cells working together – moving particles bï-lÝ¾ Þ Ý¾ Ý¾

Jangchub Choeling Nunnery Mai 2005 Biology – The Cell: Diffusion and Osmosis

Science meets Dharma Sibylle Menet

Cells working together – moving particles B ï - l Ý ¾ - y - G¸ ÞGÅ - n¤Å -¿ Ë m - T Û G - h Ý -¾Å -; - ‚ ï h ü G» ô - ºG Ý ¾ - T m - H Û - y - l Ý ¾ ü Experiment 1 zdG - hrh - hP - q ô ü A crystal (potassium permanganate) has been dropped into a beaker filled with water. Áï¾-Çoôh-Vß-z;P-»ôh-q-mP-¾-Áï¾-lô-(potassium permanganate)fÛG-q-Mzü Observation: The purple colour is slowly spreading across the beaker. ŸÛz-dôGÅü- Áï¾-Çoôh-mP-¾-¤Þ-¤ïm-±ôm-¤hôG-¿Ëôh-qô-mP-mÅ-Ez-ºIï¤Å-xÛmü Initial state after 1/2 hour after 24 hours fôG-¤ºÛ-GmÅ-ÇePÅü - Vß-±ôh-- 1/2 XïÅ-ÅÞü Vß-±ôh 24 XïÅ-ÅÞü Explanation: The colour is made of moving particles. These moving particles spread out and fill

finally the whole beaker. This spreading out of particles is called Diffusion.

ºIï¾-zÁhü Initial state Final state fôG-¤ºÛ-GmÅ-ÇePÅü ¤fº-¤ºÛ-GmÅ-ÇePÅü



Diffusion Ez -Gh¾ ü Living things need substances such as water, food and oxygen. They also need to excrete waste substances such as carbon dioxide. The substances that cells need are all particles. In a gas or liquid, these particles move in all directions, all the time. When particles move from place to place we call this diffusion. In diffusion the particles spread from an area of higher concentration to an area of lower concentration. Bï-hPôÅ-±P-¤-¾-Vß-Mã-µμÅ-¸Å-hP-ÆôG-º²Ûm-½ÀâP-hGôÅü hï-±ôÅ-»P-Vßh-¸h-µμÅ-hÝG-½ÀâP-xÛ¼-Ç+Ý¼-HÛÅ-»ôhü Bï-lÝ¾-y-G¸ÞGÅ-¾-Mã-µμÅ-hGôÅ-q-n¤Å-mÛ-y-lÝ¾-AP-AP-¼ïhü y-lÝ¾-ºhÛ-±ô-½ÀPÅ-G¸ÞGÅ-»P-m-GÁï¼-G¸ÞGÅ-mP-¾-hÝÅ-Mãm-hÝ-xôGÅ-f¤Å-Th-¾-G»ô-ºGÝ¾-‚ïhü y-lÝ¾-n¤Å-GmÅ-»Þ¾-GTÛG-mÅ-GŸm-hÝ-G»ô-ºGÝ¾-‚ïh-q-ºhÛ-¾-E z -Gh¾ - ¸ï¼ü Ez-Gh¾-Ç+zÅ-¾-y-lÝ¾-n¤Å-G¼-±h-M-¤Eôm-¤fô-z-mÅ-G¼-±h-ZÝP-zÅ-M-¤Eôm-¾-Ez-ºIï¤Å-‚ïhü Examples of diffusion in humans and plants ¯ Û - Á Û P - h P - ¤ Û º Û - m P -¾ - E z -Gh¾ - H Û - h q ï - ¤± ô m ü An example of diffusion in living beings is respiration. Oxygen diffuses into cells through the cell membrane. Carbon dioxide diffuses out of cells. Bï-hPôÅ-mP-¾-Ez-Gh¾-hqï-¤±ôm-mÛ-hzÞGÅ-GbôP-¾ïm-¼ïhü Åï¾-HÛ-ÁÝm-q-Æz-qôºÛ-zMãh-mÅ-ÆôG-º²Ûm-½ÀâP-Bï-lÝ¾-y-G¸ÞGÅ-mP-¾-Ez-Gh¾-‚ãPü hÝG-½ÀâP-mÛ-Bï-lÝ¾-y-G¸ÞGÅ-ˆÛÅ-xÛ-¾-Ez-Gh¾-‚ãPü Another example is photosynthesis. Gases diffuse in and out of plant leaves. Carbon dioxide particles diffuse from a high concentration in the atmosphere to a low concentration in the leaf cells. Oxygen particles diffuse from a high concentration in the leaf cells, where they are made, to a low concentration in the atmosphere. hqï-¤±ôm-GŸm-hG-ŸÛG-mÛ-ºôh-ºhÝ-ÆïzÅ-¢ô¼-»Ûmü ¯Û-ÁÛP-GÛ-¾ô¤ºÛ-mP-¾-½ÀPÅ-G¸ÞGÅ(gases)xÛ-hP-mP-¾-Ez-Gh¾-‚ïhü hÝG-½ÀâP-(co2)y-lÝ¾-n¤Å-½ÀâP-D¤Å-G¼-±h-¤fô-z-mÅ-G¼-±h-h¤º-z-¾ô¤ºÛ-Bï-lÝ¾-y-G¸ÞGÅ-mP-¾-Ez-Gh¾-‚ãPü ÆôG-º²Ûm-½ÀâP-GÛ-y-lÝ¾-n¤Å-z¸ô-»Þ¾-G¼-±h-¤fô-zÅ-¾ô-¤Å-Bï-lÝ¾-y-G¸ÞGÅ-mÅ-G¼-±h-h¤º-z-½ÀâP-D¤Å-mP-Ez-Gh¾-ºIô-GÛ-»ôhü



