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55 Cards in this Set

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Purpose of cell fractionation
to take cells apart, separating the major organelles so that their function can be studied
Light Microscope
uses visible light, and because of resolving power, it can magnify effectively up to 1,000 times
Transmission electron microscope
mainly used by cell biologists to study the internal ultrastructure of cells
Scanning electron microscope
Useful for detailed study of the surgace of a specimen, 3D image
Chloroplast
contains chlorophyll along with the enzymes and molecules that function in the photosynthetic production of sugar (solar energy to chemical energy)
Grana
Inside chloroplast, double membrane stacks of thylakoids; involved in light reactions
Thylakoids
membranous system inside chloroplasts in the form of flattened sacs -- site of light-dependent reactions (chlorophyll)
Cytochrome Enzymes
CF1 - needed for the energy for light independent functions
Rough Endoplasmic Reticulum
Uses the proteins from its attached ribosomes (in cisternal space), secretory proteins are made (ex. glycoproteins), makes transport vesicles and grows in place with the addition of proteins and phospholipids (membrane production)
Smooth Endoplasmic Reticulum
Contains enzymes that synthesize lipids, metabolizes carbohydrates glycogen hydrolysis, detoxify drugs and poisons, contraction of muscle cells, and make steroid hormones
Cytoskeleton
Network of fibers extending throughout the cytoplasm, organizes structures and activities of the cell, mechanical support, holds organelle in place, shape, and cell motility
Microfilaments
part of cytoskeleton, two intertwined strands of actin (maintains cell shape, changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility, cell division)
Microtubules
Part of cytoskeleton, hollow tubes, walls consists of 13 columns of tubulin molecules, cilia and flagella (maintains cell shape, motility, chromosome movements in cell division, and organelle movements)
Intermediate filaments
Fibrous proteins supercoiled into thicker cables (8 keratin strands), (maintains cell shape, anchorage of nucleus and other organelles, formation of nuclear lamina)
Actin
A globular protein, a twisted double chain of actin subunits = microfilament; with myosin works in muscle cell contraction, amoeboid movement, and cytoplasmic streaming
Tubulin
A globular protein, builds the walls of microtubules, two different polypeptide subunits (alpha and beta), ATP, cell movement, can be disassembled and reassembled
Golgi Apparatus
products of ER are modified and stored and sent to other destinations (secretion), enzymes can modify olgiosaccharide portions of glycoproteins, and products a variety of them; with ER, produces lysosomes
Parts and Faces of Golgi Apparatus
Cis Face - receives the vesicles containing ER products; Trans Face - dispatches the vesicles to other parts of the cell; Cisternae - flattened membranous sacs
Centriole function and structure
found in region of cell near the nucleus where the cells microtubules are initiated (the centrosome), made up of nine sets of three microtubules arranged in a ring; organizes microtubule assembly, and pressure resisting girders
Cilia function and arrangement
locomotor appendages that protrude from some cells, move fluid over the surface of the tissue; core of microtubules sheathed in an extension of the plasma membrane, nine doublets arranged in a ring, dynein extend from each doublet
Cell Wall
protects plant cell, maintains its shape, and prevents excessive uptake of water
Primary Cell Wall
first, outside layer -- relatively thin and flexible wall
Middle lamella
between the primary walls of adjacent cells -- thin layer rich in sticky polysaccharides (pectin), glues the cell together
Secondary Cell Wall
wall added when the cell matures and stops growing, deposited in several laminated layers -- has a strong and durable matrix that affords the cell protection and support
Tonoplast
PLANT cells - membrane that encloses a large central vacuole, can hold reserves of organic compounds (proteins), and plant cell's main repository of inorganic ions (potassium and chloride), disposal site for metabolic by-products (sap and H2O)
Why are tonoplasts important
its acts as a disposal site for metabolic by-products that would endanger the cell if they accumulated
Ribosomes
builds proteins, and coded by the nucleolus
Lysosomes
membrane-bounded sac of hydrolytic enzymes that the cell uses to digest macromolecules (made by RER and transferred to Golgi Apparatus
Importance of lysosomes
carry out intracellular digestion (phagocytosis)-- food vacuole fuses with the lysosome, enzymes also used to recycle the cell's own organic material (autophagy), destruction of cells by their own enzymes, imp. in development of multicellular organisms
Mitochondria
the sites for cellular respiration, the catabolic process that generates ATP by extracting energy from sugars, fats, and other fuels, with the help of oxygen (cristae = infolding of inner membrane)
Peroxisome
metabolic compartment bounded by a single membrane, contains enzymes that transfer hydrogen from various substrates to oxygen, producing hydrogen peroxide
Important functions of peroxisomes
uses oxygen to break fatty acids to be transported to mitochondria, detoxify alcohol, converts fatty acids to sugar, synthesizes chlosterol and bile; its is toxic but peroxisomes contain an enzyme that converts the hydrogen peroxide to water
Do prokaryotes have the same organelles?
