L3
讲座
1. What is the lecture mainly about?
Characteristics of a good laboratory experiment
The steps of a complex molecular process
A type of sensory system that humans do not have
The importance of fruit flies in laboratory experiments
2. What does the professor imply about the ability to predict the future?
She finds evidence of its existence interesting but not convincing.
She does not think it is worth discussing.
She understands why it may seem to be one effect of cryptochrome.
She believes that research will someday prove that it exists.
3. The students suggest possible experiments. What are the experiments intended to
investigate?
Fruit flies’ range of color perception
Fruit flies’ ability to sense magnetism
The influence of magnetism on fruit fly reproduction
The effectiveness of different methods of training fruit flies
4. How did biologists research the function of cryptochrome?
By breeding fruit flies without the gene that produces it
By studying its genetic makeup
By training fruit flies to fly toward a magnet
By comparing the photoreceptors of fruit flies with those of other insects
5. What point does the professor make about blue and ultraviolet wavelengths?
They are the only wavelengths of light that fruit flies can perceive.
They must be present in order for cryptochrome in fruit flies to be activated.
Studies show that fruit flies cannot distinguish them.
Fruit flies rely on them exclusively for detecting the location of food.
6. What does the professor imply when she says this?
Some fruit flies have been trained to respond to magnetism.
Only fruit flies that are specially bred in laboratories can sense magnetism.
It is obvious that most laboratory fruit flies have lost some natural sensitivities.
It is impossible to prove any connection between fruit flies and magnetism.
