Brooks Biodiversity Unit 3 Exam Questions and Correct Answers 2024 with complete solution.

Brooks Biodiversity Unit 3 Exam Questions and Correct Answers 2024 with complete solution. Plants Architecture Plant needs i. collection & conversion of solar energy - leaves ii. positioning & support of leaves - stems iii. anchorage & absorption - roots iv. transport - vascular system Leaf Structure Epidermis, Mesophyll, and Vein (Vascular Bundle) Epidermis contains what? - Cuticle - Guard cells with Stomata Epidermis outermost cell layer of a plant body cutin: (wax) excreted by epidermis Cuticle Waxy waterproof covering of a plant. Produced by the epidermis and has wax to resist desiccation. Guard Cells Responsible for opening and closing stomata. Works together with stomata to regulate gas exchange. Prevents movement of water ACROSS surface Stomata Small openings on the underside of a leaf through which oxygen and carbon dioxide can move. Mostly on lower surfaces, sometimes on upper surfaces. Found on both surfaces. Allows for gas exchange. 2 aspects of Photosynthesis light dependent reactions light independent reactions Mesophyll contains what? - Parenchyma - Dicots have Palisade & Spongy Layers Mesophyll Middle leaf structures photosynthetic layer. Parenchyma Ground tissue that forms the bulk of the mesophyll Can be modified into collenchyma and sclerenchyma Thin and flexible cells Most common and versatile ground tissue Used for metabolic functions and storage of organic products Palisade & Spongy layers Palisade layer: where light dependent reactions occur, near the surface. Top part of the mesophyll in dicot plants. Spongy mesophyll or spongy parenchyma: soft lower layer. Has access to CO2 through stomata. Kelvin Cycle: where carbon fixation occurs, converting nonorganic CO2 into sugars. Vein (Vascular bundle) Transports materials throughout the leaf and contains the xylem and phloem. Separating the VB = damage. Stem Structure Epidermis, Cortex, Collenchyma, Sclerenchyma, Vascular Tissues Xylem (Xylem Up) Distributes water from roots throughout Aimed towards stem Red Tells age of tree Contains: tracheids & vessel members Tracheids Thin, hollow, narrow tube, dead cells with perforated, tapered ends. Vestigial structure First kind of tube made Present in early vascular plants and present in angiosperms and gymnosperms (slow flow) Vessel Members Thick, hollow, wide tube, dead cells with large holes on end. Clearly visible Phloem (Phloem Down) Distributes the products of photosynthesis (sugary water) to plants tissues. Blue Contains: Sieve tube members (element) & Companion cells Sieve Tube Members hollow, living cells with perforated cells Companion Cells living cells that help keep sieve tube member cells alive. Production of sugars in Kelvin Cycle require transportation done by companion cells into phloem Which 4 cell types is most active metabolically when fully functional? companion cells Epidermis in Trees is replaced by bark or cork. Produced by the cork cambium (tissues that produce other tissues). Cork (dead) = phloem (alive) Cork cambium produces cork. Trees grow wider cause xylem will get clogged The cork is produced when? Secondary phloem Composition of Bark is produced from phloem, cork cambium, or cork. Lenticels cracks in the bark to facilitate gas exchange Secondary Growth How a plant increases in girth (diameter) 1. Vascular Cambium 2. Cork Cambium 3. Wood 4. Bark 5. Lenticels 6. "Girdling Plants" Wood produced by xylem. annual rings Heartwood: clogged xylem, little water transport. Located deeper into trunk, harder wood Sapwood: newer xylem, free flowing water transport. Phloem makes sap. Girdling Plants Weed-Whakers Cutting a HORIZONTAL band around the circumference of the plant, can be deadly because the vascular cambium, in which nutrients and water travel vertically, can be damaged. What happens to initial phloem? it gets crushed What happens to the xylem? it gets clogged Cortex Yellow layer inside epidermis Separated by a ring of vascular bundles. Ground Tissue System Includes various cells specialized for functions such as storage, photosynthesis, and support Types of Ground Tissue Parenchyma, Collenchyma, Sclerenchyma Collenchyma celery fibers for support Sclerenchyma hard fibers & nodules responsible for support (ex) rope Sclerids nodules glued together to form shells of nuts. Fibers secretions that reinforce the stem Pith Middle of stem, large because it contains nutrients. Separated by a ring of vascular bundles. Replaced by xylem Procambium Becomes Vascular Cambium Makes xylem inward and phloem outward Grows in rings Gives rise to vascular tissues Forms advanced tissues Monocots have no cortex Germ layers = stem cells Root Structure i. Epidermis (permeable) with root hairs ii. Cortex iii. Endodermis with Casparian strips iv. Stele v. Apoplastic vs