ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: Scooby on March 20, 2012, 06:56:34 pm

Title: Bio SAC 2!
Post by: Scooby on March 20, 2012, 06:56:34 pm

Hey guys, :)

For our second SAC we tested how the presence of lipase affects the pH of a milk mixture. The pH started off at about 9, and then within 20 minutes decreased to around 6.5. I get that the lipase is breaking triglycerides in the milk into glycerol and fatty acids, but how do the fatty acids actually decrease the pH given that that they haven't actually been 'added' to the milk (you know... they were already there, except they were part of a triglyceride)?

Thanks! :D

Title: Re: Bio SAC 2!
Post by: happycat on March 20, 2012, 08:39:41 pm

The fatty acids are making the mixture more acidic? But what about the glycerol with their hydroxy groups? I'm not sure what's making the mixture more acidic, could be both?

Title: Re: Bio SAC 2!
Post by: jaackyy on March 21, 2012, 06:18:48 pm

yea.. i wanna know the answer to this aswell.. can someone help? :o

Title: Re: Bio SAC 2!
Post by: Eddiee on March 21, 2012, 06:20:42 pm

ya help me too pls

Title: Re: Bio SAC 2!
Post by: saheh on March 21, 2012, 06:38:02 pm

It has something to do with taking/giving off H ions.
Let me finish my eng work and get back to you guys in about an hour (Its in my textbook i gotta look it up)
I highly doubt you'll be asked to do this on your sac though :/

Title: Re: Bio SAC 2!
Post by: saheh on March 21, 2012, 08:41:12 pm

sorry guys i read this wrong. der ><
My guess is the enzymes affect it???
orr releasing H+ ions from the triglycerides as they break up? making it more acidic?

Title: Re: Bio SAC 2!
Post by: achre on March 21, 2012, 09:23:13 pm

Yeah, what saheh said. The lipase breaks down the triglycerides, realeasing hydrogen ions during the catabolic reaction. The increase in the conc. of H+ increases the acidity.

Title: Re: Bio SAC 2!
Post by: Eddiee on March 21, 2012, 09:31:09 pm

Quote from: achre on March 21, 2012, 09:23:13 pm

Yeah, what saheh said. The lipase breaks down the triglycerides, realeasing hydrogen ions during the catabolic reaction. The increase in the conc. of H+ increases the acidity.

omg thank you so much! exactly what i needed to know :)