Question

making sense of exercise and cellular respiration

1. justify the decision to collect data on the variable that we choose for the purpose of determining the effect of exercise on homeostasis.
2. how might you improve the procedure to generate more accurate data in order to respond to the research question?
3. in this investigation, we exercised for a short time frame. how might our body respond differently when exercising for longer periods of time (like in a marathon)?
4. explain how the heart, lungs, and blood vessels work together to maintain blood oxygen levels in the body.

Explanation:

Question 1

To determine the effect of exercise on homeostasis, a suitable variable could be heart rate. Heart rate is easily measurable, changes with exercise intensity, and reflects how the body maintains homeostasis (e.g., increasing to meet oxygen demands during exercise). Measuring heart rate before, during, and after exercise shows how the body adjusts to restore balance (homeostasis) post - exercise. Other valid variables could be blood pressure, respiratory rate, or blood glucose levels, but heart rate is a common and straightforward choice.

To generate more accurate data, we can: 1. Standardize the exercise protocol (e.g., same type, intensity, and duration of exercise for all participants) to reduce variability. 2. Use calibrated and precise measurement tools (e.g., a digital heart rate monitor instead of manual pulse counting). 3. Have multiple trials (e.g., repeat the exercise - measurement process for each participant multiple times and take the average) to account for random errors. 4. Control external factors (e.g., ensure the environment is at a consistent temperature, participants have similar pre - exercise conditions like not having consumed caffeine recently).

For short - term exercise (e.g., a sprint), the body mainly uses anaerobic respiration (glycolysis) to produce ATP quickly, as oxygen supply can't meet the immediate energy demand. This leads to lactic acid buildup, causing muscle fatigue quickly. For long - term exercise (e.g., a marathon), the body relies more on aerobic respiration (using oxygen to break down glucose, fat, or protein) to produce ATP sustainably. The heart rate, respiratory rate, and blood flow to muscles increase to supply more oxygen. Over time, the body also adapts by increasing the number of mitochondria in muscle cells and improving oxygen - carrying capacity of blood.

Answer:

A suitable variable is heart rate. It is measurable, changes with exercise, and reflects homeostatic adjustments (e.g., increases during exercise to meet oxygen needs and returns to normal post - exercise).

Question 2