what is respiration?
respiration is the release of chemical energy stored in glucose. it occurs in all living cells through a series of enzyme controlled reactions.
name the five functions that require energy:
- muscle cell contraction
- active transport
- transmission of nerve impulses
- protein synthesis
- cell division
how can energy be lost during respiration?
some energy may be released to produce ATP, some energy is released is lost as heat.
what is aerobic respiration?
aerobic respiration is the process that occurs in every living cell to release chemical energy from glucose using oxygen.
explain the process of stage 2 (aerobic respiration): /
- if oxygen is present, pyruvate can diffuse into the mitochondria.
- once in the mitochondria, the pyruvate is broken down completely into carbon dioxide and water.
- from this, LOTS of ATP are yielded
what are stages 1+2 of aerobic respiration called?
stage 1: glycolysis
stage 2: aerobic respiration
what is fermentation?
fermentation is the incomplete breakdown of glucose in cells in the absence of oxygen.
give some key points about glucose:
-glucose is an energy-rich substance
-it is the most common end product of digestion of complex carbohydrates
-glucose is the main source of energy in a living cell
-when glucose reacts with oxygen, energy is released
what is ATP and ADP+Pi?
-adenosine triphosphate (ATP) is an energy-rich molecule
-it is made of adenosine and three inorganic phosphate groups.
-energy is released from ATP when the bond holding the last phosphate is broken down by enzyme activity
(this process is reversible!!)
explain the process of fermentation:
-when deprived of oxygen, in plant cells, yeast will respire to produce 2ATP, carbon dioxide and ethanol.
-in animal cells, the pyruvate molecules are converted to lactate.
-this process is irreversible
explain the process of stage 1 (glycolysis):
-glycolysis occurs in the cytoplasm
-glucose is broken down into a substance called pyruvate, yielding enough energy to produce 2ATP
-this stage doesn’t require oxygen
explain why nerve/muscle cells require many mitochondria.
muscle cells require many mitochondria to maximise the production of ATP by aerobic respiration.
