Junket (Rennin) Cows milk, and temperature prac. (1 Viewer)

[Tulii]

Gday.
I'm just completing my bio assignmnet which is prac write up. The aim is to test the effect of temperature on the reaction rate between the enzyme rennin (junket tablet) and milk.

I have nearlyfinished but I'm having trouble coming up with a way to test if the milk has coagulated.

Do I tip the test tube and see if its separated? or do I poke it? lol.

and should I have a time limit for the milk to coagulate?
Like, five minutes?

Uhh. I can't explain it well, but if I could get some help it would be great. ta

 

[jeff.wong]

I did this experiment before, basically just visually observe when the milk clot, it may be hard to determine but just try I guess. This was my experiment anyway if that would help a little on the results...

Increased temperature
Aim: To investigate the effect of temperature on the activity of the enzyme rennin.

Hypothesis: The optimum temperature for enzyme activity will be approximately temperature of mammals (30oC – 40oC)

Method:
1. Set up water baths to temperature 10oC, 20oC…70oC, 80oC.
2. Place 3mL of milk in every tube.
3. Place 2 test tube of milk in every temperature.
4. Drop 3 drops of rennin to one test tube. Label A.
5. Use the other test tube with no rennin as a control. Label B.
6. Start the stopwatch as soon as the rennin is added.
7. Maintain the constant temperature and check every minute until Test Tube A has clotted.
8. Record results and tabulate it.
9. Plot graph with temperature and 1/time (enzyme activity) on x, y axis respectively.

Class results:
Temperature Clotting time 1/Time
10oC NA 0
20oC NA 0
30oC 10 1/10
40oC 16 1/16
50oC NA 0
60oC NA 0
70oC NA 0
80oC NA 0

Graph:







Discussion:
During the experiment, the temperature was not kept to required temperature (slightly). This can lead to inaccuracy in results. The rennin also took too long to clot, perhaps due to the concentration of rennin.

This experiment can be improved by increasing the amount of rennin; this will speed up the experiment. Watch baths should also be maintained in a constant temperature to avoid inaccuracy.

Conclusion:
This experiment proves that the optimum temperature is in the 30OC – 40oC range and the reaction would not take place under 30oC and the enzyme denatures after 50oC. Therefore; initial hypothesis is accepted.

 

[Tulii]

Thanks Jeff!

I guess I just tilt the test tube every minute, and determine the 'thickness' of it through observation, it seems like the only way.

Thanks again!

 

[jeff.wong]

xD Not a problem

 

[adnan91]

i miss biology

 

[harriet.rose]

please take my place in class.

 

[possessionless]

i remember doing this prac =)

 

[TehAzner]

I remember this prac too, and this was like 2 years ago XD. I fondly remember placing test tubes in a buckets of ice, that was so cool (no pun intended). I also remember my friend's labelling of the test tubes (control and experiment) disappearing in water because the marker wasn't water resistant :rofl:

 

[heyawii]

hey
i'm doing this experiment now and i'm having some trouble...i was just wondering what were the measurements of the milk and the renin junket tablet you used in each test tube since my school only provides the tablet and not the liquid solution...thank u sooo much

 

[possessionless]

we used 10mL of milk
and half a junket tablet in all test tubes.

 

[heyawii]

thanks a lot for your help

 

[Sordafish]

I've been doing this prac too, in preparation for an assessment task, but I'm a bit stuck as to the Risk Assessment
The only real thing is not to burn yourself with the 80oC water right?
And NOT to eat the junket, but I'm sure doing so wouldn't kill you.