Movement In And Out Of The Cell PDF

MOVEMENT IN AND OUT OF THE CELL DR MOATAZ BEDEWEY  MOVEMENT IN AND OUT THE CELL 1. Diffusion: The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration grad...

MOVEMENT IN AND OUT OF THE CELL DR MOATAZ BEDEWEY  MOVEMENT IN AND OUT THE CELL 1. Diffusion: The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement. *Down and up or against concentration gradient* Down a concentration gradient means from higher concentration to lower concentration. against concentration gradient means from lower concentration to higher concentration reasons of diffusion : 1- Random movement of the different molecules that provides energy for diffusion. 2- Presence of a difference in concentration of a certain substance. *Factors affecting the rate of diffusion: (TADS) 1. Temperature Increase in temperature increases the rate of diffusion as it increases the kinetic energy of the molecules. EX : if you hold o tube containing a substance such as ammonia in your hand, rate of diffusion increases as the molecules of the substance gain heat from your hand) 2- Distance of diffusion The longer the distance the longer the time taken for diffusion and vice versa. 3-Air current If the direction of current is similar to that of diffusion, it increases the rate of diffusion and vice versa 4-Stirring It increases the rate of diffusion as it increases the kinetic energy of molecules 5-Size of molecules 6-Surface area to volume ratio When increases it leads to an increase in rate of diffusion 7-Concentration Gradient ( difference in concentration) Increase in difference of concentration leads to an increase in rate of diffusion 1 Necessary for exchange of gases in all living organisms. 2. Necessary for obtaining carbon dioxide and release of oxygen in the process of photosynthesis  2. Active transport or active uptake : Definition Movement of particles in or out of a cell through the cell membrane, from a region of their lower concentration to a region of their higher concentration against a concentration gradient using energy released during respiration Carrier proteins Protein found in cell membranes that force particles against their concentration gradient. Carrier proteins are specific means each type of carrier has a specific precise shape that can bind with specific particle) How carrier proteins act? The solute molecule or ion is taken in the binding site of the carrier molecule. The carrier molecule rotates wind energy to transfer the solute from region of its lower concentration to region of its higher concentration. Factors affecting active uptake: 1. Number of mitochondria as in the mitochondria energy is released by the process of Aerobic respiration, this energy is used in active uptake. 3. Concentration of oxygen. Increase in oxygen concentration increases the rate of aerobic respiration. 4. Number of carrier proteins in the membrane 3.OSMOSIS What is osmosis Net movement of water molecules from a region of higher water potential (dilute solution). to a region of lower water potential (Concentrated solution) through a partially permeable membrane. Plant cells and osmosis If a plant cell is placed in high If a plant cell is placed in low potential of water (e. distilled potential of water (high water or diluted solution.) concentrated solution of salt of Sugar) The cell gain water by The cell loses water by osmosis osmosis The vacuole enlarges and the if it loses a small amount of cell water The Vacuole shrinks becomes turgid and the cell becomes flaccid (Turgor pressure is the but the cell membrane pressure acting remains attached to the cell wall against an inelastic cell wall) If the cell gains water it gains its turgidity The turgidity is necessary once more ( reversible for supporting the plant process). The pressure inside the plant If it loses more water, the cell can be cell membrane separates increased due to absorption away from the cell wall and of water without being burst the cell becomes as it is surrounded by plasmolyzed. a rigid cellulose cell wall. Plasmolysis : It is the shrinkage of cytoplasm of a plant cell so that the cell membrane begins to tear away from the cell wall It is an irreversible condition because it damages the cell membrane when it tears away from the cell wall. Its a sensation caused by the process of osmosis Turgor pressure within cells water pressure acting against an inelastic cell wall eded to support plant flaccid soft and limp not firm. Animal cells and osmosis An animal cell is placed in higher water potential The cell gains water and bursts, therefore the pressure inside the animal cell cannot be higher than that inside the plant cell. If an animal cell is placed in lower water potential cytoplasm shrinks and the cell shrive up (It not