Respiratory substrates Flashcards
Word equation
glucose + oxygen- carbon dioxide + water vapour+ energy
Chemical equation
C6H12O6 +6O2-6CO2+6H20
When different substrates broken down in respiration…
…release different amounts of energy
Lipids
Fat-(lipase)-glycerol+ 3 fatty acids
-glycerol to pyruvate
-3 fatty acids to 50 acetyl coA and 500 ATP
Proteins
Protein-(protease)-amino acids
-amino acids go through deamination (requires ATP) to pyruvate
Carbohydrates
Carbohydrate-(amylase)-simple sugars for pyruvate
Lipids have the highest energy value because…
…lipids broken into fatty acids have a higher hydrogen content (made of long hydrocarbon chains) which are released will result in a greater proton gradient across the mitochondrial membrane which allows for formation of more ATP via chemiosmosis
How hydrogen atoms affect the amount of energy released?
More hydrogen atoms in a molecule- more hydrogen transported by NAD and FAD to mitochondrial membrane- greater chemiosmosis/proton gradient-more ATP produced via chemiosmosis
Respiratory Quotient definition
the ratio of carbon dioxide molecules produced to oxygen molecules taken in during respiration
RQ values of different respiratory substrates
-this is because of the number of carbon-hydrogen bonds differs in each type of biological molecule
-+ =+ H atoms used to create a proton gradient
-+H = +ATP produced
-+ O2 requires to breakdown molecule (to be final electron acceptor- in last step of oxidative phosphorylation to form water)
Glucose RQ value
1
Carbohydrate RQ value
1
Lipids RQ value
0.7
Protein RQ value
0.9
RQ value formula
RQ= moles or molecules of CO2 given out/moles or molecules of O2 taken in
Use of RQ values
1)For an organism is useful because it tells you what kind of respiratory substrate and what type of respiration
2)High RQs=organism is short of O2
3)Plants sometimes have a low RQ due to CO2 released used for photosynthesis
Measuring the rate of respiration using a respirometer process
1.Set up apparatus-manometer contains liquid that moves as oxygen in tube A is used up
2.The germinating seeds release carbon dioxide
3.Carbon dioxide is absorbed by the sodium hydroxide-therefore has no effect on volume of air inside tube A
4.Germinating seeds use up oxygen-this decreases volume of air in the tube
5.Rate of movement of liquid in manometer indicator of rate of respiration
6.Can change environmental conditions such as temperature, light intensity to observe how these factors affect rate of respiration
What are respirometers used for?
Used to measure and investigate the rate of aerobic respiration by measuring the amount of oxygen consumed by an organism over a period of time (RQs)
Volume of oxygen consumed formula
pixr^2xh or pixr^2xl/time taken
-where l=distance travelled by fluid
What is syringe for?
Resets the liquid in the manometer allowing you to take measurements over a specified period of time
RQ analysis
-can be used in experiments to investigate how different factors affect the RQ of organisms over time
-when RQ value changes it means the substrate being respired has changed
-some cells may also be using a mixture of substrates in respiration
-RQ value of more than 1 suggests excessive carbohydrate/calorie intake
-RQ value of less than 0.7 suggests underfeeding