Symplastic pathways Stele Central cylinder with vascular tissues inside. Caspian strips wax, prevents water from growing in between cells Used to aid a plant and tell weather in the past Annual rings Apoplastic vs. Symplastic pathway Water enters through root epidermis and passes in the spaces "between" cortex cells apoplastically until reaching the endodermis. Casparian strips prevent water from passing between endodermal cells. Thus, water is forced through the cell membranes symplastically where it is filtered before reaching the vascular tissues within the stele = osmosis Root nodules & Symbiotic bacteria Bacteria fix nitrogen and are housed in root nodules to supply "fertilizer," thus allowing the plant to thrive, even in soils that are nutrient poor. Nitrogenace- enzyme that breaks down the triple bond in nitrogen Microbes contain this enzyme and they're anaerobic. Mycorrhizae: most plants have an association between their roots and fungi in the soil. This association is critical in aiding water/mineral uptake by the plant. Abiotic Fixation Doesn't involve organisms Lightning converts nitrogen into other sources because N2 isn't a usable form Less important because lightning doesn't occur enough to be useful for plants Biotic Fixation Process by which free nitrogen (N2) is extracted from the atmosphere and converted (fixed) into nitrogen compounds which are plant nutrients (fertilizer). In nature, this process is carried out by certain bacteria such as cyanobacteria Usable forms of nitrogen for plants Nitrate NO3 Nitrite NO2 Ammonia NH3 Vegetative Asexual Reproductive modes of flowering plants Runner (stolon), strawberry Rhizome- underground stem (bermuda grass) Corm- modified stem Tuber- modified underground stem. Gives rise to new growth onion; Potato (however some potatoes are roots) Bulb- modified stem Parthenogenesis development of egg without fertilization Propagation vegetative reproductive. Cut off a piece of plant off and it grows. Plant Development '... After germination" Upward growth -Epicotyl or Coleoptile -Phototropism Downward growth Radicle or Hypocotyl Gravitropism Positively Phototropic Growth in response to light Structures responsible for downward growth Radicle and Hypocotyl Contain statoliths (little rocks) that can sense movement in bottom of cell, triggering the plant to grow towards the center of the earth (down) Positive Gravitropism grows in the direction of gravity via statolith sensors Meristematic Tissues Plants version of germ cells Apical Meristems responsible for increase in plant HEIGHT Lateral Meristem responsible for increase in plant DIAMETER (girth) Meristems vs. Germ Cells A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing. A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. Meristems are in plants and germ cells are in humans but in essence are essentially preforming the same function Three Primary Meristems 1. Protoderm = Epidermis 2. Ground Meristem = Parenchyma, Collenchyma, Sclerenchyma = undifferentiated or modified to store pith 3. Procambium = VB w/ xylem and phloem Exchange & Transport i. Plants obtain gases, nutrients, minerals, & water via internal fluids ii. Gas exchange begins with the stomata; roots, lenticils iii. Internal transport = xylem & phloem Fluid movement in xylem Adhesion: Attraction of 2 of different things; water molecules bind to cell wall This makes sure that the water doesn't go back down (capillary action) Cohesion: Attraction of two of the same things sticking together; water molecules bind to one another via hydrogen bonding which pulls water molecules upward through xylem, like beads on a string Evaporation: as water evaporates, it pulls on other water molecules that haven't been evaporated yet Osmosis: Occurs in roots (root pressure) Low solute concentration to high solute concentration Capillary Action: allows water to go up, just a little bit Transpiration Pull aka Cohesion/Adhesion Tension The main motive force for transporting water up to the top of a plant (sometimes several hundred feet) As water evaporates from the leaf's surface the cohesive-adhesive properties of water pull water molecules from below establishing a water tension and pressure Drawbacks w/ Transpiration Pull It requires significant water loss from the plant. In dry conditions or arid environments, this water loss for vertical transport can be critical in plants Therefore, a replenishing water supply is vital for the roots Water loss in the tropics doesn't matter cause its always raining there. Water evaporation = shade Fluid movement in Phloem Mass Flow: An active transport mechanism Source vs. Sink: Source: Sugars produced by the leaves Sink: Sugars produced by the rest of the plant. Gravity can assist in this downward movement, however getting the sugars into the cells of the Phloem requires energy Kingdom Animalia