doubts about biology

[3amak]

Any body got a revision test for the biology??

 

[abdullah jutt]

yes do past papers ur self in the official time of the papers and after ur done with the paper check ur answers with marking scheme and calculate the total marks u get that's how i do it

 

[3amak]

did that lol

 

[SomeStudent]

I want some help here. Can someone tell me the pressures in the ventricles/atrium of the heart during a cycle? and the valves: whether they open or not? You know, we get these graph question about it and I find it quite tricky.

 

[3amak]

Ok. U dont Have to know the pressure u only have to know when the chamber is relaxed or contracted so
at first the whole heart is relaxed and bicuspid and tricuspid valves are closed the blood flows in the heart this takes o.1 s then the atrium contract and semi-luner are closed and the tricuspid and bicuspid open so blood flow in the ventricles then the ventricles contract and the semi-luner valves open and the bicuspid valves and tricuspid close .

 

[SomeStudent]

Ok. U dont Have to know the pressure u only have to know when the chamber is relaxed or contracted so
at first the whole heart is relaxed and bicuspid and tricuspid valves are closed the blood flows in the heart this takes o.1 s then the atrium contract and semi-luner are closed and the tricuspid and bicuspid open so blood flow in the ventricles then the ventricles contract and the semi-luner valves open and the bicuspid valves and tricuspid close .

Righty! Ahaan, got it! Thanks!!

 

[M-16]

Is manufacturing yoghurt in the syllabus
If it is in then I need some help

 

[3amak]

No But U should know that bacteria is responsible for it

 

[3amak]

Welcome

 

[UnknownUser]

Anybody gave their pp3 varient 1

 

[roubair ashraf]

Is manufacturing yoghurt in the syllabus
If it is in then I need some help

YOGHURT
Steps:
1. The milk is heated to about 87°C to kill off any microorganisms found in the milk
2. It is then left to cool to about 35-40°C
3. A small amount of pre-prepared yoghurt is added as source of the needed microorganism
4. The milk is then left in an incubator at a suitable temperature, and during this period the bacteria feeds on the milk sugar (lactose) producing lactic acid and energy
5. The lactic acid changes the pH of the milk, and it coagulates, forming curds
6. The yoghurt is then preserved in a refrigerator, so as to stop the action of the bacteria, otherwise the lactic acid content would be too high and this makes the yoghurt sour
SINGLE CELL PROTIEN
Since microorganisms reproduce rapidly, and their cells contain a high proportion of protein, they are sometimes used as food.
Steps:
1. The fermenter is first sterilized to avoid any negative effects brought about by other microorganisms
2. Any non-harmful bacteria/fungi/algae/plankton is brought to the fermenter
3. Sterilized nutritive materials are added, like air for aerobic respiration
4. The products are then taken to be used

 

[Amal awad]

Who did biologyy paper 3 ?

 

[3amak]

i need the steps of fermentation