Cell Structure, Function & Transport Mechanisms PDF

Cell Structure and Function The Basic Unit of Life  All living things are composed of one or more cells. A cell is the smallest unit that can carry out all the processes of life.  The Discovery...

Cell Structure and Function The Basic Unit of Life  All living things are composed of one or more cells. A cell is the smallest unit that can carry out all the processes of life.  The Discovery of the Cell Robert The Hooke wordcell “____” was first used in Robert late 1665 by Hooke ____________. He looked at thin slices of cork (plant cells) 1665 under the  Cork seemed to be made of thousands of tiny, empty chambers. Hooke called these cell chambers “_____” because tiny him of the s reminded they __________rooms in which he lived in the monastery. Today we know that cells are not empty chambers but contain much living Anton van Leeuwenhoek – late 1600’s Leeuwenhoek made many simple microscopes to observe things in nature that interested him. These microscopes had magnifications10x greater __________ than the microscopes used by Hooke.  Leeuwenhoek discovered the hidden world of microorganisms in a drop of water. little beasties He called them “____________.” He was the first... see and describe to … microorganisms under the microscope.  On the road to the cell theory... Matthias Theodore Schleiden Schwann Germa German n Zoologist 1838 Botanis 1839 t Schleiden concluded Schwann concluded that all plant tissues that all animals were were composed of composed of cells. cells.  Virchow 1858 In 1858, Rudolph Virchow noted that cells could only arise from preexisting  The Cell Theory 1.All living things are composed of cells. 2. Cells are the basic units of structure and function in living things. 3.New cells are produced from existing cells.  With the development of the cell theory, scientists began to clarify the characteristics of living organisms. All living organisms are… … composed of organized parts. Living organismsobtain energy ____________ from their surroundings. There are two ways to obtain energy: Heterotrophs Autotrophs  Heterotrophs a) Heterotrophs are consumers. b) Heterotrophsmake their own cannot food __________________. Examples: They get food by consuming other living All animals organisms. and fungi are  Autotrophs a) Autotrophs are producers. make b) Autotrophs can their own food and __________________ are not dependent on outside sources for their food. Examples include: All green plants, some protists, and some bacteria. … perform chemical reactions. … change over time or evolve. ….respond to their environment. …reproduce.  ….maintain a stable internal environment in a process called homeostasis. Homeostasis is the balance between cells and their … share a common history.  All cells must be able to perform the following functions. Ingestion: Digestion: The taking in Breaking down food of into small molecules that can be used by food and the cell. Cyclosis: Respiration: Breaking down The glucose into movement simpler of materials substances and inside a releasing the cell. stored energy in a form the cell can Biosynthesi Excretion: use. s: from Using the energy The removal of foods to form liquid waste new cell parts, as in from the cell. growth and repair.  Egestio n: removal The of solid waste from the cell. Moveme nt:  Reproduction May be sexual…. …or asexual. Irritability: Responding to a stimulus Secretion: A substance made in one place but used in another place.  Diversity in Cell Shape and Size There is great diversity in the size, shape, and internal organization in the cells that compose a multicellular organism. Different cells havedifferent _______________ shapes depending on their ________. functions Each cell has a shape that has evolved to allow theefficiently perform its function cell to ___________________________.  Cell Size 1. The size of a cell is limited by … … its surface area-to-volume ratio. 2. The cell membrane is found at the cell surface and is responsible for … … the movement of materials into and out of the cell. 3. The cell membrane controls the passage of nutrients and oxygen into the cell, and the passage of wastes out of the cell.  4. As a cell grows, volume its _______ increases much faster surface than areaits ___________. 5. Iftoo the volume of a cell large becomes ________, the surface area of the cell membrane is not sufficient to … … allow for the movement of materials into and out of the cell. Materials could not enter or leave the cell quickly enough … 6. The size of… a to cell is limited meet the needs of by its … the cell.  