Term
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Definition
| The structure of a cellular membrane, in which two layers of phospholipids spontaneously align so that the hydrophilic head groups are exposed to water, while the hydrophobic fatty acid tails are pointed toward the center of the membrane |
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Term
| cell membrane/plasma membrane |
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Definition
| The membrane surrounding the cytoplasm of a cell; consists of a single phospholipid bilayer with embedded proteins |
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Term
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Definition
| Literally translates as “water-loving” and describes substances that are soluble in water. These must be either polar or charged (ions) |
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Term
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Definition
| Literally translates as “water-fearing” and describes nonpolar substances that are not soluble in water. Nonpolar molecules in water associate with each other and form droplets |
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Term
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Definition
| having both hydrophobic and hydrophilic regions |
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Term
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Definition
| membrane is a fluid structure consisting of a mosaic of different lipids, proteins, and carbohydrates |
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Term
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Definition
| affects membrane fluidity by acting as a temperature buffer (decreasing fluidity at high temps and increasing fluidity at low temps) and as a "wedge" to force apart phospholipids at low temperatures |
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Term
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Definition
| a membrane protein that is permanently attached to the plasma membrane; all transmembrane proteins are integral proteins, but not all integral proteins and transmembrane proteins |
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Term
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Definition
| membrane proteins that adhere only temporarily to the biological membrane with which they are associated |
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Term
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Definition
| some substances can cross the membrane more easily than others; allows for compartmentalization |
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Term
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Definition
| The movement of substances across a cell's membrane without the expenditure of energy |
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Term
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Definition
| random motion of molecules |
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Term
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Definition
| movement of molecules from an area of high concentration to an area of low concentration; no energy input |
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Term
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Definition
| difference in concentration between a region with a high density of molecules and a region with a low density of molecules |
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Term
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Definition
| diffusion of water across a selectively permeable membrane; no energy required |
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Term
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Definition
| the ability of a solution to cause a cell to either gain or lose water |
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Term
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Definition
| solution inside the cell has the same solute concentration as the solution outside the cell; no net movement |
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Term
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Definition
| solution inside cell has a greater solute concentration than solution outside the cell; net movement of water into the cell |
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Term
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Definition
| solution inside the cell has a lower solute concentration than solution outside the cell; net movement of water out of the cell |
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Term
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Definition
| ability to control the water balance within a cell |
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Term
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Definition
| a vacuole in some protozoans that expels excess liquid on contraction |
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Term
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Definition
| passive diffusion of molecules, from an area of greater concentration to an area of lower concentration, across a membrane via transport proteins; allows for diffusion of large and/or charged molecules |
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Term
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Definition
| involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane |
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Term
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Definition
| A transmembrane protein with a hydrophilic interior that provides an aqueous channel allowing diffusion of species that cannot cross the membrane |
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Term
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Definition
| channel proteins in some types of cells that allow water to move through more quickly than osmosis alone |
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Term
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Definition
| movement of a solute from an area of low concentration to an area of high concentration; requires energy and protein pumps |
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Term
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Definition
| "engine" that can utilize energy to move a solute up its concentration gradient |
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Term
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Definition
| actively transports H+ against their concentration gradient |
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Term
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Definition
| transport of large molecules and other objects that require specialized modes of transport; requires huge amounts of energy |
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Term
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Definition
| export from the cell; secretion of molecules by fusion of a vesicle with the plasma membrane; secretion is a controlled process |
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Term
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Definition
| uptake of molecules and particulates by formation of a new vesicle from the plasma membrane; can be specific or non-specific |
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Term
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Definition
| engulfment of a particle via extensions of pseudopods, resulting in food vacuole formation |
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Term
