首页
登录
职称英语
[img]2012q1/ct_etoefm_etoeflistz_0398_20121[/img] [br] Based on the information
[img]2012q1/ct_etoefm_etoeflistz_0398_20121[/img] [br] Based on the information
游客
2024-01-04
10
管理
问题
[br] Based on the information in the lecture, indicate whether each process below is related to the hormone ethylene. For each sentence, click in the correct box.
W: Several of the processes related to growth and aging in plants involve the effects of hormones.Today I’ll talk about two aging processes-the ripening of fruit and the falling of leaves in autumn.These processes involve a hormone called ethylene.What is ethylene? It’s achemical, a gas produced by plants as a hormone.Ethylene is unique among plant hormones because it’s the only hormone that’s a gas.The gaseous state is important because it enables ethylene to move through the plant.Like all other hormones, ethylene triggers certain responses in the plant.Ethylene is associated with a variety of aging processes.One example of the aging process is the ripening of fruit.The ripening of fruit involves several changes in structure and metabolism.Some of these changes are aging processes.One change is the weakening of cell walls, which softens the fruit.Another is the decrease in chlorophyll content, which causes the fruit to lose its greenness.Ethylene initiates or hastens both of these changes and also causes some ripened fruit to drop from the plant.A chain reaction occurs during ripening, as ethylene triggers aging.The aging cells then release more ethylene.Because ethylene is a gas, the signal to ripen spreads from fruit to fruit.You’ve heard the expression "One bad apple spoils the whole lot." Well, it really is true! Yes, Randy?
M: So, when we buy fruit, like peaches that are still kind of green, and we store them in a plastic bag, and the peaches ripen faster-is this because of ethylene? I mean, I think I get it.The bag traps the ethylene gas, and this speeds up the ripening.
W: Right.That’s exactly what happens.Ethylene accumulates inside the plastic bag, and this starts a chain reaction.The signal to ripen spreads from one peach to another, and this causes all of the peaches to ripen faster.
By the way, the role of ethylene was discovered in sort of an interesting way.A century ago, citrus growers used to ripen fruit by "curing" it in sheds that were heated by kerosene stoves.The growers thought it was the heat from the stoves that ripened the fruit.However, they later discovered that the fruit didn’t ripen after they started using newer, cleaner-burning stoves.Botanists figured out that the reason the fruit ripened in the sheds with kerosene stoves was because of ethylene-not heat-because, as it turns out, ethylene is a by product of kerosene combustion.Nowadays, a lot of fruit is ripened in huge storage containers that have ethylene gas piped in.It’s a new variation on the old curing shed.But in other cases, storage facilities have to slow down the ripening caused by natural ethylene.For example, apples are stored in bins that are flushed with carbon dioxide.Circulating the air with carbon dioxide prevents ethylene from accumulating, and carbon dioxide slows down the action of whatever ethylene isn’t flushed away.This is how apples can be stored for several months before they’re shipped to supermarkets.
Another aging process in plants where ethylene plays a role is the falling of leaves in autumn.When a leaf falls from a tree, the breaking point is a layer near the base of the leaf’s stalk.A change in the balance of two hormones-ethylene and auxin-controls the falling of leaves.An aging leaf produces less and less auxin, a hormone that stimulates cell growth.The drop in auxin makes the cells of the breaking layer more sensitive to ethylene.As the influence of ethylene becomes stronger, the cells start producing enzymes that weaken the cell walls of the breaking layer.Finally, with the help of wind or rain, the leaf breaks away at that layer and falls from the tree.
选项
答案
Yes: The decrease in chlorophyll causes fruit to lose its greenness and become ripe: ...the decrease in chlorophyll content, which causes the fruit to lose its" greenness.
Yes: Apples in storage bins are flushed with carbon dioxide to keep the air circulating: ...storage facilities have to slow down the ripening caused by natural ethylene. For example, apples are stored in bins that are flushed with carbon dioxide. Circulating the air with carbon dioxide prevents ethylene from accumulating
No: A tree’s roots grow hairs that help it absorb water from the soil: Not supported by the information in the lecture.
Yes: Weakened cell walls at the base of a leaf cause the leaf to break away: As the influence of ethylene becomes stronger, the cells start producing enzymes that weaken the cell walls of the breaking laver. Finally, with the help of wind or rain, the leaf breaks away at that layer and falls from the tree. (2.6)
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3331579.html
相关试题推荐
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentothelectureinbusinessclass[img]2011q1/ct_etoefm_etoef
NarratorListentothelectureinbusinessclass[img]2011q1/ct_etoefm_etoef
NarratorListentothelectureinbusinessclass[img]2011q1/ct_etoefm_etoef
[img]2011q1/ct_etoefm_etoefspeaka_0223_20111[/img]Q:Somepeoplebelievethatte
[img]2011q1/ct_etoefm_etoefspeaka_0336_20111[/img]Q:Describeasituationinwhi
BiologyCardiacMuscle[img]2012q1/ct_etoefm_etoeflistz_0107_20121[/img][br]Why
随机试题
TheGreatWallofChinarunsacross______Chinalikeahugedragon.A、thenorth
Whatisthepurposeofthenationalsurvey?[br][originaltext]Chinesegove
Peoplevisitothercountriesformanyreasons.Sometravel【11】;otherstrav
治疗囊尾蚴病疗效好的药物是A.槟榔、南瓜子 B.仙鹤草根芽 C.氯硝柳胺
A.AFP B.T C.CA125 D.E E.β-hCG颗粒细胞瘤或
可将裂缝粘合起来或形成凝胶,起到堵水防渗以及补强的作用的灌浆方法是()。A、固
治疗泄泻之食滞肠胃者,除主穴外,应加用A.中脘 B.神阙 C.内庭 D.太
患者,女性,27岁,既往体健,暴饮暴食后突然出现上腹剧痛,频繁呕吐,面色苍白,疑
A注册会计师负责审计甲公司的存货项目,在监盘过程中,下列做法不正确的是()。
哪个健康教育和健康促进的关系的表述不准确A.健康教育本身已经包括了健康促进的目标
最新回复
(
0
)