Cell Structure and Functions PDF

HAT IS CELL? WHAT IS A CELL? SCIENCE 2024 CELL STRUCTURE AND FUNCTIONS  CELL STRUCTURE AND FUNCTIONS Cells are the smallest form of life. Your body contains several billion cells, organized into over 200 major types, with hundreds of cell-specific functions. Cells are...

HAT IS CELL? WHAT IS A CELL? SCIENCE 2024 CELL STRUCTURE AND FUNCTIONS  CELL STRUCTURE AND FUNCTIONS Cells are the smallest form of life. Your body contains several billion cells, organized into over 200 major types, with hundreds of cell-specific functions. Cells are the basic structural and functional units of living tissue, whether plant or animal.  Cellular functions include such basic life processes as protein and lipid (fat) synthesis, cell division and replication, respiration, metabolism, and ion transport as well as providing structural support for tissues, protecting the body against disease or injury, and serving as selective barriers to the passage of various materials into and out of the cell.  Cellular physiology is a term that is sometimes used to describe the study of cellular functions and processes There are three basic parts of a cell Plasma membrane, Cytoplasm and Nucleus The plasma membrane or cell membrane is a thin coat of lipids that surrounds a cell. It forms the physical boundary between the cell and its environment, so you can think of it as the “skin” of the cell. Cytoplasm. This refers to all of the cellular material inside the plasma membrane, other than the nucleus. Cytoplasm is made up of a watery substance called cytosol, and contains other cell structures such as ribosomes. Nucleus. This considers as the central part of a cell. It contains the genetic instructions that cells need to make proteins. This is called as DNA which a nucleic acid found in cells. Mitochondria are oval-shaped, double membrane organelles that have their own ribosomes and DNA. These organelles are often called the “energy factories” of a cell because they are responsible for making adenosine triphosphate (ATP), the cell’s main energy-carrying molecule, by conducting cellular respiration. The endoplasmic reticulum modifies proteins and synthesizes lipids, while the Golgi apparatus is where the sorting, tagging, packaging, and distribution of lipids and proteins takes place. Peroxisomes are small, round organelles enclosed by single membranes; they carry out oxidation reactions that break down fatty acids and amino acids. Peroxisomes also detoxify many poisons that may enter the body. Vesicles and vacuoles are membrane- bound sacs that function in storage and transport. Other than the fact that vacuoles are somewhat larger than vesicles, there is a very subtle distinction between them: the membranes of vesicles can fuse with either the plasma membrane or other membrane systems within the cell. Animal Cells Animal cells have a centrosome and lysosomes, whereas plant cells do not. The centrosome is a microtubule- organizing center found near the nuclei of animal cells while lysosomes take care of the cell’s digestive process. Plant Cell Plant cells have a cell wall, a large central vacuole, chloroplasts, and other specialized plastids, whereas animal cells do not. Plant Cell The cell wall protects the cell, provides structural support, and gives shape to the cell while the central vacuole plays a key role in regulating the cell’s concentration of water in changing environmental conditions. Chloroplasts are the organelles that carry out photosynthesis. Plant Cell Plants are unique among the eukaryotes, organisms whose cells have membrane- enclosed nuclei and organelles, because they can manufacture their own food. Chlorophyll, which gives plants their green color, enables them to use sunlight to convert water and carbon dioxide into sugars and carbohydrates, chemicals the cell uses for fuel. Bacteria Cell They are as unrelated to human beings as living things can be, but bacteria are essential to human life and life on planet Earth. Although they are notorious for their role in causing human diseases, from tooth decay to the Black Plague, there are beneficial species that are essential to good health. Capsule. Some species of bacteria have a third protective covering, a capsule made up of polysaccharides (complex carbohydrates). Capsules play a number of roles, but the most important are to keep the bacterium from drying out and to protect it from phagocytosis (engulfing) by larger microorganisms. Cell Envelope. The cell envelope is made up of two to three layers: the interior cytoplasmic membrane, the cell wall, and -- in some species of bacteria -- an outer capsule. Cell Wall. Each bacterium is enclosed by a rigid cell wall composed of peptidoglycan, a Plasmids. Plasmids are passed on to other bacteria through two means. For most plasmid types, copies in the cytoplasm are passed on to daughter cells during binary fission. Cytoplasmic Membrane. A layer of phospholipids and proteins, called the cytoplasmic membrane, encloses the interior of the bacterium, regulating the flow of materials in and out of the cell. Flagella. Flagella (singular, flagellum) are hairlike structures that provide a means of locomotion for those bacteria that have them. Nucleoid. The nucleoid is a region of cytoplasm where the chromosomal DNA is located. It is not a membrane bound nucleus, but simply an area of the cytoplasm where the strands of DNA are found. Pili. Many species of bacteria have pili (singular, pilus), small hairlike projections emerging from the outside cell surface. These outgrowths assist the bacteria in attaching to other cells and surfaces, such as teeth, intestines, and rocks.