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Definition
| when a vesicle membrane physically touches the cell membrane and the membranes fuse, releasing vesicle contents to the exterior of the cell |
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Term
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Definition
| membrane-bound structures inside the cell cytoplasm filled with "stuff" |
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Term
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Definition
| A nonpermanent cytoplasmic extension of the cell body |
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Term
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Definition
| A type of chemical signaling between cells in which the effects are local and short-lived |
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Term
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Definition
| long-lived chemical signaling that travels through the blood to reach specific target cells |
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Term
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Definition
| A molecule, usually a peptide or steroid, that is produced in one part of an organism and triggers a specific cellular reaction in target tissues and organs some distance away |
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Term
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Definition
| the target cell detects a signalling molecule present in the exogenous environment |
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Term
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Definition
| the conversion of the signal to a form that can bring about a specific cellular response |
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Term
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Definition
| the specific cellular effect brought about by the signalling molecule |
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Term
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Definition
| A signaling molecule that binds to a specific receptor protein, initiating signal transduction in cells |
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Term
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Definition
| A specialized cell or group of nerve endings that responds to sensory stimuli |
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Term
| Describe the importance of phospholipids to the structure of a biological membrane. |
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Definition
| allows for selective permeability and formation of cellular compartments |
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Term
| Why does a membrane need to be fluid? |
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Definition
| to allow for passage of molecules and spontaneous repairs of ruptures or breakage; in case of animal cells, allows for a wide variety of shapes |
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Term
| What are some factors that can influence how fluid a membrane is? |
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Definition
| temperature, ratio of unsaturated:saturated fatty acids, amount of cholesterol |
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Term
| Describe the types of proteins you might find associated with a cellular membrane. Where are they located? |
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Definition
| transporter, enzyme, cell-surface receptor, cell-surface identity marker, cell-to-cell adhesion, cytoskeleton marker; can be found across cell membrane or attached peripherally |
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Term
| Where on a cell membrane would you find carbohydrates? What is one function they serve? |
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Definition
| found only on the extracellular leaflet; function in cell-to-cell recognition |
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Term
| Explain how the structure of a cell membrane functions to selectively inhibit the passage of some molecules while allowing the passage of others. |
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Definition
| only small and hydrophobic molecules can diffuse freely across the cell membrane; larger and/or charged molecules must pass through channel or transport proteins, which may only allow for the passage of certain molecules |
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Term
| Explain the relationship between Brownian motion, diffusion & osmosis. |
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Definition
| diffusion and osmosis are a result of Brownian motion |
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Term
| How does a concentration gradient relate to diffusion and osmosis? |
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Definition
| both diffusion and osmosis only occur DOWN a concentration gradient |
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Term
| How might different tonicities affect an animal cell? A plant cell? |
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Definition
hypotonic: plant cells become turgid; animal cells lyse
isotonic: plant cells become flaccid; ideal for animal cells
hypertonic: plant cells plasmolyze (wilt); animal cells shrivel |
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Term
| How do different types of cells regulate their internal water concentrations? |
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Definition
| animal cells pump ions out of the cell to create an isotonic environment; protozoan cells pump water out via contractile vacuoles |
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Term
| What is the difference between diffusion & facilitated diffusion? |
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Definition
| diffusion is passive movement across the cell membrane; facilitated diffusion makes use of transport proteins in the cell membrane |
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Term
| What is the difference between passive transport & active transport? |
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Definition
| active transport expends energy while passive transport does not |
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Term
| Provide at least one example each of diffusion, facilitated diffusion and active transport. |
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Definition
diffusion: oxygen in the lungs diffuses from the alveolar air space into the blood circulating around the lungs
facilitated diffusion: sodium-potassium pump
active transport: proton pump transports H+ against its concentration gradient |
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Term
| How is bulk transport different than diffusion, facilitated diffusion or active transport? |
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Definition
| it requires huge amounts of energy, and utilizes vacuoles and the plasma membrane to move large quantities out of, in to, or within the cell |
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Term
| What types of bulk transport are there? What is the function of each type? |
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Definition
exocytosis: exports from the cell
endocytosis:uptake of molecules into the cell
phagocytosis: engulfment of a particle |
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Term
| Describe the relationship between bulk transport & membrane fluidity. |
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Definition
