Respiration Flashcards
What is respiration?
Respiration is chemical reactions that breakdown nutrients (glucose) to release energy inside cells
What are the 7 uses of energy in living oragnisms?
- Muscle contraction
- Protein synthesis
- Cell division
- Active transport
- Growth
- The passage of nerve impulses
- The maintenance of a constant body temperature
What is aerobic respiration?
The chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
What is the word equation for aerobic respiration?
glucose + oxygen → carbon dioxide + water (opposite of photosynthesis)
What is the chemical equation for aerobic respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O
How to measure the effect of temperature on yeast respiration?
- An indicator can be used to investigate the effect oftemperatureon therate of aerobic respirationin yeast. Methylene bluedye is a suitable indicator. This dye can be added to a suspension of livingyeast cellsbecause it doesn’t damage cells
- Yeast can respire both aerobically and anaerobically, though in this experiment it is their rate ofaerobic respirationthat is being investigated
- The time taken for the methylene blue to discolour (lose its colour) is a measure of the rate of respiration of the yeast cells in the suspension. The faster the dye changes from blue to colourless, the faster the rate of respiration
Variables during temperature effect on yeast respiration experiment
Independent variable: Temperature
Dependent variable: Rate of respiration (recording thetime takenfor methylene blue dye to change fromblue to colourless)
Controlled variables: pH, volume/concentration of dye added, volume/concentration of yeast suspension added, concentration of glucose
What effect does temperature increases during yeast respiration?
- As thetemperature increasesup to 40 °C, therate of respiration increasesso the time taken for the solution to become colourless reduces
- Raising the temperature of a solution gives the molecules in the solution more kinetic energy, so they move around more and the enzymes and substrates involved in respiration collide with each other more frequently
- Astemperature increases above 40 °C, therate of respiration decreasesso the time taken for the solution to become colourless increases
- Increasing the temperature above a certain point causes the enzymes involved in respiration to denature; the shape of their active site changes and they can no longer form enzyme-substrate complexes
What is anaerobic respiration?
The chemical reactions in cells that break down nutrient molecules to release energy without using oxygen. Anaerobic respiration releases much less energy per glucose molecule than aerobic respiration
Word equation of anaerobic respiration in the yeast
glucose → alcohol + carbon dioxide
Chemical equation of anaerobic respiration in the yeast
C6H12O6 → 2C2H5OH + 2CO2
How do we use anaerobic respiration in yeast?
- We take advantage of the products of anaerobic respiration inyeastby using it inbread making, where the carbon dioxide produced causes dough to rise
- And inbrewing, where the ethanol produced gives the beer its alcoholic nature and the carbon dioxide produced gives beer its fizz
The word equation for anaerobic respiration in muscles during vigorous exercise
glucose → lactic acid
Why does anaerobic respiration take place in muscle cells?
Anaerobic respiration mainly takes place in muscle cells during vigorous exercise. When we exercise vigorously, our muscles have ahigher demand for energythan when we are resting or exercising normally. Our bodies can only deliver so much oxygen to our muscle cells for aerobic respiration. Lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt and causes a decrease in pH of cells which could denature enzymes in cells so it needs to be removed
What is oxygen debt?
Oxygen debt is the oxygen needed after exercise to remove the lactic acid through aerobic respiration
