Presentation By Jaspreet Rekhi Introducing Sites: -

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Presentation By Jaspreet Rekhi Introducing Sites: - www.rhombnet.com www.ppt.rhombnet.com www.wallpapers.rhombnet.com Slide 2 Slide 3 Cell wall :- A cell wall is a tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell. They are found in plants, bacteria, fungi, algae, and some archaea. Animals and protozoa do not have cell wall and it permits the organism to build and hold its shape (morphogenesis). The cell wall also limits the entry of large molecules that may be toxic to the cell. It further permits the creation of a stable osmotic environment by preventing osmotic lysis and helping to retain water. Slide 4 Cell membrane:-The cell membrane (also called the plasma membrane or plasma lemma) is one biological membrane separating the interior of a cell from the outside environment. The cell membrane surrounds all cells and it is selectively- permeable, controlling the movement of substances in and out of cells. It contains a wide variety of biological molecules, primarily proteins and lipids, which are involved in a variety of cellular processes such as cell adhesion, ion channel conductance and cell signaling. The plasma membrane also serves as the attachment point for the intracellular cytoskeleton and, if present, the extracellular cell wall. Golgi apparatus:-The Golgi apparatus (also Golgi body or Golgi Complex) is an organelle found in most eukaryotic cells. Slide 5 It was identified in 1898 by the Italian physician Camillo Golgi and was named after him. The primary function of the Golgi apparatus is to process and package macromolecules, such as proteins and lipids, after their synthesis and before they make their way to their destination; it is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the cellular endomembrane system. Cytoplasm:-The cytoplasm is the part of a cell that is enclosed within the cell membrane. the cytoplasm contains organelles, such as mitochondria, which are filled with liquid that is kept separate from the rest of the cytoplasm by biological membranes. Slide 6 The cytoplasm is the site where most cellular activities occur, such as many metabolic pathways like glycolysis, and processes such as cell division. The part of the cytoplasm that is not held within organelles is called the cytosol. The cytosol is a complex mixture of cytoskeleton filaments, dissolved molecules, and water that fills much of the volume of a cell. The cytosol is a gel, with a network of fibers dispersed through water. Mitrochrondia:-In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle found in most eukaryotic cells.These organelles range from 0.5 to 10 micrometers (m) in diameter. Slide 7 Mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several human diseases, including mitochondrial disorders and cardiac dysfunction and may play a role in the aging process. Slide 8 Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis. Slide 9 Chromatin:- is the combination of DNA and proteins that makes up chromosomes. The major components of chromatin are DNA and histone proteins, although other proteins have prominent roles too. The functions of chromatin are to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication. Chromatin contains genetic material-instructions to direct cell functions. Chromoplasts :- are plastids responsible for pigment synthesis and storage. They, like all other plastids (including chloroplasts and leucoplasts), are organelles found in specific photosynthetic eukaryotic species. Slide 10 Chromoplasts in the traditional sense are found in coloured organs of plants such as fruit and floral petals, to which they give their distinctive colors. This is always associated with a massive increase in the accumulation of carotenoid pigments. The conversion of chloroplasts to chromoplasts in ripening tomato fruit is a classic example. Deoxyribonucleic acid:- DNA is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses Slide 11 The main role of DNA molecules is the long-term storage of information. Chemically, DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti- parallel. Attached to each sugar is one of four types of molecules called bases. Endoplasmic reticulum :-is an eukaryotic organelle that forms an interconnected network of tubules, vesicles, and cisternae within cells. Slide 12 Rough endoplasmic reticulum synthesize proteins, while smooth endoplasmic reticulum synthesize lipids and steroids, metabolize carbohydrates and steroids, and regulate calcium concentration, drug detoxification, and attachment of receptors on cell membrane protein. Leucoplasts:- are a category of plastid and as such are organelles found in plant cells. They are non- pigmented, in contrast to other plastids such as the chloroplast. Lacking pigments, leucoplasts are not green, so they are predictably located in roots and non- photosynthetic tissues of plants. Slide 13 They may become specialized for bulk storage of starch, lipid or protein and are then known as amyloplasts, elaioplasts, or proteinoplasts respectively Lysosomes :-are spherical organelles that contain enzymes (acid hydrolases) that break up endocytized materials and cellular debris. They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. They are frequently nicknamed "suicide-bags" or "suicide- sacs" by cell biologists due to their role in autolysis. Slide 14 Nuclear envelope:- is a double lipid bilayer that encloses the genetic material in eukaryotic cells. The nuclear envelope also serves as the physical barrier, separating the contents of the nucleus (DNA in particular) from the cytosol (cytoplasm). Many nuclear pores are inserted in the nuclear envelope, which facilitate and regulate the exchange of materials (proteins such as transcription factors, and RNA) between the nucleus and the cytoplasm. Slide 15 Ribonucleic acid (RNA) is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate. RNA is very similar to DNA, but differs in a few important structural details: in the cell, RNA is usually single-stranded, while DNA is usually double-stranded; RNA nucleotides contain ribose while DNA contains deoxyribose (a type of ribose that lacks one oxygen atom); and RNA has the base uracil rather than thymine that is present in DNA. RNA is transcribed from DNA by enzymes called RNA polymerases and is generally further processed by other enzymes. RNA is central to protein synthesis Slide 16 Ribosomes:- are the components of cells that make proteins from amino acids. Vacuole is a membrane bound organelle which is present in all plant and fungal cells and some animal and bacterial cells. functions of the vacuole include: Isolating materials that might be harmful or a threat to the cell Containing waste products Maintaining internal hydrostatic pressure or turgor within the cell Maintaining an acidic internal pH Containing small molecules Exporting unwanted substances from the cell Slide 17 Slide 18 http://www.nobel.se/medicine/laureates/2001/press.html Slide 19 Slide 20 The process of cell division which results in the production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell. Slide 21 Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis Slide 22 Animal Cell DNA replicated Organelles replicated Cell increases in size Plant Cell DNA replicated Organelles replicated Cell increases in size Slide 23 Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Slide 24 Animal Cell Packages DNA into chromosomes Plant cell Packages DNA into chromosomes Slide 25 Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Slide 26 Animal Cell Chromosomes line up at the center of the cell Spindle fibers attach from daughter cells to chromosomes at the centromere Plant Cell Chromosomes line up at the center of the cell Spindle fibers attach from daughter cells to chromosomes at the centromere Slide 27 Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Slide 28 Animal Cell Spindle fibers pull chromosomes apart of each chromosome (called chromotid) moves to each daughter cell Plant Cell Spindle fibers pull chromosomes apart of each chromosome (called chromotid) moves to each daughter cell Slide 29 Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Slide 30 Animal Cell DNA spreads out 2 nuclei form Cell memb