Chapter 1, Problem 12RQ

In 1976, a team of chemists in the United Kingdom was developing new insecticides by modifying sugars with chlorine Cl2, phosgene Cl2CO, and other toxic gases. One young Member of the team misunderstood his verbal instructions to test a newly made candidate substance. He thought he had been told to taste it. Luckily for him, the substance was not toxic, but it was very sweet. It became the food additive sucralose. Sucralose has three chlorine atoms substituted for three hydroxyl groups of sucrose table sugar. It binds so strongly to the sweet-taste receptors on the tongue that the human brain perceives it as 600 times sweeter than sucrose. Sucralose was originally marketed as an artificial sweetener called Splenda, but it is now available under several other brand names. Researchers investigated whether the body recognizes sucralose as a carbohydrate. They began by feeding sucralose labeled with 14C to volunteers. Analysis of the radioactive molecules in the volunteers urine and feces showed that 92.8 percent of the sucralose passed through the body without being altered. Many people are worried that the chlorine atoms impart toxicity to sucralose. How would you respond to that concern?

With stomata closed, a waterproof cuticle ______. a. minimizes water loss through plant surfaces b. permits gas exchange between the plant and the air c. both a and b

Sudoriferous glands produce______. a. sweat b. lipids c. sebum d. milk

Describe an example of a plant with leaves that are adapted to cold temperatures.

Tracheids, vessel elements, sieve-tube cells, and companion cells are components of.______ vascular tissue meristematic tissue ground tissue dermal tissue

Piotists with the capabilities to perform photosynthesis and to absorb nutrients from dead organisms are called _____________. photoautotrophs mixotrophs saprobes heterotrophs

Cells of Thecontain chloroplasts epidermis vascular tissue stomata mesophyll

Which process produces an inorganic compound that plants can easily use? photosynthesis nitrogen fixation mycorrhization Galvin cycle

Which molecule must enter the Calvin cycle continually for the light-independent reactions to take place? RuBisCO RuBP 3-PGA CO2