi Apparatus • The Golgi apparatus is the distribution and shipping department for the cell's chemical products. It modifies proteins and fats built in the endoplasmic reticulum and prepares them for export as outside of the cell.

·Microfilaments · Microfilaments are solid rods made of globular proteins called actin. These filaments are primarily structural in function and are an important component of the cytoskeleton. ·Microtubules · These straight, hollow cylinders are found throughout the cytoplasm of all eukaryotic cells (prokaryotes don't have them) and carry out a variety of functions, ranging from transport to structural support.