Respiration In Humans Flashcards
Why do we respire?
- need energy to live (move, grow, excrete, reproduce)
- oxidation is the process where food molecules as broken down to use energy available in food
- oxidation of food molecules to produce energy is called respiration
Aerobic respiration
- breakdown of food molecules in presence of oxygen
- produces large amts energy
- waste products: CO2, H2O
- chemical eqn: C6H1206 +602 to 6C02+6H2O+energy
ATP
- energy released during respiration is stored in a small molecule called adenosine triphosphate (ATP)
- main energy currency used in all cells
- energy released when a phosphate bond is broken
- ATP converted to ADP (Adenosine diphosphate)
- aerobic respiration occurs in mitochondria of cells
Anaerobic respiration
- breakdown of food molecules is absence of oxygen
- also know as incomplete oxidation of oxygen
- release less energy, produce lactic acid
- C6H12O6 to 2C3H6O3 (lactic acid) +energy
Anaerobic respiration in humans
- formation of lactic acid/ lactic acid fermentation
- glucose partially broken down
- lactic acid produced still contains energy, only small amt of energy is released
- energy released helps muscles to keep contracting
What happens during exercise and why?
- muscles contract vigorously to enable movement
- respiratory and heart rate increase to allow more oxygen to reach the muscles
- if increased oxygen intake is unable to meet oxygen demand, resulted in oxygen debt and anaerobic respiration to provide the energy required
- oxygen debt is the vol of oxygen required to remove lactic acid that has built up
- anaerobic respiration results in the accumulation of lactic acid
- accumulation of lactic acid can result in muscle fatigue
Recovery
- during period of rest, breathing rate remains fast to provide sufficient oxygen to muscle cells and repay oxygen debt
- lactic acid gradually removed from muscles and transported to liver
- in liver, some of the lactic acid is oxidized to release energy, energy used to convert rest of lactic acid to glucose
- once all lactic acid has been converted, oxygen debt is repaid
- glucose then transported back to muscles
Anaerobic respiration in plants
- yeast releases ethanol (alcohol) and carbon dioxide as waste products (irreversible)
- called alcoholic fermentation
- chemical eqn: C6H12O6 to C2H5OH +CO2+ small amts of energy
- glucose only partially broken down
- ethanol produced contains energy, small amt of energy released
Differences between alcoholic and lactic acid fermentation (where it occurs)
Alcoholic fermentation: plants and yeast
Lactic acid fermentation: mammals
Differences between alcoholic and lactic acid fermentation (Waste products)
Alcoholic fermentation: ethanol and carbon dioxide
Lactic acid fermentation: lactic acid, no carbon dioxide
Differences between alcoholic and lactic acid fermentation (oxidation/conversion to glucose)
Alcoholic fermentation: ethanol cannot be further oxidized or converted back to glucose
Lactic acid fermentation: can be oxidized and converted back to glucose
Difference between respiration and photosynthesis
energy
Respiration: energy released
Photosynthesis: energy stored in carbohydrate molecules
Difference between respiration and photosynthesis
uses and products
Respiration: oxygen used, CO2 and water given off
Photosynthesis: CO2 and water used, O2 given off
Difference between respiration and photosynthesis
catabolic/anabolic process
Respiration: catabolic process, breakdown of carbohydrate molecules
Photosynthesis: anabolic process, building up of carbohydrate molecules
Difference between respiration and photosynthesis
where it occurs
Respiration: occurs at all times in all cells, independent of chlorophyll and sunlight
Photosynthesis: occurs only in cells containing chlorophyll and in presence of sunlight
Difference between respiration and photosynthesis
dry mass
Respiration: results in loss of dry mass
photosynthesis: results in gain of dry mass
Why do we need a respiratory system?
- humans are large organisms, made up of millions of cells, small SA:V unlike unicellular organisms
- need a special system of organs for gaseous exchange between cells in body and environment
- mechanism of exchange is called external respiration, involves a process called breathing