Experiment 2: zdG - hrhGZ ÛÅ - q ü The dialysis tube represents the cell membrane. It is filled with a concentrated sugar solution. The concentrated sugar solution represents the cytoplasm. The tube is put in pure water and left for an hour. ±GÅ-º‚ïh-Ç~äG-Çoôh-ºhÛ-Bï-lÝ¾-y-G¸ÞGÅ-ÁÝm-q-Æz-qô-¤±ômü hïºÛ-mP-¾-G¼-±h-¿km-qºÛ-¤P¼-µμÅ-ŸÝm-DÞºÛ-DïPÅ-»ôhü G¼-±h-¿km-qºÛ-¤P¼-µμÅ-ŸÝm-DÞ-ºhÛÅ-y-G¸ÞGÅ-GÁï¼-DÞ-¤±ômü Ç~äG-Çoôh-ºhÛ-¿Ëh-¤ïh-VßºÛ-mP-¾-Vß-±ôh-GTÛG-®¤-ºWôG-hGôÅü Observation: The bag swells. ŸÛz-dôGÅü ¿eô-wh-Ç~ôÅü

Initial state After one hour fôG-¤ºÛ-GmÅ-ÇePÅü Vß-±ôh-GTÛG-XïÅ-ÅÞü Explanation: Pure water has a lot of water molecules. The concentrated sugar solution has fewer

water molecules. After an hour the water has moved onto the bag by osmosis. ºIï¾-zÁhü ¿Ëh-¤ïh-Vß-mP-¾-VßºÛ-ºhÝÅ-µμÅ-¤P-qô-»ôhü G¼-±h-¿km-qºÛ-¤P¼-µμÅ-¾-VßºÛ-ºhÝÅ-

lÝ¾-ZÝP-z-»ôhü Vß-±ôh-GTÛG-µμïÅ-ÅÞ-¿eô-wh-mP-¾-±GÅ-zÅÛP-‚ãP-z¼-zdïm-Vß-G»ô-ºGÝ¾-‚ïhü



