SAC 3

Question 1

What trend(s) can you see in your data?

Answer 1

As temperature increased from 2°C to 65°C, the rate of reaction also increased. The highest reaction rate was observed at 65°C.

Question 2

● What relationship can you observe between your independent and dependent variable?

Answer 2

The independent variable (temperature) directly affected the dependent variable (oxygen concentration). Higher temperatures increased catalase activity, producing more oxygen

Question 3

● Can you explain this using biological terminology (linking to enzyme activity)?

Answer 3

increased temperature raises kinetic energy, = more frequent collisions between catalase and hydrogen peroxide. = forms more enzyme-substrate complexes, = speeds up the breakdown into oxygen and water = enzyme denatures at too high a temperature.

Question 4

● Does your data support your hypothesis?

Answer 4

Partially. Rate increased with temp as predicted, but didn’t decrease—suggesting 65°C wasn’t high enough to cause denaturation during the test time.

Question 5

● Do you have any anomalous data or outliers?

Answer 5

The data appears consistent. No clear outliers were identified, but the reaction rate at 65°C being highest is unusual since many enzymes denature at that point.

Question 6

● What limitations or uncertainties did you have in your experimental method?

Answer 6

• set measurement time may have been too short to capture full reaction = missing later changes in oxygen production
• inconsistent yeast ball size
• slight delays in sensor calibration could have affected accuracy. (oxygen sensor not fully calibrated when starting measurements)

Question 7

● Are your results what you expected? Can you account for any unusual results?

Answer 7

Mostly yes, though the highest activity at 65°C may suggest this particular catalase tolerates heat well or wasn’t denatured within the timeframe.

Question 8

● What sources of error may have been present? How did they affect your results?

Answer 8

Systematic error: If the enzyme or substrate is consistently too concentrated or diluted, it would affect enzyme activity in the same way for every trial, leading to systematic errors.
Random error: inconsistent water temperatures (eg 49.7 not 50 degrees, or 36.2 not 36)

Question 9

● How could you improve your experimental method?

Answer 9

I could use more precise measuring tools, better timing (like a timer), and increase temperature control. I’d also repeat the experiment more times for better reliability.

Question 10

● What implications are there from your findings? What further investigations could be undertaken?

Answer 10

Understanding enzyme activity helps in biotech, medicine, and food industries. further investigations could test temperature range for denaturation: Test a range of temperatures (e.g., 30°C, 40°C, 50°C) to find the optimal temperature for enzyme activity and the point at which denaturation begins.

Question 11

● What is a real-life application of your finding

Answer 11

This experiment relates to how enzymes break down substances in the body—for example, catalase breaking down hydrogen peroxide in cells.

Question 12

Accuracy

Answer 12

How close a measurement is to the true or accepted value.

Question 13

Precision

Answer 13

How close a measurement is to the true or accepted value.

Question 14

Repeatability

Answer 14

The ability to obtain the same results when the same person repeats the experiment using the same method and equipment

Question 15

Reproducibility

Answer 15

The ability to get the same results when different people repeat the experiment using the same method.

Question 16

Validity

Answer 16

Whether the experiment actually tests what it claims to

Question 17

Reliability

Answer 17

How consistent and dependable the results are, often improved through repeated trials and clear procedures.

Question 18

Controlled Experiment:

Answer 18

A controlled experiment tests one independent variable while keeping all other controlled variables constant.

Question 19

Qualitative

Answer 19

Descriptive data (e.g., color changes); shown in bar graphs or pie charts.

Question 20

Quantitative

Answer 20

Numerical data (e.g., reaction rate); shown in line graphs or histograms.

Question 21

Variables:
Independent -
Dependent -
Controlled -

Answer 21

I: What you change.
D: What you measure.
C: What you keep the same.

Question 22

Purpose of a Control Group

Answer 22

baseline for comparison. To compare results and see if the change in the independent variable actually causes a difference

Question 23

role of systematic errors

Answer 23

• Caused by flaws in equipment or method.
• Affect all results in the same direction (e.g., always too high).
• Impact accuracy.
• Example: Miscalibrated oxygen sensor, incorrect solution concentrations.

Question 24

role of random errors

Answer 24

• Caused by unpredictable changes in conditions.
• Vary in magnitude and direction between trials.
• Impact precision.
• Example: Slight temperature shifts in water bath, bubble interference during measurement.

Question 25

structure of enzymes and role as organic catalysts.

Answer 25

enzymes are organic catalysts that increasing the rate of chemical reactions without being consumed, by lowering the activation energy required

Question 26

Function of Enzymes in Cells

Answer 26

Enzymes speed up and control most chemical reactions in the body, (ie digestion, energy release, and DNA processes) by helping them happen faster under normal cell conditions.

Question 27

What is the activation energy for a chemical reaction?

Answer 27

Activation energy is the minimum energy needed for a chemical reaction to proceed. Enzymes lower this energy barrier by forming an enzyme–substrate complex and allowing the reaction to occur more easily and quickly.

Question 28

Factors Affecting Enzyme Activity

Answer 28

Temperature: Increases kinetic energy up to an optimum; beyond that, enzymes may denature. pH: Affects the enzyme’s shape and charge, altering the active site. Substrate concentration: Increases reaction rate until enzyme saturation occurs. Enzyme concentration: More enzyme generally increases the rate, provided there is enough substrate.

Question 29

Interpreting Enzyme Activity Graphs

Answer 29

Temperature graph: Shows a rise to an optimum point, followed by a sharp decline (denaturation). pH graph: Shows a bell-shaped curve with reduced activity at extremes. Substrate concentration: Rapid initial increase, then plateaus (enzyme saturation). Enzyme concentration: Linear increase in rate if substrate is in excess.

Question 29

measuring Enzyme Activity via O₂ Concentration

Answer 29

Oxygen concentration was used as an indirect measure of catalase activity by quantifying the rate at which O₂ was released during the breakdown of hydrogen peroxide (H₂O₂). A faster increase in O₂ indicated a higher rate of enzyme activity.

Question 30

Summary of Independent Variable Effects

Answer 30

As temperature increased, enzyme activity increased because particles moved faster and collided more often. After the optimum temperature, activity dropped because the enzyme denatured and its active site changed, stopping it from working properly.