plasmolysed as plasmolysis includes separation of the cell membrane away from the cell wall and the animal cell has no cell wall) animal cell in lower water potential (shriveled cell) animal cell in higher water potential (cell burst) Comparison diffusion osmosis 1- It is applied for movement 1.It is applied for the of any type of is applied for movement of molecules of the movement of water only molecules 2. A partially permeable 2-A partially permeable membrane must be always membrane not always involved involved Variant questions The differences between uptake of water and uptake of minerals by the root hair cells 1- Uptake of water takes place by the process of osmosis which is a passive process does not need energy) while uptake of minerals takes place by the process of active uptake which is an active process (needs energy). 2- In uptake of water, the molecules of water move from regions of their higher concentration (potential), while in uptake of minerals the molecules move from regions of their lower concentrations to regions of their higher concentrations against their concentration gradient). Remember that No active transport for water or gases Water potential of a substance: It is the measure of how much water there is in it, and how easily the water molecules can move around EX : A substance containing a lot of water has a higher water potential, while a substance containing little water has a lower water potential. What is meant by water potential gradient Presence of difference in water potential of different media. Water molecules move down concentration gradient, means move from region of higher water potential to region of lower water potential. WHAT is the Importance of osmosis to plants Absorption of water by the root hair cells Prevents wilting of the plant and provides support by turgidity  Practical work 1. If a piece of plant such as potato tuber is placed in a concentrated solution of salt or sugar its length decreases This due to loss of water from the cell where water potential is higher to the surrounding solution where the water potential is lower. (Decrease in this represented in a negative value ex: -1, -2) 2. In the above condition if a weight is hanged to the potato tuber as in figure below the tuber becomes unable to support the weight as its cells become flaccid) 3. piece of plant such as potato tuber is placed in distilled water or a dil solution of salt or sugar its length increases This is because it is water from the surrounding solution where water potential is other than that of potato tissues Increase in length is repented a positive value +1 , +2...) 4- In the above condition weight is hanged to the potato tuber as in figure below the tuber becomes able to support the weight as its cells become turgid. 5- Salting (e. salting of, c Sugaring of food (e.q. making lam) are important ways in food preservation. Explain why As most microorganisms such as bacteria and fungi cannot live in media of high concentration of salt or sugar, because such media have low water potential, as a result of this microorganism lose water by osmosis and then die 6-Plants die as a result of irrigation with sea water Sea water has high contractions of salts ex : low potential outside the plant roots so the water moves from inside the plant to outside by osmosis , so the plants wilt and die. 7- Mean average length samples The total of the samples divided by the number of samples Example If potato strips of the same length Ex: If 50 mm of potato strips is put in the same water for the same period of , the final lenghth is measured the result are 51,52,54 and 59 to calculate the mean add the lengths then divide the produced value by 4 In the above example how to get more reliable values Exclude the value 59. as it seems to be anomalous and calculate the mean of the 3 values 8- Why reposting an experiment are times in important before takin conclusion ? For more reliable results as taking the average may reduced due to defect in one or more of the samples or due to personal errors In measurements. 9. How to determine glucose concentration in potato Put potato rods of the same length and obtained from the some potato in different concentrations of glucose, the concentration of glucose that result in no change in potato is equal to that in potato because at this concentration of water net movement is zero ( means that the amount of water lost is equal to that gained) 10-if a plant stem is cut vertically as shown and each of the produced parts is placed in a different concentration of sugar 1. The outer layer in waterproof layer therefore it is not affected by changes in water potential 2. and therefore, it does not change in length but the inner soft tissue in the one placed in a concentrated sugar solution lost water by osmosis causing cells to shrink or become plasmolyzed. 