Osmosis ±GÅ - zÅ Û P ü Osmosis is a special type of diffusion. It only happens through a special membrane like the cell membrane. This membrane is partially permeable. Water particles are small enough to move through the membrane. Bigger particles such as sugars and salts cannot move through the membrane. ±GÅ-zÅÛPü mÛ-Ez-Gh¾-Eh-q¼-Tm-ŸÛG-»Ûmü ±GÅ-zÅÛP-mÛ-h¤ÛGÅ-zÅ¾-ÁÝm-q-Åï¾-HÛ-ÁÝm-q-Æz-qô-¿e-zÞ-ŸÛG-GÛ-mP-¾-‚ãP-GÛ-»ôhü hï-ºiºÛ-ÁÝm-q-¾-ÅÛ¤-Ez-ÁÝm-q-¸ï¼ü VßºÛ-y-lÝ¾-n¤Å-VßP-PÞ-»ôh-q¼-zdïm-ÁÝm-q-ºhÛºÛ-mP-¾-G»ô-ºGÝ¾-‚ïh-fÞzü y-lÝ¾-Vï-z-¤P¼-µμÅ-hP-±-¿e-zÞ-ÁÝm-qºÛ-ºhÛºÛ-mP-¾-G»ô-ºGÝ¾-‚ïh-¤Û-fÞzü

If there are more water particles (a higher concentration) on one side of the membrane, the water particles will move to the side with the lower concentration. Osmosis happens until the concentration of water particles is almost the same on both sides. G¾-ÆÛh-ÁÝm-qºÛ-xôGÅ-GTÛG-¾-VßºÛ-y-lÝ¾-¤P-z-»ôh-mü (G¼-±h-¤P-z-) VßºÛ-y-lÝ¾-n¤Å-G¼-±h-ZÝP-zºÛ-xôGÅ-ÅÞ-G»ô-ºGÝ¾-‚ïhü xôGÅ-GZÛÅ-ÅÞ-VßºÛ-y-lÝ¾-GÛ-G¼-±h-V-Ç‰ô¤Å-¤-ºHã¼-z¼-hÝ-±GÅ-zÅÛP-HÛ-‚-¼Û¤-Gbm-qô¼-GmÅü

Sugar molecule ¤P¼-µμÅ-ºhÝÅ-lÝ¾ü

Water molecule VßºÛ-ºhÝÅ-lÝ¾ü

Partially permeable membrane V-¤-±P-ÅÛ¤-Ez-ÁÝm-qü

Pure water ¿Ëh-¤ïh-Vßü

Sugar solution ¤P¼-µμÅ-ŸÝm-DÞü



Experiment: Osmosis and Raisins zdG - hrh ü ±GÅ - zÅ Û P - h P -L Ým - ºƒ â ¤ - Ç + ¤ - q ô ü Raisins are dried grapes. They are made up of plant cells. The grapes are left in the sun to dry. A lot of the water inside their cells evaporates, leaving each cell full of a very concentrated sugar solution. RaisinsmÛ-LÝm-ºƒâ¤-Ç+¤-qô-¼ïhü hï-hG-¯Û-ÁÛP-Bï-lÝ¾-y-G¸ÞGÅ-ˆÛ-z¸ôÅ-q-ŸÛG-¼ïhü LÝm-ºƒâ¤-ZÛ-¤¼-Çeôm-mÅ-Ç+¤-¼Þ-zTßG-hïºÛ-Bï-lÝ¾-y-G¸ÞGÅ-mP-¾-Vß-¤P-qô-»ôh-q-n¤Å-fÛ¤-mÅü Bï-lÝ¾-y-G¸ÞGÅ-¾-G¼-±h-¿k-qºÛ-¤P¼-µμÅ-ŸÝm-DÞ-¿ËG-GÛÅ-»ôhü 1. You have two petri dishes and two different solutions: normal water and a strong sugar

solution. Fill every dish with a different solution. Take six raisins of the same size and put three in each of the dishes. Label the dishes.

