Chapter 10 Homework questionsHomework questions for Chapter 12Homework questions Chapter 13Chapter 14 Homework questionsChapter 15 Homework questionsChapter 17 Homework questionsChapter 18 Homework questionsChapter 10 Homework questionsDescribe phloem anatomy and how it contributes to sugar transport? In what ways does phloem differ from xylem?Phloem anatomy. The phloem transports sugars from leaves to stems and roots. Whereas the xylem transports water and nutrients from soil to stems and leaves. The phloem has sieve tube elements, phloem cells that transport sugars (these are living cells whereas the xylem is dead). Phloem has companion cells and sieve plates.Outline the source sink relationships that define sugar transport in the phloem: give the definition for source and sink organs and give at least two examples of each; what three factors usually determine source to sink pathways?Source to sink – sources are exporting organs (typically mature leaves) that are capable of producing photosynthetic in excess of their own needsStorage organs are like tree stems and roots during the winter, tubers in the beets.Sinks = organs that don’t produce enough photosynthetic to support their own growth, includes immature leaves, roots, developing fruits.Explain the pressure-flow hypothesis that scientist use to explain sugar transport in the phloem.Scientist explain the pressure flow hypothesis as such, high sucrose content drivees the solute potential up as water flows in the creates high turgor which will flow the water out of the cell and carry with it solute that naturally wants to move away from high solute concentrations, as the solute potential increase lower turgor pressures result, this water is the circulated and flows up to where water from lower solute potential is flowing because of the osmotic potential. Thus going from source to sink.Homework questions for Chapter 12Describe the cellular steps necessary for a plant cell to transport NO3 into the cytosol and then assimilate it into an amino acidIn order for plants to move NO3 into the cytosol then assimilate it into an amino acid it must absorbed nitrate via the nitrate proton cotransports, then in the cytosol nitrate reductase reduces nitrate to nitrite with reducing power from NADH, then Nitrite is transported to chloroplast (or plastids) where it is converted to ammonium by nitrate reductase with reducing power from ferredoxin (this is light dependent). Once as ammonium Glutamate dehydrogenase combines with oxogulatarate from the Krebs cycle to form glutamate with reducing power from NADPH the glutamate synthetize combines HN4with glutamate to form glutamine with reducing power from ATP. Finally Glutamate synthase combines glutamine and ozoglutarate to form two glutamates with reducing power from NADHDescribe how bacteria are able to convert N2 into ammonia (NH3).Bacteria are able to convert N2 into ammonia through symbiotic fixation. N2 + 8e + 8H+ + 16 ATP  2 NH3N fixation requires anaerobic conditions. Uses the NOD genes(T) Describe the signaling exchange that occurs between legumes and rhizobia that establishes compatibility. Explain how nodule formation occurs and describe its final structure.Signaling exchange between legumes and rhizobia. This occurs with N fixation within the root nodules which create an environment conducive to nitrogenize activity and recourse exchange between the symbionts. Nodule formation is a large investment and conditions must be right. Plants exude isoflavaniods and butanes which cause bacterial migration toward the roots and activate the Nod gene inthe bacteria. Nod the binds to the Dodd box promoter =, transcriptionally activating several other Nod genes. Nod genes Aare then involved in the biosynthesis of Nod factors. Which are signaling molecules that activate hormonal regulated responses in the legume host.Homework questions Chapter 13Define secondary metabolites, describe the three primary functions they have (as discussed in class) and explain how those functions increase plant fitness. Name the three major groups of secondary compounds and give a brief overview of how they are synthesized; describe their distinguishing characteristic and explain their important functions.Secondary metabolites deter herbivory, recruited helpful bacteria, protect against harmful pathogens. This increase plant fitness by allowing the plant to assimilate nitrogen, not gets eaten, and not fall prey to harmful diseases. Pathogen protection = cuticles that are made from lips and inserted into epidermal cells. Herbivory deterrents can be toxicity, palatability; these can by synthesized from compounds in the cell like phenolic, terpenes, and alkaloids.Outline the novel weapon hypothesis and explain how allopathy has helped spotted knapweed be so successful in its invasion of North America. Novel weapon hypothesis states that invasive (new) plants have weapons (defensive and offensive) that no other plant in the area is used to dealing with and thus invasive species can enjoy high levels of success. Knapweed poisons those around it, the plants have no built in defense b/c they are never seen it before.Explain the difference between a constitutive and inducible defense response. What are the advantages and disadvantages of each?Inducible defense = activated only after damage occurs. No wasted recourse, could act to slowConstitutive defense = defense compounds are always present, can be a waste of energy and recourses ifthey are not needed, however always there. Like insuranceChapter 14 Homework questionsExplain how a plant senses and responds to an environmental stimulus. Begin with receptor activationand end with the formation of a response protein. Environmental stimuli will trigger a chemical receptor in the cell that will then activate proteins (this is called signal transduction) that will induce transcription (called activation of cellular response) or repression of a gene. This gene will encode for mRNA that will them be translated by ribosomes and converted into amino acids that will fold together to create a protein.Explain replication, transcription and translation and outline how they contribute to the formation of aprotein. Replications are the duplication of a DNA molecule/cell. This is when DNA is duplicated. Transcription is when DNA is converted into RNA. Translation is the conversion of RNA sequence into amino acid synthesis.All these contribute to the formation of protein.