DAT BIO Question.

[ichiban1234]

Breaking down of fats into glycerol and fatty acids with the help of lipase is carried out in the:

A. Gullet
B. Stomach
C. Small Intestine
D. Liver
E. Kidneys

Answer is D. However, I thought it was C. Aren't there pancreatic lipases that are secreted into the small intestine that also break down fats? I thought this because villi have lacteals that transport dietary fats so the breakdown of lipases must occur in the small intestine.

Thanks in advance.

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[wantVCUdental]

Where did you get the question from?
i think it's C also, though liver has bile to emulsify fat and some fats are broken down there....

 

[Ninja9]

I think pancreatic lipases technically break down lipids into a monoglyceride (a glycerol with 1 fatty acid chain attached) and free fatty acids, not glycerol and fatty acids.

Are you sure it's D? With the help of digestive liquids, the monoglycerides are broken down further into glycerol in the small intestine.

I would hate for this question to show up on my DAT!

 

[dentalWorks]

I'm pretty sure that's C

Think about it, fats are digested in small intes. And carried out by lymph, which eventually drop into the blood near the shoulder area, I've never read anywhere anything that relates liver to lipid digestion... Has anyone?

 

[ichiban1234]

Thanks guys. I suspect its another error. This was from an older version of IQ publications (Canadian DAT).... not happy with their products so far.

 

[dentista123]

I thought it was D. Because I thought that the liver actually emulsified the fats. But you all raised good points.

 

[Ninja9]

I thought it was D. Because I thought that the liver actually emulsified the fats. But you all raised good points.

I thought they emulsified lipids with bile, not with lipases. And emulsifying doesn't break them down into glycerol and fatty acids, does it? I thought it made it easier for other enzymes to act on them to break them down...

So confused. lol

 

[MsDoC19]

"Fats, such as the fats in milk, need to be digested by your body. They are broken down into fatty acids and glycerol by an enzyme called lipase. Gastric lipase, secreted by the stomach lining, has a pH value for optimal activity around neutrality and would appear, therefore, to be essentially inactive in the strongly acid environment of the stomach. It is suggested that this enzyme is more important for infant digestion since the gastric pH in infancy is much less acid than later in life. Most lipid digestion in the adult occurs in the upper loop of the small intestine and is accomplished by a lipase secreted by the pancreas.
Lipases are enzymes which catalyse the hydrolysis of triglyceride to give di- and mono- glycerides, glycerol and free fatty acids.
Lipase breaks down neutral fats (triglycerides) into glycerol (an alcohol) and fatty acids. Before lipase can digest fat, bile, an emulsifier, must break the fat down into smaller units" (http://www.diet-and-health.net/Nutrients/Lipase.html)

Hmm not quite sure first they make it clear that it is in small intestine but then they go on to say that before it can digest fat the bile needs to break into smaller units first....

anybody find anything else??
🙂

 

[sw1sschez]

I thought they emulsified lipids with bile, not with lipases. And emulsifying doesn't break them down into glycerol and fatty acids, does it? I thought it made it easier for other enzymes to act on them to break them down...

So confused. lol

Liver makes bile which is stored in the gall bladder and released into the small intestine where fats are broken down by lipases.

Bile emulsifies fat by breaking down down into smaller bits to increase their surface area so that lipases can degrade them. It's like when you drop a dishwashing liquid into a fatty pan....the oil is broken into droplets which increases the surface area so the detergents can work on it. Same principle.

 

[Stacker]

Uh, I don't know the answer but am I supposed to know if I've taken only General Biology 1 and 2? In what class would I know these questions? Sorry I'm not of any help to your question. 🙂

 

[dentalmagnet]

...

 

[dentalmagnet]

Uh, I don't know the answer but am I supposed to know if I've taken only General Biology 1 and 2? In what class would I know these questions? Sorry I'm not of any help to your question. 🙂

Really this is physiology. What happens is you are (your general bio experience) expected to cover this..but not every school does. Maybe it differs per state or something. Don't feel bad..I didn't cover it either and I got a decent Bio score. Just read Cliffs AP Biology a few times and you will get a feel for this stuff.

 

[Stetson]

I think that was covered in my A&P class-but it's been a while so..

 

[amberphana]

i am pretty sure its in the small intestine. Again.. someone said this already..but liver only produce bile and it then gets stored in gall bladder for use. Only when fats are in the stomach does the gastrointestinal hormone cholecytokenin ..ughh i think thats how u spell it.. anyways.. the hormone stimulates the gall bladder to contract and release bile into the small intestine.

I really think emulsifying comes before the real digestion by lipase. It makes sense. Bile doesn't break down fats.. only emulsify it to increase surface area. W/o bile, fat digestion won't occur...says so in kaplan books.

 

[jay47]

I know it is C. Would bet money on it.