3. therefore, it decreases in length than its outer waxy layer while the other one placed in distilled water (zero sugar gained water by osmosis therefore its cells become turgid and increase in length.  CHAPTER 3 Movement in and out of cells DR.MOATAZ BEDWEY 1 Active transport is the movement of A molecules from a region of their higher concentration to a region of their lower concentration. B particles from a region of lower concentration to a region of higher concentration using energy from respiration. C urine by relaxation of a sphincter muscle in the bladder. D water through a partially permeable membrane from a more dilute to a more concentrated solution. 2 The diagram shows an experiment to demonstrate the movement of molecules. inverted thistle red ink solution funnel beaker of water permeable membrane attached to funnel After one hour, the water in the beaker turned red. What is the most likely reason for this colour change? A Molecules of red ink move through the membrane by diffusion. B Molecules of red ink move through the membrane by osmosis. C Molecules of water move through the membrane by diffusion. D Molecules of water move through the membrane by osmosis. 3 Why does oxygen diffuse into the blood from an alveolus in the lungs? A The oxygen concentration in the alveolus is greater than the carbon dioxide concentration in the blood. B The oxygen concentration in the alveolus is greater than in the blood. C The oxygen concentration in the blood is greater than in the alveolus. D The oxygen concentration in the blood is greater than the carbon dioxide concentration in the alveolus. 4 The diagram shows water and sugar molecules on either side of a partially permeable membrane. partially permeable membrane key sugar molecule X Y water molecule What happens during osmosis? A More sugar molecules pass through the membrane from X to Y than from Y to X. B More sugar molecules pass through the membrane from Y to X than from X to Y. C More water molecules pass through the membrane from X to Y than from Y to X. D More water molecules pass through the membrane from Y to X than from X to Y. 5 A jar of air was placed upside down on top of a jar containing a brown gas as shown. air air and brown gas brown gas at start after one hour Which process has taken place? A diffusion both upwards and downwards B diffusion downwards only C diffusion upwards only D diffusion and osmosis 6 Which statement describes how young plants are supported? A the pressure of water inside the cells pressing outwards on the cell membranes B the pressure of water inside the cells pressing outwards on the cell walls C the pressure of water passing from the roots through the phloem D the pressure of water passing from the roots through the xylem 7 The diagram shows a test-tube containing clear jelly. A drop of blue ink is injected into the middle of the jelly. clear jelly drop of blue ink The blue colour of the ink spreads throughout the jelly. By which process does the blue ink spread through the jelly? A active transport B catalysis C diffusion D osmosis 8 Which diagram shows the changes in appearance of a plant cell when it remains in a concentrated sugar solution for thirty minutes? A B  C D 9 The diagram shows a fish in a pond. Why does oxygen diffuse from the air into the water before reaching the fish? A Oxygen is more concentrated in the air than in the water. B Oxygen is more concentrated in the water than in the air. C Oxygen is needed by the fish for aerobic respiration. D Oxygen is needed by the fish for anaerobic respiration. 10 Which structure provides the best surface for diffusion? A atrium B bronchioles C ileum D trachea 11 The diagram shows a plant cell. What is the appearance of this cell after it has been placed in pure water for 30 minutes? A B C D 12 A student cuts out four pieces of carrot root of equal size. The pieces are treated as shown in the diagram, and then left for two hours. After two hours, which piece of carrot will be the smallest? A B C D sugar water sugar water solution solution boiled carrot boiled carrot fresh carrot fresh carrot 13 The diagrams show how a cell appears under the microscope at the start of an experiment and after it has been placed in a dilute solution of salts for 5 minutes. start of the after placing in a experiment dilute solution of salts Which statement explains what happens? A Dissolved salts enter the cell by diffusion. B Dissolved salts leave the cell by diffusion. C Water enters the cell by osmosis. D Water leaves the cell by osmosis. 