Respiration and Food Production Flashcards
Why do living organisms respire?
To produce energy(ATP)
Where does aerobic respiration happen?
Mitochondria
Where does anaerobic respiration occur?
Cytoplasm
What are the different types of respiration?
Anaerobic and aerobic
What is the word equation for aerobic respiration in animals?
glucose + oxygen -> carbon dioxide and water(+energy(ATP))
What is the chemical/symbol equation for aerobic respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O
How are the reactants for aerobic respiration obtained?
glucose via digestion
oxygen via breathing
Why would there be more mitochondria in a muscle cell than in a cheek cell?
A muscle cell needs to work more which means in needs to contract more which requires more energy which requires more respiration which requires more mitochondria
Why does breathing rate increase when humans exercise?
Humans exercise more
more muscle contraction
more energy needed
more aerobic respiration
more oxygen needed
what is the word equation for anaerobic respiration in animals
glucose -> lactic acid
How is lactic acid broken down and what is the word equation
Lactic acid is broken down with oxygen
lactic acid + oxygen -> carbon dioxide + water
Why is lactic acid toxic
- Due to low pH which lowers pH in cells which denatures enzymes
- Causes muscle cramp and fatigue
where is excess lactic acid taken?
To the liver to process the toxic lactic acid
Why do you breathe heavily after excercising?
Because of the oxygen debt which is built up in you muscles which need to be repaid
What does oxygen do to lactic acid?
oxidise it into carbon dioxide and water
What is the anaerobic respiration in plants and fungi?
glucose -> ethanol + carbon dioxide (+energy (ATP))
How do plants obtain carbon dioxide and oxygen?
diffusion through stomata controlled by guard cells
Why do more stomata mean that there are more gas exchanges?
Greater SA:V ratio
What are examples of yeast products
bread, wine, beer, quorn
What are the parts in a yeast cell?
budding, nucleus, cytoplasm, cell wall, cell membrane, vacuole and food storage granules
What are the factors affecting the rate of respiration?
Temperature, pH, ethanol concentration(or lactic acid), glucose concentration
Why does temperature affect the rate of respiraton
Higher temperature leads to more kinetic energy and more collisions to form more enzyme substrate complexes. If too high temperature, enzymes denature
Why does pH affect the rate of respiration?
If not optimum pH, enzymes denature
Why does ethanol (or lactic acid) concentration affect the rate of respiration?
Ethanol or lactic acid is a toxic waste product produced in anaerobic respiration which eventually kills cells
Why does the concentration of glucose affect the rate of respiration?
Glucose is a substrate needed for respiration which increases the number of enzyme substrate complexes, which increase the rate of respiration till the limiting factor is the concentration of enzymes
Why is ethanol toxic?
Ethanol is toxic because it dissolves most bacteria’s, viruses’ and fungi’s cell walls and denatures the proteins
Why does bread need to be heated
- fungi or bacteria will start respiring anaerobically and will eventually die due to the ethanol concentration there will be and high temperatures which will denature enzymes
- This will make carbon dioxide which will rise the bread
- The ethanol will be burnt so that the bread is not alcoholic
Why does bread rise?
Because fermentation produces carbon dioxide which is trapped in air bubbles causing the bread to rise
What are fermenters?
Fermenters are machines used to grow fungi and other micro-organisms
What different parts are there in a fermenter?
A nutrient input, a water jacket, an air inlet, a motor, a temperature and pH probe, a stirring paddle and a harvest line
What is the use of a nutrient input
to provide glucose and nitrates and amino acids
what does a water jacket do?
Keep the temperature at optimum
What does the air inlet do?
- prevents contamination
- provides oxygen
What does the motor do?
turns stirring paddles
What does temperature and pH probes do?
measure the temperature and the pH
what do stirring paddles do?
mix the contents to make sure that all microorganisms have equal nutrients
What is the harvest line
Where the produces of fermentation are released
What is penicillin?
an anti-biotic fungi produced by penicillium which can be found naturally or grown in a fermenter
What happens to the fermenter before use
fermenters are sterilised with steam before use to that unwanted organisms are killed and removes competition and contamination
What are the steps in making yogurt
Milk is pasteurised at 85-95 degrees for 15 minutes
milk is homogenised
milk is cooled to 40 degrees and lactobacillus is added
mixture is incubated where fermentation occurs
yogurt is stirred and cooled to 5 degrees
Flavouring and colorant can be added
What is pasteurising
when heating kills any other microorganism as high temperatures denature enzymes
what is homogenised?
when fat globules are dispersed evenly
why is milk cooled to 40 degrees and lactobacillus is added?
lactobacillus: lactose + water -> lactic acid
lowers pH of the milk
milk proteins coagulate as they denature
coagulation of milk proteins makes the yogurt thicken
Why is thick milk cooled to 5 degrees
so that microbial growth is slowed down.
