教育学习   常速英语

Keywords:

Mutations arise at random in a population. Suppose a mutation arises that causes adults to produce lactase in a population that doesn't have any dairy cows. Adults don't drink milk, so producing the l...

Keywords:

Polymerase chain reaction-- or PCR-- uses repeated cycles of heating and cooling to make many copies of a specific region of DNA. First, the temperature is raised to near boiling, causing the double s...

Keywords:

So this squid is a nocturnal animal. And so what we've done is we put this poor guy in his water during the day. And he doesn't like it. So he looks kind of uncoordinated, he looks a...

Keywords:

So let's look at what these guys will eat. If I could have the video, please. So this snail has its proboscis stuck out. That's the translucent yellow tube. And you can see, it stings...

Keywords:

So what you're seeing first, this is just DNA in the bacterial cell. And we've color-coded the genes. So that's the LUX operon. There's five genes in that operon. And somewhere else ...

Keywords:

And so we grew up some Vibrio harveyi for you this morning. And all the lights are going to go out in the room, so don't worry. And I'm going to show you this bioluminescence, I hope, ...

Keywords:

So here is a fish and electrical signals are coming down the nerve, and this is how a fish swims. At the junction between nerves and muscles, the electrical signals have to get through th...

Keywords:

What we're going to show you is the next animation, which illustrates how these different components are able to paralyze a fish. So here is the electrical signal coming down the nerve. ...