cell structure
Terms
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- plasma membrane
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1. Barrier
2. communicates with outside by environmental cues and other cells
3. selectivity
4. membrane potential to do work - cytoplasm
- everything between nucleus and plasma membrane. "cellular chowder"
- cytosol
- internal fluid of a cell. mostly water with salts and proteins
- organelles
-
1. tiny organs
2. specialized functions
3. membrane bound - nucleus
- "brains" of the cell. contains most of the cells DNA
- nuclear envelope
-
1. encloses nucleus
2. double lipid bilayer (inner & outer)
3. pores - chromosome
-
1. discrete units
2. variable # from species to species - chromatin
- composed of DNA and protein
- ribosomes
-
1. translate mRNA into polypeptides
2. outside of nucleus
3. 2 flavors for 2 "kinds" of proteins - free ribosomes
- cytosolic proteins
- bound ribosomes
- membrane associated, secreted, or organeller proteins
- endoplasmic reticulum
- extensive network of membrane-bound tubules and sacs. separates lumen from cytosol.
- smooth ER
-
1. metabolic processes
2. lots of surface area for enzymes - rough ER
-
1. modify proteins for those destined to be transported
2. polypeptides threaded in - endomembrane system
-
1. system of membranes
2. physically connected or related through transfer of membrane pieces - transport vesicle
- comes from ER to golgi apparatus
- glycoprotein
- peptides with carbohydrate mods
- golgi apparatus
- receiving, modifying, shipping apparatus
- cis to trans
- front to back
- cisternal maturation model
-
1. dynamic structure
2. cisternae move cis-trans
3. carry and modify cargo - lysosomes
-
1. cell's stomach
2. recycling bin (recycling dead organelles) - phagocytosis
- ameoba eating
- mitochondria
-
1. cellular respiration: sugar to ATP
2. own DNA
3. Own ribosomes
4. two membranes - cytoskeleton
-
1. maintain cell shape
2. gives entire cells motility
3. anchor point for organelles
4. tracks=movement of cell parts - motor protein
-
1. hold cargo
2. uses energy to move along cytoskeleton - microtubule
-
1. hollow tube
2. tubulin dimers
3. not permanent structure
4. (+) end more dynamic - microfilament
-
1. helical double chain
2. bear tension to maintain shape
3. shape shifting for moving cells
4. muscle contraction - intermediate filament
-
1. maintain cell structure
2. permanent - centrosome
-
1. microtubule-organizing center
2. in animals there are two centrioles with 9 triplet microtubules (9-2) - cilia
-
1. many
2. move cells
3. move things past cells - flagella
-
1. fewer and longer
2. snake-like motion
3. (NOT the same as in prokaryotes) - basal body
- anchor to cell
- dynein
-
motor protein
1. attaches to neighboring doublet
2. energy-driven
3. pulls
4. doublet slides - gel
- network of microfilaments
- sol
- actin subunits
- amphipathic
- having both hydrophilic and phobic
- integral membrane proteins
- sticks into one layer
- transmembrane proteins
- type of integral; spans both layers
- peripheral membrane proteins
- weakly associated to membrane or protein
- selective permeability
-
1. Allowed: small & nonpolar
2. Deterred: large & polar
3. membrane proteins are selective (channels & carriers) - diffusion
- affects direction of movement across membranes
- passive transport
-
1. high to low concentration
2. diffusion across a membrane
3. no energy cost
4. small nonpolar molecules - facilitated diffusion
-
1. high to low
2. (diffusion) is facilitated by proteins
3. normally impeded by membranes
4. Channels: hydrophilic corridor, "gated"-open to stimuli - active transport
-
1. low to high
2. done through action of proteins
3. costs energy
- membrane potential
- charge difference across the membrane
- electrochemical gradient
- two forces that drive ion movement, concentration gradient & electrical force
- proton pump
-
1. pump H+
- co-transport
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1. energy to move H+ against gradient
2. movement of H+ down electrochemical gradient - osmosis
-
1. diffusion of water
2. down concentration gradient (high to low) - tonicity
-
1. effect of osmosis on cell
2. hypo- animal cell lyse, plant cell turgid
3. iso- no effect
4. hyper- animal cell shrivel, plant cell plasmolysis - fluid mosaic model
- not a rigid structure and has a mosaic of proteins for different functions