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plasma membrane
- surrounds cell
- made of proteins and lipids
- composition and function can vary from one region of cell to another
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cytoplasm
- cytosol
- cytoskeleton
- organelles
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structures in the cytoplasm
- organelles, cytoskeleton, inclusions
- all embedden in clear cytosol
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organelles
internal structures of a cell that carry out specialized metabolic traits
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membranous organelles
- those surrounded by one or more layers of membrane
- nucleus, mitochondria, lysosomes, peroxisomes, ER, golgi complex
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organelles not surrounded by membrane
ribosomes, centrosome, centriole, basal bodies
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cytoskeleton
- keeps everything together
- collection of protein filaments-microfillaments, intermediate filaments, microtubules
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inclusion
stored cellular components and fat droplets
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What is the function of the cytockeleton?
to determine shape of the cell, lend structural support, organize its contents, direct movement of substances through the cell, and contribute to cell movement as a whole
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microfilaments
- made of actin
- form a network on cytoplasmic side of plasma membrane celled the terminal web-supports cell
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intermediate fibers
- are thicker and stiffer than microfilaments and resist stresses placed in the cell
- help junction with other cells
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microtubules
- cylinders that are thick tubes
- very important in drug target
- long and hollow and made of globular porteins
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Definition of a cytoskeleton functions
- determines shape of cell
- lends structural support
- organizes its contents
- directs movement of substances through the cell
- contributes to the movement of cells as a whole
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miotic spindle
array of microtubules and associated molecules that form between the opposite poles of a eukaryotic cell during mitosis and serves to move the duplicated chromosomes apart
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microtubules are in a state of
dynamic instability and constantly assembling and disassembling
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Molecular motors
- kinesins, dyneins, dynamin and myosin
- molecular molecules move things and require ATP to move
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nucleus
- largest organelle
- most cells have one
- consists of nuclear envelope and nucleoplasm
- keeps DNA
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nuclear envelope
- 2 unit membranes surrounds nucleus
- perforated by nuclear pores that regulate molecular traffic
- supported by nuclear lamina
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nucleoplasm
- materials in nucleus
- chromatin and nucleoli
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chromatin
thread like material composed of DNA and protein
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nucleoli
one or more dark masses where ribosomes are produced
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nucleus composition
made up of chromosomes which are DNA
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Endoplasmic reticulum
- system of interconnected channels called cisternae enclosed by unit membrane
- rough and smooth
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Rough ER
- composed of parallel flattented sacs covered with ribosomes
- produces the phospholipids and proteins of the plasma membrane
- synthesizes proteins
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smooth ER
- lack ribosomes
- synthesize steroids and other lipids
- detox alcohol
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ribosomes
small granules of protein and RNA
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Where are ribosomes found
nucleoli, cytosol, outer surfaces of rough ER, nuclear envelope
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What do ribosomes do?
- They read coaded genetic messages from mRNA and assemble amino acids into proteins
- where proteins are made
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Golgi complex
- a small system of cisternae that synthesizes carbohydrates and put the finishing touches on protein and glycoprotein synthesis
- gets from rough ER and packages them
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lysosomes
package of enzymes bound by a single unit membrane
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what are the functions of lysosomes?
- intracellular hydrolytic digestion of proteins, nucleic acids, etc
- autophagy and autolysis
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autophagy
digest and dispose of worn out mitochondrial and other organelles
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autolysis
- cell suicide
- some cells are mant to do certain jobs and then destroy themselves
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peroxixomes
resemble lysosomes but contain different enzymes and not produced by the golgi complex
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what are the functions of peroxisomes
- they convert things to H2O2
- detox alcohol and break down fatty acids
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inclusions
- stored cellular products and foreign bodies
- not needed in cell ofr survival and never enclosed by a membrane
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diffusion
the process by which a gas or a substance in a solution expands because of the motion of its particles to fill all the available volume
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what is the flow in diffusion?
from solute particles from high to areas of low concentration
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osmosis
- the diffusion of solvent molecules into a region in which there is a higher concentration of a solute to whihc the membrane is impermeable
- a certain pressure involved
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osmotic pressure
- one osmole equals the gram molecular weight of a substance divided by the number of freely moving particles that heach molecule liberates in solution
- ex- if solution ionizes= number of moles/ions present
- if does not ionize= 1
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tonicity
- ability of a solution to affect fluid volume and pressure in a cell
- depends on concentration and permeability of solute
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hypotonic solution
- has a lower concentration of non permeating solutes than ICF
- cells absorb water and swell and may burst
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hypertonic solution
- has a higher concentration of non permeating solutes and a low water concentration
- cell loses water and shrivels
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isotonic solution
concentrations in cell and ICF are the same so there is no change in cell volume or shape
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cell membrane
- it is a semipermeable membrane where only certain things can go through
- it has a hydrophilic heads on the outside and hyrophobic region inside the membrane
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transmembrane proteins
proteins that completely span the bilayer
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proteins can be embedded in the inner or outer of the lipid bilayer
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peripheral proteins
loosely bound to the outer or inner surface of the membrane
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glycocalyx
- unique fuzzy coat external to the plasma membrane
- functions are protection, cell adhesion, immunity, defense, fertilization, embryonic development
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microvilli
- serve to increase surface area of cell
- serve to help increase absorption and are made of actin
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cilia
- hair like things that are on cell for sensory (ear nose) and can beat in waves and move mucus out
- move by power strokes
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flagella
- tail of a sperm
- move around in a whip like structure and are very long
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