Life in a Cell PDF

Life in a Cell Dr. Catherine M. Precioso, PhD. Visit this site: https://www.biomanbio.com/HTML5Quizzes/ CellQuizzes/cellquiz2html5page.html  All living things have cells that share fundamental structural parts: Cell Also called plasma membrane...

Life in a Cell Dr. Catherine M. Precioso, PhD. Visit this site: https://www.biomanbio.com/HTML5Quizzes/ CellQuizzes/cellquiz2html5page.html  All living things have cells that share fundamental structural parts: Cell Also called plasma membrane The outer boundary that regulates the passage membrane of materials into and out of the cell. Genetic region The gel-like substance that makes Cytoplasm up the cell’s internal environment Genetic Contains the genetic material in the form of DNA that provides instructions to make proteins, region regulates activities, and enables cells to reproduce its kind  CELL/PLASMA MEMBRANE  A thin barrier that forms the boundary separating an individual cell from the external environment  Consists of a double layer of phospholipids embedded with a variety of molecules  Controls what enters and leaves the cell (semi-permeable)  The CYTOPLASM  Fills the space between the nucleus and the cell membrane  It is made up of ORGANELLES suspended in the gel-like CYTOSOL  Many metabolic reactions take place in the cytoplasm.  NUCLEUS  The storehouse of genetic information in the form of DNA inside the cell.  It directs all activities of the cell  Directs the synthesis of ribosomes and proteins  Stores chromatin in a gel-like substance called the nucleoplasm.  The nucleolus is a condensed region of chromatin where ribosome synthesis occurs.  The boundary of the nucleus is called the nuclear envelope.  The nuclear membrane is continuous with the endoplasmic reticulum.  Nuclear pores allow substances to enter and exit the nucleus.  RIBOSOMES  The cellular structures responsible for protein synthesis.  They appear either as clusters or single, tiny dots that float freely in the cytoplasm.  The ENDOMEMBRANE SYSTEM  The ENDOMEMBRANE SYSTEM is a group of membranes and organelles in eukaryotic cells that works together to manufacture, store, distribute and breakdown lipids and proteins.  Consists of the following organelles:  Endoplasmic reticulum  Golgi apparatus  Vesicles  Vacuoles  Lysosomes  Peroxisomes  ENDOPLASMIC RETICULUM  Interconnected network of thin and folded membranes that fills much of the large portion of the cytoplasm  ER membranes are arranged like maze of enclosed spaces with many creases and folds  Rough Endoplasmic Reticulum (RER)  Smooth Endoplasmic Reticulum (SER)  ROUGH ENDOPLASMIC RETICULUM  The region in the endoplasmic reticulum that is dotted with ribosomes that joins amino acids to for proteins.  Rough because it looks bumpy under the microscope  Site of protein synthesis that will be secreted from the cell.  RER is abundant in cells that secrete proteins (eg. liver). ROUGH ENDOPLASMIC RETICULUM  SMOOTH ENDOPLASMIC RETICULUM  Continuous with the RER but has few or no ribosomes on its cytoplasmic surface  SER functions include:  Synthesis of carbohydrates, lipids, and steroid hormones;  Detoxification of medications and poisons; and  Storage of calcium ions.  GOLGI APPARATUS  Layered stacks of membrane-enclosed spaces where proteins are transported from the ER  In this organelle, sorting, tagging, packaging, distribution of proteins and lipids occur  VESICLES  After a protein has been manufactured, part of the ER pinches off to form a small, membrane-bound sacs called vesicles enclosing the protein.  A new vesicle will be formed at the end of the Golgi apparatus for storage, transport or secretion.  Storage vesicles  Transport vesicles  Secretory vesicles  Generally short-lived and are formed and recycled as needed by the cell. GOLGI APPARATUS  VACUOLES  A fluid-filled sac for the storage of materials needed by the cell, which includes water, food molecules, inorganic ions, and enzymes.  Most animal cell contain many SMALL vacuoles while plants have a CENTRAL vacuole that it unique only to them.  The CENTRAL VACUOLE plays a key role in regulating the cell’s concentration of water in changing environmental conditions.  It also supports the expansion of the cell.  LYSOSOMES  Round-shaped, membrane- bound structures containing chemicals that can break down material in the cell.  Contain enzymes known as lysozyme that can defend a cell from invading bacteria and viruses.  Break down damaged or worn- out cell parts.  Fewer lysosomes in plant cells. LYSOSOMES  PEROXISOMES  Similar to lysosomes, peroxisomes also exist as small vesicles around the cell.  Contains digestive enzymes for breaking down toxic materials  Oxidative enzymes  Break down complex molecules into smaller molecules (e.g. H2O2)  Absorb nutrients that had been acquired by cells  MITOCHONDRIA  Bean-shaped structure surrounded by two membranes.  Inner and outer membrane  Supply energy to the cell by generating ATP through cellular respiration  Have their own ribosomes and DNA (from mother)  CENTROSOME AND CENTRIOLES  Centrioles.  Barrel-like structures that are perpendicular to each other  Made of nine triplets of short microtubules arranged in rings  Aids in cell division forming mitotic spindle  Organize microtubules to form cilia and flagella  CILIA AND FLAGELLA  Cilia and flagella are two locomotory projections in eukaryotes  Both contain nine microtubule doublets arranged in circle around 2 central microtubules.  Cilia – looks like little hair with much shorter length  Flagella – look like a whip or a tail.  CYTOSKELETON Three types of fibers  A network of protein fibers that within cytoskeleton:  help maintain the shape of the cell  secure some organelles in specific positions Microfilament  allow cytoplasm and vesicles to move within the cell Intermediate filaments  enable cells within multicellular organisms to move. Microtubules  CYTOSKELETON Microfilam Intermediate Microtubul ent filaments es  Narrowest  Structural function  Widest  Function in cellular  Maintain the shape  Help the cell resist movement of the cell compression  Provide some rigidity  Anchor the nucleus  Provide a track along and shape to the and other organelles which vesicles move through the cell cell. in place.  Pull replicated chromosomes to opposite ends of a dividing cell. Group Activity – Group the organelles based on their general function – Manufacture – Breakdown – Energy Processing – Support and Movement – Storage – Be able to identify their specific function n a cell