Respiration
Cells require energy for activities such as growth and cell division. In animals, muscle cells require energy for contracting and nerve cells require energy for transmitting nerve impulses.
The energy is supplied by food that the cells take in.
The break down of food to release energy is called respiration. The main food used by cells for respiration is glucose.
If oxygen is present then animal, plant and yeast cells can carry out aerobic respiration. The overall process of aerobic respiration is illustrated below.
Factors that affect the rate of respiration include:
- Temperature - respiration is controlled by enzymes, will the rate of respiration increase or decrease as a result of altering the temperature?
- Oxygen level - oxygen is a requirement of aerobic respiration, will the rate of respiration increase of decrease as a result of altering the oxygen level?
- Availability of glucose - glucose is respired (broken down) in this process, will the rate of respiration increase or decrease as a result of altering the availability of glucose?
Here are a few examples of how Scientists can measure the rate of aerobic respiration:
- Measure how much oxygen was taken in by an organism in a set period of time
- Measure how much carbon dioxide was given out by an organism in a set period of time
- Measure the mass of glucose used in a set period of time
