The Cell (Slideshow)

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The Cell (Slideshow)

  1. 1. CELL ANATOMY
  2. 2. THE CELL THREE MAIN REGIONS OF A GENERALIZED CELL 1. THE NUCLEUS > the control center (gene-containing)‏ > has DNA - contains all instructions needed to build the whole body > has the instruction for building proteins necessary for cell reproduction 2. PLASMA MEMBRANE > fragile, transparent barrier that contains the cell contents bilipid layer contains phospholipids* and cholesterol** *impermeable to most water-soluble molecules **has a stabilizing effect and helps keep the membrane fluid 3. CYTOPLASM > cellular material outside the nucleus and inside the plasma membrane “ factory area”- site of most cellular activities
  3. 4. The Nucleus <ul><li>3 Distinct Structures: </li></ul><ul><li>NUCLEAR MEMBRANE / NUCLEAR ENVELOPE </li></ul><ul><li>> double membrane (fluid-filled space) with nuclear pores </li></ul><ul><li>> selectively permeable </li></ul><ul><li>> nucleoplasm- nucleoli and chromatins are suspended </li></ul><ul><ul><ul><li>NUCLEOLI </li></ul></ul></ul><ul><li>> site where ribosomes are assembled </li></ul><ul><ul><ul><li>CHROMATIN </li></ul></ul></ul><ul><li>> loose network of bumpy threads </li></ul><ul><li>> when cell is not dividing, it will coil and condense and form dense, rod like bodies called chromosomes </li></ul>
  4. 7. The Plasma Membrane bilipid layer contains phospholipids* and cholesterol** *impermeable to most water-soluble molecules **has a stabilizing effect and helps keep the membrane fluid CHONS are scattered in the bilipid layer > some proteins are enzymes > receptors sites for hormones or other chemical messengers > some have transport functions ( those that span the membrane) glycoproteins are attached to proteins whose functions are: > determine blood type > acts as receptors that certain bacteria and viruses can bind to > play a role in cell to cell interaction
  5. 10. The Cytoplasm 3 Major Elements: CYTOSOL > semi-transparent fluid INCLUSIONS > non-functioning units > chemical substances that may or may not be present depending on the cell type > mostly are stored nutrients or cell products e.g., melanin, mucus, fat droplets ORGANELLES / CYTOPLASMIC ORGANELLES > metabolic machinery of the cell
  6. 12. The Cytoplasmic Organelles 1. RIBOSOMES > tiny, round, dark bodies made of proteins > Acts to protein synthesis
  7. 16. The Cytoplasmic Organelles 2. ENDOPLASMIC RETICULUM > minicirculatory system A. RER (Rough Endoplasmic Reticulum)‏ > s tudded with ribosomes; cell’s membrane factory > proteins made inside its tubules are dispatched to other cell areas > the amount of RER a cell has is a good clue to the amount of CHON that cell makes B. Smooth Endoplasmic Reticulum > no role in CHON synthesis a. cholesterol synthesis and breakdown b. fat metabolism c. detoxification of drugs
  8. 19. The Cytoplasmic Organelles 3. GOLGI APPARATUS > a stack of membranous stack of flattened membranous sacs, associated with swarms of tiny vesicles > found close to the nucleus > “traffic director” for cellular proteins > major function: modify and package proteins
  9. 22. The Cytoplasmic Organelles 4. LYSOSOMES “ demolition sites”- contain powerful digestive enzymes capable of digesting worn-out or non-usable cell structures and most foreign substances that enter the cell > abundant in WBC
  10. 26. The Cytoplasmic Organelles 5. PEROXISOMES > membranous sacs containing powerful oxidase enzymes that use molecular oxygen to detoxify a number of harmful or poisonous substances. E.g., alcohol, formaldehyde > important function: disarm dangerous free radicals how? Peroxisomes + free radicals = hydrogen peroxide + catalase = water > numerous in liver and kidneys > they replicate by dividing in half
  11. 27. The Cytoplasmic Organelles 6. MITOCHONDRIA > “ sausage-shaped” organelles > walls are composed of a double membrane outer membrane- smooth inner membrane- has cristae > “power house of the cell”- produce energy to form ATP molecules ATP provides energy for all cellular work
  12. 30. The Cytoplasmic Organelles 7. CYTOSKELETON > network of protein structures scattered throughout the cytoplasm > cell’s bones and muscles a. microtubules b. microfilaments c. intermediate filaments
  13. 33. The Cytoplasmic Organelles 8. CENTRIOLES > come in pairs that lie near the nucleus > rod shaped bodies that lie at right angles to each other > during cell division, centrioles direct the formation of mitotic spindle
  14. 37. CELL PHYSIOLOGY
  15. 38. MEMBRANE TRANSPORT SOLUTION > homogenous mixture of two or more components SOLVENT > substance present in largest amount in a solution > dissolving medium SOLUTES > substances present in smaller amounts
  16. 39. MEMBRANE TRANSPORT INTRACELLULAR FLUID > collectively the nucleoplasm and cytosol > solution containing small amounts of gases( Oxygen and Carbon Dioxide) nutrients and salts, dissolved in water > fluids found inside the cell INTERSTITIAL FLUID > fluid that continuously bathes the exterior of the cell >contains nutrients (amino acids, sugars, fatty acids, vitamins), regulatory substances such as hormones and neurotransmitters, salts and waste products
  17. 40. MEMBRANE TRANSPORT SELECTIVE PERMEABILITY > a barrier that allows some substances to pass through it while excluding others > allows nutrients to enter the cell but keeps many undersirable substances out > valuable cell proteins and other substances are kept within the cell, and wastes are allowed to pass out of it
  18. 41. MEMBRANE TRANSPORT PASSIVE TRANSPORT PROCESSES > substances are transported across the membrane without any energy input from the cell ACTIVE TRANSPORT PROCESSES > cell provides a metabolic energy (ATP) that drives the transport process
  19. 42. TRANSPORT PROCESSES 1. PASSIVE TRANSPORT PROCESS A. Diffusion B. Filtration 2. ACTIVE TRANSPORT PROCESS A. Solute Pumping B. Bulk Transport
  20. 43. PASSIVE TRANSPORT PROCESS 1. DIFFUSION > process by which molecules tend to scatter themselves throughout the available space > molecules move down their concentration gradient > speed of diffusion is affected by the size of the molecules and temperature > plasma membrane is a physical barrier to diffusion > molecules will move passively through the plasma membrane by diffusion if: they are small enough to pass through the pores they can dissolve in the fatty portion of the membrane
  21. 44. PASSIVE TRANSPORT PROCESS DIFFUSION Simple Diffusion > unassisted diffusion through the plasma membrane > solutes transported this way are either lipid soluble or small enough to pass through the pores Facilitated Diffusion > provide a means for certain substances (glucose) that are both lipid insoluble and too large to pass through the membrane pores > a protein carrier is needed as a transport vehicle > some of the proteins in the plasma act as carriers to move glucose passively across the membrane and make it available for cell use
  22. 45. PASSIVE TRANSPORT PROCESS 2. FILTRATION > process by which water and solutes are forced through a membrane by a fluid or hydrostatic pressure > pressure gradient pushes solute containing fluid from a high pressure area to the lower pressure area
  23. 46. ACTIVE TRANSPORT PROCESS 2. FILTRATION > process by which water and solutes are forced through a membrane by a fluid or hydrostatic pressure > pressure gradient pushes solute containing fluid from a high pressure area to the lower pressure area

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