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Dive into the world of cells and membranes with fascinating insights on cell theory, membrane structure, transport mechanisms, and real-life medical scenarios. Uncover the fundamental principles of biology at a microscopic level.
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I. The Cell Theory • In 1655 Robert Hooke observed “compartments” in a thin slice of cork which he named cells • In 1700 Anton van Leeuwenhoek had developed light microscopes to observe tiny living organisms which he named “animalcules”
The Cell Theory C. Cell theory is the generalization that all living things are composed of cells, and that cells are the basic unit of structure and function in living things
II. Microscopes as Windows to Cells • Light microscopes can magnify objects up to about 1,000 X • Electron microscopes can magnify objects up to about 1,000,000 X C. A photograph of the view taken through a microscope is called a micrograph
Microscopes SEM- scanning electron microscope TEM- transmission Both must use preserved specimens.
III. An Overview of Animal and Plant Cells • Each part of a cell with a specific job to do is called an organelle B. The plasma membrane defines the boundary of the cell and regulates traffic in and out of the cell
Overview of animal and plant • The nucleus stores the genetic material of the cell D. The region of the cell between the nucleus and the plasma membrane is called the cytoplasm
IV. Two Major Classes of Cells • A prokaryotic cell lacks a nucleus and most other organelles B. A eukaryotic cell has a membrane bound nucleus and organelles
I. Membrane Structure • Membranes regulate the transport of substances across it • Membranes are composed mostly of proteins and phospholipids
Membrane structure • The phospholipids form a two-layer sandwich called a “phospholipid bilayer” which surrounds the organelle or cell D. The membranes are fluid-like rather than sheets of molecules locked rigidly into place
II. The Many Functions of Membrane Proteins • Many types of proteins are embedded in the membranes phospholipid bilayer B. Some proteins carry out some of the cells important chemical reactions, others helps cell communicate and recognize each other, other proteins move substances like sugar and water across the membrane
Dye Demo • How will the dye mix with the water (if it mixes at all)? • How long will it take?
I. Diffusion • Diffusion is the net movement of the particles of a substance from where they are more concentrated to where they are less concentrated B. Equilibrium is reached when the movement of particles in one direction is equal to the number of particles moving in the other
II. Passive Transport • A selectively permeable membrane allows some substances to cross the membrane more easily than others and blocks the passage of some substances altogether
Passive transport • Diffusion across a membrane is called passive transport because no energy is expended by the cell, only the random motion of molecules is required to move them across C. Facilitated diffusion is when transport proteins provide a pathway for certain molecules to pass
Passive transport CO2 & O2- nonpolar molecules H2O & C6H12O6- polar molecules
III. Osmosis • The passive transport of water across a selectively permeable membrane is called osmosis • A solution with a higher concentration of solute is called hypertonic hyper = “above” C. A solution with a lower concentration of solute is called hypotonic hypo = “below”
III. Osmosis D. A solution that has an equal concentration of solute is called isotonic iso = “equal” • When an animal cell is placed in a hypotonic solution it swells • - When an animal cell is placed in a hypertonic solution it shrinks
IV. Active Transport • When a cell expends energy to move molecules or ions across a membrane it is called active transport B. A specific transport protein pumps a solute across a membrane, usually in the opposite direction it travels in diffusion
Active Transport Sodium / potassium pump
V. Transport of Large Molecules • Large molecules have to be packed into vesicles, which are small membrane sacs that specialize in moving products into, out of and within a cell
Transport of large molecules • When a cell exports its protein products, a vesicle fuses with the plasma membrane and spills its contents outside the cell-a process called exocytosis • The reverse process, endocytosis, takes materials into the cell within vesicles that bud inward from the plasma membrane
Mrs. Potts - Day 1 • The Mrs. Potts, a 62-year-old female is admitted to the hospital with increased fatigue, lethargy, and occasional confusion from chronic uremia secondary to End Stage Renal Disease (ESRD). The client has a long history of diabetes mellitus resulting in permanent damage to the kidneys. Diagnostic test ordered include: Renal scan and ultrasound, bloodwork, a urine test, and fingerstick blood sugars
Mrs. Potts - Day 3 The client's renal status has continued to deteriorate. Creatinine clearance is 6 ml per minutes and the client is showing evidence of retaining fluid despite conservative measure to restrict fluid. Blood Pressure is 160/96 (Normal is 120/80), weight has increased by 5 lbs. Since admission, swelling is noted in ankles and feet, fine crackles are present bilaterally heard in bases of lungs. The doctor has prepared the client for the possibility of hemodialysis.
Mrs. Potts - Discharge The client had an internal arteriovenous fistula surgically created two days ago. She will receive hemodialysis through a temporary access catheter in her right subclavian until the fistula is ready for use. The nurse schedules the client for dialysis at the outpatient dialysis center three times per week. The dietitian has met with the client and instructed her on fluid, sodium, and potassium restriction and a low protein, 2000 calorie diabetic diet. Mrs. Potts lives alone on a fixed income. She expresses concern regarding her ability to get to the dialysis center three times per week and her financial ability to afford the dialysis.
Mrs. Potts - Question Mrs. Potts may not do well on dialysis, then a renal transplant may be the only other option. Considering the scarcity of donor organs, she will be placed on a waiting list with many others. Recently, there has been public debate about donor organs being given to someone who may have damaged their organs through drug abuse or chronic alcoholism. How do you feel about this matter? What are some of the issues that must be considered in such a debate
Organ Recipients -16 yr old athlete - football scholarship -24 yr old pregnant female -30 yr old HIV positive mother of 3 -70 yr old grandmother of 20 grandkids -32 yr old lawyer for the supreme court -40 yr old alcoholic who is in rehab -49 yr old religious leader -36 yr old successful actor/rap artist
Organ Recipients -16 yr old athlete – from GlenOak HS got killed in a DUI accident -24 yr old pregnant female- prostitute and murderer -30 yr old HIV positive mother of 3 – Doctor working on the cure for HIV -70 yr old grandmother of 20 grandkids- your grandma -32 yr old lawyer for the supreme court- argued Brown v. Board of Ed -40 yr old alcoholic who is in rehab- Dr. Bob founder of AA -49 yr old religious leader- Martin Luther King Jr. or Billy Graham -36 yr old successful actor/rap artist- Drake