TOEFL Listening: How does the bacteria become resistant to antibiotics?

Listen to part of a conversation between two students. The woman is helping the man review for a biology examination.

Male Student

OK, so . . . what do you think we should go over next?

Female Student

How about if we go over this stuff about how bacteria become resistant to antibiotics.

Male Student

OK.

Female Student

Um, but first of all, though, how many pages do we have left? I told my roommate I’d meet her at the library at seven o’clock.

Male Student

Ummm . . . There’s only a few pages left. We should be finished in a few minutes.

Female Student

OK. So, ummm . . .

Male Student

About how bacteria become resistant to antibiotics.

Female Student

Oh yeah, OK. So you know that some bacteria cells are able to resist the drugs we use against them, and that’s because they have these special genes that, like, protect them from the drugs.

Male Student

Right. If I remember correctly, I think the genes like . . . weaken the antibiotics, or like …stop the antibiotics from getting into the bacteria cell, something like that . . .

Female Student

Exactly. So when bacteria have these genes, it’s very difficult for the antibiotics to kill the bacteria.

Male Student

Right.

Female Student

So, do you remember what those genes are called?

Male Student

Umm . . .

Female Student

Resistance genes.

Male Student

Resistance genes. Right. Resistance genes. OK.

Female Student

And that makes sense, right? Because they help the bacteria resist the antibiotics.

Male Student

Yeah, that makes sense. OK.

Female Student

OK. But the question is: how do bacteria get the resistance genes?

Male Student

How do they get the resistance genes? They just inherit them from the parent cell, right?

Female Student

OK, yeah, that’s true. They can inherit them from the parent cell, but that’s not what I’m talking about.

Male Student

OK.

Female Student

I’m talking about how they get resistance genes from other cells in their environment, you know, from the other cells around them.

Male Student

Oh, I see what you mean. Umm, is that that stuff about “hopping genes,” or something like that?

Female Student

Right. Although actually they’re called “jumping genes,” not “hopping genes.”

Male Student

Oh, OK. Jumping genes.

Female Student

Yeah, but they have another name, too, that I can’t think of. Umm . . . lemme see if I can find it here in the book . . .

Male Student

I think it’s probably on . . .

Female Student

Oh, OK. Here it is. Transposons. That’s what they’re called.

Male Student

Lemme see. OK. Trans . . . po . . . sons . . . trans . . . posons. So “transposon” is another name for a jumping gene?

Female Student

Right. And these transposons are, you know, like, little bits of DNA that are able to move from one cell to another. That’s why they’re called “jumping genes.” They kind of, you know, “jump” from one cell to another.

Male Student

OK.

Female Student

And these transposons are how resistance genes are able to get from one bacteria cell to another bacteria cell. What happens is that a resistance gene from one cell attaches itself to a transposon and then, when the transposon jumps to another cell . . .

Male Student

The other cell gets the resistance gene and . . .

Female Student

Right.

Male Student

That’s how it becomes resistant to antibiotics.

Female Student

Right.

Male Student

Wow. That’s really cool. So that’s how it happens.

Female Student

That’s how it happens.

Nghĩa trong bài:
Antibiotics: Kháng sinh.
Transposon = Jumping genes: Gen nhảy (cũng có thể gọi là hopping genes nhưng jumping genes được gọi phổ biến hơn).