Cell Structure and Functions PDF

Cell Structure and Functions Major Parts of the Cell Cell membrane Cytoplasm  Nucleus  Cell Membrane  is the outermost part. It has the role of protecting the cell and its content.  It controls the exchange of the cell’s essential components  Cell Membrane  Composed of phospho...

Cell Structure and Functions Major Parts of the Cell Cell membrane Cytoplasm  Nucleus  Cell Membrane  is the outermost part. It has the role of protecting the cell and its content.  It controls the exchange of the cell’s essential components  Cell Membrane  Composed of phospholipid bilayer (double layer of fats and proteins)  it controls the materials’ entry and exit from the cell.  Phospholipid is a prominent type of lipid molecule present in the plasma membrane.  Cell Membrane  Lipids such as cholesterol, can pass through the membrane because of its hydrophobic interior.  Polar substances, cannot cross the membrane independently as they cannot penetrate the membrane’s hydrophobic interior. Cell Membrane  Cytoplasm  It is an area in the cell where organelles are located. It is composed primarily of water, proteins, and salts.  the organelles are suspended in a gel- like solution called cytosol, which composed of compounds such as water and ions of sodium, potassium, and calcium  Cytoplasm  It is predominantly made up of water, it contains a rich supply of macromolecules and smaller organic molecules.  the cytoplasm also contains enzymes that break down waste and enable metabolic reactions. It accommodates essential activities that allows for cellular expansion and growth  Cytoplasm  Together with the cytoskeleton, which is a network of proteins outlining the cytoplasmic framework, the cytoplasm determines cell shape and accommodates movement for some cell types.  Nucleus  the “control center” of a cell  It directs all the cell’s activities and determines how a cell should appear and function  It takes up 10% of the volume of the cell  Inside the nucleus is the nucleolus, which serves as the site of ribosome synthesis  Nucleus  It holds the chromosomes which carry the tightly wrapped and coiled DNA (deoxyribonucleic acid), the genetic material of an organism Nucleus  Endomembrane  It consists of System a network of structures involved in many functions, such as ensuring adaptation, wrapping, and transfer of proteins across the cell.  It also functions as depository of nutrients and as a disintegrator of organisms that are harmful to the living system. Endoplasmic Reticulum  Endoplasmic Reticulum  It transports molecules across the cytoplasm and is also capable of assembling new lipids for export to other cell membrane.  Rough or granular ER – synthesizing and modifying of proteins, significant parts in the formation of plasma membrane proteins and proteins outside the cell. This type of ER has a rough appearance because of the ribosomes attached to it.  Endoplasmic Reticulum Smooth or agranular ER – this incorporates proteins into the cisternae and transports synthesized proteins across cytoplasm, thereby allowing the synthesis of fatty acids and phospholipids.  It is abundant in liver cells, where it detoxifies hydrophobic chemicals Ribosomes Ribosomes  it is involved in providing a frame for protein synthesis; hence, they are sites of protein production.  G.E. Palade in 1952  Present in prokaryotic and eukaryotic cells Vacuoles Vacuoles  It is a fluid-filled vesicle enclosed by a membrane.  It has a selective membrane freely allowing water passage but retaining smaller molecules within it and stores chemicals within the cells  Acidic environment Lysosomes  Lysosomes  It serve as digestion slots for cellular materials that are due for expiration or are no longer useful  Cell’s “suicide bags” because it is capable of self-destruction in order to save the rest of the other organelles from being poisoned. Peroxisomes Peroxisomes  It disintegrate proteins and accommodate the breakdown of fatty acids  It shields the cell from serious damage caused by reactive oxygen species (ROS) molecules  ROS molecules are by-products of normal cellular metabolism Golgi Apparatus Golgi Apparatus  The Golgi bodies were observed as stalks of flat framework which held several sacs of secretory granules.  It functions as the manufacturer and the shipping center of the cell  It modifies, sorts, and packages the macromolecules synthesized by the cells Centrosomes Centrosomes  It assist in arranging microtubules (hollow tubes of protein) to be utilized during cell division.  It also enable the said microtubules to form part of the cell’s cytoskeleton. In this way, the cellular shape is maintained and the cell structure is stabilized. Mitochondria Mitochondria  “animal cell’s powerhouse”  It has the chief role to produce energy through cellular respiration  Its responsible for the production of adenosine triphosphate (ATP), the cell’s energy currency  The mitochondria fill up about 25% of the cytoplasmic volume. Chloroplast Chloroplast  It can only be found in plants.  It serves as the site of energy conversion in plant cells.  It is best known for housing chlorophyll, the pigment that causes the green color of plant.  The most significant function of chloroplast is to serve as the site of cellular respiration. Animal Cell Plant Cell