14 The diagram represents the molecules in two solutions either side of a fully permeable membrane. Key solute molecules water molecules fully permeable membrane In which directions are the net movements of the molecules? solute molecules water molecules A left to right left to right B left to right right to left C right to left left to right D right to left right to left 15 How do carbon dioxide and oxygen move in and out of a mesophyll cell? A active transport B diffusion C respiration D transpiration 16 During osmosis, which molecules move and through which type of membrane? molecules type of moving membrane A oxygen partially permeable B oxygen permeable C water partially permeable D water permeable 17 Which process in humans does not use energy released from respiration? A cell division B diffusion of oxygen C muscle contraction D protein synthesis 18 Which statements are correct for both diffusion and osmosis? molecules move from higher involves movement requires energy concentration to lower of water only from the cell concentration A


B

 C  
D    19 The diagram shows a plant shoot and the same shoot six hours later. plant shoot same shoot six hours later Which change in environmental conditions could cause this change in the shoot? A a decrease in available water B a decrease in light intensity C a decrease in wind speed D an increase in humidity 20 The diagram shows an experiment set up to investigate osmosis in living cells. water (X) potato glass dish concentrated sugar solution (Y) What happens to the volumes of water (X) and sugar solution (Y) after 12 hours? volume of water (X) volume of sugar solution (Y) A decreases ecreases increases B increases ncreases increases C increases remains the same D remains the same decreases 21 The diagram shows apparatus which can be used to demonstrate osmosis. 1 2 glass tube liquid level very concentrated concentrated water sucrose solution sucrose solution partially permeable membrane After one hour, what would happen to the liquid levels in the glass tubes? 22 By which process does oxygen pass out of a leaf? A diffusion B osmosis C translocation D transpiration 23 Which characteristics are correct for both osmosis and diffusion? 24 How does oxygen move from the alveoli into the blood? A by diffusion B by evaporation C by osmosis D by transpiration 25 Which process occurs by osmosis? A plant roots absorbing mineral ions from the soil B plant roots absorbing water from the soil C the small intestine absorbing fatty acids into the blood D the small intestine absorbing glucose into the blood 26 Red blood cells were placed in a dilute solution. Movement of water across the cell membrane caused a change in their appearance. What explains this movement? 27 The diagram shows a cell. Which type of cell does the diagram show? A an animal cell in a concentrated solution of salts B an animal cell in pure water C a plant cell in a concentrated solution of salts D a plant cell in pure water 28 Two identical cylinders, 40 mm long, are cut from a potato. One (W) is placed in water and the other (X) is placed in a concentrated sugar solution. What are the lengths of the cylinders after two hours? 29 The diagram shows the movement of a concentrated sugar solution up a glass tube. The glass tube is connected firmly to a hollowed-out carrot. at the start after 2 hours glass tube carrot watertight seal concentrated sugar solution dilute sugar solution at the start after two hours Why does the sugar solution in the glass tube rise? A Sugar molecules move across the carrot tissue into the glass tube. B Sugar molecules move across the carrot tissue into the beaker. C Water molecules move across the carrot tissue into the glass tube. D Water molecules move across the carrot tissue into the beaker. 30 A plant absorbs water and oxygen into its roots. How are these substances absorbed? 31 Which diagram shows the appearance of a plant cell several minutes after it has been placed in a concentrated solution of sugar? A B C D 32 The diagrams show an experiment when set up and the same experiment two hours later. when set up two hours later partially permeable membrane dye has concentrated moved sugar solution pure into this coloured with dye water side What explains the movement of water and dye? movement of water movement of dye A diffusion osmosis B osmosis diffusion C osmosis translocation D translocation diffusion 33 The diagram represents two liquids, separated by a membrane through which osmosis can occur. membrane left eft r key molecule of water molecule of dissolved sustance What movement of molecules will occur? A Molecules of dissolved substance move from left to right. B Molecules of dissolved substance move from right to left. C Overall, water molecules move from left to right. D Overall, water molecules move from right to left. 34 The scent from a bunch of flowers spreads throughout a room. How does the scent spread? A by