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26 Cards in this Set
- Front
- Back
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Modern Cell Theory
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-All organisms composed of cells and cell products
-Cell is the simpliest structural and functional unit of life -Organism's structure and functions are due to the activities of its cell -cells come only from prexisiting cells -cells of all species have many fundamental similarities |
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Plasma Membrane
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-pair of dark parallel lines around cell (viewed with the electron microscope)
-defines cell boundaries -Controls passage of materials in and out of cell -Oily film of lipids with diverse proteins embedded in it |
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Membrane Protein Functions
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Receptors
exzymes channel proteins (gates) cell-identity markers cell-adhesion molecules |
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Membrane Receptors
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-Cell communication via chemical signals (receptors bind these chemicals-hormones, neurotransmitters-receptor specificity)
-Receptor activation produces a second messenger (chemical) inside of the cell |
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Membrane Enzymes
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-Break down chemical messengers to stop their signaling effects
-Final stages of starch and protein digestion in small intestine -Produce second messengers (cAMP) |
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Membrane Channel Proteins
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-Transmembrane proteins with pores
---some constantly open ---gated-channels open and close in response to stimuli (ligand (chemically)-regulated gates, voltage-regulated gates, mechanically regulated gates-stretch and pressure) -Important in nerve signal and muscle contraction |
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Membrane Carriers or Pumps
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-Transmembrane proteins bind to solutes and transfer them across membrane
-Pumps=carriers that consumer ATP |
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Membrane Cell-Identity Markers
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-Glycoproeins form the glycocalyx (surface coating, acts as a cell's identity tag)
-Enables body to identify "self" from foreign invaders |
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Cross section of a Microvillus
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actin microfillaments are found in center of each microvilli
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Cilia-Hairlike
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Hairlike processes 7-10um long
--single, nonmotile cilium found on nearly every cell --sensory in inner ear, retina, and nasal cavity |
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Cilia-Motile Cilia
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-beat in waves
-power stokes followed by recovery strokes |
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Flagella
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-Whiplike structure with axoneme identical to cilium (much longer than cilium)
-Tail of the sperm=only functional flagellum |
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Membrane Transport-Plasma Membrane
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Plasma Membrane selectively permeable (controls what enters or leaves cell)
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Membrane Transport-Passive
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Passive Transport requires no ATP
-movement down concentration gradient -filtration and simple diffusion |
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Membrane Transport-Active
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Active Transport requires ATP
-movement against concentration gradient -carrier mediated (facilitated diffusion and active transport) -vesicular transport |
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Active Transport
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-Transport of solute across membrane up (against) its concentration gradient
-ATP energy required to change carrier EX-1. sodium-potassium pump 2. bring amino acids into cell 3. pump Ca+ out of cell |
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Sodium Potassium Pump
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-Needed becasue Na+ and K+ cpnstantly leak through membrane (half of daily calories utilized for pump)
-One ATP utilized to exchange three Na+ pushed out for two K+ brought into cell |
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Functions of Na+ and K+ Pump-Regulation
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Regulation of cell volume
-"fixed anions" attract cations causing osmosis -cell swelling stimulates the Na+-K+ pump to lower ion concentration, lower osolarity and cell swelling |
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Functions of Na+ and K+ Pump-Heat
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Heat Production (thyroid hormone increase # of pumps; heat a by-product
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Functions of Na+ and K+ Pump-Maintenance
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Maintenance of a membrane protential in all cells
-pump keeps inside negative, outside positive |
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Functions of Na+ and K+ Pump-Secondary Active Transport
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Secondary active transport (no ATP used)
-steep concentration gradient of Na+ and K+ maintained across the cell membrane -Carriers move Na+ with 2nd solute easily into cell |
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Cytoplasm-Organelles
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Organelles=specialized tasks
-Bordered by membrane ---nucleus, mitochondria, lysosome, perioxisome, endoplasmic reticulum, and Golgi complex -Not bordered by membrane ---ribosomes, centrosome, cantriole, basal bodies |
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Cytoplasm-Cytoskeleton
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Microfilaments and Microtubules
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Cytoplasm-Inclusions
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stored products
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Ribosomes
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-Granules of protein and RNA (found only in nucleoli, free in cytosol and on rough ER)
-Uses directions in messenger RNA to assemble amino acids into proteins specified by the genetic code (DNA) |
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Inclusions
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-No unit membrane
-Stored cellular products (glycogen granules, pigments and fat droplets) -Foreign bodies (dust particles, viruses and intracellular bacteria) |
