Study Guide for Test 2 Lecture 11 I Definitions a Plastid Organelle in the cells of certain groups of eukaryotes that is the site of such activities as food manufacture and storage plastids are bounded by two membranes b Proplastic An early stage of plastids present in meristems little c Chloroplast modified plastid for photosynthesis green and is double thalakoid membrane bound 1 Grana Stacks of thylakoids 2 Stroma ground substance of plastids 3 Thylakoid Membraneous sacs that house the chlorophyll 4 Lumen Thylakoid space in chloroplasts d Amyloplast modified plastid for starch storage 1 Also plays role in plant s sense of gravity e Chromoplast modified plastid for caretenoid pigment storage 1 Carotenoid responsible for orange color of some plants f Etioplast modified plastid of plants grown in the dark that contains a prolamellar body 1 Prolamellar body Semicrystalline structure found in plastids arrested in development by the absence of light g Lignins Phenolic compounds polymerized into a matrix that is a stiff rigid glue t II h Cellulose Long polymer of glucose with Beta 1 4 linkages Cell Wall a Two types of cell walls that provide structural support 1 Primary cell wall found in plant cells still growing enlarging 2 Secondary cell wall found in some plants after cell growth has ceased b Structure 1 Primary cell wall Has rods of cellulose microfibrils embedded in a matrix of other shorter chain polysaccharides It can be stretched and enlarged to accommodate for growth 2 Secondary cell wall Composed of equal parts of cellulose microfibrils and lignin Does not allow for growth and are found in collenchyma cells tracheids vessel elements and fibers III IV Cell wall a Contains concentrated solution of Potassium salts b Primary function to generate turgor pressure a positive internal hydrostatic pressure that keeps plant cells rigid and provides the driving force for plant cell enlargement Plasmodesmata a Cytoplasmic connections b t neighboring plant cells b Primary Function Permit the movement of small molecules b t plant cells c Also actively transport proteins and RNAs Lecture 12 I Definitions a Photosynthesis Conversion of light energy to chemical energy the production of carbohydrates from carbon dioxide and water in the presence of chlorophyll by using light energy Occurs by light reaction and Calvin cycle 1 Chemical eq 3CO2 6H2O C3H6O3 3O2 3H2O 2 Driven by red and blue light 3 Chlorophyll b captures light and absorbs most effectively at blue 470 but also at 430 and 640 absorbs what a cannot 4 Carotenoids guards to protect photosynthesis machinery b Light reaction rxn takes place on the thylakoid membranes and light captured by chlorophyll leads to electron transport and finally to the formation of ATP from ADP and the reduction of NADP to NADPH 1 Antenna Complex located at periphery captures photos and passed energy to reaction center 2 Reaction center H2O is split into O2 and H and it uses 2 molecules of chlorophyll a c Calvin cycle aka dark rxn takes place in the stroma of the chloroplast and fixes CO2 into carbohydrates using ATP and NADPH CO2 is converted to sugar using the chemical energy produced in the light rxn 1 Rubisco is enxyme catalyst used 2 Six turns of the Calvin cycle are needed to make one glucose Excess glucose can be stored as starch d Rubisco the enzyme that carries out CO2 fixation and converts a 5 carbon sugar RuBP into two 3 carbon sugars PGA e Photorespiration The oxygenase activity of Rubisco combined with the salvage pathway consuming O2 and releasing CO2 occurs when Rubisco binds O2 instead of CO2 Has dual activity carboxylase oxygenase 1 Problem Oxygenase is an unwanted activity when CO2 is low rubisco binds O2 and breaks down RuBP to glycolyate and eventually CO2 2 Reduces phtotsyntheteic efficiency by 30 40 3 Occurs in peroxisome and mitochondria conditions 4 Occurs in C3 plants when T is high f Photosystem II uses high energy 680nm and evolved later g Photosystem I Uses electron produced in II and energy 700nm lower It is not strong enough to split water More primitive than II II Action Spectrum VS Absorbtion Spectrum a Action spectrum The spectrum of light waves that elicits a particular reaction 1 Shows where the leaf is more efficient in photosynthesis based on absorbance b Absorbtion spectrum The spectrum of light waves absorbed by a particular pigment 1 Leaf color is b t yellow and green C3 Plants a Fix CO2 into PGA 3 carbon compound b When T is high photorespiration occurs III IV C4 plants Solution to photorespiration e g sugar cane maize tropical a Fix CO2 in to malate 4 carbon compound b Spatial separation of CO2 fixation and Calvin Cycle 1 Mesophyll cells site of CO2 fixation CO2 malate 2 Bundle Sheath cells Site of Calvn Cycle release CO2 3 The chloroplasts of Mesophyll and BSC are connected Plasmodermata c CAM Photosynthesis A modification of C4 Plants that temporally separate CO2 fixation and the Calvin Cycle e g cactus 1 Uses malate which is stored in vacuole as malic acid AKA Crassulacean Acid Metabolism 2 Daytime Stomata open Night Stomata open Lecture 13 I Definitions a Macronutrients inorganic chemical elements required in large amounts for plant growth 1 Ex C H O N K Ca Mg S 2 Limitations for plants growth N K P 3 Nitrogen in the soil is Nitrate and easily leaches from soil b Micronutrients Inorganic chemical elements required in very small trace amounts for plant growth c Apoplast Cell wall continuum where substances can move from cell to cell d Symplast A continuum made up of protoplasts of the plant body and their plasmodesmata Transport from cell to cell in the plasmodermata is called symplastic transport e Casperian Strip A bandlike region of primary wall containing suberis and lignin found in anticlinal radial and transverse walls of endodermal and exodermal cells f Nitrogen Fixation The incorporation of atmospheric nitrogen into nitrogen compounds carried out by certain free living and symbiotic bacteria nitrogen fixing bacteria g Nitrification The oxidation of ammonium ions or ammonia to nitrate a process carried out by free living soil bacterium h Ammonification Decomposition of amino acids and other nitrogen containing organic compounds resulting in the production of ammonia NH3 and ammonium ions NH4 i Denitrification The conversion of nitrate to gaseous nitrogen j Mychorrhizae fungus roots intimate and mutually beneficial symbiotic associations between fungi and roots Obtain sugar from plant in exchange for
View Full Document
Unlocking...