The Cell Theory Further observations in the 1800’s by Schleiden and Schwann 4/11/2017 Fatchiyah, Ph.D. JB UB http://members.tripod.com/blustein/Schwann_Cells/schwann_cells.htm

Pengertian Sel Sel merupakan satuan struktural dan fungsional terkecil dari makhluk hidup. Sel melakukan semua proses kehidupan.

Penemuan Pertama Sel Robert Hooke, ilmuwan Ingris(1665)  sel gabus dalam buku Micrographia Anton van Leeuwenhoek, 1674 (pembuat lensa dari Belanda)  sel hidup dalam air

Penemu Sel Mathias Schleiden (ahli tumbuhan dari Jerman), 1838  semua tanaman terdiri atas sel Theodor Schwann (zoologis dari Jerman), 1839  sel merupakan unit struktur terkecil dari makhluk hidup Rudolp Virchow (Jerman), 1855  sel berasal dari sel yang sudah ada (TEORI SEL)

Teori Sel Teori Sel menyatakan bahwa : Semua makhluk hidup tersusun atas satu atau lebih sel Sel merupakan satuan struktural terkecil dari makhluk hidup, sel melakukan semua proses kehidupan Sel berasal dari sel yang lain

What are cells? Fundamental, replicating units of living organisms. Machines with complex regulation and behaviors; based on networks of chemical reactions called pathways. They carry the information needed to reproduce themselves. All cells based on molecules of a limited number of classes DNA RNA Proteins “etcetera” (Lipids, Carbohydrates, Metabolites) 4/11/2017 Fatchiyah, Ph.D. JB UB

Cell structure and function The components of a cell The cell membrane: how materials get into and out of the cell Are all cells the same? The life and death of a cell 4/11/2017 Fatchiyah, Ph.D. JB UB

Trillions of cells in the human body All have DNA, organelles and membranes Cells are very different in size, shape and activity- and how they are arranged in tissues Do cells mimic organ systems, or do organ systems mimic cells? 4/11/2017 Fatchiyah, Ph.D. JB UB

Bacterial cell Plant cells Animal cells 4/11/2017 Fatchiyah, Ph.D. JB UB

Observe the “composite cell” (no cell looks like this) Cells are capable of: reproducing themselves synthesizing the organelles they need metabolism eliminating waste materials regulating movement of materials into and out of themselves 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

What is so special about the cell membrane? Cell is in an aqueous environment phospholipid membrane provides a “selectively permeable” barrier Water and carbon dioxide move easily Water-soluble molecules do not How DO these molecules get through the membrane? 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

Membrane-bound proteins Transport proteins or channels for water- soluble molecules “Signal transduction”- cell receives a signal and responds to it Adhesion molecules Each type of protein has a specific function 4/11/2017 Fatchiyah, Ph.D. JB UB

Structure and function of organelles Protein synthesis Endoplasmic reticulum Rough- site of protein synthesis and processing Smooth- lipid metabolism and detoxification Ribosomes- site of the initial steps of protein synthesis Golgi apparatus- the “UPS” of the cell 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

mitochondria- where most ATP is made II. Metabolism mitochondria- where most ATP is made mitochondria have their own DNA and ribosomes some cells have more than others III. The by-products of metabolism lysosomes contain enzymes that break down large molecules, recycle old organelles peroxisomes- specialized for detoxification in liver and kidney cells 4/11/2017 Fatchiyah, Ph.D. JB UB

IV. Cytoskeleton- support and movement of the cell Microfilaments- (actin, myosin) involved in cell division, cell movement arrangement is significant in muscle cells Microtubules (tubulin) found in centrioles, flagella, cilia 4/11/2017 Fatchiyah, Ph.D. JB UB

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4/11/2017 Fatchiyah, Ph.D. JB UB

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The nucleus and its contents Contains chromatin (material that makes up chromosomes) Nucleoli- ribosome synthesis Specialized nuclear membrane: double membrane with nuclear pores 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

Features of the cell membrane Semi-permeable remember: membrane is phospholipid bilayer, with embedded and peripheral proteins Movement of materials across membrane is regulated: size of molecule solubility in water or lipid concentration gradient 4/11/2017 Fatchiyah, Ph.D. JB UB

What is a concentration gradient? Molecules move spontaneously, from areas where they are highly concentrated to where they are less concentrated Equilibrium: molecules are uniformly distributed Molecules tend to seek equilibrium, i.e., diffuse 4/11/2017 Fatchiyah, Ph.D. JB UB

Diffusion across a cell membrane occurs if: There is a concentration gradient (more of the substance on one side of the membrane than the other) The membrane is permeable to the substance No energy is required for diffusion Examples: oxygen and carbon dioxide why can they diffuse through the membrane? 4/11/2017 Fatchiyah, Ph.D. JB UB

Facilitated diffusion The membrane is not permeable to all molecules Ion channels Specialized pores Carrier molecules 4/11/2017 Fatchiyah, Ph.D. JB UB

Osmosis- diffusion of water Water will move through membrane when solutes cannot So cell might take on water, or lose water, if it is in a solution that is not isotonic Water will move down the concentration gradient Processes allow for filtration of body fluids 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

Diffusion and osmosis do not require energy Active transport: substances are moved from area of low concentration to high Examples: sugars, amino acids, various ions ATP is required release of energy change in shape of transport protein Endocytosis, exocytosis 4/11/2017 Fatchiyah, Ph.D. JB UB

The cell cycle 4/11/2017 Fatchiyah, Ph.D. JB UB

Cell cycle is carefully controlled Cells can divide a limited number of times (Hayflick limit) Proto-oncogenes Tumor suppressors: genes that control the cell cycle If these genes are damaged cancer (tumors) may result Cell death (apoptosis) is also regulated 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

We all started out as one cell! How do we develop so many different kinds of cells? How does cell differentiation occur? hormones, growth factors, etc. What are stem cells? 4/11/2017 Fatchiyah, Ph.D. JB UB

4/11/2017 Fatchiyah, Ph.D. JB UB

All living things are composed of one or more cells Summary All living things are composed of one or more cells Eukaryotic cells contain organelles that have specialized functions Membranes (and physical laws) regulate the movement of materials into and out of Grwoth and differentiation of cells is carefully regulated 4/11/2017 Fatchiyah, Ph.D. JB UB