Cell Biology Lecture 1 PDF

Cell biology PB 101 Cell Biology Dr. Amal Ghanim Associate professor of Biochemistry, faculty of Pharmacy, Nile Valley University  Course aims By the end of this course, the student should be able to: 1. Describe the cell theory and cell structure 2. Recognize the different types of cellular tran...

Cell biology PB 101 Cell Biology Dr. Amal Ghanim Associate professor of Biochemistry, faculty of Pharmacy, Nile Valley University  Course aims By the end of this course, the student should be able to: 1. Describe the cell theory and cell structure 2. Recognize the different types of cellular transports of biomolecueles across biological membrane 3. Discuss the diverse forms of Intercellular communications and cellular signalling 4. Distinguish the cell cycle phases and the different cell cycle regulators 5. Demonstrate DNA structure and replication with emphasis on genetic code illustration 6. Examine the steps from gene to protein sunthesis (Biological chemistry) It is the study of chemical processes within and relating to living organisms. Biochemical processes give rise to the complexity of life. Bio-chemistry It includes the study of chemistry behind biological processes and the synthesis of biologically active molecules.  The cell Biology 1 It is the basic structural, functional, and biological unit of all known organisms. A cell is the smallest unit of life, and therefore, cells are often described as the “building blocks of life”. Cells were discovered by Robert Hooke in 1665. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells.  Cell biology (Cellular Biology 1 biology or Cytology) It is the study of cells. Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Most plant and animal cells are only visible under a light microscope, with dimensions between 1 and 100 micrometers Organisms Biology 1 It can be classified as unicellular (consisting of a single cell such as bacteria) or multicellular (including plants and animals). Most unicellular organisms are classed as microorganisms.  Types of cells Eukaryotic cells Prokaryotic cells Presentations are tools that can be Which is now divided into 2 domains used as lectures. Eubacteria Archeabacteria (Archea)  Prokaryotic Cell Eukaryotic Cell vs. Contain membrane-bound No nucleus, No mitochondria, No ER. organelles, such as the nucleus, Usually unicellular mitochondria, ER. Cell size 1-10 µm Usually multicellular cell size 10-100 µm  Cell Structure Biology 1 (organelles) Overview Cell is the unit of living system Structurally ; it consists of an aggregate of molecules that enabling the survival and growth of the whole organism these molecules are cell organelles Most organelles are membrane-enclosed structures, Their membranes are composed of the same components as plasma membranes that form the outer boundaries of cells. Cell Structure Organelles do not float freely within the cytosol but reside within the framework established by the cytoskeleton Each organelle carries out a specific function Cytosol (liquid portion of the cytoskeleton)+ Cell organelles = Cytoplasm (composed of all materials contained within plasma membrane boundaries) Biology 1  Nucleus Ribosomes Endoplasmic reticulum Cell Golgi apparatus Mitochondria organelles Lysosomes and peroxisomes (Vesicles) 1- Nucleus (plural = nuclei) All eukaryotic cells except mature erythrocytes (red blood cells) contain a nucleus. It is surrounded by nuclear envelope with nuclear pores to permit transfer of materials between the nucleus and the cytosol. The interior of the nucleus contains the nucleoplasm; the fluid in which the DNA (which carry our genetic information) are found. DNA combine with specific protein to form chromosome Within the nucleus there is a suborganelle called the nucleolus. The nucleolus is the site of ribosome production. Biology 1 Nucleus function Biology 1 During mitosis, chromosomes undergo replication of their DNA and separation into daughter chromosomes. DNA directs the protein biosynthesis inside the cell 2- Ribosomes Each ribosome has a large and a small subunits They are composed of 40%proteins and 60%ribosomal RNA (rRNA). Ribosomes are found within the cytosol either free or bound to the endoplasmic reticulum. Function: Ribosomes are the cellular machinery for protein synthesis. Biology 1  3- Endoplasmic reticulum (ER) ER appearing like a series of interconnected, flattened tubes surround the nucleus Two types: A-Rough endoplasmic reticulum (rER): B- Smooth endoplasmic reticulum (sER) Refers to the regions of ER where refers to the regions of ER without ribosomes are bound to the outer attached ribosomes, membrane. Its function is site for lipid synthesis Bound ribosomes and the associated ER are involved in the production and modification of proteins. 