| bulk transport relies on the fluidity of the cell membrane either by vesicles fusing with it to release particulates to the extracellular environment, or to form new vesicles from the cell membrane for uptake of particulates into the cell |
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Term
| Provide at least one example of each exocytosis, endocytosis & phagocytosis. |
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Definition
exocytosis: secretion of insulin from pancreatic cells
endocytosis: uptake of neurotransmitters by post-synaptic neuron
phagocytosis: ingestion of bacteria by white blood cells |
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Term
| Discuss the role/influence of the membrane in regulating signaling events? |
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Definition
| proteins and signaling molecules found on the surface of the cell membrane receive and transmit signals |
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Term
| What must occur to/with signaling molecules in order for a signal to be sent from one cell to another? |
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Definition
| the signal must leave the signaling cell, travel to the target cell, be received by the target cell, and ultimately produce a cellular response |
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Term
| Describe some common cellular responses to signaling events. |
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Definition
| altering the activity of an enzyme(s), rearranging the cytoskeleton, altering transcription of particular genes in a genome |
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Term
| What do animal, plant, and prokaryotic cells have in common? |
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Definition
| DNA, cell membrane, cytoplasm, ribosomes |
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Term
| What are some differences between animal, plant, and prokaryotic cells? |
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Definition
| prokaryotes have small ribosomes and round DNA; eukaryotes have large ribosomes (except on the ER) and linear DNA (except in the mitochondria & chloroplasts) |
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Term
| What do plant & animal cells have in common? |
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Definition
| SER, RER, golgi body, mitochondria, vesicles, cytoskeleton |
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Term
| What are some differences between plant & animal cells? |
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Definition
plant cells have: cell wall, central vacuole, chloroplasts
animal cells have: flagellua, cilia, centriole |
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Term
| Why is it critical that cells are small? |
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Definition
| the larger the ratio of surface area to volume, the harder it is to move stuff around (diffusion, osmosis) |
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Term
| Where in a cell might you find ribosomes? |
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Definition
| cytoplasm, mitochondria, chloroplasts, rough endoplasmic reticulum |
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Term
| What are the endomembrane system's major functions within a cell? |
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Definition
| modify, package, and transport lipids and proteins |
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Term
| Trace the path a protein might take through the endomembrane system, beginning with protein synthesis and ending with exocytosis from the cell. |
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Definition
| synthesized in rough ER -> transport vesicle -> cis face of the golgi -> through the golgi -> sorted and packaged into vesicles sprouting from trans face of golgi -> other parts of the cell or secretion (exocytosis) from the cell |
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Term
| What role do vesicles play within the endomembrane system? |
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Definition
| transportation and storage |
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Term
| Can all organelles produce vesicles? If not, which organelles can? |
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Definition
| no; the golgi apparatus, endoplasmic reticulum, and cell membrane can produce vesicles |
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Term
| What role do vacuoles play within cells? |
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Definition
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Term
| Are vacuoles found in all cells? If not, which types of cells are they found in? |
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Definition
| no, vacuoles are only found in plant cells |
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Term
| What role to lysosomes play within cells? |
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Definition
| vesicle that contains digestive enzymes |
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Term
| Are lysosomes found in all cells? If not, which types of cells are they found in? |
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Definition
| no, just eukaryotic cells |
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Term
| What is the endosymbiotic theory? Describe the pieces of evidence that support endosymbiotic theory. |
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Definition
| Theory that proposes that eukaryotic cells evolved from a symbiosis between different species of prokaryotes. Evidence includes small ribosomes and circular DNA in mitochondria and chloroplasts |
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Term
| What are they three major components of the cytoskeleton? Compare and contrast the 3 components. |
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Definition
| microtubules, microfilaments, & intermediate filaments; microtubules are everchanging and anchor organelles, microfilaments rearrange to allow for cell movement, and intermediate filaments are strong and rope-like and provide strength and support for the fragile tubuline structures |
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Term
| What is the difference between a stable structure & a dynamic structure? |
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Definition
| stable structure (intermediate filaments) provide support for ever-changing dynamic structures (microtubules & microfilaments) |
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Term
| How is a centriole related to the cytoskeleton? |
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Definition
| centrioles make up centrisomes, which are responsible for organizing microtubules in animal cells (& some protists) |
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Term
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Definition
1. all organisms are made of cell(s)
2. all cells arise from preexisting cells by division
3. cells are the smallest living things |
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Term
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Definition
| the larger the ratio of surface area to volume, the harder it is to move stuff around |
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Term
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Definition
| a cell lacking a membrane-bounded nucleus or membrane-bounded organelles. |
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Term
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Definition
| A cell characterized by membrane-bounded organelles, most notably the nucleus |
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Term
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Definition
| The material within a cell, excluding the nucleus |
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Term
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Definition
| The fluid portion of the cytoplasm; it contains dissolved organic molecules and ions |
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Term
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Definition
| The rigid, outermost layer of the cells of plants, some protists, and most bacteria |
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Term
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Definition
| The membrane surrounding the cytoplasm of a cell; consists of a single phospholipid bilayer with embedded proteins |
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Term
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Definition
| The molecular machine that carries out protein synthesis; prokaryotes have small ribosomes, eukaryotes have large ribosomes (except for mitochondria, chloroplasts, and RER) |
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Term
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Definition
| Specialized part of a cell; literally, a small cytoplasmic organ |
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Term
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Definition
| holds DNA; surrounded by double layer membrane with pores |
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Term
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Definition
| The bounding structure of the eukaryotic nucleus. Composed of two phospholipid bilayers with the outer one connected to the endoplasmic reticulum |
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Term
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Definition
| The complex of DNA and proteins of which eukaryotic chromosomes are composed |
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Term
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Definition
| In eukaryotes, the site of rRNA synthesis |
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Term
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Definition
| A system of connected membranous compartments found in eukaryotic cells |
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Term
| rough endoplasmic reticulum |
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Definition
| attached directly to nucleus; covered in ribosomes; makes proteins |
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Term
| smooth endoplasmic reticulum |
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Definition
| further from nucleus; doesn't make proteins; lots of different functions (making lipids, filtering toxins, etc.) |
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Term
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Definition
| A small intracellular, membrane-bounded sac in which various substances are transported or stored |
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Term
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Definition
| not attached to nucleus or cell membrane; "sac" enclosed in its own membrane; "packaging & processing center" of the cell; receives vesicles from RER & sorts contents, then sends contents into cell |
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Term
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Definition
| produced by golgi; pumps in protons to lower pH & activate enzymes; acts like a "stomach" |
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Term
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Definition
| A membrane-bounded sac in the cytoplasm of some cells, used for storage or digestion purposes in different kinds of cells; plant cells often contain a large central vacuole that stores water, proteins, and waste materials |
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Term
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Definition
| found throughout cell; double membrane; processes sugars & makes ATP; have their own ribosomes & their own circular DNA |
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Term
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Definition
| A cell-like organelle present in algae and plants that contains chlorophyll (and usually other pigments) and carries out photosynthesis |
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Term
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Definition
| colorless plastids found in endosperm, tubers, roots and other non-photosynthetic tissues of plants; serve various functions such as storage of starch, lipids, or proteins |
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Term
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Definition
| A plant organelle called a plastid that specializes in storing starch |
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Term
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Definition
| A network of protein microfilaments and microtubules within the cytoplasm of a eukaryotic cell that maintains the shape of the cell, anchors its organelles, and is involved in animal cell motility |
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Term
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Definition
| provides mechanical support for the plasma membrane where it comes into contact with other cells or with the extracellular matrix |
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Term
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Definition
| Smallest diameter of the three cytoskeletal elements; involved in cell motility and with myosin part of myofilaments |
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Term
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Definition
| G-actin or F-actin; both of which are essential for such important cellular functions as the mobility and contraction of cells during cell division |
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Term
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Definition
| a long, hollow protein cylinder, composed of the protein tubulin; these influence cell shape, move the chromosomes in cell division, and provide the functional internal structure of cilia and flagella |
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Term
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Definition
| a long, hollow protein cylinder, composed of the protein tubulin; these influence cell shape, move the chromosomes in cell division, and provide the functional internal structure of cilia and flagella |
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Term
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Definition
| divides and organizes spindle fibers during mitosis and meiosis |
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Term
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Definition
| microtubule organizing center |
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Term
| What is the first law of thermodynamics? |
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Definition
| energy can be transferred or transformed, but it cannot be created or destroyed |
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Term
| What is the second law of thermodynamics and how does it affect living organisms? |
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Definition
| every energy transfer or transformation increases the disorder of the universe; it takes work (energy) for living things to stay organized |
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Term
