cheat sheet biology and more essays title s and all, Lecture notes of Biology

Download cheat sheet biology and more essays title s and all and more Lecture notes Biology in PDF only on Docsity! Revision plant nutrition DR. Nihal Gabr Study notes 1. Balanced equation of photosynthesis : 6CO2 + 6H2O ……………………………..C6H12O6 + 6O2 Light energy Trapped by chlorophyll 2.Definition photosynthesis : its the process by which the plant makes organic substances ( carbohydrates) from inorganic substances ( carbon dioxide and water ) using light energy , where light energy is converted into chemical energy stored in glucose 3. Describe how photosynthesis takes place Describe how carbon-dioxide forms glucose 1. Carbondioxide : Diffuse down its concentration gradient into the leaf through the stomata ..the pass through air spaces of spongy mesophyll ....dissolve in the layer of water surrounding mesophyll cells to diffuse through cell wall then cell membrane 2. Water Absorbed from the soil by root (root hair cells ) down water potential gradient then transported up through xylem vessels to enter mesophyll cells by osmosis 3.Light energy : Absorbed by chlorophyl in the chloroplast , used to help CO2 react with water producing glucose where light energy is converted into chemical energy stored in glucose Describe pathway taken by CO2? 4. Explain why oxygen leaves the leaf Diffuse out of the leaf through stomata Down concentration gradient Where higher oxygen concentration is inside the leaf (its a product of photosynthesis ) Than outside . 1. Upper epidermis : 1. Transparent to allow passage of light to reach the palisade mesophyll for photosynthesis 2. Protective layer that prevent entry of pathogens 3. Produce waxy cuticle....transparent and reduces water evaporation thus reducing water Vapour loss ( cuticular transpiration) Role in photosynthesis 2. Palisade mesophyll 1. Packed with large number of chloroplast for maximum absorption of light energy 2. Cells arranged close together with tiny air spaces so absorb more light energy 3. Arranged in columns ends on to allow light to pass through minimum number of cell walls to avoid scattering of light by cell wall 4. Chloroplast are arranged broad side on for maximum absorption of light energy ( suggest why chloroplast arranged at one side ?in case of high light intensity to absorb less light .) 3. Spongy mesophyll 1.Loosely arranged/ packed with large air spaces to allow diffusion of gases 2. Surrounded by layer of water on cell walls that evaporates into the air spaces ...so water vapor diffuse out of the leaf through stomata down concentration gradient by transpiration to help cool down the plant 3. Water layer on cell wall to dissolves the gases to diffuse into cells : 4. Stomata 1. Allow gas exchange by allowing diffusion of gases such as A) carbon-dioxide into leaf for photosynthesis B) oxygen into leaf for respiration C) allow diffusion of water vapour out of leaf by trasnpiration 5. Guard cells Control opening and closing of stomata To allow .....same as stomata keywords 10. Stomata ( open and close ) explain the shape of the guard cells Temperature is below optimum Plant is rich in water Temperature is very high Plant in shortage of water A) plant has plenty of water.........more water enter the cells by osmosis........guard cells become turgid....stomata open B) shortage of water ...guard cells become flaccid ...stomata close .....to reduce water loss by transpiration 11. Factors affecting rate of photosynthesis : 1, carbon dioxide concentration......carbon dioxide is a reactant/ raw material for photosynthesis / substrate 2. Light intensity ....light absorbed by chlorophyll , used as a source of energy needed converted into chemical energy stored in glucose 3. Temperature ......photosynthesis is a process catalysed by enzymes in addition temperature affects the closing and opening of stomata 12. Limiting factors definition : It is an environmental factor present in short supply That limits rate of reaction ( for plant growth: light intensity , minerals concentration , temperature and carbondioxideconcentration ) Graph 3 vs graph 4( why temperature is limiting factor at f in graph 3) At point F ( leveled off) , the temperature is the limiting factor Where in graph 4 at same light intensity and same carbon dioxide concentration but higher temperature , the rate of photosynthesis increased . Graph 4 , whose is the limiting factor ? Light intensity is a limiting factor At all light intensities , the rate of photosynthesis is increasing Graph 2 , the blue part what is the limiting factor ? Carbon dioxide concentration is the limiting factor Where in graph 4 , at same light intensity and same temperature Upon increasing carbon dioxide concentration , the rate of photosynthesis increase( kept increasing ) What are the advantages of growing crops in green / glass houses Green house can maintain, optimum conditions for photosynthesis ; Control limiting factors for, photosynthesis / growth such as light intensity and temperature . to increase yield Where it can provide high light intensity by using artificial light source Where light sensors can be used / light can be lit to allow light energy to be available all time during day . control of temperature by air conditions / ventilation To provide and maintain optimum temperature ; control of carbon dioxide concentration By carbon dioxide enrichment / high carbon dioxide concentration ; Using a composter or CO2 cylinders control of water and nutrients. By water supply / humidity ; Supplying nutrients / minerals ; control of pests and weeds. Using a biological control / chemical control. herbicides not required . Sodium hydrogen carbonate …..source of carbon dioxide Hydrogen carbonate Indicator for CO2 Increase inCO2 concentration acid …..lower the pH Respiration > photo Decrease in CO2 concentration Increase PH Photo> respiration . Yellow Dark Red Purple Light Investigation effect of different .............on rate of photosynthesis Independent :light intensity / temp/ carbon dioxide concentration Controlled variables : A) temperature by thermostatic water bath and heat shield B) CO2 conc.: HCO3- of same volume C) plant species /age /size of leaves Temperature / light intensity / carbon dioxide concentration ) is a limiting factor / a factor that affects the rate of photo. So it has to be kept constant / its a controlled variable that be kept constant. As temperature affect the enzymatic activity./ light is absorbed by chlorophyll as a source of energy / CO2 is a reactant. Where any increase in temperature increase kinetic energy of molecules / collisions thus affecting rate of enzymatic activity (reference to the effect of temp on enzyme activity) To have fair test and valid comparison Suggest and explain why the scientists kept the temperature of the leaves at 20 while they recorded the results? Suggest and explain why the scientists kept the temperature of the leaves at 20 while they recorded the results? Why use tank of water ? ' Acting as a heat shield to absorb excess heat from the lamp and avoid over heating thus maintaining a constant temperature Dependent: measure volume of oxygen gas produced in unit time using a gas syringe '