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57 Cards in this Set
- Front
- Back
cells are made up of primarily four elements:
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carbon, hydrogen, oxygen, nitrogen
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_________carry out all chemical activities
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cells!
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cells are about ______% water
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60%
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cells vary in length
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2 micrometers to 3 feet
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possible cell shapes
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disk
threadlike pointed cubelike |
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3 main regions of the cell
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cytoplasm, plasma membrane, nucleus
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nucleus: function
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control center-- contains instructions for controlling the body
necessary for cell reproduction |
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nucleus: structure
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nuclear envelope, nucleoli, chromatin
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nuclear envelope: (nuclear membrane)
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--semi-permeable phospholipid bilayer
--nuclear pores |
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nucleoli
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sites where the ribosomes are assembled before they migrate to the cytoplasm
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chromatin
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composed of DNA and protein; condense to form chromosomes when the cell divides; runs throughout the cell
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plasma membrane:structure
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phospholipid bilayer: semi-permeable--> phosphate hydrophilic heads and lipid hydrophobic tails
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plasma membrane: function
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contains the cell contents and separates them from the surrounding enviornment
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function of proteins scattered in plasma membrane
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hormone receptors, binding sites, transporting
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specializations of the plasma membrane
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microvilli, membrane junctions-- tight, desmosomes, gap
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membrane junctions
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desmosomes, gap, tight
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microvilli:
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fingerlike projections that increase the surface area of the cell for absorbtion
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tight junctions:
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bind cells to other cells--> hold cells together
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desmosomes
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anchor the cells together-- last resort stick
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gap junctions
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allow communication between cells
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cytoplasm consists of three main elements
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cytosol, organelles, inclusions
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cytosol:
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fluid that suspends other elements
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organelles
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machinery of the cell
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inclusions
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non-functioning units: wastes, electrolytes--chemical substances that may or may not be needed
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cytoplasmic organelles:
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mitochondria, ribosomes, endoplasmic reticulum, golgi aparatus, lysosomes, peroxisomes, cytoskeleton, centrioles
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mitochondria:
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sausage shaped--> provide ATP for cellular energy
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ribosomes:
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small, dark bodies-->sites of protein synthesis: make protein--> found in the cytoplasm and the rough e.r
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golgi apparatus:
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modify and package proteins, produce different kinds of packages: secretory vesicles, cell membrane components, lysosomes
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lysosomes
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vescicles: demolition sites that breakdown wastes and recycle-- digestive enzymes
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peroxisomes
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small vesicles: used to disarm dangerous free radicals/chemicals: repicate by pinching in half
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cytoskeleton
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protein strutures along the cytoplasm: determines the cell shape; provides framework
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centrioles
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rod shaped bodies used during cell division: create spindle fibers
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fibroblasts
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protein extentions: net, meshlike material-- connect body parts (star shaped)
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erythrocytes
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no organelles when fully mature: blood cells-- transports oxygen (innertube shaped)
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epithelial cells
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square, tight junctions
create a protective lining |
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skeletal muscle cells
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involved in large scale movements (rod shaped)
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smooth muscle cells
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involved in involuntary movement (tongue, uterus, intestines, organs)
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fat cell
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cell that stores nutrients: large and globular: purpose to store fat
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nerve cell
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gathers information and controls body functions: must be able to recieve information: crazy shape (long)
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sperm cell
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reproductive cell (contain tails)
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cellular transport
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the movement of compounds across the outer wall or cell membrane
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cellular transport is critical to functioning
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take in and release compounds, reulates the amount of compounds that it needs
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_____ are embedded in the plasma membrane
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proteins, cholesterol
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2 characteristics that prevent a molecule from passing through the cell membrane
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size, polarity: polar substances have difficulty passing becuase of the non-polar heads
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polar molecules do not pass through the membrane
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too large, dont mix well with non-polar molecules
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water is able to pass through the plasma membrane although it is polar
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small enough to pass through, random vibrations
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Diffusion:
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the net movement occures from regions of higher concentration to areas of lower concentration
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osmosis:
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water moves from regions of low solute concentration to areas of high solute concentration
aim: to produce more equal solute concentrations |
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distilled water/ cells
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if a cell is submerged, then the cell will swell because of lack of solute and it will eventually burst-- water moves to areas with higher solute concentrations
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transporters
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facilitate the passage of molecules across membranes
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three steps involved in passage of a molecule into a cell
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bindong, conformational change of the protein, release
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difference between passive and active transporters
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passive: dont use energy
active: use energy |
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example of passive transporter
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glucose permease
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glucose permease
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enzyme
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passive transporters move molecules:
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from high concentration to low concentration--> absense of glucose permease--> water moves fast, glucose moes fast
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diffusion process
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water enters the cell with greater concentration, and then both water and solute enter at an equilibrium back to the cell with lesser concentration
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Sodium Potassium Pump
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present in all cells: especially in nerve cells--- move solute from areas of lower concentration to areas of higher concentration
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