There are Two Types of Cells: Prokaryotic and Eukaryotic Cells Three basic characteristics are common to all types of cells. All cells are surrounded barrier by a _______ cell called a _______________. membrane All materialsenter or exit the cell by passing ____________ through the cell membrane. The cell membrane is also referred to as the ___________________. plasma membrane  There are Two Types of Cells: Prokaryotic and Eukaryotic Cells Three basic characteristics are common to all types of cells. All cells have an interior substance cytoplasm called ___________. Cytoplasm is the portion of the cell within the cell membrane that includes … fluidthe … all of the organelles except the and nucleus.  There are Two Types of Cells: Prokaryotic and Eukaryotic All cells have control Cells a ____________. center Coded information in the form of DNA … … stores the instructions for regulating cell functions and for the Free-floating reproduction of the cell. DNA In some cell types, the DNA floats freely in the cytoplasm. In other cell types, the DNA is contained within a membrane- Nucleus bound structure called the nucleus.  There are Two Types of Cells: Prokaryotic and Eukaryotic Cells Cells fall into two broad groups, depending on whether or not they contain a nucleus. Prokaryotic Cells Eukaryotic Cells  Prokaryotic Cells Prokaryotic cells do not have… … a nucleus or membrane-bound organelles. Prokaryotic cells have genetic material nucleus (DNA) that is not contained inside a _______. No membrane separates the DNA from the rest of the cell. Prokaryotic cells are generally smaller and simpler than eukaryotic cells. Bacteria are Prokaryotic cells do have … prokaryotes. …a cell wall, cell  Eukaryot ic Cells Eukaryotic cells are generally larger and much more complex than prokaryotic cells. Eukaryotic cells have a … … true nucleus and membrane-bound organelles. Eukaryotic cells contain a membrane-bound nucleus which is kept separate from the rest of the cell. Plants, animals, protists, and fungi are eukaryotes.  The Structure of Eukaryotic Cells Organelles are the subcellular specialized structures found within aEach cell.organelle has a specific job or function. A cell is divided into 2 parts: Nucleus:The control center of the cell. Cytoplasm:The portion of the cell within the cell membrane that includes the fluid and all of the organelles except the nucleus.  Organelles Found in a Generalized A. Cell membrane Animal Cell (Plasma membrane) B. Cytoplasm C. Nucleus (Nuclear membrane) D. Chromatin (Chromosomes) E. Nucleolus F. Rough endoplasmic reticulum G. Ribosomes  Organelles Found in a Generalized Animal Cell H. Smooth endoplasmic reticulum I. Vacuole J. Golgi apparatus K. Vesicle L. Mitochondria M. Centrioles N. Lysosome  The Cell Membrane Also called the plasma Lipids membrane. Separates the internal chemical reactions of the cell from the external environment. Separates one animal cell from the next. Protein Regulates the passage of materials into and out of the s cell by allowing only certain Made mostly of molecules to enter and lipids and leave. proteins. The nucleus is the control center of The Nucleus the cell. A. Nuclear membrane B. Chromatin / Chromosome C. Nucleolus D. Nuclear pores E. Smooth endoplasmic reticulum F. Rough endoplasmic reticulum  The Nucleus The nucleus is filled with ___________. nucleoplas Nucleoplasm m is a … … jellylike liquid similar to the cell’s cytoplasm. The nucleoplasm holds the contentsnucleus of the _______. The nucleus contains nearly all DNAof the cell’s ____. coded The DNA contains the ________________ for the instructions genetic making makeup of future cells as well as instructions proteins for ______________ and other important molecules for the daily functioning  The Nucleus nuclear membrane The nucleus is chromatin surrounded by a nuclear membrane ________________. The nuclear membrane doubl is e a ______ membrane pores that is dotted with thousands of _____. These pores allow materials to move … pores nucleolus … into and out of the nucleus. RNA carries The nucleusto ________________________ protein-building is the site the riboso _________. instructions where… mes … DNA is RNA travels to the cytoplasm transcribed through the numerous pores in theinto RNA.membrane. nuclear  Chromatin or Chromosome? a) When the cell is not dividing, the DNA is in the form of a threadlike material called chromatin. b) When the cell is actively dividing, the chromatin condenses to form chromosomes.  Nucleolus The nucleolus manufactures subunits the ________ that ribosomes make up __________. There are 2 subunits: The large subunit and the small subunit. Large subunit Small subunit ribosome These subunits then pass through thenucleus porescytoplas of the _______ to the _________ ribosome where  Functions of the The nucleus is the carrier of genetic Nucleus information. Chromosomes are composed genes of the _____ which determine trait _____ in living organisms. s The nucleus The nucleus directs The nucleus protein controls controls all synthesis the of the by sending reproductio activities of messages n of the the cell. out to the cell. ribosomes.  