.

[TrueLight]

Cell replication - we're at the end of Unit 1 AOS 1.

yr 11 bio? mmm thats like meiosis and mitosis stuff... never liked that stuff...

dna replication by itself and that process is alright

[TrueLight]

we are learning about cellular respiration and photosynthesis, and are also in the process of doing our enzyme prac/sac

also here is a vid i found really helpful on dna transcription, translation and protein synthesis
http://www.youtube.com/watch?v=983lhh20rGY&feature=related

ah atp production and stuff.... never liked that too.. lol

yeah that video is pretty basic.. theres some better more detailed videos

[slothpomba]

We started AOS 2 the other day.

[lexitu]

We are going way too slowly... Only up to molecular bio in medicine. Really, AOS 1 should be completed in 5-6 weeks, it's mostly revision from year 11.

[akira88]

We are going way too slowly... Only up to molecular bio in medicine. Really, AOS 1 should be completed in 5-6 weeks, it's mostly revision from year 11.

I swear my class is going far too slow as well! And definitely agree with you, it is basically year 11 revision, I don't see why it should take that long.

[TrueLight]

ha man u go through stuff in like terms 3 months... at uni in 3 months we finish everything lol

[stonecold]

didn't wan't to start a new thread so i'll just ask here

basically we tested the reaction rate of an enzyme at different temperatures by testing for glucose conc at the end of the experiment.  (we put starch in at the beginning)

our controls were a test tube of enzyme and a test tube of starch both at 22 degrees.  
we tested all our other tubes (containing both enzyme and starch) at a range of temps including 4, 22, 37 and 60 degrees.

what do I say for this question:
explain whether the controls in the experiment served their purpose...

edit: and obviously there was no glucose present in either of the controls at the end.  we were using amylase btw...

[stonecold]

okay thanks.  but i'm confused.  the control showed the difference of enzyme by itself  and starch by itself giving nothing.  then when they were together, glucose was produced.

our teacher said the purpose of the experiment was to test the variable 'temperature.'

[stonecold]

exactly.  i get why you have amylase and glucose on their own, to ensure that they don't produce glucose on their own, but that is really a separate experiment.

In the context of this experiment, if we were testing for temp, then shouldn't all test tubes contain the same thing (amylase + starch) and the control (only one) has a set temp, and then all the other tubes are tested at a range of different temps, and the glucose conc. compared to the control to see how temperature alters the reactions rate?

but that would mean that the controls didn't serve their purpose, and i doubt that would be the answer.
it is a two mark question, so maybe you say no, and then explain why?

[lexitu]

Schools always stuff up their experiments. Mention the ambivalence in your answer.

[stonecold]

^its so annoying.  the sac is on thursday, i guess i'll have to ask my teacher then...

[lexitu]

Yeah I suppose, very annoying stuff.

[stonecold]

umm, can someone quickly explain what are the functional differences between salivary amylase and pancreatic amylase.

Amylase:
-Digestive enzyme, that breaks down starch into simple sugars such as dextrin, maltose and glucose.
-Humans have alpha amylase, which makes random products, vs. beta amylase in plants which only produces maltose.
-Both salivary amylase and pancreatic amylase have optimal pH of ~6-7 and optimal temp of 37 degrees.

are there any functional properties of amylase I should know about, which are unique to either the pancreas or saliva...

thanks.

[stonecold]

haha yeah, but my sac tomorrow unfortunately does...

[TrueLight]

im going to copy what this textbook (Human physiology, Lauralee Sherwood) says..

'Digestion in the mouth involves the hydrolysis of polysaccharides into disaccharides by amylase. However, the most digestion by this enzyme is accomplished in the body of the stomach after the food mass and saliva have been swallowed. Acid inactivates amylase, but in the center of the food mass, where stomach acid has not yet reached, this salivary enzyme continues to function for several more hours.'

'Like salivary amylase, pancreatic amylase contributes to carbohydrate digestion by converting polysaccharides into disaccharides. Amylase is secreted in the pancreatic juice in an active form, because active amylase does not present a danger to the secretory cells. These cells do not contain any polysaccharides.'