1 / 35

Cells

Cells. Honors Human Anatomy and Physiology Coach Denson. Introduction to Cell. Cells are the structural and physiological unit of all living organisms . A cell’s function is determined by its anatomy. Nerve cells are very long Epithelial cells in the mouth are flat like floor tiles.

silver
Download Presentation

Cells

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cells Honors Human Anatomy and Physiology Coach Denson

  2. Introduction to Cell • Cells are the structural and physiological unit of all living organisms. • A cell’s function is determined by its anatomy. • Nerve cells are very long • Epithelial cells in the mouth are flat like floor tiles. • Muscle cells are made of telescoping fibers that can contract. • Although cells vary greatly, they have some things in common. All the various parts make a composite cell.

  3. Composite Cell • Three main parts in a eukaryotic cell. • Cell Membrane • Functions: • Boundary of the cell • Controls entrance and exit to cell • Site of many metabolic reactions • Signal transduction • Characteristics • Extremely thin (only 2 molecules thick) • Flexible • Somewhat elastic • Selectively permeable

  4. Composite Cell • Structure • Double layer of phospholipids • Water soluble substances can’t pass • Lipid soluble substances pass • Embedded proteins • Receptor proteins extend into and out of the cell • Integral proteins form pores and channels. • Peripheral proteins function as enzymes. • Glycoproteins function in recognition and binding.

  5. Composite Cell • Intercellular Junctions • Tight junctions fuse adjacent cell membranes. • Desmosomes join cells in “spot welds” • Gap Junctions connect with tiny tubes that allow movement of materials. 2. Cytoplasm • Functions: • Support Organelles • Medium for diffusion • Provide dissolved materials for metabolism. • Structure-Cytosol(fluid) and cytoskeleton(protein rod and tubule support) • Organelles

  6. Composite Cell: Organelles: • Endoplasmic Reticulum (ER)-Zig-zag appearance in cell • Rough and Smooth (As as “Flow Control” • Structure- • complex membrane tubes, canals, sacs; connect cell membrane and nucleus (Membrane Structure) • Function- • Intracellular transport; provide surfaces for protein synthesis and other metabolic reactions. • Ribosomes • Structure- • Protein (2) and RNA (2) • Function- • Protein synthesis

  7. Composite Cell: Organelles: • Golgi Apparatus • Structure- • Stack of flattened membranous sacs (cisternae) • Function- • Modify, package, deliver proteins produced by ribosomes on rough ER for cellular export • Mitochondria (~1700/Cell) • Structure- • Double membrane; inner membrane consists of folds(cristae); non-chromosomal DNA; motile(moves on it’s own) • Function- • Assist in releasing energy from glucose in the form of ATP(cellular respiration)

  8. Composite Cell: Organelles: • Lysosomes • Structure- • Tiny, membranous sacs containing digestive enzymes; much variety of shape. • Function- • Dismantle debris; destroy worn cell parts; break down engulfed material. • Peroxisomes (special type of lysosomes) • Structure- • Tiny membranous sacs containing enzymes • (Peroxidase, Catalase) specific to the function. • Can break down hydrogen peroxide • Function- • Regulate metabolic reactions that produce dangerous by-products and then break down those by-products

  9. Composite Cell: Organelles: • Centrosomes-made up of 2 centrioles-90 degrees to each other • Structure- • Nonmembranous; 2 cylinders (centrioles) of a protein microtubules at right angles; near the nucleus • Function- • During cell division centrioles migrate to opposite poles, form spindle fibers attached to chromosomes and assist in proper disjunction. • Cilia and Flagella • Structure- • Found on the free surfaces of some cells; distinct cylindrical patter of microtubules, attached to modified centrioles called basal bodies. • Function- • Produce undulating motions for moving the cell or moving material past the cell.

