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Bacteria

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Sci Files segment describing different types of bacteria and how they can help or hurt us.

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Hi, are you Mr. Greg Frank? 00:00:00
Yes, you must be the treehouse detectives. 00:00:02
I hear you have some beetroot dishes for me to look at. 00:00:04
This is the one from the treehouse. 00:00:07
This is the control dish. 00:00:09
It looks like you've been very careful in labeling these dishes. 00:00:11
We made sure that each dish was only open for 10 minutes at the same time of day 00:00:14
so that any microbes would have the same chance of growing. 00:00:19
And to make sure we were manipulating only one variable, 00:00:22
we've kept them together for the last 24 hours 00:00:25
so they have the same growing conditions. 00:00:28
Let's take a look under this dark field colony counter. 00:00:30
It will illuminate the colonies and make them larger. 00:00:33
Wow, this is pretty cool. 00:00:40
I count 45 colonies in the treehouse dish. 00:00:42
I couldn't see anything yesterday. What's happened? 00:00:45
Individual bacterial cells are so small they're hard to see with your eye and even some microscopes. 00:00:48
However, they grow so rapidly that over a 24-hour period they grow from one to a thousand cells 00:00:53
and that's what you're seeing in these colonies. 00:00:58
There are about 15 colonies in my dish. 00:01:00
The control dish doesn't have any colonies. 00:01:03
Why do you think the treehouse has more colonies? 00:01:06
I think it has something to do with the fact that the treehouse is outside. 00:01:08
That could be one reason. 00:01:12
Dr. D warned us that it's hard to control everything. 00:01:13
Perhaps the treehouse is not as isolated as you thought. 00:01:16
We know that microbes like bacteria and viruses cause diseases, 00:01:20
but we don't know much about them. 00:01:23
Can you tell us about microbes? 00:01:25
It would be very difficult to show you viruses since they are so small, 00:01:27
but let's take a look at some bacteria. 00:01:30
We can remove them from the inside of your mouth with this swab. 00:01:32
RJ told us that there's bacteria inside us all the time, even when we're not sick. 00:01:36
Let's rub this on a clean microscope slide. 00:01:42
Before we look at it, let's stain the cells so we can see them better. 00:01:44
Let's magnify this a thousand times and project it up onto the TV monitor. 00:01:49
There are lots of different shapes. What's the round one? 00:01:55
That's a bacteria that we call a caucus. 00:01:58
That one looks like a cylinder. What's it called? 00:02:00
Yes, we call that a rod shape or a bacillus bacteria. 00:02:03
That bacteria is round, but it's in chains. 00:02:06
Yes, we call that a streptococcus. 00:02:09
Is that like strep throat? Does that mean I'm sick? 00:02:11
Not necessarily. There are other bacteria that look like the strep throat kind, 00:02:14
but they're actually beneficial to us. 00:02:17
Are you saying that bacteria can be helpful? 00:02:19
Most bacteria are good, and in fact, we couldn't survive without them. 00:02:22
I never thought about bacteria being good. 00:02:25
Think about termites. As you know, termites eat wood, but they cannot digest it. 00:02:28
It is the bacteria in their gut that digests the wood. 00:02:32
This is also true of our own stomachs, where a bacteria known as E. coli 00:02:35
helps us digest our own food and produce vitamins. 00:02:38
What about the bad bacteria? 00:02:41
Some bacteria enters our cells and destroys them from within. 00:02:43
Others produce very deadly toxins like botulism. 00:02:46
If bacteria can multiply so fast and cause such damage to the body, how do we survive? 00:02:49
The body has its own defense system to fight off disease. 00:02:54
It's called the immune system, and most of the time, it keeps us pretty healthy. 00:02:57
Sounds like we need to learn more about the immune system. Thanks, Mr. Frank. 00:03:01
You're welcome. Good luck, and come back if you need anything else. 00:03:05
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Idioma/s:
en
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
485
Fecha:
28 de mayo de 2007 - 15:32
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
03′ 10″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
19.08 MBytes

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