Question

Indicators

Starch and maltose when dissolved in water are colorless. To determine if starch or maltose are present chemical indicators must be used for the researcher to qualitatively visualize the presence of starch and maltose. The indicators used in this experiment are listed below.

• IKI (potassium iodide) starch test is an indicator of starch. In a positive IKI test a blue-black color change occurs, even if the blue-black color disappears after the addition of IKI. A negative result is recorded if a blue-black color is not observed.

Experimental Procedure

Due to Covid-19 this experiment is taking place at the home of Dr. Amanda Vega using basic kitchen supplies and mail order enzyme kit. The experiment was filmed and uploaded to Youtube. The experiment is being conducted at room temperature and is being conducted as a spot plate analysis

What is a spot plate analysis? A spot plate is typically a ceramic rectangle glass with depressions through the ceramic plate. The depressions, called wells, are loaded with the desired chemical reagents and then are checked for results using a color indicator. In the absence of owning a spot plate, the spot plate analysis was used on a clean kitchen cutting board.

1. Prior to starting the experiment video make a hypothesis for how pH will affect salivary amylase’s ability to chemically digest starch. Record your answers in table 1 below.

2. Watch the video by visiting the link below.

https://www.youtube.com/watch?v=y0uhLf_h_Ks

3. Fill in the reagents placed in each spot of the cutting board in table 2 below.

4. Record the results of the IKI starch test as positive, negative, or partially negative for starch in table 3 on the next page.

This is the answer to table 1

Table 1: Hypothesis on how pH will affect salivary amylase’s ability to chemically digest starch

pH Condition	Hypothesis
Salivary Amylase, pH = 2.0	Pretty low pH values result in a total loss of activity of the enzymes.
Salivary Amylase, pH = 7.0	The enzymes are denatured at high temperature.
Salivary Amylase, pH = 9.0	The enzymes are denatured at greater temperatures.

The optimal pH for an amylase starch reaction is pH 7. PH values below or above the value can result in a slower reaction rate. Amylase acts in the pH 3 to pH 11 range. Extremely high or low pH values result in a total loss of activity of the enzymes.

Table 2: Chemical reagents in spot of the cutting board spot plate

Experimental Row	Spot 1	Spot 2	Spot 3	Spot 4
Controls
Effect of pH				Empty Spot
Effect of Pepsin + pH				Empty Spot

Record the results of the IKI starch test as positive, negative, or partially negative for starch in table 3 on the next page.

Table 3: Results of the Experiment

Experimental Row	Spot 1	Spot 2	Spot 3	Spot 4
Controls
Effect of pH				Empty Spot
Effect of Pepsin + pH				Empty Spot

I didn't answer for table 2 and 3

Thank you

Answer 1