Respiration - Notes
Class- X Sub: - Biology
Respiration: - It is the process of oxidation of food and to release energy in the form of ATP.
Types of Respiration: - 1. Aerobic Respiration
2. Anaerobic Respiration
1. Aerobic Respiration: - The kind of respiration which takes place in the presence of oxygen where complete oxidation of food takes place in the presence of oxygen where complete oxidation of food takes place to produce energy. Organism which perform aerobic respiration is called aerobes.
C6H12O6 + 6 O2 6CO2 + 6 H2O +38 ATP
Aerobes are higher animals.
Krebs Cycle:- It is the second metabolic pathway of anaerobic respiration where 2 molecules of Pyruvate oxidized in mitochondria to form 6 molecules of CO2 and 6 molecules of H2O along with 38 ATP.
2 Pyruvate +6O26CO2 +6H2O+38ATP
2. Anaerobic Respiration: - It is a kind of respiration which takes place in absence of O2 where food is incompletely oxidized to form Ethyl Alcohol , CO2 or lactic acid by the release of small amount of energy.
Ex: - In yeast
C6H12O6 2 Pyruvate
2 Pyruvate >2 C2H5OH + 2 CO2 + 2 ATP
The organisms that perform anaerobic respiration are called anaerobes. They are lower organisms.
Fermentation:- Second metabolic pathway of anaerobic respiration which takes place in yeast. The product of fermentation are Ethyl alcohol, CO2 and two molecules of ATP.
2 Pyruvate >2 C2H5OH + 2 CO2 + 2 ATP
Difference between Aerobic and Anaerobic Respiration
Takes place in the presence of Oxygen.
Complete break down of food takes place.
End products is Carbon dioxide and water.
38 ATPs are produced.
Takes place in the absence of oxygen.
Partial break down of food takes place.
End products may be ethanol and carbon dioxide(in yeast) or lactic acid (in muscle tissues).
2 ATPS are produced
Breakdown of Glucose by Various Pathways
ATP:- The energy released during cellular respiration is used to synthesis a molecule called ATP (Adenosine Triphosphate) which is used to fuel all life process and cellular activities . Thats why its called energy currency of the cell.
ADP + iP ADPP = ATP
Gaseous Exchange in Plants: -
In Leaf: - Stomata
In Stem: - 1. Stomata in herbaceous stem
2. Lenticels in woody plant.
In Root: - 1. Root Hairs
Phenomenon: - Diffusion
Respiration in Animals: -
- In Unicellular Animals: - By diffusion through cell membrane.
In Earthworm and Frog: - Through moist skin by diffusion. (Cutaneous Respiration)
In Terrestrial Organisms: - By lungs. (Pulmonary Respiration)
In Aquatic Animals: - Fish and prawns extract dissolved oxygen from water through their gills.
Since the amount of dissolved oxygen is fairly low as compared to the atmosphere so their rate of breathing is more.
In Insects: - Grasshopper, cockroach, housefly and mosquitoes has tiny pores present in the body which is called spiracles. Inside their body spiracles makes a tubular structure called tracheal system.
Common Features of All Respiratory Organs: -
1.All the respiratory organs have a large surface area to get enough oxygen.
2.All the respiratory organs have thin walls for easy diffusion of respiratory gases.
3. All the respiratory organs have rich supply of blood.
Human Respiratory System
Lungs are the respiratory organs in humans and are in the thoracic cavity.
Respiration by lungs is called Pulmonary Respiration.
1.Nostrils: - Intake of O2 rich air.
2 . Nasal Cavity; - Nostrils contain fine hairs and mucus which entraps dust, pollutants and germs.
3. Trachea; - It is provided by rings of cartilage so that it doesnt collapse when air is not present in it.
4. Alveoli:- These are the unit of exchange of gases. Alveoli are thin walled balloon like structures which is provided by extensive network of blood vessels.
Mechanism of Breathing: -
Step 1 Inspiration/ Inhalation: - During this step volume of thoracic cavity increases as ribs moves outward and diaphragm downward. Due to increased volume of thoracic air cavity pressure decreases. So, air rushes from lungs through respiratory system.
Step 2 Expiration/Exhalation: - During this step volume of thoracic cavity decreases as ribs comes downward and diaphragm attains normal position. Due to decreased volume of thoracic cavity pressure of air in the thoracic cavity increases and air rushes out of the lungs through respiratory passage.
Residual Volume: - Volume of air left in the lungs after a forceful expiration. It is about 500 ml.
Importance of Residual Volume: -
Residual volume is needed during breathing cycle so that there is sufficient time for oxygen to be absorbed and CO2 to be released
.Gaseous Exchange in Alveoli: -
Alveoli has higher concentration of oxygen as compared to blood capillaries.
Therefore, O2 diffuses into the capillary and combine with hemoglobin to form Oxyhemoglobin and in this way transported throughout the body.
Same time blood capillary has higher concentration of CO2 as compared to lungs.
Therefore CO2 diffuses out of the capillaries and moves to alveoli of the lungs.
Transport of Oxygen and Carbon Dioxide: -
O2 + Hemoglobin Oxyhemoglobin
Transport of CO2 :-
CO2 is transported by blood plasma.
Gaseous Exchange in Tissues: -
- In the cell concentration of CO2 increases by cellular respiration and concentration of O2 gradually decreases.
So oxyhemoglobin breaks down by releasing CO2 from cell.
Blood plasma at the same time absorbs CO2 from cell.