2. Make a drawing of the raisins for each petri dish. 3. Leave the raisins in the solutions for 24 hours. 4. Discuss using your knowledge about osmosis, what will happen to the raisins. Make a

drawing of your predictions. 5. Draw the raisins again after 24 hours. 1 Eïh-¼P-¾-Çkï¼-¤-GZÛÅ-hP-ŸÝm-DÞ-¤Û-ºi-z-GZÛÅ-»ôh-q-mÛ-uÛ¼-zbP-Vß-hPü ¤P¼-µμÅ-ŸÝm-DÞ-G¼-qô-»ôhü Çkï¼-¤-¼ï-¼ï-¾-ŸÝm-DÞ-¤Û-ºi-zºÛ-ºGïP.ü LÝm-ºƒâ¤-Ç+¤-qô-Vï-VßP-GTÛG-q-GÅÞ¤-Çeôm-mÅ-Çkï¼-¤-¼ï-¼ï-mP-GZÛÅ-¼ï-¼ï-ºWôGü Çkï¼-¤-n¤Å-¾-¤ÛP-dôGÅü

2 Çkï¼-¤-¼ï-¼ïºÛ-mP-LÝm-ºƒâ¤-Ç+¤-qô-»ôh-q-hïºÛ-¼Û-¤ô-ƒÛÅü 3 ŸÝm-DÞºÛ-mP-¾-LÝm-ºƒâ¤-Ç+¤-qô-ºhÛ-Vß-±ôh- 24 ºWôGü 4 ±GÅ-zÅÛP-ÁïÅ-»ôm-zïh-uôh-zbP-mÅ-LÝm-ºƒâ¤-Ç+¤-qô-¾-ºHã¼-z-TÛ-º‚ãP-ÇKô-zÇkÝ¼-‚ïhü ¼Û-¤ô-ƒÛÅ-bï-ÇSôG-hqG-‚ïhü

5 Vß-±ôh- 24 XïÅ-¾-»P-B¼-LÝm-ºƒâ¤-Ç+¤-qôºÛ-¼Û-¤ô-ƒÛÅü

Initial state fôG-¤ºÛ-GmÅ-ÇePÅü

After 24 hours Vß-±ôh-24 XïÅ-ÅÞü

Predictions

Result



ÇSôm-hqGü Iâz-ºƒÅü Water solution VßºÛ-ŸÝm-DÞü

Strong sugar solution ¤P¼-µμÅ-ŸÝm-DÞ-G¼-qôü

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6. Compare the result with your predictions. Explain what happened. 6 Iâz-ºƒÅ-hP-Eïh-ˆÛ-ÇSôm-hqG-hz¼-¤±ßPÅ-zÇkÝ¼-‚ïhü

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Exercise Osmosis: ¢ ô P - z l¼ ü ±GÅ - zÅ Û P ü A plant cell has been put into a concentrated sugar solution. What happened? Label the two diagrams with following terms: ¯Û-ÁÛP-Bï-lÝ¾-y-G¸ÞGÅ-ŸÛG-G¼-±h-¿km-qºÛ-¤P¼-µμÅ-ŸÝm-DÞ-G¼-±h-mP-¾-ºWôG-q-mü G-¼ï-‚ãP-GÛ-¼ïh-h¤ü GÁ¤-GÅ¾-f-Ç‰h-n¤Å-ˆÛ-¼Û-¤ô-GZÛÅ-qô-¾-¤ÛP-dGÅü concentrated sugar solution G¼-±h-¿km-qºÛ-ŸÝm-DÞü cell wall Bï-lÝ¾-y-G¸ÞGÅ-¿UGÅ-¼Ûü cell surface membrane Bï-lÝ¾-y-G¸ÞGÅ-ÁÝm-q-Æz-qôºÛ-PôÅü fairly concentrated solution ºƒÛP-T¤-HÛ-G¼-±h-ŸÝm-DÞü

Initial state: fôG-¤ºÛ-GmÅ-ÇePÅü

After 30 minutes: Ç+¼-V- 30 XïÅ-ÅÞü

cells working together – moving particles bï-lÝ¾ Þ Ý¾ Ý¾

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