4-Golgi apparatus (Golgi complex) It appears as flat, stacked, membranous sacs; Three regions are described within Golgi complex The Cis: which is closest to ER The medial The Trans: which is near plasma membrane Biology 1 Golgi apparatus Biology 1 Proteins from the rough ER enter at its cis face (entry face), which is usually oriented toward the nucleus. They are then transported through the Golgi and exit from its trans face (exit face). As they pass through the Golgi, proteins are modified and sorted for transport to their destinations within the cell. Golgi apparatus function Biology 1 Receiving protein synthesized in ribosomes (pack it and sort it) Performing modifications to it to make it well functioning protein 1-Glycosylations (addition of carbohydrate) 2- Phosphorylations (addition of phosphate) 3-Proteolysis (enzyme-mediated breakdown of protein) Secretion of protein to cell outside through formation of vacuoles called secretory vesicles in which secretory proteins are concentrated and transported to their destinations within the cell or outside. 5- Lysosomes and peroxisomes (Vesicles ) Involved in digestion and detoxification Lysosomes: are vesicles filled with potent enzymes have an acidic internal pH, known as acid hydrolases that breakdown macromolecules. Peroxisomes: responsible for detoxification of peroxides that damage cells lysosomes Biology 1 1-Hydrolyze or break down macromolecules (proteins, nucleic acids, carbohydrates and lipids) that have reached the end of their functional life. accumulation of non function macromolecules is very toxic to cells. 2-Degrade materials that taken up by the cell through endocytosis or phagocytosis as accumulation of this material is very toxic to cells. 5- Peroxisomes Peroxisomes resemble lysosomes in size and in structure. They have single membranes enclosing them and contain hydrolytic enzymes. Function : It helps in: 1-Detoxification of hydrogen peroxide (a toxic by-product of many metabolic reactions). 2- Break down of fatty acids and purines (AMP and GMP). 3-Synthesis of myelin (the substance that forms a protective sheath around many neurons). 4- In liver cells, peroxisomes participate in cholesterol and bile acid synthesis. 6-Mitochondrion (plural = mitochondria) The mitochondrial membrane is double phospholipid bilayer membranes that form the outer boundary of the organelle The inner mitochondrial membrane forms folded structures called cristae that protrude into the mitochondrial lumen (mitochondrial matrix). Mitochondria function Biology 1 Mitochondria is the power house of the cell Their unique membranes are used to generate ATP through respiration (greatly increasing the energy yield from the breakdown of carbohydrates and lipids). All enzymes of electron transport chain , energy liberation and ATP formation are located in the inner membrane  Nucleus Ribosomes Endoplasmic reticulum Cell Golgi apparatus Mitochondria organelles Lysosomes and peroxisomes (Vesicles)  Peroxisomes helps in ……. The rough endoplasmic reticulum has ____ located This organelle functions in A.generate ATP on it. cellular respiration B. performing modifications on protein A. Lysosomes C. Synthesis of myelin B. cytosol A. lysosome D. Synthesis of proteins C. ribosomes B. endoplasmic reticulum D. proteins C. mitochondrion D. Golgi apparatus Questions Genetic material is Which of the following cells This organelle is contained within the ___ of does not have a nucleus? responsible for destroying the cell. excess macromolecules A-Mature red blood cell. being engulfed by the cell A. Ribosomes B. Muscle cell. B. cytoplasm C.Liver cell. A. Lysosomes C. nucleus D. Heart muscle cell. B. mitochondrion D. nucleolus C. golgi apparatus D. ribosomes Questions  Resources Online sources used Biology 1 - Lippincott Illustrated Reviews: Cell and Molecular Biology by Nalini Chandar and Susan Viselli 1st Edition (Lippincott Illustrated Reviews Series, 2011) - Cell Biology and Histology by Gartner, Leslie P., Hiatt, James L., Strum, Judy, 5th Edition [Lippincott Williams & Wilkins, 2006] - Journal of biology (https://jbiol.biomedcentral.com/) - Current Biology (https://www.cell.com/current-biology) - Cell reports (http://www.cell.com/cell-reports)