4.4.2.1 Aerobic and Anaerobic Respiration Flashcards
Where does energy come from?
- energy for life comes from the sun via food chains
- food is broken down to release energy to be used by cells
- the process which cells release energy is called cellular respiration - occurs in the mitochondria of the cell
Cell respiration:
- an exothermic reaction which is continuously occurring in living cells where cells break down glucose and which releases energy (+byproducts) to fuel cells’ living processes (can use oxygen)
- the energy transferred supplies all the energy needed for all the cells living processes
- respiration is a vital process that is speeded up and controlled by enzymes
How can respiration take place in cells?
aerobically (using oxygen) or anaerobically (without oxygen) to release energy
What is respiration needed for?
To release energy for:
- for chemical reactions to keep them alive and to build larger molecules
- for movement e.g. muscle contraction
- for keeping warm (body warmth
- for transmitting nerve impulses
- for cell division
- for maintaining a constant environment within our bodies
- active transport of substances
How is the cytoplasm involved in respiration?
- where enzymes are made
- location of reactions in anaerobic respiration
How is the nucleus involved in respiration?
holds genetic code for enzymes involved in respiration
How is the mitochondria involved in respiration?
contains enzymes for aerobic respiration
How is the cell membrane involved in respiration?
- allows gases and water to pass freely into and out of the cell
- controls the passage of other molecules
Aerobic respiration:
- A form of respiration that uses oxygen to release energy from molecules like glucose
- It yields the most energy
- Most of the reactions that make up aerobic respiration take place in the mitochondria
Word equation and formula for aerobic respiration in muscles:
Function of mitochondria:
site of aerobic respiration which releases energy for the cells processes (function)
Adaptations of mitochondria:
folded inner membranes to increase the surface area for a higher rate of aerobic respiration
Cells which carry out the most aerobic respiration in order:
- retinal eye cells
- muscle cells
- sperm cells
- red blood cells
Estimated number of mitochondria in typical animal cells:
1500
Estimated number of mitochondria in hair cells:
0
Estimated number of mitochondria in retinal eye cells:
10,000
Estimated number of mitochondria in heart muscle cells:
5000
Estimated number of mitochondria in bacterial cells:
0
Estimated number of mitochondria in muscle cells:
3000
Estimated number of mitochondria in sperm cells:
75
Estimated number of mitochondria in red blood cells:
0
Is the number of mitochondria related to the energy produced by the cell?
the cells that release the most energy have the most mitochondria because they are very active cells e.g. retinal eye cells
Which cells have very few mitochondria and why?
hair cells, bacterial cells and red blood cells as they would be the least active and therefore need the least energy
Anaerobic respiration:
- A form of respiration that releases energy from molecules like glucose without using oxygen
- Used to obtain if insufficient oxygen is reaching the muscles for aerobic respiration
- Less energy is transferred compared to aerobic respiration as the oxidation of glucose is incomplete
- It is only used as a last resort (e.g. during hard exercise) for example during a sprint where it is difficult to breathe in enough oxygen
Word equation and formula for anaerobic respiration in animals:
Word equation and formula for anaerobic respiration in organisms like yeast:
What is anaerobic respiration in yeast called?
anaerobic respiration in yeast is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks
Why will anaerobic respiration eventually kill yeast?
because the ethanol will become toxic to the yeast
What are products of anaerobic respiration in yeast for?
CO2 is used to make bread rise
What food products utilise anaerobic respiration?
- bread
- alcohol
- vinegar
- cheese
- yoghurt
What are the stages of anaerobic respiration?
- vigorous exercise
- aerobic respiration provides less and less energy
- heart and lungs cannot supply oxygen to muscle cells fast enough to satisfy demand
- anaerobic respiration provides energy
- glucose is broken down into lactic acid
- lactic acid accumulates in muscles causing fatigue
- forced to stop the exercise
- lactic acid transported from the muscles to the liver by the blood
- lactic acid oxidised to O2 and CO2
- oxygen debt has been repaid
Oxygen debt:
the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells (as although lactic acid is energy it is also toxic)
Metabolism:
the sum of all the reactions in a cell or the body
What sort of a molecule is glycogen?
Carbohydrate used as an energy store
What is glycogen made of?
Glucose molecules joined in chains
Where is glycogen found?
In animals, in liver (mainly) and muscles
When is glycogen made?
When blood glucose levels are high (after meals and when resting)
Which hormone promotes glycogen formation?
Insulin
When is glycogen used?
When blood glucose levels are low (when fasting and exercising)
How is glycogen used?
Broken down into glucose molecules which are then respired
Exothermic reactions:
reactions which transfer energy to the surroundings
What does the energy transferred by aerobic and anaerobic respiration supply?
the energy transferred supplies all the energy needed for living processes