  10. Composite Cell: Organelles: • Vesicles • Structure- • Membranous sacs that vary in size and contents (i.e. lysosomes, peroxisomes, etc.)……enzymes. • Function- • Storage; movement of particles and materials • Microfilaments • Structure- • Mesh or bundle of actin rods-made up of actin (also in muscles) • Function- • Causes various kinds of internal movement in cells

  11. Composite Cell: Organelles: • Microtubules-bigger than microfilaments, made up of tubulin • Structure- • Long, rigid tubes of tubulin • Function- • Provides cytoskeletal framework • Inclusions- not necessary for the cell to stay alive • Structure- • bundle of chemicals that do not directly assist in the function/survival of the cell • Function- • Temporary storage of chemicals (melanin, lipids, etc)

  12. Composite Cell 3. Nucleus • Functions- • Direct the activities of the cell • Safeguard DNA • Structure • Relatively large, spherical • Nuclear envelope (phospholipid membrane) • Double Bilayer • Nuclear Pores-used for nucleotides to enter the nucleus • Nucleoulus • Nonmembranous • Site of ribosome production (RNA part)-where ribosomal RNA is made.

  13. Composite Cell • Nucleus continued…. • Chromatin • Loosely coiled DNA • Protein histones act as spools for chromatin

  14. Movement into and out of the cell • Diffusion • Osmosis • Filtration • Active Transport • Endocytosis/Exocytosis

  15. Diffusion • Movement from greater concentration to lesser concentration. • Simple diffusion requires NO ENERGY • Facilitated diffusion uses a carrier molecule to assist materials across the membrane.

  16. Osmosis • Movement of water from relative greater concentration of water to relative lesser concentration of water. (Selectively Permeable) • Isotonic solution- • Water concentration is equal on both sides of cell membrane. Net movement=0 • Hypertonic solution- • Water is relatively less concentrated in the solution. Water moves across the membrane out of the cell toward the hypertonic solution. • Hypotonic solution- • Water is relatively more concentrated in the solution. • Water moves across the membrane into the cell away from the hypotonic solution.

  17. Filtration • Movement of materials across a membrane due to some force. • Blood pressure-causes blood to be filtered. • Hydrostatic pressure

  18. Active Transport • Opposite of diffusion • Movement of materials from lower concentration to higher concentration • Requires Energy (ATP) • Pump Mechanisms

  19. Endocytosis/Exocytosis • Movement of particles across a membrane, but particles are encapsulated within a membrane vesicle. • Pinocytosis- • Movement of water (“pino”-drink) • Membrane eventually breaks down inside cell and releases water. • Phagocytosis • Movement of food particles (“phago”-eat) • Lysosomes attach and break down material • Receptor mediated Endocytosis • Protein molecules “receive” specific materials and vesicles are formed around them.

  20. Cell Cycle • Stages that a cell goes through from the time it forms until it divides. • Interphase- cell carries out its normal activity; DNA replicates • Mitosis-genetic material divides (Nuclear Division) • Cytokinesis- the rest of the cell divides • Mitosis: • Prophase • Metaphase • Anaphase • Telophase

  21. Mitosis • Cell division/ Nuclear division • Dividing chromosomes

  22. Mitosis: Prophase • Chromatin (indistinguishable strands) condenses into chromosomes (visible bodies) • Nuclear membrane disintegrates • Centrioles begin to migrate to opposite poles

  23. Mitosis: Metaphase • Chromosomes line up on equator between centrioles • Spindle fibers form and attach to chromosome centromeres and centrioles.

  24. Mitosis: Anaphase • Chromosomes are pulled apart to opposite sides. • Centrioles “reel” in chromosomes to opposite poles.

  25. Mitosis: Telophase • Chromosomes begin to unravel into chromatin • Spindle fibers detach and disintegrate • Nuclear membrane reforms around new nuclei

  26. For Mitosis Know… • What’s going on in: • The nuclear membrane • Centrioles • Chromosomes

  27. Cytoplasmic Division • Cytokinesis • Cytoplasm divides • Begins during anaphase; ends when two “new” daughter cells are formed.

  28. Cellular Differentiation • Process of cells taking on special anatomy and physiology • All cells go through this • Stem cells have not differentiated yet.

  29. Control of Cell Division • Loss of telomeres on the ends of chromosomes triggers cell division to stop. • Cell size- • cells reach a certain size and divides • Presence of kinases and cyclins • Hormones • Local Growth Factor • Space availability

More Related