Ribosomes Ribosomes may be found free floating in Attached to the cytoplasm, or they ER may be found attached to the endoplasmic reticulum. Ribosomes are the most Free floating numerous of the cell’s ribosomes organelles.  Ribosomes Newly formed protein Ribosomes are composed of protein and RNA and are not… … membrane-bound organelles. RNA Ribosomes are the site of protein synthesis. All proteins of the cell are made by the ribosomes.  Endoplasmic Reticulum The internal membrane system of a cell is known as the endoplasmic reticulum. Nucleus Rough endoplasmic reticulum This system of Smooth membranes is so endoplas extensive throughout the mic cell that it accounts for reticulum  Endoplasmic The Reticulum ER functions as an intracellular thatmolecul “__________________” highway provides a path along which _________ esmove from one part of the cell to another. Therough _____ endoplasmic reticulum is covered with ribosome attached _________. s This type of endoplasmic reticulum proteins is involved in the making of ________. Newly made proteins leave the ribosome and are inserted into spaces of Rough endoplasmic the endoplasmic reticulum reticulum where they are modified  Endoplasmic Reticulum Thesmooth _______ endoplasmic reticulum has no ribosom _________. es The function of the smooth endoplasmic lipids reticulum membrane is to make s _____ that Smooth endoplasmic will be used in reticulum ___________.  Golgi Apparatus Proteins that are produced in the rough endoplasmic reticulum are … … Thetransported to the Golgi apparatus Golgi appearsapparatus. as a _____ of stac loosely membran k connected __________. es The function of modify, the Golgi is to sort and _____________________ the proteins package that have endoplasmic arrived from the ____________________. reticulum  Golgi Apparatus These proteins will either be __________________ stored inside the or be secreted cell to outside the of the cell _______________. The Golgi apparatus completes the modifications on proteins before they are shipped off to their final destinations.  Vesicles 1. Vesicles are small, spherical _____________ that are sacs surrounded by a single membrane. 2. Vesicles are classified according to their contents ________. 3. Types of vesicles include … … transport vesicles, Vesicl lysosomes, and e peroxisomes.  Protein Synthesis and Transport The manufacture and distribution of proteins can be seen in this diagram. a)Proteins are assembled by ribosomes on the rough endoplasmic reticulum. b)Vesicles transport proteins to the Golgi apparatus. c) The Golgi apparatus completes the modifications on proteins  Protein Synthesis and Transport The manufacture and distribution of proteins can be seen in this diagram. d) Functional proteins are packaged in vesicles and leave the Golgi apparatus. e) Vesicles fuse with the cell membrane to release the newly formed proteins to the outside of the cell. f) Vesicles containing enzymes remain inside the cell as lysosomes.  Lysosomes 1. Lysosomes bud from the Golgi apparatus and are filled with very strong digestive ________________. enzymes 2. These digestive enzymes are used to __________ break down large molecules of carbohydrates, Golgi proteins, and lipids into apparatus ________________. smaller molecules The enzymes recycle the cell's own organic materials, breaking them down into their ______________, building blocks and returning them to the _________ cytoplasm to be Lysosome used again.  Lysosomes 3. Lysosomes are responsible for destroying old organelles that can no longer carry out their function. 4. Lysosomes help to “clean up” or destroy any debris that might build up inside the cell. 5. Lysosomes are surrounded by a thick membrane (lysosomes) because the cell would be destroyed if the enzymes were released.  Peroxisom es 1. Peroxisomes contain ________________ different enzymes and are not produced by the ______________. Golgi apparatus 2. Peroxisomes break down ________ alcohols and kill ________, bacteria producing _________________ hydrogen peroxide as a result. Since hydrogen peroxide is _____ toxic to cells, peroxisomes go one step further and convert the hydrogen Peroxisome peroxide into ________________. water and oxygen 3. Peroxisomes also break down _________ fatty acids which can be used by mitochondria as an _____________. energy source H2O + O2  Vacuoles Central vacuole A vacuole is a storage area inside a cell. Contractile vacuole A vacuole may store water, salts, proteins, and Food carbohydrates. vacuole  Mitochondria The mitochondria is the “___________” of powerhouse the cell. The purpose of the mitochondria is … … cellular respiration. Cellular respiration is the process of … … converting glucose or sugar molecules into a usable form of energy for the cell.  