Ask A Scientist , top bar
Office of DOE Science Education Department of Energy Office of Science
image 1
image 2
image 3
image 4
Digesting Grasses

Welcome Teachers and Students


Visit Our Archives
How to Ask a Question
Ask A Question
Question of the Week
Our Expert Scientists

About Ask A Scientist
Referencing NEWTON BBS Articles
Frequently Asked Questions

Digesting Grasses


name        Kaede
status       other
grade        other
location     N/A

Question -   why can cows digest grasses while persons don't?
----------------------------------------------------------------
They have a complex digestive system designed for slow digestion and
also have a microbe that breaks down the cellulose sugar that makes up
grass. Humans posess neither the digestive system nor the enzyme to
live off of grass and such.

PF
====================================================================
Cows don't actually digest grass, which contains cellulose.  They have
a ruminant stomach, which means that their stomach is
compartmentalized.  Some would say they have more than one stomach.
But in one of the "stomachs" they have bacteria which are able to
break a specific chemical bond in cellulose that breaks it down into
glucose.  This is an example of mutualistic symbiosis, where both
organisms benefit from a relationship.  The cow benefits by being able
to take advantage of a food source, and the bacteria get a ready
supply of food and protection.  Did you know that termites can't
digest wood?  They also have organisms living in their guts that break
down the cellulose in wood.

vanhoeck
====================================================================

image 5
image 6
image 7
image 8
image 9
image 10
image 11

 

We provide a means to have questions answered that are not going to be easily found on the web or within common references.

 

Return to NEWTON's HOME PAGE

For assistance with NEWTON contact a System Operator, at Argonne's Division of Educational Programs

NEWTON BBS AND ASK A SCIENTIST Division of Educational Programs

Building DEP/223 9700 S. Cass Ave. Argonne, Illinois 60439-4845 USA

Last Update: January 2007