Part 6 - Respiration Flashcards
What is respiration?
The chemical release of energy from food
Consists of a series of enzyme controlled reactions to produce ATP
What is the energy released form the breakdown of glucose used for?
Cellulose activities such as:
Muscle cell contraction
Cell division
Protein synthesis
Transmission of nerve impulses
What happens when glucose is broken down to 2 molecules of pyruvate?
Enough energy is released to yield 2 ATP molecules
What is glucose?
The main source of energy in a living cell
What is ATP?
A high energy molecule which is used to link the energy producing reactions like aerobic respiration with the energy requiring reactions like the production of proteins
What does breakdown depend on?
If oxygen is present- aerobic respiration
If oxygen is absent- fermentation
Explain stage 1 of aerobic respiration
Stage one: glycolysis
Occurs in the cytoplasm of all cells
Each glucose molecule breaks into pyruvate molecules
Yields 2 ATP molecules
Doesn’t require energy
Glucose
|___ 2 ATP
|
Pyruvate
Explain stage 2 of aerobic respiration
O2 dependant
Occurs in the mitochondria (which are found in the cytoplasm of animal, plant and fungal cells)
Only takes place if oxygen is available
Breakdown of pyruvate to produce carbon dioxide and water through a series of enzyme controlled reactions
Lots of ATP molecules are produced
The more energy a cell uses, the more mitochondria it has
Pyruvate + oxygen
|___lots of ATP
|
Carbon dioxide+water
Aerobic respiration
Begins in the cytoplasm
Completed in the mitochondria
Higher the energy of the equipment of a cell, the greater the number of mitochondria present in that cell
Explain fermentation in animal cells
Occurs in cytoplasm
Breakdown of one glucose molecule during fermentation yields 2 ATP molecules
Glucose is converted to pyruvate then lactate in animal cells
Glucose
|___ 2 ATP
| ________
Pyruvate________lactate
Explain fermentation in plant and yeast cells
Occurs in the cytoplasm
Breakdown of one glucose molecule during fermentation (without oxygen) yields 2 ATP molecules
Glucose is converted to pyruvate and then carbon dioxide and alcohol in plant and yeast cells
Glucose
|
|
Pyruvate—— carbon dioxide + alcohol
Fermentation
Yields only the initial 2 molecules of ATP
Respiration begins in the cytoplasm
Completed in the cytoplasm
Explain measuring respiration in animals
Respirometer can be used to show gas changes during respiration
Only air available is in the tube
Sodium hydroxide absorbs any carbon dioxide produced by the organism
As oxygen gas is used up, coloured water moves down the tube
Distance travelled can be used to calculate respiration rate
Explain measuring respiration in plants
Germination is the growth of seeds
They must carry out respiration to grow
Limewater changes from clear to cloudy in the presence of carbon dioxide
