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Plasma Membrane
- * Barrier to cell contents
- * Double layered
- * Embedded with proteins, Cholesterol, and Glycoproteins
- * Flexible and elastic
- * Selective permeability
- * Small molecules such as oxygen and carbon dioxide can pass freely [some move through lipids]
- * Water soluble molecules such as amino acids, sugars, and ions can not pass [some move through protein]
- * Proteins embedded within the membrane functions as channels to allow water soluble molecule to pass through
- * Proteins act as hormone receptors
- * Glycoproteins act as cell markers
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Phospholipid Bilayer
- * Polar Head
- o Hydrophilic
- * Soluble in water
- * Non-polar Head
- o Hyrophobic
- * Insoluble in water
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Golgi Apparatus
- * Composed of flattend membranous sac
- * Modifies, packages and ships proteins
- * Proteins are shipped in vesicles to various location in the cell
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Smooth Endoplasmic Reticulum
- * Lacks Ribosomes
- * Contains enzymes important for lipid synthesis
- * Important in metabolism of drugs and alcohol
- [allows cells to make lipids]
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Rough Endoplasmic Reticulum
- * Membrane-bounded flatten sacs
- * Fluid filled vesicles
- * Functions in protein synthesis
- * Attached to nucleus
- * Studded with ribosomes [appears rough]
- * Ribosomes may exist freely in the cytoplasm to synthesis protein
- * Ribosomes are made of RNA and protein
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Cytoplasm
- * The inside of the cell
- * Contains network of organelles suspended in clear liquid called Cytosol
- * This is where nutrients are received and processed
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Mitochondria
- * Elongated fluid filled sacs
- * Double membrane
- * Extensive folding of inner membrane
- * Produce energy molecule (ATP)
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Cytoskeleton
- * Thin strands in the cytoplasm called microfilaments
- * Microfilaments
- o Tiny rods of actin proteins
- o Provide cell motility
- o Abundant in muscle cells
- * Microtubules
- o Long slender tubes with big diameter
- o Strength and movement of material within the cell
- [i.e. a structure of a house]
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Cells
- * 75 trillion cells that make the human body
- * ~200 different cells
- * Vary greatly in size and shape
- * All cells exhibit various structures known as organelles, that allow them to function and survive
- * Cells must carry chemical reactions to survive
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Additional organelles
- Lysosomes
- o Tiny membrane sac
- o Contains enzyames to breakdown nutrient or foreign particles
- o Garbage disposal cell
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Additional organelles
- Peroxisomes
- o Membranous sac are abundant in liver and kidney cells
- o Contains enzynes to speed uo chemical reaction
- o Detoxification of alcohol
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Additional organelles
- Centrosome
- o Consists of two hollow cylinders called centroles
- o Important function in cell division
- [helps mitosis]
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Nucleus
- * Houses the genetic material (DNA)
- * Double layer Nuclear Membrane
- * Membrane contains nuclear pores
- * Nucleoplasm the inside of the nucleus contains
- o A nucleolus where ribosomes are synthesized
- o Chromatin which is made of DNA and proteins
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Cilia & Flagella
- * Made of microtubles
- * Cilia (hair like structure)
- o Move fluid on surface of cells
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Flagella
- o Allows cells to move
- [sperm cells]
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How can cells survive?
- * Water: most abundant chemical in the body
- * Food used as energy source
- * Oxygen to drive metabolic process
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Membrane Transport
- * Is the movement of substances in and out of the cell
- * There are two basic methods
- o Passive transport that does not require energy
- o Active transports that required the use of energy
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Passive transport
- Simple diffusion
- Through the lipid
- Facilitated diffusion
- Through the Protein
- Osmsis
- Diffusion of water
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Chemical terminology
- Water
- Solvent
- Sugar
- Solute
- Water + sugar = solution
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Solutions and cells
- * cytosol is known as intercellular fluid
- * Interstital fluid is known as Extracellular fluid
- * Molecules or ions move from a region of high concentration to low concentration
- * The difference in concentration is known as concentration gradient
- [passive transport]
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What would happen if you place a cell in a solution?
- * Hypertonic More solute (H2O moves out; shrink)
- * Hypotonic Less solute (H2O moves in; Blow up)
- * Isotonic Equal solute inside and outside (nothing)
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It depends on the solution
- * Hypertonic solution
- o Higher solute (low water) compaired to the intercellular fluid
- * Hydrotonic solution
- o Lower solute (high water) compared to the intercellular fluid
- * Isotonic solution
- o Same amount of solute compared to the intercellular fluid
- * The movement of water from high concentration to low concentration
- * Solution A has a higher solute concentration which means low water concentration
- * Solution B has less solute and therefore more water concentration
- * How would water move?
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Facilitated diffusion
- * Molecules tend to move from high concentration to low concentration
- * However, molecules can not pass through the membrane
- * Molecules pass through protein channels embedded within the membrane
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Diffusion through a cell membrane
- * Oxygen molecules move from a high concentration to a low concentration
- * Carbon dioxide molecules move high to low to low concentration
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Endocytosis & Exocytosis
- * Large molecules that cannot get to the cell by passive or active transport
- * Endocytosis:
- o Phagocytosis = cell eating
- o Pinocytosis = cell drinking
- * Exocytosis:
- o Moving large molecules out of the cell
- * [Bulk transport; bring in large particles]
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Active Transport
- * Movement of molecules from low concentration to high concentration
- * It required expenditure of energy
- [through Protein only]
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Filtration
* Filtration forces molecules to move through the membrane
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