Mitochondr cristae ia Mitochondria have an … … inner membrane and an outer Outer The folds on the membrane. membrane inner membrane are Inner known as cristae. membrane The cristae increase the … … surface area for respiration.  Mitochondr ia 100's or 1000's may be found in a cell. Mitochondria have their own DNA____ and carry out their own __________. replicatio n The Cytoskeleton The organelles of a cell do not float freely in the cytoplasm. Cells must have an internal framework and support system to give shape and organization to a cell.  Cytoskelet on shapthe cell to The cytoskeleton is a networkprotein of _____________________ that helps tubes and fibers maintain its ______. e The cytoskeleton provides shape and support from inside the cell much like the tent poles inside a tent. The cytoskeleton is also involved in cell movement. Two of the types of fibers found in the cytoskeleton are microfilaments and microtubules. Cytoskeleton in green. Nucleus of each cell in blue.  Microfilam ents Microfilaments are solid, threadlike, protein structures. Microfilaments form extensive frameworks inside the cell to give support to the cell. Microfilaments in green. They help to bear Nucleus of each cell in blue. mechanical stress. Microfilaments also help cells to move. They can assemble and disassemble rapidly and are involved in muscle contraction.  Microtubules are hollow structures. Their functions include: Maintaining cell shape. The separation of chromosomes during cell division. The formation of cilia and flagella  Centrioles Centrioles are _________________ two short cylinders at right angle to one another. nuclear membrane They are found near the _________________. Centrioles organize the microtubules during cell division to form a framework for separating A plant cell has many of the same parts found inside an animal cell, but there are a few organelles that are only found in plant cells. A: Cell membrane B:Cell wall C:Cell wall of neighboring cell D: Nucleolus E: Nucleus F: Smooth ER G: Rough ER H: Ribosomes I: Cytoplasm J: Chloroplast K:Mitochondria L: Central vacuole M: Peroxisome N: Golgi Differences Between Plant and Animal Cells These organelles are These organelles are never found in plant never found in animal cells: cells: lysosomes plastids (chloroplasts) centrioles central vacuole flagella (except for cell wall. sperm cells).  Cell Wall The cell wall is a Cell supporting structure membrane found in the cells of plants and fungi. It lies to the outside of the Cell wall cell’s plasma membrane. The main function of the cell wall is to provide support and protection for the cell. The cell wall is composed mostly of  Central Vacuole Centr al A central vacuole is a Vacuo fluid-filled very largevacuole le ________________plant found cells in mature _________. When filled withwate _____, it creates turgor ______________ rto give strength pressure and support to the cell. Turgor pressure is … It can also serve … the pressure that water as a storage area molecules exert against the cell for organic wall. compounds. This allows the plant to support heavy structures such as flowers  Plastids Like mitochondria, plastids are organelles that are surrounded by a ________________ and contain double membrane DNA their own _____. There are three types of plastids found in plant cells: Chloroplast s Chromoplas ts Leucoplasts (Amyloplast s)  Chloroplasts 2. Chloroplasts are found only in plant cells and other organisms that carry photosynthe out ______________. sis 3. A chloroplast is … … the site of photosynthesis 1.Structures of the in autotrophic cells. chloroplast: 4. Chloroplasts absorb the A: Outer energy from the sun and membrane convert it to the chemical B: Inner energy stored in molecules membrane of glucose or sugar. C: Stroma D: ThylakoidsA chloroplast is similar to a solar power plant.  Chloroplasts Inner membraneOuter Chloroplasts are membran surrounded by an outer and an inner membrane. Inside the chloroplast are large stacks of other membranes called Thylakoids thylakoids Stroma _________. These thylakoids contain the green pigment chlorophyll which is required for photosynthesis. Stroma: The dense solution that surrounds the thylakoids.  Chromoplast s “chromo” means The prefix color. Chromoplasts contain pigments of … … all colors except green. Chromoplasts give fruits and flowers their colors.  Leucoplasts (Amyloplasts) 1. Leucoplasts have no color. 2. These plastids store starch in plant cells.  