Respiration is the process by which living organisms extract energy from food molecules, like glucose, to fuel essential cellular activities.
Respiration is a metabolic process during which cells break down nutrients
releasing energy in the form of ATP (adenosine triphosphate).
Respiration is an enzyme-controlled process.
Important Note ICON It’s important to note that respiration is a chemical process that occurs within cells and should NOT be confused with breathing, which involves the exchange of gases.
Living organisms engage in various energy-consuming processes vital for their survival and functioning.
These processes require energy derived from the breakdown of nutrients through the process of respiration.
Common energy consuming processes in living organisms:
Muscle Contraction:
Muscle cells require energy to contract, enabling movement in organisms. Such as:
- Locomotion
- Peristalsis for moving food along the alimentary canal
- Uterine contractions during childbirth.
- Building proteins from amino acids demands energy. This process is essential for cell repair, growth, and the synthesis of enzymes and structural proteins.
Cell Division and Growth:
The process of cell division, including mitosis and meiosis, consumes energy. It produces new cells for
- Growth
- Tissue repair
- Formation of reproductive cells.
Active Transport:
Energy is needed to transport molecules across cell membranes against concentration gradients, ensuring the regulation of ions and molecules within cells.
- The growth of organisms involves the formation of new cells or an increase in cell size, which requires energy for biosynthesis and metabolic activities.
Generation and Passage of Nerve Impulses:
Nerve cells conduct electrical impulses, which require energy to propagate signals along neural networks for
- Sensory perception
- Motor control
- Information processing.
Maintaining a constant body temperature:
Warm-blooded animals expend energy to maintain a constant body temperature, ensuring optimal conditions for biochemical reactions and physiological processes.
Mindmap Bring these ideas together
Effect of Temperature on Respiration
The rate of cellular respiration is influenced by temperature.
Low temperatures:
Low temperatures slow down respiration due to decreased kinetic energy, resulting in fewer enzyme-substrate collisions and reduced energy release.
Higher temperatures:
Higher temperatures speed up respiration by increasing molecular collisions, leading to enhanced energy production.
Info IconHowever, excessive heat can denature enzymes, inhibiting respiration. It’s crucial to avoid extreme temperatures to preserve enzyme activity and cellular function.
Investigating the rate of respiration in organisms
Yeast Respiration
Materials:
- Glucose solution (5%)
- Dried yeast suspension (10%)
- Side-arm boiling tube or conical flask
- Beaker
- Gas syringe or delivery tube
- Stopwatch
Procedure:
- Prepare a 5% glucose solution and a 10% suspension of dried yeast.
- Place 5 cm^3 of the glucose solution and 1 cm^3 of the yeast suspension in a side-arm boiling tube or conical flask. Adjust volumes accordingly if using a conical flask.
- Place the container with the yeast and glucose in a beaker of water at 20°C.
- Allow the yeast to adjust to the temperature of the water in the beaker for a few minutes.
- Attach the side arm to a gas syringe, ensuring the plunger is pushed fully in.
- Start the stopwatch and allow the gas produced by yeast to collect in the gas syringe for a fixed time.
- Record the time and the volume of gas produced.
- Repeat the experiment for a range of different temperatures.
- Calculate the gas production per minute for each temperature.
Note: If a gas syringe is unavailable, attach the side arm to a delivery tube inserted into a boiling tube containing water. Count the bubbles produced for a fixed time.
Results:
The volume of gas produced increases as the temperature is increased to 35 or 40°C.
Higher temperatures slow down the rate of gas production.
Low temperatures may result in less gas being produced.
