the importance of carbon dioxide for organisms and the ecosystem

Question 1

the importance of carbon dioxide in the light independent reaction

Answer 1

-carbon dioxide is used in the light independent reaction of photosynthesis taking place in the stroma
-a reaction occurs between carbon dioxide and ribulose bisphosphate which is catalysed by rubisco (5C + 1C)
-this reaction forms two molecules of glycerate 3-phosphate (2 x 3C)
-the two molecules of glycerate 3-phosphate is reduced by reduced NADP using energy from ATP to produce two molecules of triose phosphate.
-some triose phosphate is converted to glucose and other useful organic substances
-some triose phosphate is used to generate RuBP in the calvin cycle
-carbon dioxide is essential in for the light independent reaction to occur which manufactures substances necessary for the plant growth

Question 2

the importance of carbon dioxide as a limiting factor

Answer 2

-the direct involvement of carbon dioxide in the light independent reaction means that is is a limiting factor for the rate of photosynthesis which impacts the growth rate of plants
-carbon dioxide is a typical limiting factor in plants with insufficient carbon dioxide in the atmosphere to supply the optimum carbon dioxide level of 0.1 percent which ensure consistently high levels of photosynthesis
-the insufficient carbon dioxide affects enzyme activity in the light dependent reaction, in particular rubisco which catalyses the combination of ribulose bisphosphate with carbon dioxide
-the limitation can be overcome through growers of greenhouse crops enriching the air with more carbon dioxide through burning small amounts of propane in a carbon dioxide generator
-this will increase the rate of photosynthesis which contributes to higher productivity and therefore higher crop yields. this can result in a higher profit for the grower

Question 3

the importance of carbon dioxide in haemoglobin

Answer 3

-where concentration of carbon dioxide is low such as at the surface of the lungs the haemoglobin has a higher affinity for oxygen meaning the oxygen is more readily loaded onto the protein
-in regions where the concentration of carbon dioxide is high the hemoglobin has a lower affinity for oxygen meaning oxygen is more readily unloaded into respiring tissues
-this is due to effect of carbon dioxide lowering the pH in the blood causing the shape of the haemoglobin to alter
-therefore the level of carbon dioxide affects the degree of association of oxygen from haemoglobin to control how much oxygen is loaded or unloaded at different parts of the body

Question 4

the importance of carbon dioxide in controlling heart rate

Answer 4

-chemoreceptors are responsible for detecting stimuli in the blood
-chemoreceptors are sensitive to changes in blood pH resulting from higher carbon dioxide levels causing carbon dioxide to dissolve in the blood. this is an indication of oxygen availability
-the chemoreceptor increases the frequency of impulses sent to the medulla
-this increases the frequency of impulses sent along the sympathetic neurons to the sinoatrial node
-the neurotransmitter noradrenaline is secreted at the synapse and bands to receptors on the sinoatrial node
-this increases the rate of production of the electrical waves the sinoatrial node so heart rate increases
-carbon dioxide is significant in increasing the heart rate as this ensures faster removal of waste products from respiration including the carbon dioxide. it also ensures more oxygen and glucose is delivered to the muscle cells through faster pumping of the blood which would delay anaerobic respiration and the build up of lactic acid which causes muscle fatigue