The Diversity of Cellular Life Unicellula r Coloni Multicellul al  Unicellular Organisms A unicellular organism is a ____________________. single-celled organism Examples include: Ameba Bacter ia Paramec ia Yeasts  Colonial Organisms Volvox A colonial organism is a group of genetically identical cells _____________________ that live together in a connected group. Colonial organisms are not considered multicellular because coordinatthere is little ___________ ion of cell activities among the cells. There is no … Siphonophore … cell specialization or  Multicellular 1. A multicellular Organisms organism consists of groups of specialized cells that live and work together. 2. There is a very high level of … differentiation, cell specialization, and coordination of cellular activities. 3. Cell specialization: The evolutionary adaptation of a cell or group of cells to carry out one particular Multicellular OrganismsAdvantage of cell specialization: A cell that carries out only one function can be much more efficient at that one job. Disadvantage of cell specialization: The cells are dependent upon one another. If one group of cells fails to do its job, the other cells will perish.  Levels of Cellular 1. Cell: Organization A cell is the smallest unit that can carry out all the processes of life. 2. Tissue: A group of similar cells that carry out a specific function. 3. Organ: Groups of tissues functioning as a unit, performing the same function. 4. Organ System: A group of organs that work together to carry out related tasks. How Do Materials Enter and Leave a Cell A. Phospholipid bilayer B.Protein C.Transport Protein D.Phospholipid E. Cholesterol F. Carbohydrate The cell membrane regulates _________ what enters and what leaves the cell. It also provides protection and ____________________ to the cell. support  The Cell Membrane The membrane consists of a __________________ phospholipid (double layer) in which protein ________ are bilayer embedded. s Phospholipids are the structural components flexible of membranes. structure The lipid bilayer gives the membrane a _______________ that forms a strong barrier  The Cell Membrane 4. Different types of proteins are embedded within the phospholipid bilayer and carry out specific functions: a) Transport proteins form __________________ channels and to help move materials across the membrane. pumps b) Receptor proteins recognize and bind to substances at the cell surface, forming a method of communication between the cell and the external environment. c) Some membrane proteinsenzymesare ________ that assist the chemical _________________ inside the cell.  The Cell Membrane carbohydrates The carbohydrates serve as identification markers to help individual cells identify one another.  The Fluid Mosaic Model of Membranes The term “fluid mosaic” is used to describe the nature of membranes in cells. The phospholipid bilayer acts more like a liquid than a solid. The lipids and proteins in the membrane move laterally within the bilayer. Because of this constant movement in the bilayer, the pattern or “mosaic” of the lipids and proteins is constantly changing.  1.Living cells must maintain stable internal conditions, and all living cells have mechanisms in place that allow them to control their internal environment. 2. For example, a cell must closely regulate the water content of the cell. If the cell takes in too much water, it will rupture and die. If it takes in too little water, it will shrivel and die. Homeostasis is the process by which … … cells maintain a stable internal environment, even when the external environment is constantly changing. Maintaining homeostasis requires self-_____________ of the regulationcoming into materials the cell and going out of the cell. ope The cell is an _____ system. n constant inflow of matter and It requires the energy and the constant out flow of waste. The cell membrane is called a selectively permeable membrane or a semipermeable membrane. It has the ability to let some substances pass through more It can control the speed readily than others. at which molecules are Some materials are allowed to enter. not allowed to enter at all. The Concentration Gradient 1.The cytoplasm of a cell contains solutio a _______ ofn many different substan __________ in water. ces Theseconcentrat substances exist in various ions _____________. 