EQ 4.4 - Transport and Photoperiodism Notes PDF

Hello, friends! Today’s tasks: - Discuss productivity activity - Photosynthesis diagram HW: HW #3, HW quizzes 1 & 2 on day 2! ET50: the effective time it takes for 50% of the leaves to float.  Photosynthesis diagram Just as you did for cellular respiration in the mitochondrion,...

Hello, friends! Today’s tasks: - Discuss productivity activity - Photosynthesis diagram HW: HW #3, HW quizzes 1 & 2 on day 2! ET50: the effective time it takes for 50% of the leaves to float.  Photosynthesis diagram Just as you did for cellular respiration in the mitochondrion, you will now draw a detailed diagram of all of the reactions of photosynthesis. Make sure to grab a piece of green paper for your diagram, and follow the instructions on the next slide! This will be due on test day  Photosynthesis Diagram Requirements Draw/label the following: Cytoplasm Cyclic electron flow Chloroplast structure – Where? When? Why? – Outer membrane – Inner membrane – Thylakoids – Grana Light-Independent Reactions (Calvin Cycle) – Stroma – Location – Lumen – Inputs/reactants Energy carriers Light reactions Carbons – Location – Starting compound – Inputs/reactants – Rubisco and carbon fixation Source of e- – Regeneration of starting product Source of H+ – Outputs/products – Photosystem I and II – Path of electrons – Electron transport chains – H+ gradient – NADPH formation – ATP synthase – Outputs/products due on test day! Source of O2 waste  greetings, biologists! Today’s tasks: - Stamp HW #3 - HW quizzes #1 and #2 - EQ 4.4a: Transpiration - Activities: - transpiration interactive - Transpiration lab (dry lab) HW: hw quiz #3 on day 3 Productivity Activity due on day 3  Transport and Photoperiodism in Plants EQ 4.4a: How are substances transported in plants? EQ 4.4b: How do plants respond to conditions in their environment?  The movement of water in plants: the Transpiration Cohesion-Tension theory Water moves up a plant through xylem tissue Molecules evaporate out through leaf stomata, and pull up the column of water through cohesion and adhesion  Evaporation (strong pull) Upward movement (moderate pull) Root pressure (weak push)  Root Pressure Root hairs increase surface area – mycorrhizae: fungi living in roots; increase surface area Selective transport of minerals occurs, then water follows via osmosis. No energy needed to move the water! Pathway is: soil → root hair → epidermis→ cortex → Casparian strip → xylem wn! is d o e th n ’t writ d o Root pressure leads to guttation  Transpirational Pull The evaporation of water vapor from leaves which pulls more water up the xylem through cohesion and adhesion (tension) Occurs due to differences in Ѱw between xylem, leaf spaces, and the air.  Water potential (Ѱw) High in xylem, low in the air (in general) Water moves from high Ѱw to low Ѱw, so it leaves the xylem and moves into the air When water evaporates from the air space, it creates a slight vacuum (negative pressure), creating tension that causes more water to leave the xylem.  Translocation of Phloem Sap Source to sink Sugar is moved from the source cells into the phloem cells (sieve-tube members), driven by proton pumps Steps in Translocation: 1. Sugar moves into phloem cells 2. Water from neighboring xylem moves into phloem through osmosis 3. This extra volume moves the phloem contents through the cells 4. Sugars are moved into sink cells, and water diffuses back into xylem  stop notes here on day 2! (we’ll talk through the rest on day 3) Now what? - go through the Transpiration interactive, linked on Schoology. Pay attention to water potential! - Complete the Transpiration lab (worksheet) this is the image that is supposed to have printed on the first page of the lab!  greetings, biologists! Today’s tasks: - HW quiz #3 - Collect Productivity Activity - EQ 4.4b: Signaling - work time! - Finish Transpiration lab - Finish Photosynthesis diagram - AP Classroom Progress Check & Topic Questions - Summaries HW: Enjoy your break! Test on Day 2  Plant cell signaling EQ 4.4b: How do plants respond to conditions in their environment? Plant use chemical signaling to accomplish a number of behaviors Photoperiodism – Reproduction (flowering) – Germination Tropisms – Phototropism – Gravitropism – Thigmotropism …and more!  Photoperiodism Seasonal behaviors – some plants flower in winter, some in summer. Some flower independent of light conditions.  Germination (a seasonal behavior ☺) Plant seeds break dormancy and sprout at the beginning of their ideal growing season Phytochromes are light-absorbing pigments that respond to light and influence a plant’s behavior – Red light – increases germination, branching. Red light is abundant in direct sunlight – Far-red light – inhibits germination, increases upward growth (shade avoidance). Far-red wavelengths are found in shade, where the taller plants have absorbed the red.  Phytochromes are photo-reversible Alternate between an active (Pfr) and inactive (Pr) form Pfr induces germination. Red light is absorbed by mature plants, who are in a good spot to grow Seeds in the shade receive more far-red light which is not conducive to growth, so the seed stays dormant. The effect is reversible. Bursts of red light can counter the effect of darkness or far-red light. The seeds respond to the last light signal they receive.  Timing is everything Phytochromes allow plants to synchronize breeding for a particular season – Variations in breeding seasons between plant species increases diversity and reduces competition for pollinators. Night length is the critical factor for flowering – Summer = short night, long day – Winter = long night, short day You can disrupt the normal flowering patterns of a plant by disrupting their night length with strong bursts of red light! Red light switches phytochromes to Pfr (active), causing flowering. You can reverse the effect with a subsequent burst of far-red light to switch the phytochrome back to Pr (inactive)