REVISION

Lab ( 6 ) Solutions

Solutions Solution:is the homologous mixture of 2 or more substances in different proportion,substances can be solids, liquids or gases or combination of the three.

Living organism’s tissue contains high percentage of aqueous solutions called Tissue fluid and divided into: 1) Intercellular fluid 2)extracellular fluid -These fluids serves in exchanging substances between cell and its surrounding to insure performing vital biological functions of the cell and to maintain cell shape and volume. -Water is the main component of living cell and protoplasm, and the main solvent on living tissues.

Physical and Chemical Properties of Water 1- Water has broad range between freezing and boiling degrees. 2- Has the ability to bind to macromolecules such as proteins, carbohydrates and nucleic acids with hydrogen bonds (H-bond). 3- Has many physical characteristics such as: surface tension, viscosity, cohesion and adhesion. 4- Polarity of water helps adhesion to surface of many molecular organic components such as: starch, proteins and moisten them and form colloidal solutions. 5- Water is an ideal solvent of wide range of ionic substances, also to non-ionic substances. 6- water is inactive chemically. This property provides ideal medium for biochemical reactions such as photosynthesis.

Types of Aqueous Solutions 1- True Solution: homologous, does not precipitate with time, and filtrate through filter paper such as aqueous sucrose solution and copper sulphate solution. 2- Suspension: Heterogeneous. Solute particles diffuse into large particles that can be seen by eye or microscope. They do not filtrate through filter paper, and can be easily separated such as aqueous solution of calcium sulphate.

3- Emulsion: The mixture of 2 immiscible liquids (such as water and oil). One liquid particles suspend in form of tiny globes in the other liquid, and when left aside they separate into two layers. By adding a emulsifying agent (as NaOH) it helps stabilize the emulsion. 4- Colloidal solution: Molecules spread between solvent’s particles, and does not precipitate or float. Also they do not filtrate through membranes (animal membranes or artificial membranes such as cellophane), but they can filtrate though regular filter paper. Colloidal solutions are viscous. Solute is called dispersed phase, and the solvent is called dispersion medium. (surface aggregation- Brownian motion- membrane semi-permeability- The ability to absorb water )

Types of Aqueous Solutions Conclusion Observation Steps Types of Aqueous Solutions Exp Resulted solution is a true solution Sugar or copper sulphate particles, forming homologous clear solution put 1 gm of sucrose or copper sulphate + 100 ml distilled water. True Solution 1 Resulted solution is a suspension White precipitate formed. Solution is opaque and heterogeneous In test tube, put 10 ml of calcium chloride solution (5%) + 10 ml sodium sulphate (5%) and heat in water bath for 10 minutes. Suspension 2 -The two liquids are immiscible and separate into two layers - NaOH is an emulsifying agent that can dissolve oil and form emulsion. Two layers are formed oil divided into small droplets Divided into 2 parts (A) In test tube, put 1 ml oil + 5 ml distilled water and shake well. (B) In new test tube put 1 ml oil + 4 ml distilled water + 1 ml 5% NaOH. Sake well. Emulsion 3

Types of Aqueous Solutions Conclusion Observation Steps Types of Aqueous Solutions Exp The increase in weight is due to absorption of solidified colloidal substances to water and convert into viscous colloids. Weight increased after water soaking   1- Weigh two slides of dry gelatin, or dry bean seeds. 2- Soak in water in Petri dish for 15 minutes, and weigh again. Calculate difference in weight Colloidal solution Demonstration of absorption of solidified colloidal substances 4 The dye color was adsorbed by coal molecules, then color reappeared because acetone inhibits the action of the coal and prevents adsorption between dye and the coal. A- Filtrate liquid color is dark blue (dye color) B- Filtrate liquid color is clear(dye color disappeared) C- Filtrate liquid color is light blue. A- In test tube, put10 ml of methylene blue dye (0.1 %) and filtrate through filter paper. Observe color. B- In test tube, put10 ml of methylene blue dye (0.1 %) and filtrate through filter paper + add 0.5 gm of animal coal. Observe color. C- In test tube, put10 ml of methylene blue dye (0.1 %) and filtrate through filter paper + add 0.5 gm of animal coal + add 5 ml of alcohol (or acetone). Observe color. Colloidal solution Demonstration of Surface Aggregation of Colloidal Substances 5 The constant vibrating motion of the particles is indication of Brownian motion of the solution Vibrating motion of colloidal sulfur particles. On glass slide, put 1 drop of colloidal sulfur solution, and examine with microscope. (colloidal sulfur solution: sodium thiosulfate (3M) + conc. Sulfuric acid ). Observing Brownian Motion of Colloidal Particles 6

Diffusion, Osmosis and Photosynthesis Lab ( 9 ) Diffusion, Osmosis and Photosynthesis

Diffusion:The net spontaneous movement (transport)of particles through a semi-permeable membrane resulting from particles motion energy, and driven by concentration gradient in the medium.

