Concept explainers
What important role does lignin play in vascular plants?
a. It is the major component of the cuticle, which prevents plants from drying out.
b. It forms the outer layer of pollen grains.
c. It forms the tough, rigid cell walls of water-conducting cells.
d. It nourishes the embryo in seed plants.
Introduction:
The lignin is the polymer made of the monomers of monolignol. The polymers of the lignin are filled in the voids in the cell walls. The xylem is the tissue, which performs the function of the conduction of the water and dissolved minerals in the plant.
Answer to Problem 1TYK
Correct answer:
It makes rigid and tough cell walls of water-conducting cells.
Explanation of Solution
Explanation/justification for the correct answer:
Option (c) is given as forming of rigid and tough cells walls for water-conducting cells. The lignin is present in the xylem tissues. The hemicellulose is linked with the lignin by the covalent bonding to provide the strength to the vascular cell wall, which further provides strength to the vascular plants. Therefore, the lignin forms the rigid and tough cell walls of the vascular cells. Hence, the Option (c) is correct.
Explanation for incorrect answer:
Option (a) is given as a major component of the cuticle, which plays a role in preventing drying out of a plant. The plant organs, such as leaves and young shoots are covered with the thin layer of a waxy substance called the cuticle. The cuticle is composed of the cutin, which is hydrophobic in nature. The cutin is present instead of lignin in the cuticle. So, it is a wrong answer.
Option (b) is given as forming the outer layer of pollen grains. The outer layer of the pollen grain is called exine. The exine is made up of the substance sporopollenin. The sporopollenin is the chemically inert substance found in the pollen grain. The lignin is not present in the outer layer of the pollen grains. So, it is a wrong answer.
Option (d) is given as nourishment of embryo in the seed plants. The embryo is the developing tissue inside the seed of the plant. The embryo requires the nutrients for the further development. The necessary nutrients are provided by the endosperm. The main constituent of the endosperm is the starch. The endosperm surrounds the developing embryo. Therefore, the lignin does not provide the nourishment to the embryo cells.
Hence, the options (a), (b), and (d) are incorrect.
Lignin is responsible for providing strength to the plant by forming the tough and rigid cell wall. The cuticle is present on the surface of leaves and shoots that prevent drying out of a plant. Exine forms the outer layer of pollen grains and endosperm provide nourishment to the developing embryo.
Want to see more full solutions like this?
Chapter 28 Solutions
Biological Science (6th Edition)
- How is a protein destined for the Endoplasmic Reticulum (ER), imported into the ER? Be concise.arrow_forwardFind out about the organisations and the movements aimed at the conservation of our natural resources. Eg Chipko movement and Greenpeace. Make a project report on such an organisation.arrow_forwardWhat are biofertilizers and mention the significancearrow_forward
- PCBs and River Otters: Otters in Washington State’s Green-Duwamish River have high levels of polychlorinated biphenyls (PCBs) in their livers. PCBs can bind to the estrogen receptors in animals and disrupt the endocrine system of these otters. The PCBs seem to increase the estrogen to androgen ratio, skewing the ratio toward too much estrogen. How would increased estrogen affect the river otter population? Based on your reading of the materials in this unit, what factors can affect fertility in humans? Explain how each of the factors affecting human fertility that you described can disrupt the human endocrine system to affect reproduction.arrow_forwardOther than oil and alcohol, are there other liquids you could compare to water (that are liquid at room temperature)? How is water unique compared to these other liquids? What follow-up experiment would you like to do, and how would you relate it to your life?arrow_forwardSelection of Traits What adaptations do scavengers have for locating and feeding on prey? What adaptations do predators have for capturing and consuming prey?arrow_forward
- Competition Between Species What natural processes limit populations from growing too large? What are some resources organisms can compete over in their natural habitat?arrow_forwardSpecies Interactions Explain how predators, prey and scavengers interact. Explain whether predators and scavengers are necessary or beneficial for an ecosystem.arrow_forwardmagine that you are conducting research on fruit type and seed dispersal. You submitted a paper to a peer-reviewed journal that addresses the factors that impact fruit type and seed dispersal mechanisms in plants of Central America. The editor of the journal communicates that your paper may be published if you make ‘minor revisions’ to the document. Describe two characteristics that you would expect in seeds that are dispersed by the wind. Contrast this with what you would expect for seeds that are gathered, buried or eaten by animals, and explain why they are different. (Editor’s note: Providing this information in your discussion will help readers to consider the significance of the research).arrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage Learning