WEBVTT - How do herbicides like Roundup work?

0:00:00.520 --> 0:00:03.800
<v Speaker 1>Welcome to Brainstuff from house Stop works dot com where

0:00:03.840 --> 0:00:14.880
<v Speaker 1>smart happens. Hi Am Marshall Brain with today's question, how

0:00:14.920 --> 0:00:18.919
<v Speaker 1>does the herbicide round up work? Round Up, which is

0:00:18.960 --> 0:00:23.320
<v Speaker 1>a trade name used by Monsanto, and other herbicides based

0:00:23.360 --> 0:00:27.120
<v Speaker 1>on glyphosphate, which is the generic name, are probably the

0:00:27.160 --> 0:00:31.600
<v Speaker 1>most commonly applied weed killers in use today. These herbicides

0:00:31.600 --> 0:00:35.560
<v Speaker 1>are used by everyone from farmers to foresters, to gardeners

0:00:35.600 --> 0:00:39.440
<v Speaker 1>to biologists who are trying to control invasive exotic plants.

0:00:39.920 --> 0:00:44.440
<v Speaker 1>Glyphosphate based herbicides all work on the same biochemical principle.

0:00:44.840 --> 0:00:48.440
<v Speaker 1>They inhibit a specific enzyme that plants need in order

0:00:48.440 --> 0:00:53.720
<v Speaker 1>to grow. The specific enzyme is called EPSP synthase. Without

0:00:53.840 --> 0:00:57.840
<v Speaker 1>that enzyme, plants are unable to produce other proteins essential

0:00:57.880 --> 0:01:00.680
<v Speaker 1>to growth, so they yellow and dye over the course

0:01:00.720 --> 0:01:04.400
<v Speaker 1>of several days or weeks. Majority of plants use this

0:01:04.600 --> 0:01:08.080
<v Speaker 1>same enzymes, so almost all plants to come to round up.

0:01:08.560 --> 0:01:11.280
<v Speaker 1>If you've read the How Stuff Works article called how

0:01:11.440 --> 0:01:14.440
<v Speaker 1>Cells Work, you know a good bit about DNA and

0:01:14.520 --> 0:01:18.200
<v Speaker 1>how it produces enzymes in the same way that many

0:01:18.280 --> 0:01:23.880
<v Speaker 1>antibiotics gum up enzyme production to kill bacteria. Glyphosphate gums

0:01:23.959 --> 0:01:28.240
<v Speaker 1>up enzymes and plants to kill them. Glyphosphate kills plants

0:01:28.319 --> 0:01:32.839
<v Speaker 1>like antibiotics kill bacteria. If you've been following farming news

0:01:33.000 --> 0:01:37.039
<v Speaker 1>or the genetically modified food debate, you know that glyphosphate

0:01:37.120 --> 0:01:42.160
<v Speaker 1>tolerance seeds are now available. You can buy genetically modified corn, soybeans,

0:01:42.160 --> 0:01:46.000
<v Speaker 1>and so on that are immune to glyphosphate. These plants

0:01:46.120 --> 0:01:50.560
<v Speaker 1>use an enzyme that performs the same function as EPSP synthas,

0:01:50.560 --> 0:01:54.560
<v Speaker 1>but is not inhibited by glyphosphate. Round up will kill

0:01:54.680 --> 0:01:58.320
<v Speaker 1>almost any plant, including aquatic plants, so you want to

0:01:58.320 --> 0:02:01.720
<v Speaker 1>be sure to avoid spray drift onto other plants or

0:02:01.800 --> 0:02:06.240
<v Speaker 1>into the water. Any pesticide should be applied carefully. Do

0:02:06.280 --> 0:02:09.800
<v Speaker 1>you have any ideas or suggestions for this podcast? If so,

0:02:09.960 --> 0:02:12.680
<v Speaker 1>please send me an email at podcast at how stuff

0:02:12.680 --> 0:02:15.359
<v Speaker 1>works dot com. For more on this and thousands of

0:02:15.440 --> 0:02:18.600
<v Speaker 1>other topics, go to how stuff works dot com and

0:02:18.639 --> 0:02:20.800
<v Speaker 1>be sure to check out the brain stuff blog on

0:02:20.840 --> 0:02:22.639
<v Speaker 1>the how stuff works dot com home page.