O2 and CO2 diffusion in leaf Examples for Diffusion O2 and CO2 diffusion in leaf (photosynthesis) Plant root absorption of water Exchange of O2 and CO2 in animal lung

Factors Affecting Solute Diffusion Concentration (high low) The difference in conc. Diffuse faster Temperature Higher temperature Diffuse faster Size of particles Smaller particles Diffuse faster Particles (molecules, ions) Particles diffuse independently of each other.

Diffusion Through Cellular Membranes: The membrane is a barrier separates two mediums. 1-natural : ex. the cellular (plasma) membrane 2-artificial : ex. cellophane plasma cellophane

Selective permeability Types of Membranes Selective permeability Semi-permeable Impermeable Permeable Allows solvent molecules to permeate and some solute molecules Permeate solvent (water) molecules only. Does not allow either solute or solvent particles to permeate. Allows solutes particles to permeate Cell membranes cellophane Nylon Tin filter paper Cell wall in plant cells

Toxic Substances Solute substances Factors Affecting Membranes Permeability Temperature 4˚C - 50˚C permeability Increase Toxic Substances mercuric chloride HgCl2, acids and lipids’ solvents (in specific concentrations ) permeability Increase Solute substances Solutes in the cells surrounding affect membranes permeability(antagonism)

Experiments for Diffusions

indicating the diffusion of these gases in the air (gas in gas) Conclusion Observation Steps Exp. NO. indicating the diffusion of these gases in the air (gas in gas) we smell the distinctive scent of each Open a bottle of fragrance or ammonia or ether Demonstration of Gas-Gas Diffusion 1 indicating diffusion of liquid dye in water (liquid in liquid). we can see water coloring with the dye Put 1 drop of blue methylene dye or eosine dye in beaker filled with water Demonstration of Liquid-Liquid Diffusion 2 indicating the diffusion of the solid substance in the water (solid in liquid) we can see the water coloring blue Put 1 crystal of blue copper sulfate in beaker filled with water Demonstration of Solid-Liquid Diffusion 3

due to diffusion of ammonia vapors into flower’s cells. Conclusion Observation Steps Exp. No. due to diffusion of ammonia vapors into flower’s cells. color changes to blue Expose red vinca flower to ammonia vapors Demonstration of Gas Diffusion in Plant Cells 4 Starch molecules are large, whereas iodine molecules are small. In 1st beaker, starch is diffusing slowly, in 2nd beaker iodine diffuses faster Prepare gelatinous solution, then divide into 2 parts in 2 beakers. a- 1st beaker: Add drops of iodine, mix well, and cool in fridge till solidified, and add 2 ml starch solution, leave aside. b- 2nd beaker: Add starch solution, mix well, and allow to cool in fridge, then add 2 ml of diluted iodine solution, leave aside. Comparison between Molecules and Ions Diffusion in Gelatinous medium 5

Demonstration of Temperature Effect on Plasma Membrane Permeability Conclusion Observation Steps Exp. NO Color density increases due to increase in temperature because hot temperatures increases permeability of membranes and leading to increase diffusion of red dye from the plant cells of beetroot. Water color red because anthocyanin dye diffuses from beetroot to water due to increase in temperature. When measuring with Spectronic we notice increase in readings. 1- Cut beetroot into even pieces (2 ml thick) then rinse with water till red color disappears (red color is due to anthocyanin dye). Divide equally in 3 large test tubes filled with distilled water and expose to different temperatures (0˚C – 10- 20- 30- 40- 50- 60˚C). 2- After 15 minutes, take tubes out for 5 minutes to reach room temperature. Shake tubes, and transfer solutions to new special tubes (cuvettes) and measure color density at spectrophotometer (or Spectronic) device at 475nm (nanometer). Demonstration of Temperature Effect on Plasma Membrane Permeability 6

Osmosis: is the diffusion of water from a diluted solution to concentrated solution through a semi-permeable membrane. Osmotic Pressure: is the force that pulls water molecules from the surrounding. concentration of solutes osmotic pressure