2.The outside of a cell is surrounded by a different water solution containing different concentrations of  The Concentration Gradient The concentration gradient is … … the difference in the concentration of molecules across a distance. In the absence of other forces, materials will tend to move from … … an area of high concentration to an area of lower Lower concentration. concentration In the drawing: Label the area of higher concentration. Label the area of lower concentration. Draw an arrow on the drawing showing the direction of movement for this solute. Higher concentration  Describe what is happening in the A. drawing below. There is a higher concentration of solute molecules on one side of the membrane. B. The solute molecules move from the side of higher ______ lower concentration to C. Equilibriu __________ has been the side of _____ reached. m equal concentration. The concentration is This movementequal _____ on both sides of the will continue until membrane. the concentration Once equilibrium has is _____ on both been reached, the solute molecules will  The Concentration Gradient The movement of molecules across a membrane may or may not require an expenditureenergy of ______. Molecules are moved into and out of cells passive by _______ transport and active ______ transport.  Passive transport is the movement of substances across a cell membrane without the use of energy. spreading Diffusion is the out of molecules from a ____________ high of ____ concentration tolow region a region of ___ concentration. For Example: In which The salt will move direction will from the high side 20% the salt salt to the low side. molecules solutio The salt will move n move? out of the bag and 5% salt solution into the water. The diffusion of molecules Higher across the membrane concentration Nonpolar Polar depends size on themolecule ____ and substances substances type of _________. oxygen Small, and carbon nonpolar substances suchdioxide as phospholipid _______________________ can bilayer directly through the dissolve __________________. Polar molecules such as protein water, ions, and channels proteins may pass through the transport proteins membrane by moving Lower concentration through ______________ or by the use of _______________.  Osmosis Osmosis is the movement of water across a membrane from a region of high concentration to a region of low concentration. In which direction will the water molecules move? The water will move H2O H2O from the high side to the low side. The 20 % salt water will move into The bag is 80% solution water. the bag. H2O 5% salt solution The solution is 95% water. Osmosis is the passive transport of water. No cell energy is required. The net direction of osmosis depends on the relative concentrations of solutes on the two sides of the membrane. As a result, there are three types of water solutions: Isotonic solution Hypertonic solution Hypotonic solution  Type of Water Solution: Isotonic Isotoni Animal Plant Cell Thec Cell concentrations of solutes outside and equ inside the cell al are _____. sam The e concentration of water is the _____ on back andthe Water diffuses Water diffuses inside and the forth into and out of into and out of outside sameof the the cell at the cell at cell.directio rate equal rates. equal rates. Waterns will still  Type of Water Solution: Hypertonic Hypertonic Animal Plant Cell If a cell is placed Cell in a hypertonic solution, thesolut concentration e of ______high molecules outside er the cell is ______ than the diffuse concentration of solutes inside out the equilibriu cell. Plasmol Water m will More water More water ___________ ysis of the leaves the cell leaves the cell cell until than enters. than enters. ___________ is Plasmolysis Plasmolysis reached. has occurred. has occurred. ___________ may  Type of Water Solution: Hypotonic Hypotonic Animal Plant Cell If a cell is placed in Cell a hypotonic solution, the solut concentrationeof lowemolecules _______ outside r the cell is ______ than the More water enters the cell than leaves concentration of the cell. cell wall into the solutes cell the inside not a In cells with equilibriu cell. _______, cytolysis is Cytolysi Water m diffuses ____ likely to occur. ____________ s until More water full of The central vacuole ___________ is enters the cell of water a plant Turgor cell will reached. than leaves become pressureextremely _________ may occur. the cell. ___________. Cytolysis: Cytolysis may ______________ will Too much water increase. This  Practice Problems Label the drawing as we work through this. 1. The bag contains a 20% salt solution. 2. The water surrounding the bag is H2O pure (100%) water. 20% salt 3. What is the 80%concentration water of water 80% inside the bag? water hypertonic 100% hypotonic hypertonic 4. Is the bag hypotonic or hypertonic water to the water on the outside? 5. Is the water on hypotonic the outside hypertonic or hypotonic to the bag? Into the bag 6. In which direction will water  Practice Problems 7. In which direction will salt move? Out of the bag 8. What process might occur if too much water moves intocytolysis the bag? Water moves into Salt moves 9. The movement of the salt and the the bag. out of the water will continue Both until?sides are bag. equal. 