| Where is potential energy stored inside cells? |
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Definition
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Term
| Why is energy required within cells? What is it used for? |
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Definition
| energy is needed to do work; ATP synthesis, movement, cell division, phagocytosis, any cellular process that needs energy input |
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Term
| Why do some reactions require energy input and others (spontaneous) do not? |
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Definition
| reactions that release energy & decrease order do not need energy input |
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Term
| What’s ATP and what do cells use it for? |
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Definition
| adenosine triphosphate; used for most energy-dependent cellular processes due to its enormous potential energy |
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Term
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Definition
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Term
| What is the relationship between ATP and enzymes? |
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Definition
| ATP powers cellular work, and most cellular work is performed by enzymes |
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Term
| What is an enzyme? Why do cells have so many enzymes? |
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Definition
| an enzyme is a catalytic protein; each enzyme carries out only one specific reaction |
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Term
| How does an enzyme work/how does it do what it does? |
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Definition
| an enzyme speeds up the rate of a chemical reaction; each enzyme has an active site that fits a very specific reactant |
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Term
| What is the relationship between structure and function for an enzyme? How is that related to its active site? |
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Definition
| the structure of the active site determines what reactant can interact with the enzyme |
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Term
| How do changes in temperature affect enzyme function? |
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Definition
| as temperature increases, the rate of the reaction increases, until it reaches its optimum condition and any further heat input denatures the enzyme |
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Term
| How do changes in pH affect enzyme function? |
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Definition
| Changes in pH may not only affect the shape of an enzyme but it may also change the shape or charge properties of the substrate so that either the substrate connot bind to the active site or it cannot undergo catalysis |
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Term
| What is an enzyme inhibitor? |
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Definition
| a molecule that bonds to either the active site or the inhibition site; binding the the active site blocks access for reactants; binding to the inhibition site changes the shape of the enzyme, making it so that reactants cannot bond to the active site |
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Term
| What happens to a cell/organism if its enzyme function is compromised? |
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Definition
| chemical reactions wouldn't happen fast enough and a cell could not maintain homeostasis |
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Term
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Definition
| break down molecules into smaller molecules & release energy |
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Term
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Definition
| consume energy to build big molecules from smaller ones |
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Term
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Definition
| all of the catabolic & anabolic reactions that occur within a cell (or organism) |
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Term
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Definition
| those metabolic reactions that result in the breakdown of complex molecules into simpler compounds, often with the release of energy |
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Term
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Definition
| The biosynthetic or constructive part of metabolism; those chemical reactions involved in biosynthesis |
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Term
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Definition
| could do work or stored energy; not currently moving |
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Term
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Definition
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Term
|
Definition
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Term
| 1st law of thermodynamics |
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Definition
| energy cannot be created nor destroyed, it can only be transferred or transformed |
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Term
| 2nd law of thermodynamics |
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Definition
| every energy transfer or transformation increases the disorder of the universe |
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Term
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Definition
| reaction that doesn't need energy input |
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Term
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Definition
| ATP; responsible for most of the energy available to cells; nucleotide with 3 phosphate groups |
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Term
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Definition
|
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Term
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Definition
| a chemical agent that speeds up a chemical reaction without being consumed or permanently altered by that reaction |
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Term
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Definition
| the amount of energy reactants must absorb to begin a chemical reaction; prevents many molecules from breaking down spontaneously |
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Term
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Definition
| the reactant acted upon by an enzyme |
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Term
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Definition
| region of the enzyme that binds to the substrate |
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Term
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Definition
| enzymes only act on certain substrates; due to a good fit between the shapes of active site & the substrate(s) |
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Term
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Definition
| environmental conditions at which an enzyme functions its best; will be different for different enzymes, even within the same cell or organism |
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Term
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Definition
| substance that binds to an enzyme and decreases its activity |
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