Nutrition in plants

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 1 LO: Identify and label the cellular and tissue structure of a dicotyledonous leaf, as seen in transverse section using the light microscope and describe the significance of these features in terms of their functions, such as the • distribution of chloroplasts in photosynthesis • stomata and mesophyll cells in gaseous exchange • vascular bundles in transport Internal leaf Structure

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 2 Structure Function Upper epidermis ● Contains cuticle (waxy layer that reduces excessive evaporation of water) ● Single, protective layer of cells ● Transparent to allow light to pass through to reach the mesophyll cells ● No chloroplasts Palisade Mesophyll cells ● Closely packed, large number of chloroplasts to absorb maximum light energy for photosynthesis. Spongy Mesophyll cells ● Lesser chloroplasts for photosynthesis ● Loosely packed with intercellular air spaces to facilitate diffusion of carbon dioxide and water vapour ● Surface covered with layer of moisture to allow carbon dioxide to dissolve first before diffusing into cells Vascular bundles (xylem + phloem) Xylem ● Transports water and minerals salts from roots to leaves ● Strengthens leaf to prevent tearing Phloem ● Transports sucrose and amino acids from leaves to other parts of plant (Translocation) Lower epidermis ● Single, protective layer of cells ● Presence of stomata for gaseous exchange Guard Cells ● Regulate the opening and closing of the stomata ● Contain chloroplasts for photosynthesis

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 3 LO: State the equation, in words and symbols, for photosynthesis Word Equation: carbon dioxide + water glucose + oxygen Chemical Equation: 6CO2 + 6H2O C6H12O6 + 6O2 • Rate of respiration in plants is taken to be constant. • When rate of photosynthesis is higher than rate of respiration, net carbon dioxide is taken in. • When rate of photosynthesis is lower than rate of respiration, net carbon dioxide is given out. light energy → chlorophyll light energy → chlorophyll

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 4 LO: Describe the intake of carbon dioxide and water by plants Entry of carbon dioxide through the leaves of the plant ● Enters the leaves through the stomata from the surrounding atmosphere ● By diffusion down a concentration gradient (higher concentration in the atmosphere than in the inside of the leaves) ● Moves into the intercellular air spaces ● Dissolves in the film of moisture surrounding the mesophyll cells ● Diffuse into the chloroplasts of the mesophyll cells Entry of Water through the roots of the plant From the roots • Enters root hair cells from the soil ● By osmosis down the water potential gradient (higher water potential in the soil than the cell sap of the root hair cells) ● Moves from cell to cell, via osmosis until it reaches the xylem ● Root pressure moves water from cells into the xylem Up the xylem ● Water moves up the xylem from the roots to the leaf by o root pressure o cohesion and adhesion of water molecules through capillary action o transpiration pull In the leaf ● Water moves out of xylem and moves from cell to cell, via osmosis until it reaches the mesophyll cells

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 5 LO: State that chlorophyll traps light energy and converts it into chemical energy for the formation of carbohydrates and their subsequent uses ● Chlorophyll absorbs light energy from the sun and converts it into chemical energy for the formation of glucose in photosynthesis. In the light dependent stage: ● Light energy is absorbed by chlorophyll and then converted into chemical energy. ● Light energy is used to split water molecules into oxygen and hydrogen atoms through photolysis of water. In the light independent stage: ● Hydrogen atoms (from the photolysis of water), chemical energy (from light dependent stage) and enzymes are used to reduce carbon dioxide to glucose. ● Glucose formed is used for respiration and formation of cellulose cell walls. ● Glucose is converted to sucrose and transported to storage organs via translocation. ● Excess glucose is stored as starch or fats, and converted into proteins to form new protoplasm.

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 6 LO: Investigate and discuss the effects of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis (e.g. in submerged aquatic plant) Experimental set-up to investigate factors affecting rate of photosynthesis Factors affecting rate of photosynthesis: Light intensity ● vary the distance of light source from the plant ● As light intensity increases, rate of photosynthesis increases. Carbon dioxide concentration ● vary the concentration of dilute sodium hydrogen carbonate solution ● As carbon dioxide concentration increases, rate of photosynthesis increases. Temperature ● vary the temperature of the water bath ● As temperature increases, rate of photosynthesis increases until optimum temperature is reached. Increased in temperature beyond the optimum temperature causes enzymes to be denatured and r ate of photosynthesis decreases.

Name: __________________ Topic: Nutrition in plants Concepts Summary Notes Nan Hua High School Biology 7 LO: Discuss light intensity, carbon dioxide concentration and temperature as limiting factors on the rate of photosynthesis • A factor that directly affects or limits a process if its quantity or concentration is altered is called a limiting factor. ● As light intensity increases, stomata opens wider ● More carbon dioxide can diffuse into the plant through the stomata ● Rate of photosynthesis increases ● As concentration of carbon dioxide increases, more carbon dioxide can diffuse into the plant through the stomata ● Rate of photosynthesis increases • As temperature increases, enzymes and substrates have higher kinetic energy, hence higher frequency of effective collisions • Rate of formation of enzyme substrate complex increases • Rate of photosynthesis increases •