20% salt 10. After equilibrium has been reached, 80% what will happen to the movement water hypertonic of these molecules? Movement will continue in both directions, but the 100% hypotonic equilibrium will be water maintained. 11. Water always moves from an high area of _____ concentration low to an area of ____ concentration. In other words, water hypotonic moves from the hypertonic _________ side to the _________ side.  Practice Problems Label the drawing as we work through this. 1. The bag contains a 40% sugar solution. Water 2. The water solution surrounding the moves in 60% bag contains a 40% sugar solution. water and out. 40% sugar 3. What is the 60%concentration water of water 60% inside the bag? water 60% water 4. What is the concentration of water 40% sugar on the outside of the bag? isotonic 5. What type of solutions are these? 6. In which direction Water moveswill waterin both equally move? directions  Practice Problems Label the drawing as we work through this. 1. The bag contains a 5% salt solution. 2. The water surrounding the bag contains a 25% salt solution. 75% water 3. What is the concentration of water 5% salt inside95% the bag? water 95% 4. What is the concentration of water water hypotonic outside the 75%bag? water 25% hypertonic salt 5. Is the bag hypotonic or hypertonic to the water on the outside? hypotonic 6. Is the water on the outside hypertonic or hypotonic to the bag? hypertonic  Practice Problems 7. In which direction will water move? Out of the bag 8. In which direction will salt move? Into the bag 9. What process might occur if too much water leaves the bag? plasmolysis 75% water Salt 10. The movement of the salt and the H 2O 5% salt Bothuntil? water will continue sides are equal. 95% 11. After equilibrium has been reached, water hypotonic what will happen to the movement of 25% hypertonic these molecules? Movement will continue in salt both directions, but the equilibrium will be maintained. 12. Water always moves from an high area of _____ concentration low to an hypotonic area of ____ concentration. In other words, water moves from the hypertonic __________ side to the __________ side.  Facilitated Diffusion passive Facilitated diffusion is a type of _______________ used for molecules that do______ not readilytransport diffuse through membranes. These molecules may polar (water and be ______________________ and cannot diffuse throughglucose) the lipid bilayer. Other molecules are too________ to pass through pores in the membrane. large Carrier proteins or transport proteins help these molecules to pass through the membrane more easily. Label the drawing below. Carrier Protein High Concentration Protein Low Concentration Channel Facilitated Diffusion This is known as facilitated diffusion because these proteins “facilitate or help” the diffusion of these molecules across the membrane. passive Facilitated diffusion is transport down considered _______________ because the solute is moving _____ its concentration gradient. Facilitated diffusion speeds the passage of a solute by providing a passage through  Active Transport Materials must sometimes move _______ against i g h the concentration gradient. The cell h must often move materials from low an area of ____ concentration to higher an area of ______ concentration. This is called active transport, and the cell must expend energy to low accomplish it. protein pump If small molecules and need to be moved across the ______________________ against ions membrane _______ the concentration gradient, it will require transport pumps the use of _______________ or “______” that are proteins embedded in the membrane. energy This use of protein pumps requires ______. Large molecules may have to be transported by a movement of the cell membrane in processes called endocytosis and exocytosis. food outside of cell cell membrane inside of cell vesicle Endocytosis is the process of taking material ___________ into the cell membrane by means of infoldings, or pockets, of the cell______________. The pocket that results ____________ breaks loose from the cell membrane and forms a ______ within the cytoplasm. vesicle _______________ Large molecules and clumps of food are taken up in this way. energ y ______ from the cell. This requires Two types of endocytosis are: Phagocytosis Pinocytosis Phagocytosis is … … the engulfing of large food particles.  Pinocytosis is cellular “______________.” drinking The cell surrounds and Ameba engulfs droplets of extracellular fluid. It is not the fluid that is needed, but the molecules dissolved in the droplets. Exocytosis Release from the cell cell membr ane vesicle Exocytosis is the release of large materials from the cell. A vesicle fuses with the cell membrane, forcing the contents out of the cell.