Cytogenetics Lecture Notes 2024-2025 PDF

Ain Shams University Faculty of Agriculture Genetics Department English Program of Biotechnology Second Level Lecture 3 2024/2025 THE ENDOMEMBRANE SYSTEM Smooth endoplasmic Rough e...

Ain Shams University Faculty of Agriculture Genetics Department English Program of Biotechnology Second Level Lecture 3 2024/2025 THE ENDOMEMBRANE SYSTEM Smooth endoplasmic Rough endoplasmic reticulum (SER) reticulum (RER) Synthesis lipids and a synthesis proteins also performs various and packages them in other functions vesicles; vesicles commonly go to the Golgi apparatus Transport vesicles Transport vesicles Shuttle proteins and Shuttle (‫ )نقل‬proteins lipids to various and lipids to various locations such as the locations such as the Golgi apparatus Golgi apparatus Lysosome Contains digestive enzymes that break Golgi apparatus down worn-out cell ( ‫خلية‬ modifies proteins and ‫ )متهالكة أو بالية‬parts or lipids from the ER; substances entering the sorts them (‫ )فرزها‬and cell at the plasma packages them in membrane vesicles Secretory vesicles Incoming vesicle Fuse (‫ )تندمج‬with the Brings substances into plasma membrane as the cell that are digested secretion occurs when vesicle fuses with Lysosome THE ENDOMEMBRANE SYSTEM THE ENDOMEMBRANE SYSTEM Endoplasmic reticulum (ER)  ‫التعلم الذاتى‬ SELF LEARNING float (‫ )عائمة أي طافية‬in the cell's fluid solution called cytosol. synthesize proteins for use primarily within the cell. are found on the of an organelle called the endoplasmic reticulum. synthesize proteins primarily for secretion or for use in lysosomes consist of and , the smaller unit and the larger unit respectively whereas have smaller subunit and larger subunit as and respectively. In cells, are in and form, whereas cells have form. THE ENDOMEMBRANE SYSTEM THE ENDOMEMBRANE SYSTEM THE ENDOMEMBRANE SYSTEM THE ENDOMEMBRANE SYSTEM Lysosomes THE ENERGY-RELATED ORGANELLES The Energy-Related Organelles Photosynthesis vs Respiration THE ENERGY-RELATED ORGANELLES Photosynthesis vs Respiration Carbon dioxide water solar energy glucose oxygen glucose oxygen Carbon dioxide water THE ENERGY-RELATED ORGANELLES Photosynthesis Stages of photosynthesis ( ) THE ENERGY-RELATED ORGANELLES Stages of photosynthesis THE ENERGY-RELATED ORGANELLES Cellular respiration Stages of Cellular respiration. THE ENERGY-RELATED ORGANELLES Stages of Cellular respiration THE ENERGY-RELATED ORGANELLES  Autotrophs vs Heterotrophs Producers vs Consumers Decomposers?!!! Self learning Decomposer: An organism, often a bacterium, fungus, or invertebrate that feeds on and breaks down dead plant or animal matter, making organic nutrients available to the ecosystem. THE ENERGY-RELATED ORGANELLES Hypothesis of Endosymbiosis ‫فرضية التعايش الداخلي‬ THE ENERGY-RELATED ORGANELLES Mitochondrion Engulfing of photosynthetic Prokaryote Some Cells Host cell Chloroplast Engulfing of aerobic Prokaryote Mitochondrion Host cell THE ENERGY-RELATED ORGANELLES ‫التعلم الذاتى‬ SELF LEARNING THE ENERGY-RELATED ORGANELLES Chloroplast structure THE ENERGY-RELATED ORGANELLES THE ENERGY-RELATED ORGANELLES The process of photosynthesis THE ENERGY-RELATED ORGANELLES Mitochondrion structure THE ENERGY-RELATED ORGANELLES THE ENERGY-RELATED ORGANELLES Cellular respiration THE ENERGY-RELATED ORGANELLES Phases of glucose breakdown THE NUCLEUS AND RIBOSOMES THE NUCLEUS AND RIBOSOMES Anatomy of the nucleus THE NUCLEUS AND RIBOSOMES THE NUCLEUS AND RIBOSOMES THE NUCLEUS AND RIBOSOMES Prokaryotic ribosomes vs Eukaryotic ribosomes SELF LEARNING THE OTHER VESICLES AND VACUOLES THE OTHER VESICLES AND VACUOLES Animal cell Plant cell  ‫التعلم الذاتى‬ SELF LEARNING Difference Between Lysosome and Peroxisome THE INTERNAL AND EXTERNAL SUPPORT THE INTERNAL AND EXTERNAL SUPPORT  Vesicle ATP Receptor for motor protein Diagram Motor protein Microtubule (ATP powered) of cytoskeleton Microtubule Vesicles 0.25 µm EM micrograph Motor proteins and the cytoskeleton  Nucleus Nucleus Actin subunit Tubulin subunit ‫وحدة آكتين فرعية‬ Fibrous subunits ‫وحدة توبيولين فرعية‬ ‫وحدات ليفية فرعية‬ 7 nm 10 nm 25 nm Microfilament Intermediate filament Microtubule ‫خيط دقيق‬ ‫خيط متوسط‬ ‫انيبية دقيقة‬ Fibers of the cytoskeleton Cilia the way that something such as an animal or a vehicle moves ▪ Adjacent cells communicate, interact, and adhere through specialized junctions between them ‫تتواصل الخاليا المتجاورة وتتفاعل وتلتصق ببعضها عبر اتصاالت متخصصة فيما بينها‬ ▪ – Tight junctions prevent leakage of extracellular fluid across a layer of epithelial cells ‫ اإلتصاالت المحكمة تمنع تسرب السائل الخلوي الخارجي عبر طبقة الخاليا الطالئية‬- – Anchoring junctions fasten cells together into sheets ‫االتصاالت المثبتة تشد الخاليا ببعضها البعض على هيئة صفائح‬ - – Gap junctions are channels that allow molecules to flow between cells ‫االتصاالت الفجوية عبارة عن قنوات تسمح بتدفق ومرور الجزيئات بين الخاليا‬ -  ‫‪Tight junctions‬‬ ‫االتصاالت المحكمة‬ ‫‪Anchoring junction‬‬ ‫االتصاالت المثبتة‬ ‫‪Gap junctions‬‬ ‫االتصاالت الفجوية‬ ‫‪Plasma membranes‬‬ ‫‪of adjacent cells‬‬ ‫غشاءآن بالزميان‬ ‫لخليتين متجاورتين‬ ‫‪Extracellular matrix‬‬ ‫المادة الخارج خلوية‬ ‫‪Three types of cell junctions in animal tissues‬‬ ‫ثالث أنواع من االتصاالت الخلوية في االنسجة الحيوانية‬ ▪ Cell walls enclose and support plant cells ‫▪ تغلف الجدر الخلوية الخاليا النباتية وتدعمها‬ ▪ Plant, but not animal cells, have a rigid cell wall ‫▪ تملك الخاليا النباتية ال الحيوانية جدر خلوية صلبة‬ – It protects and provides skeletal support that helps keep the plant upright against gravity ‫– تحمي الجدر الخلوية النبات وتدعمه هيكليا ً ليبقى منتصبا ً إلى أعلى ضد الجاذبية‬ – Plant cell walls are composed primarily of cellulose ‫– تتألف الجدر الخلوية النباتية من السيليلوز بصفة أساسية‬ ▪ Plant cells have cell junctions called plasmodesmata that serve in communication between cells ‫▪ الخاليا النباتية لديها إتصاالت خلوية تعرف بالبالزموديزماتا تعمل على االتصال بين الخاليا‬  Walls of two adjacent plant cells ‫جداران لخليتين نباتيتين‬ Vacuole ‫متجاورتين‬ ‫فجوة‬ Plasmodesmata ‫بالزموديزماتا‬ Primary cell wall ‫جدار خلوي أولي‬ Secondary cell wall ‫جدار خلوي ثانوي‬ Cytoplasm ‫سيتوبالزم‬ Plasma membrane ‫غشاء بالزمي‬ Plant cell walls and cell junction ‫جدر الخاليا النباتية واإلتصال الخلوي‬  Cell Signaling and Cell Communication ▪ In biology, cell signaling is the process by which a cell interacts with itself, other cells, and the environment. ▪ Cell signaling is a fundamental property of all cellular life in prokaryotes and eukaryotes. ▪ “Cell signaling is the process by which cells communicate with other cells within their body or with the external environment.” Cell signaling occurs by several distinct pathways. Multicellular organisms need cell signaling to regulate different functions. ▪ In plants and animals, signaling between cells occurs either through release into the extracellular space.  Cell Signaling and Cell Communication Forms of Cell Signaling Autocrine: Autocrine signaling involves a cell secreting a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in the cell itself. This can be contrasted with paracrine signaling, intracrine signaling, or classical endocrine signaling. Intracrine: In intracrine signaling, the signaling chemicals are produced inside the cell and bind to cytosolic or nuclear receptors without being secreted from the cell. In intracrine signaling, signals are relayed without being secreted from the cell. The intracrine signals not being secreted outside of the cell is what sets apart intracrine signaling from the other cell signaling mechanisms such as autocrine signaling. In both autocrine and intracrine signaling, the signal has an effect on the cell that produced it. Juxtacrine: Juxtacrine signaling is a type of cell–cell or cell–extracellular matrix signaling in multicellular organisms that requires close contact. Cell Signaling and Cell Communication Forms of Cell Signaling  Cell Signaling and Cell Communication Forms of Cell Signaling Paracrine: In paracrine signaling, a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to cell signaling by endocrine factors, hormones which travel considerably longer distances via the circulatory system; juxtacrine interactions; and autocrine signaling. Endocrine: Endocrine signals are called hormones. Hormones are produced by endocrine cells and they travel through the blood to reach all parts of the body. Specificity of signaling can be controlled if only some cells can respond to a particular hormone. Endocrine signaling involves the release of hormones by internal glands of an organism directly into the circulatory system, regulating distant target organs. Cell Signaling and Cell Communication Forms of Cell Signaling Cell Signaling and Cell Communication Forms of Cell Signaling Cell Signaling and Cell Communication Forms of Cell Signaling  Cell Signaling and Cell Communication Cell signaling can be divided into 3 stages: 1. : A cell detects a signaling molecule from the outside of the cell. A signal is detected when the chemical signal (also known as a ligand) binds to a receptor protein on the surface of the cell or inside the cell. 2. : When the signaling molecule binds the receptor it changes the receptor protein in some way. This change initiates the process of transduction. Signal transduction is usually a pathway of several steps. Each relay molecule in the signal transduction pathway changes the next molecule in the pathway. 3. : Finally, the signal triggers a specific cellular response. Cell Signaling and Cell Communication  Cell Signaling and Cell Communication Ligands and Receptors ▪ Chemical signals are released by signaling cells in the form of small, usually volatile or soluble molecules called ligands. ▪ A ligand is a molecule that binds another specific molecule, in some cases, delivering a signal in the process. ▪ Ligands can thus be thought of as signaling molecules. Ligands interact with proteins in target cells, which are cells that are affected by chemical signals; these proteins are called receptors. Ligands and receptors exist in several varieties; however, a specific ligand will have a specific receptor that typically binds only that ligand. Cell Signaling and Cell Communication Ligands and Receptors  FUNCTIONAL CATEGORIES OF CELL STRUCTURES ▪ It is possible to group cell organelles into four categories based on general functions of organelles – In each category structure is correlated with function Eukaryotic cell structures and functions 1. Manufacturing DNA synthesis: RNA synthesis; assembly of Nucleus ribosomal subunits (in nucleoli) Ribosomes Polypeptide (protein) synthesis synthesis of membrane lipids and proteins, Rough ER secretory proteins, and hydrolytic enzymes; formation of transport vesicles Lipid synthesis; detoxification in liver cells; Smooth ER calcium ion storage Modification and transport of Golgi apparatus macromolecules; formation of lysosomes and transport vesicles Eukaryotic cell structures and functions (continued) 2. Breakdown Digestion of ingested food, bacteria, and a Lysosomes (animal cell’s damaged organelles and cells) macromolecules for recycling Digestion (like Lysosomes); storage of Vacuoles chemicals; cell enlargement; water balance Peroxisomes Diverse metabolic processes, with (not part of endomembrane system) breakdown of H2O2 by-product Eukaryotic cell structures and functions (continued) 3. Energy Processing Conversion of chemical energy of food to Mitochondria chemical energy of ATP Chloroplasts Conversion of light energy to chemical (plant cells) energy of sugars Eukaryotic cell structures and functions (continued) 4. Support, Movement, and communication between cells Maintenance of cell shape; anchorage Cytoskeleton for organelles; movement of organelles (including cilia, flagella, and within cells; cell movement; mechanical centrioles in animal cells) transmission of signals from exterior of cell to interior Binding of cells in tissues; surface Extracellular matrix protection; regulation of cellular (in animals) activities Communication between cells; binding Cell Junctions of cells in tissues Maintenance of cell shape and skeletal Cell walls support; surface protection; binding of (in plants and fungi) cells in tissues