Archive of ‘Grade 12’ category

22
Apr
2019

Bio 12 Lab – Lactase Drops vs Glucose Production

categories: Bio 12, Grade 12

April 18th,2018:  Lactase Vs. Lactose [ ] lab

Experiment: Same glucose solution mixed with a different number of drops of lactase:

Purpose: To see the effect an increased or decreased amount of concentration of lactase enzyme mixed with a dairy substance will effect the rate of production of glucose within a reaction

Hypothesis: If more lactase drops are added into the milk, then the greater amount of glucose is produced, because more of the enzymes that break down lactose are working in larger amounts to produce different amounts of glucose.

Materials:

  1. 5 Test Tubes
  2. Test Tube Rack
  3. Milk (2%)(60ml, 12ml per test tube)
  4. Lactase Drops
  5. 10 Glucose Strips
  6. Graduated cylinder (50ml)

Procedure:

  1. Prepare 5 test tubes with the required amount of milk (30 ml per test tube).
  2. Prepare the lactase dropper and drop the required amount of milk into the test tubes except for one, this is your control tube
  3. Test each solution with a glucose strip before adding any drops, and record information in data chart below.
  4. According to the chart below, drop the required amount of lactase drops into the milk.
  5. Make sure the solution is mixed well with the milk.
  6. Wait 10 minutes before testing each test tube with the glucose strips.
  7. Once it has been 10 minutes, place a glucose strip into each test tube wait 30 seconds, compare colour to chart below and record the data below.
  8. Graph your data, [ ] of Glucose vs. # of Lactase drops, with # of Lactase drops on x-axis, and [ ] of Glucose on y-axis

Data/Observations:

Test Tube #

       Lactase Drops

Initial Glucose

(Strip colour + mmol/L)

Final Glucose

(Strip colour + mmol/L)

1

0

Negative

Blue , 0 mmol/L

2

2

Negative

Light brown, 56mmol/L

3

4

Negative

Medium brown 56mmol/L

4

6

Negative

Medium brown 56mmol/L

5

8

Negative

Dark brown 111mmol/L

I of Glucose (mmol/L) vs. # of Lactase Drops # of drops

Analysis/Conclusion:

In this lab it could be inferred from the data table that as we added more lactase drops the rate and breakdown of lactose into glucose was increased and therefore it can be said that they are directly related (add more of one produce more of the other through breakdown). Due to the low volume of milk that we used, our hypothesis cant 100% really support our findings because almost all the results were very similar, so no facts were able to truly be compared based on the similarities within the colour indicators (some of the tubes with more drops of lactase had the same colour indicator change). However in generalization with more lactase drops a higher amount of glucose found then starting levels. Therefore it can be concluded that the more lactase added to the milk changes (higher) the production of glucose within the milk substance.

How do you think you could improve this experiment for the most accurate outcome? (Errors/Improvement)                                                                                                             Ways that would be most affective in improving this experiment would be having a greater volume of milk. This would have made the results show a larger difference of change greatly due to the concentration of the lactase drops to milk being lower than what they were in this particular experiment, changing the results so they had visible differences within the colour indicator scale, and therefore giving a more accurate reading.

By : Alex, Molly and Sophie

14
Mar
2019

Diffusion in Agar Cubes

categories: Bio 12, Grade 12

1. In terms of maximising diffusion, what was the most effective size cube that you tested?

In terms of maximum diffusion, the most effective size cube that was tested would be the smallest one (the 1cm x 1cm x 1cm cube).

2. Why was that size most effective at maximizing diffusion? What are the important factors that affect how materials diffuse into cells or tissues?

The reason the 1cm3 cube was the most effective at maximizing diffusion was because its surface area to volume ratio was the highest out of the 3, this happens because the larger surface area ratio to volume allows for diffusion to happen over the entire cube (or cell) while only having a smaller volume to actually “take over”/ diffuse and in this case it can be seen by the way the pink colour has spread throughout the different size cubes (see above). Important factors that affect how materials diffuse into cells or tissues are surface area (volume ratio will affect part of this.), concentration gradient, temperature, the permeability (of the cell membrane), these will all be needed to reach maximum diffusion efficiency.

3. If a large surface area is helpful to cells, why do cells not grow to be very large?

Although a large surface area is helpful to cells, cells do not grow to be very large because that means that the volume would also be larger and would have a larger area internally that would need to be diffused which means complete diffusion would take longer because of the ratio between the two, you want a high surface area to a small volume for a more efficient diffusion.

4. You have three cubes, A, B, and C. They have surface to volume ratios of 3:1, 5:2, and 4:1 respectively. Which of these cubes is going to be the most effective at maximizing diffusion, how do you know this?

Cube C will be the most effective at maximizing diffusion, it will be the most effective because its surface area to volume is the best ratio for efficient diffusion (high surface area to a low volume).

5. How does your body adapt surface area-to-volume ratios to help exchange gases?

As cells grow in size the surface area to volume ratio becomes less and less efficient for gas exchange to happen, and at some point the cell will grow to be too big for gas exchange to serve the internal needs of the cell, and when this occurs the cell either has to undergo mitosis or potentially lose function. Our bodies have adapted to having larger organs too by having them as spherical shapes which allow for maximum surface area exposure.

6. Why can’t certain cells, like bacteria, get to be the size of a small fish?

Certain cells can’t get to be the size of a small fish because it would be a bad surface area to volume ratio, and would lose its functional abilities, therefore it would have to undergo division to maintain their needed ratio. Bacteria are almost always single celled organisms which means they can only depend on their organelles within to survive, but that’s not the same with multicellular (next question).

7. What are the advantages of large organisms being multicellular?

Large organisms that are multicellular have specialized cells which are able to perform different functions (instead of a single cell that can only have one function). These multicellular organisms can function because the cells within are specialized for specific tasks, meaning the organism can grow and still be composed of the same cells because they arn’t effected by the surface area to volume ration because there are more of them composing this one thing.