Respiration Flashcards
What kind of process is respiration?
It is an exothermic process - it releases energy.
What is photosynthesis?
Photosynthesis is the process by which plants, and some bacteria, synthesise food molecules - which they then use, in addition to other things, for respiration. The process of photosynthesis requires energy - it is endothermic.
What is breathing or ventilation?
Breathing (ventilation) is the mechanical movement of air in and out of the lungs.
What is respiration?
Respiration is the process of releasing energy from glucose to a usable form for the cells (ATP).
Why do organisms need energy?
- to drive the chemical reactions needed to keep them alive
- movement
- cell division
- to maintain constant conditions in the cells and the body - homeostasis
- to move molecules against the concentration gradients in active transport
- for the transmission of nerve impulses
What is aerobic respiration?
Aerobic respiration is respiration using oxygen to break down food molecules, such as glucose. Glucose is the main respiratory substrate - or the molecule normally used for respiration. Gucose is oxidised to release its energy.
Word equation of aerobic respiration
glucose + oxygen —> carbon dioxide + water + energy released
Chemical equation for aerobic respiration
C6H12O6 + 6O2 —> 6CO2 + 6H2O + energy released
Where does aerobic respiration occur?
The first stages of respiration occur in the cytoplasm of cells, but most of the energy is released in the mirchendria.
What is anaerobic respiration?
Most organisms cannot respire without oxygen but some organisms and tissues can continue to respire if oxygen runs out; this is known as anaerobic respiraton.
Human muscle can respire anaerobically for short periods of time.
Anaerobic respiration in animals word equation
glucose —> lactic acid + energy released
Anaerobic respiration in animals chemical equation
C6H12O6 —> 2C3H6O3 + energy released
Anaerobic respiration in yeast (fermentation) word equation
glucose —> ethanol + carbon dioxide + energy released
Anaerobic respiration in yeast (fermentation) chemical equation
C6H12O6 —> 2C2H5OH + 2CO2 + energy released
Where does anaerobic respiration occur?
Cytoplasm
Aerobic Respiration Vs Anaerobic Respiration
Aerobic:
- Presence of oxygen
- Complete oxidisation of glucose
- Relatively large amount of energy released
- Slower but releases more energy
- More frequent
Anaerobic:
- Absence or short supply of oxygen
- Incomplete oxidisation of glucose
- Small amount of energy released
- Faster but less energy released
- Less frequent
Photosynthesis word equation
carbon dioxide + water - sunlight + chlorophyll -> glucose + oxygen
Photosynthesis chemical equation
6CO2 + 6H2O —> C6H12O6 + 6O2
What is the response to exercise?
Muscles need energy to contract. While exercising, the muscles need additional energy as:
—> the breathing rate and volume of each breath increases
—> the heart rate increases
What happens during long periods of vigorous exercise?
—> lactic acid levels build up
—> glycogen reserves in the muscles become low as more glucose is used for respiration, and additional glucose is transported from the liver
What are the side effects of anaerobic respiration?
Build up of lactic acid produces oxygen debt
As body stores of glycogen become low, a person suffers from muscle fatigue
What happens when a period of exercise is over?
Lactic acid must be removed, as the body’s tolerance of lactic acid is limited.
How is lactic acid removed?
Lactic acid is taken to the liver by the blood, and either:
- oxidised to carbon dioxide and water, or
- converted to glucose, then glycogen, for levels in the liver and muscles to be restored
What happens to breathing rate after exercise?
The removal of lactic acid requires oxygen, hence, after exercise, you continue to breathe deeply and quickly for a short period of time, known as EPOC (excess post-exercise oxygen consumption).