all cells are bounded by a plasma membrane, and contain cytosol, chromosomes, and ribosomes; difference = chromosomes in euk. cells are in nucleous and in pro. DNA is in nucleoid (no true nucleus)
Prokaryotes organelles
DNA is concentrated in the nucleoid, and no membrane separates this region, absence of membrane-bound organelles, absence of a nucleus; contains pili, ribosomes, pm, cell wall, capsule, flagella
Cell Membrane make-up
peripheral proteins, carbohydrates, cholesterol, and integral proteins
Peripheral proteins
proteins NOT embedded in the lipid bilayer, appendages loosely bound to the surface of the membrane often to the exposed parts of integral proteins
Carbohydrates
restricted to the exterior surface, important for cell to cell recognition (usually branched oligosaccharides with fewer than 15 sugar units)
Cholesterol
steroid cholesterol is wedged between the phospholipid molecules in the pm of animal cells, different effects on membrane fluidity (warm = less fluid), lowers the temp. required for membrane to solidify
Integral Proteins
proteins that penetrate the hydrophobic core of the lipid bilayer, many are transmembrane proteins that span the membrane; (ex. integrins = give cells a stronger external framework)
4 Functions of Integral proteins
signal transduction (transmits stimuli between the cell's external environment and its interior), provides as transport, hydrophilic channel across the membrane, intercellular joining, cell to cell recognition - gylcoproteins, attachment of cytoskeleton to ECM
Glycoproteins/ glycolipids
carbohydrates that are covalently bonded to either lipids or proteins, important in cell-cell recognition, and body immunity
What is meant by fluid mosiac model
membrane is a fluid structure with various proteins embedded in or attached to a double layer of phospholipids (proteins float in bilayer), membranes held together by hydrophobic interactions
why does water go through cell membrane
because of osmosis, the concentration gradient, and the positive and negative charges
Active Transport
the pumping of solutes against the concentration gradient, requiring the cell to spend its own metabolic energy (ATP), imp. for cell to maintain internal concentrations of small molecules that differ from the environment
Passive Transport
in diffusion across a membrane, a substance will diffuse down its concentration gradient, spontaneous, and requires no energy
Membrane potential
the voltage across a membrane, that acts as an energy source that affects the traffic of all charged substance across the membrane (favors the passive transport of cations into the cell, and anions out)
Na+ and K- importance
with every pump, 3 sodium ions move out and 2 potassium ions into the cell (net transfer of one positive charge from cytoplasm to ECM), stores energy in the form of voltage
Gated channel
opens and closes the cell when itis electrically stimulated
Nerve cell function
ion diffuses down its electrochemical gradient, gated channels allow resting Na ion to fall down its electrochemical gradient, CALCIUM
Carrier molecules
in facilitated: forms a channel through which H2O molecules or a specific solute can pass, alternating between two conformations (aquaporins and gated channels), Active transport - ATP induces protein to change conformation
Glucose movement
goes into blood from the small intestines by facilitate diffusion
hydrophilic molecule passage
facilitated diffusion, active transport, endo and exocytosis
Cotransport protein
works in different directions, ATP pump leaks a substance to one side of the membrane and another substance leaks back across through specific transport proteins
Ions move due to...
the inside of the cell is negative compared to the outside, the membrane potential favors the passive transport of cations into the cell and anions out; electrochemical gradient
Amphipathic properties
molecule with both hydrophobic and hydrophilic regions, related to the need of transport proteins and selectively permeable layer