soart
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This is an A-level question:


12(a). Some companies offer snack foods that contain a higher protein content than usual.
'Protein cookies' are an example of this kind of food. Some protein cookies contain up to 37 g of protein per cookie.

A student examined these foods by measuring the respiratory quotient (RQ) of maggots that were fed different types of cookie.

The student measured the oxygen consumption and carbon dioxide production of maggots when they were fed protein cookies and normal cookies.

The cookies were powdered and treated to remove all fat before being fed to the maggots.

Table 21 is a summary of the results.
Cookie 1:
Carbon dioxide produced (cm3 min−1): 13.29
Oxygen absorbed (cm3 min−1): 13.56
Cookie 2:
Carbon dioxide produced (cm3 min−1): 13.04
Oxygen absorbed (cm3 min−1): 13.87


Use the information in Table 21 to deduce which of the two cookies is the protein cookie. Explain your choice.

(b). The student then changed the experiment to investigate whether respiration of the cookies by yeast was different from respiration of the cookies by maggots.

The student planned to allow yeast cells and maggots to respire the cookie powder in anaerobic conditions and measure the RQ over 2 minutes.

State and explain one problem with the student's method.

And the next question:

Plant hormones affect the growth of plant tissues in different ways.

One such effect is to promote the formation of seedless fruit.

Cytokinins are a group of plant hormones.

A commercial plant hormone firm carried out research into three different cytokinins: kinetin, zeatin and diatin.

The firm investigated the effect of adding different volumes of each cytokinin on the production of seedless fruit.

The cytokinins were sprayed on the flowers of different plants. Over time, the mass of seedless fruits produced by the plants was measured.

Fig. 21 Is the summary of their results.
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On the basis of these results, the firm decided to use diatin in their new plant spray.

The firm made the following claim on their packaging:

Diatin is scientifically proven to cause production of seedless fruit when applied to flowers.

Evaluate the firm’s claim, using the evidence in Fig. 21.
Last edited by soart; 7 months ago
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Ashprit
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So, this seems hard and is kind of hard. Firstly you need to calculate the respiratory quotient for both cookies. the lower RQ has more protein so it must be 2

For B yeast fermentation will produce co2 whereas maggots (since they are living beings) carry out lactate fermentation sometimes so dont produce co2 so the RQ will be somewhat lower than usual.
for the plant one i dont know since I am an AQA student
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soart
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(Original post by Ashprit)
So, this seems hard and is kind of hard. Firstly you need to calculate the respiratory quotient for both cookies. the lower RQ has more protein so it must be 2

For B yeast fermentation will produce co2 whereas maggots (since they are living beings) carry out lactate fermentation sometimes so dont produce co2 so the RQ will be somewhat lower than usual.
for the plant one i dont know since I am an AQA student
That's alright, thanks for helping me out with question 1 though! I did figure out the RQ value, but I didn't know where to go from there, and how to answer part B, so you were a big help !
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HarisMalik98
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Here's a few pointers to help you:

-There is a correlation, but correlation does not always equal causation
-Graphs are poorly displayed (No units, axes inverted, no error bars)
-No method given
-No specified control of any confounding variables (E.g. temperature, light intensity, soil/mineral composition, CO2 concentration, type of fruit, pests?, and more....)
-No control (untreated) group
-No consideration of the interaction of other hormones or biological processes
-No replicates

On top of this, looking at the graphs Zeatin looks far more productive that Diatin.
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