conduction B by diffusion C by osmosis D by transpiration 35 The diagram shows an experiment kept at room temperature. tubing containing test-tube starch, protease, protein and simple sugars distilled water membrane permeable to small molecules only What is present in the water surrounding the membrane after 45 minutes? A amino acids and simple sugars B protein and amino acids C protein and simple sugars D starch and simple sugars 36 Osmosis is defined as the diffusion of water molecules A down their concentration gradient through a partially permeable membrane. B down their concentration gradient through a permeable membrane. C up their concentration gradient through a partially permeable membrane. D up their concentration gradient through a permeable membrane. 37 The diagram shows part of a section through a leaf. Which arrow shows the direction of movement of water by osmosis in a leaf? D A leaf cells B C 38 Which structures must be present in a cell for osmosis to take place? A cell (sap) vacuole and cell wall B cell wall and cell membrane C chloroplast and cytoplasm D cytoplasm and cell membrane 39 A frog’s skin is permeable to oxygen and carbon dioxide. When a frog is swimming in pond water, in which directions will oxygen and carbon dioxide diffuse? from the frog’s skin from the water into into the water the frog’s skin A carbon dioxide oxygen B carbon dioxide and oxygen – C oxygen xygen carbon dioxide D – carbon dioxide and oxygen 40 The diagram shows a fetus attached by the placenta to the uterus wall of the mother. fetus placenta uterus wall By which process do all substances pass between the fetus and the mother in the placenta? A diffusion B nutrition C osmosis D respiration 41 What happens in osmosis? A movement of solute molecules against their concentration gradient B movement of solute molecules down their concentration gradient C movement of water molecules against their concentration gradient D movement of water molecules down their concentration gradient 42 Boiling potatoes destroys their cell membranes. A peeled, boiled potato strip is placed in a concentrated solution of salts. concentrated solution boiled potato strip of salts What takes place? solute osmosis diffusion A   key: B   = takes place C   = does not take place D   43 A red blood cell is placed in a concentrated sugar solution. What happens and why? A The cell bursts as sugar molecules diffuse into it. B The cell bursts because the concentrated sugar solution enters it. C The cell shrinks because sugar molecules leave it. D The cell shrinks because water leaves it. 44 The diagram shows two solutions that are separated by a partially permeable membrane. partially permeable membrane dilute concentrated solution solution of of sucrose sucrose X Y In which direction will most water molecules move in relation to their concentration gradient? A from X to Y against their concentration gradient B from X to Y down their concentration gradient C from Y to X against their concentration gradient D from Y to X down their concentration gradient 45 On a dry, sunny day, how does water vapour move through the stomata of a leaf? A into the leaf by diffusion B into the leaf by osmosis C out of the leaf by diffusion D out of the leaf by osmosis 46 The diagram shows an experiment using a potato. concentrated sugar solution fresh potato water Which shows the result of the experiment after 24 hours? A B C D 47 The dots represent molecules of a gas in four tubes at the beginning of an experiment. In which tube will more molecules move from X to Y than in the opposite direction? X Y A B C D 48 An experiment on diffusion was set up as shown in the diagram. partially mixture of protein permeable solution and membrane protease water at 37 °C What was found in the water after 15 minutes? A amino acids B fatty acids C glucose D glycerol 49 A student investigated osmosis in potatoes. He set up the apparatus shown. potato cylinder potato cylinder P Q scales distilled very concentrated water sugar solution At the beginning the potato cylinders were exactly balanced. He immersed the cylinders into the liquids for 4 hours, after which the cylinders were lifted out of the liquids. Cylinder P was now heavier than cylinder Q. Which statement explains what happened? A Water moved into both cylinders. B Water moved out of both cylinders. C Water moved into the cylinder in the distilled water and out of the cylinder in the sugar solution. D Water moved out of the cylinder in the distilled water and into the cylinder in the sugar solution. 50 An experiment is set up as shown. membrane permeable to iodine molecules mixture of starch and water iodine solution What is the colour of the starch and water mixture after 30 minutes? A blue-black B orange C white D yellow-brown