Biology 123 1st EditionExam # 1 Study Guide Lectures: 1 - 6Lecture 1 (January 17)Plant Life CycleSporophyte (diploid) > Meiosis > Spores (haploid) > Mitosis > Gametophyte (Haploid) > Sperm and Eggs (haploid) > Fertilization > Mitosis > Sporophyte (diploid)Plant BodyLecture 2 (January 21) Root System- Underground - Obtains water and dissolved materials- AnchorShoot System- Aerial- Obtains sunlight- Exchange gases: CO2, oxygen, water vapor- Vertical stem w/ leaves (photosynthesis)- Reproductive structures (flowers and fruits)- Buds o Undeveloped embryonic shoots in stemsStems- Node - where leaf attaches- Internode - region between nodesVascular tissue system- Conducts material throughout plant body- Strength- SupportLecture 3 (January 26)Monocot and DicotXylem- Conducts water & dissolved minerals from soil into root tissue- Tension-cohesion model- Explains rise of water- Transpiration- Evaporative pull causes tension at top of plant- Water potential gradient- Pulls water upPhloem- Conducts sugar- Conducting cells:- Sieve tube elements- Assisted by companion cellsPressure-Flow hypothesis- Companion cells actively load sugar into sieve tubes (ATP)- Sugar accumulates in sieve tube element- Water into sieve tubes by osmosis- Companion cells unload sugar at sink- Water leaves tubes by osmosis decreasing turgor pressure inside tubesTurgor Pressure Gradient• Produced by water entering phloem at source and water leaving phloem at sink• DRIVES FLOW OF MATERIALS BETWEEN SOURCE AND SINLecture 4 (January 28) Sugar Translocation- Dissolved sugar translocated upward or downward in phloem- Mostly sucrose- Area of excess sugar (leaf) to a sink (area of storage)Vascular Tissue CellsDermal Tissue- Outer protective covering of plant body- Epidermis- Covers herbaceous plants- Periderm- Covers woody parts Plant Growth- Grow at meristems- Cell division- Cell elongation- Cell differentiationRoot TipLecture 5 (February 2) Primary Growth - Increase in stem or root length in all plants- Occurs throughout plant life spanApical Meristem - Responsible for primary growthLateral meristems- Vascular cambiumo Produces secondary xylem (wood) and secondary phloem (inner bark)- Cork cambiumo Produces periderm- Secondary growth- Increase girth (thickness)Woody EudicotLecture 6 (February 4) Parts of a leafVenation Patterns- Parallel- Pinnately netted- Palmately nettedLeaf TissueEpidermis- Upper and lower surface of leaf- Coated by waxy cuticleStomata- Pores- Permit gas exchange- Surrounded by 2 guard cellsMesophyll- Palisade mesophyllo Photosynthesis - Spongy mesophyllo Gas exchangeVeinsXylem - water and minerals to leafPhloem - sugar to rest of the plantPhotosynthesis adaptations• Broad and flat leaves• Good for collecting suns energy• Stomata open during day• Needed for gas exchange, close at night to conserve water (CAM plants open at night)• Transparent epidermis• Light can penetrate into middle of leaf so photosynthesis can occur• Air spaces in mesophyll tissue• Permit rapid diffusion of CO2 and water into mesophyll cellsTranspiration• Loss of water vapor from aerial parts of plants• Through stomata• Rate affected by• Temp• Wind• Relative humidity• Beneficial and harmful• Tradeoff between CO2 requirement for photosynthesis and need for water conservation• Loss of leaves does not cause water
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