2. The shapes of the curves are different as on a linear graph points are equally spaced whereas on a log graph spaces are seperated by log intervals. On a log graph the shape is sigmoidal, flat at the bottom and top and linear in the middle region. On a linear graph both the ach with and without atropine dont have

3. Krebs solution is a physiological salt solution which is similar to extracelluar fluid and contains sodium, potassium, calcium and chloride ions along with the continual gassing of 5% CO2 present in O2 .As a result of the cells and its receptors being located in an environment similar to their normal in vivo environment, we are likely to see a physiological response which is the same of that behaivour of the cells when in the body.

4. The tissue was able to survive after being removed from the animal as the krebs solution stiumlates the extracellular fluid that the isolated tissue is normally found in, it contains ions which are essential for cellular processes to occur and the gassing of O2

provides a source of oxygen which is essential for cell life. The isoltaed tissue itself was able to function due to the action of the enteric nervous system which was responible for the contraction and relaxation of tissue as ach was added to the bath and binded to the muscarinic receptors. The test that was used to test the viability of the cell was the addition of strong K+ solution at the begining and completion of the data collection for the concentration response curves. This test checks for viability by measuring for maximal contraction response by the ileum tissue. The high concentration of K+ lead to hyperpolarisation of the cell as it was flooded with a high concentration of KCl solution.

The threshold concentration occurs when a response (i.e. contraction and reaxation of ileum tissue) occurs due to the presence of the ach which for the ach without the presence of atropine was and with the presence of atropine was.

Sources of errors could also occur due to poor pipetting technique, inaccurate formulation and creation of the serial dilutions from the stock solution and being absent minded while preforming the experiment by not keeping track of which diluted solution to add to the bath and the correct quantity which was to be added.