Hypertonic solution Isotonic solution Hypotonic Solution Types of Solution Concentrations and Osmosis Hypertonic solution Isotonic solution Hypotonic Solution When cell is put in saline or hypertonic solution (high concentration solution), the rate of water exit from the cell is higher than the rate of entry (by osmosis), this leads to cell shrinking. This process is known as Plasmolysis. When cell is put in isotonic solution, its volume and natural shape do not change because the rate of water entry into the cell equals the rate of exit. Isotonic solution concentration equals the intracellular concentration. When living cell is put in distilled water or hypotonic solution, the rate of water entry into cell is higher than water exit, which lead to continuous entry of water inside the cell ( by osmosis) causing cell swelling, and in extreme cases cell explode.

Experiments on Osmosis

Demonstration of Osmosis by Tropism Conclusion Observation Steps Exp. NO Distilled water is a hypotonic solution because its concentration is less than intracellular solution, and water move to the inside of the cell. Whereas the saline solution is a hypertonic solution and water moves from the inside of the cell to outside. Leaf tips in distilled water swollen and bend (tropism) with cortex to the outer side and derma in the inside. Tips in saline solution bend with cortex inside and derma to the outside. Cut tips of freshly grown castor plant leaves horizontally (vertically) and identify cortex and derma. Then immerse some of them in distilled water, and some in 10% saline solution for 10 minutes Demonstration of Osmosis by Tropism 1 -Distilled water is a hypotonic solution because its concentration is less than potato cells, so water moves into the cell and increase its weight. -Whereas saline solution is a hypertonic solution, its concentration is higher than that of the cell, so water exit from the cell to the saline solution and decreases cell weight. -Potato part that was put in saline solution decrease in weight, -- -whereas the part put in distilled water increase weight. Cut a potato into small pieces and weigh. Divide into 2 parts. -Put one part in saline solution (10%) for 15 minutes, dry and weigh again. -Put the other part in distilled water for 15 minutes, then dry and weigh again. Demonstration of decrease weight Due to Plasmolysis, and Increase weight Due to Swelling( by Osmosis) 2

Conclusion Observation Steps Exp. 3 the rate of water entry into the cell equals the rate of exit. the rate of water entry into cell is higher than water exit, the rate of water exit from the cell is higher than the rate of entry. In control, normal RBCs shape and size because they are in normal isotonic RBCs that are mixed with distilled water swollen (increase volum), RBCs in NaCl solution shrunk (decrease volume). Cleanse a finger with alcohol swab. With a sterile lancet, make a puncture on a fingertip. Apply 3 drop of blood on 3 clean glass slides and make smear: 1st slide is a “control”, examine RBCs under microscope. 2nd slide: mix blood with drops of distilled water, examine under microscope. 3rd slide: mix blood with drops of 5% NaCl solution, examine under microscope. Demonstration of Effect of Extracellular Solution on Red Blood Cells (RBCs) 3

Photosynthesis:Green plants and some protozoa (cyanobacteria and algae) can build their own nutrients via photosynthesis, They absorb light energy and coverts it into chemical energy, producing organic compounds. Carbon dioxide + water + sunlight = sugar + oxygen  

Experiments on Photosynthesis

Blue color appear on leaves Conclusion Observation Steps Exp. NO The blue color is indication of starch formation distributed in the leaf Blue color appear on leaves Pick fresh green plants on afternoon, boil to kill germs and put in 70% alcohol to extract pigments till leaves become white and transfer to cold water (to regain lost water) and add a drop of diluted iodine Demonstration of Photosynthesis by Detecting Starch Formation in Green Leaves 1

Assignment (9): Fill in the table with your results: 1) Diffusion Experiment: Conclusion Observation Experiment Gas-gas diffusion Liquid-liquid diffusion Solid-liquid diffusion Gas diffusion in plant cells Comarison of molecules and ions diffusion in gelatinous medium

طريقة الأسئلة

- Put ( T ) for true statements and ( F ) for false statements:

-Fill in the blanks with the correct word to complete the following phrases

- From the data given, how to prepare the following issues . SHOW ME YOUR CALCULATIONS AND PLEASE DO NOT FORGET UNITS!!).

3-Compare : Types of definition Example

Conclusion Observation Steps The experiment - fill the spaces with the required: Conclusion Observation Steps The experiment NO 1 2

- Do the experiment then fill the table . Conclusion Observation The experiment NO.

ملاحظة: سيتم وضع الخطوات (Steps) مكتوبة أمام كل تجربة في اختبار المعمل.

- BONUS: