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Chapter 3 The Cell Joe Pistack MS/ED

Chapter 3 The Cell Joe Pistack MS/ED. Cell-structural and functional unit of all living matter. Cells vary in size, shape, and function. Cells vary in structure. Structure and function are closely related. Typical Cell. Different shapes of cells. Cell membrane-encases the cell.

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Chapter 3 The Cell Joe Pistack MS/ED

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  1. Chapter 3The Cell Joe Pistack MS/ED

  2. Cell-structural and functional unit of all living matter. • Cells vary in size, shape, and function. • Cells vary in structure. • Structure and function are closely related. Typical Cell

  3. Different shapes of cells

  4. Cell membrane-encases the cell. • Separates the intracellular material from the extracellular material. • Physically holds the cell together. • Chief function- selection of substances allowed to enter and leave the cell. Cell Membrane

  5. Semipermeable-ability of the cell membrane to choose substances allowed to cross it. • Cell membrane is composed of phospholipids and protein. • Phospholipids are arranged in two layers. Cell Membrane

  6. Functions of the protein molecules in the membrane: • Provide structural support for the membrane. • Binding sites for hormones. • Pokes holes or pores through the lipid membrane. These pores form channels through which water and dissolved substances can flow.

  7. Typical Cell

  8. The inside of the cell is divided into two compartments: 1. the nucleus 2. cytoplasm • Nucleus-control center of the cell, controls the workings of the entire cell. • Nucleus contains genetic information and controls all protein synthesis. Inside the Cell

  9. Nuclear Membrane-double layered membrane that surrounds the nucleus. • Nucleoplasm-substance that fills the nucleus. • Cytoplasm-gel-like substance found inside the cell but outside the nucleus • Composed primarily of water, electrolytes, and nutrients. Inside the Cell

  10. The cytoplasm contains: • Organelles-small organs with a specific role. • Inclusion bodies-temporary structures that appear and disappear. Inside the Cell

  11. Mitochondria-power plant of the cell. • Tiny slipper-shaped organelles. • Number of mitochondria per cell depends on the metabolic activity of the cell. (How hard the cell works) eg. Liver, bone Cytoplasmic Organelles

  12. Mitochondrial membrane: • Consists of 2 layers. • Smooth outer layer • Inner layer contains many folds or cristae. • Enzymes associated with ATP are located along the cristae. • Called the “power plant” of the cell because of production of ATP. Cytoplasmic Organelles

  13. Mitochondria

  14. Cytoplasmic Organelles: • Ribosomes-concerned with protein synthesis. • Endoplasmic Riticulum-network of membranes within the cytoplasm, membranes form channels through which substances move. Inside the Cell

  15. Endoplasmic Riticulum(ER): • 2 types: - Rough endoplasmic riticulum-(RER) - sandpaper-like appearance - concerned with protein synthesis -Smooth endoplasmic riticulum-(SER) -concerned with the synthesis of lipids and steroids Inside the Cell

  16. Golgi apparatus-series of flatted membraneous sacs. • Proteins synthesized along the RER are transported to the Golgi through channels formed by the ER. • The Golgi apparatus packages the protein for synthesis. Inside the Cell

  17. Lysosomes-membranous sacs containing powerful enzymes. • Lysosomes are digestive organelles. • Lysosomal enzymes break down intracellular waste and debris. “clean house” Inside the Cell

  18. Cytoskeleton-composed of threadlike structures called microfilaments and microtubules. • Cytoskeleton helps to maintain the shape of the cell and assists the cell in cellular movement. • Centrioles-paired, rod-shaped microtubular structures, play a key role in cellular reproduction. Inside the Cell

  19. Cilia-short, hairlike projections on the outer surface of the cell. • Cilia use wavelike motions to move substances across the surface of the cell. • Eg. Resp. tract-cilia help to move mucous and dust toward the throat, away from the lungs. On the Cell Membrane

  20. Flagella-(meaning whip) • Whip-like projections, longer, thicker and fewer in number than cilia. • Help to move the cell. • Eg. The tail of the sperm enables the sperm to swim. On the Cell Membrane

  21. Passive and Active Transport: • Both are transport mechanisms that assist in the movement of water and dissolved substances across the cell membrane. • Passive transport-requires no additional energy in the form of ATP. Movement Across the Cell Membrane

  22. Passive transport-water and dissolved substances move without additional energy. • Passive Transport Mechanisms: • Diffusion • Facilitated diffusion • Osmosis • Filtration Movement across the Cell Membrane

  23. Diffusion-most common transport mechanism. • Movement of a substance from an area of higher concentration to an area of lower concentration. • Equilibrium-point at which no further net diffusion occurs. Passive Transport Mechanisms

  24. Facilitated diffusion-form of diffusion responsible for the transport of many substances. • Substances move from an area of higher concentration to an area of lower concentration but requires a helper molecule. Transport Mechanisms

  25. Osmosis-diffusion of water through a selectively permeably membrane. • Semipermeable or selectively permeable membrane allows the passage of some substances while restricting the passage of others. • The strength of the osmotic pull is directly related to the concentration of the solution. The greater the concentration, the greater the pulling or osmotic pressure. Transport Mechanisms

  26. Edema-accumulation of water in the tissue spaces. • Osmotic pressure pulls water into a compartment causing swelling. • Tonicity-ability of a solution to affect the volume and pressure within a cell. Transport Mechanisms

  27. Isotonic Solution-”iso=same”. • Same concentration as intracellular fluid. Movement Across a Cell Membrane

  28. Hypotonic Solution-solution containing no solute. Movement Across a Cell Membrane

  29. Hypertonic Solution-very concentrated solution, causes cells to shrink or crenate. Movement Across the Cell Membrane

  30. Isotonic Solutions do not cause the cells to swell or shrink. • Most IV solutions are isotonic. • Commonly used isotonic solutions: • Normal saline (0.9% NaCl) • 5% D/W (dextrose or glucose in water) • Ringers lactate Isotonic Solutions

  31. Filtration-water and dissolved substances cross the membrane in response to differences in pressure. (Pressure pushes the substance across the membrane.) Filtration

  32. Active transport-transport mechanism requires an input of energy ATP to achieve its goal. • Endocytosis-intake of food or liquid by the cell membrane. • Particle is too large to move across the cell membrane by diffusion. Active Transport Mechanisms

  33. Endocytosos: • Particle surrounds the cell membrane, engulfs it and takes it into the cell. • 2 types: • Phagocytosis-the cell eating solid particles. • Pinocytosis-ingestion of water droplets, cellular drinking. Active Transport Pumps

  34. Exocytosis-moving of substances out of the cells. Active Transport Mechanisms

  35. Cell division-necessary for growth and repair. • Some cells reproduce frequently, whereas others do not reproduce at all. • Most cells grow in an orderly manner, cells that grow abnormally may be tumors which may be benign or malignant. . Cell Division

  36. Rate of cell division depends on type of tissue: • Some cells don’t divide but are replaced at incredible rates: • Cells of digestive tract replace every few days • Red blood cells-2 million per second • Nerve cells-not at all • Two types of cell division-Mitosis and Meiosis • Mitosis Mitosis is involved with bodily growth and repair Mother cell splits into two identical “Daughter Cells” • Meiosis • Special type of cell division only found in sex cells Cell Division

  37. Cell Cycle has two major parts • Interphase • Cell carries on normal functions • Prepares for mitosis through growth and DNA replication • Mitosis • The splitting of a cell into two cells with exactly the same genetic information • Divided into four phases • Prophase • Metaphase • Anaphase • Telophase Cell Cycle

  38. Prophase • Chromosomes coil tightly and are composed of two identical strands of DNA • Metaphase • DNA align in a narrow central zone • Anaphase • DNA split into pairs and move to opposite ends of the cell • Telophase • Cell wall pinches together forming the daughter cells and both cells enter interphase Mitosis

  39. Stem cells are cells that have not differentiated • Cells differentiate due to the addition of different enzymes • Sometimes cells reproduce in an uncontrolled and disorganized way and form tumors - there are two types: • Benign-noncancerous • Malignant-cancerous • Metastasis is when cancer cells spread. • A widespread invasion of cancer can cause death Stem Cells

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