B9 Respiration Flashcards
(15 cards)
Aerobic respiration and what occurs
-Aerobic respiration is an exothermic reaction as it transfers energy to the environment
-it’s an enzyme-controlled process in all plants and animals
-aerobic respiration uses oxygen and most efficient way to transfer energy fom glucose
What occurs:
-During aerobic respiration glucose reacts with oxygen. This reaction transfers energy that your cells can use
-Carbon dioxide and water are produced as waste products of the reaction.
-Process is called aerobic respiration as it uses oxygen from air
What is respiration
Respiration is the process of transferring energy from glucose, which goes on in every cell
Formula for aerobic respiration
Glucose+oxygen—–>Carbon dioxide+Water
C6H12O6 + 6O2——> 6CO2 + 6H2O
Mitochondria-site of respiration
Most of reactions take place in mitochondria cells.
They are tiny-rod shaped organelles that are found in almost all plant and animal cells as well as fungal and algal cells. Folded inner membrane that provides a large surface area for the enzymes involved in aerobic respiration
The need for respiration
-Living cells need to carry out basic functions of life. They build up large molecules from smaller ones to make new cell material. Energy is also transferred to break down larger molecules to smaller ones, during digestion and within cells.
-In animals, energy from respiration is transferred to make muscles contract
-Mammals and birds use energy to keep their body temperature steady
-in plants, energy from respiration is transferred to move mineral ions such as nitrates from the soil into root hair cells. Also converts nutrients into amino acids which are then built up into proteins
Effect of exercise
-in order for an individual to move,their muscles need to contract,which requires energy from respiration
-when exercising, the number of muscle contraction increases, therefore there is a greater energy demand, which means that muscles need greater supply of oxygen for aerobic respiration.
How human body reacts to increased demand of oxygen:
-increased breathing rate and breath volume to increase amount of oxygen absorbed into bloodstream by diffusion and mount removed by carbon dioxide
-the heart rate increases to make blood flow more quickly, delivering more oxygen and glucose to cells for respiration and more carbon dioxide away
If your exercising vigorously, the body may not be able to supply sufficient amount of oxygen to muscles to meet demand for energy
-so some of energy supplied to muscles come from anaerobic respiration which is incomplete breakdown of glucose without oxygen
-releases much less energy than aerobic and results in formation of lactic acid as glucose is incompletely oxidised
Oxygen debt
-the body can deal with lactic acid in one of two ways
-it can be oxidised to form carbon dioxide and water-the same products in aerobic respiration. So pulse and breathing rate stay high whilst there are high levels of lactic acid and carbon dioxide to deliver more oxygen to the cells and take away carbon dioxide
-alternatively, blood flowing through muscles transports lactic acid to liver where it is converted back to glucose
Definition of oxygen debt
The amount of extra oxygen that body needs after exercise to react with the build up of lactic acid and remove it from the cells
Anaerobic respiration
-respiration in cells can take place anaerobically (without oxygen); it simply involves the incomplete breakdown of glucose into lactic acid
-this occurs when body can’t supply enough oxygen for aerobic respiration, such as during vigorous exercise
Word equation for anaeribic respiration
Glucose—> lactic acid
Anaerbic respiration in plants and yeast
-anaerobic respiration in yeast is called fermentation
-plants and yeast can respire without oxygen as well, breaking down glucose in the absence of oxygen to produce ethanol and carbon dioxide
Metabolism (synthesis and breakdown of molecules)
Can be defined as- the sum of all reactions in a cell or body.
-energy released during respiration allows enzyme-controlled reactions to occur inside cells e.g to produce new molecules
Synthesis and breakdown of molecules:
-organisms gain organic molecules,either by consuming food or photosynthesis by plants
-the molecules gained can be broken down and used to produce or synthesise new molecules
Examples:
-carbohydrates;complex carbohydrates are built from sugars e.g glucose
-lipids;built from 3 fatty acids and glycerol
-proteins; synthesised by amino acids
Examples of metabolic reactions
Carbohydrates:
Glucose is used in synthesis of:
-starch;energy storage in plants
-glycogen;energy storage in animals
-cellulose;strengthens plant cell walls
Lipids:
-glycerol is combined with 3 fatty acids in the synthesis of lipids,which can be used in energy storage
Proteins:
-glucose and nitrates are involved in production of amino acids
-amino acids are used in synthesis of proteins
-excess protein broken down into urea,which is excreted from body
Role of liver
-detoxifying poisonous substances such as ethanol from alcohol
-passing the breakdown products into the blood so can be excreted in urine
-breaking down old, worn out blood cells and strong iron until is needed to synthesise more blood cells
Role of liver-removing lactic acid
-blood flowing through muscles transport lactic acid to liver where it is converted back to glucose
