respiration Flashcards
what occurs during cellular respiration
the formation of ATP from the break down of glucose takes place during the process of cellular respiration
what are the 2 different cellular respiration
aerobic respiration
anaerobic respiration
what is aerobic respiration
require oxygen and produces carbon dioxide, water and much ATP
what is anaerobic respiration
this takes place in the absence of oxygen and produces lactate (in animals) or ethanol and carbon dioxide (in plants and fungi ) but only a little ATP in both cases
what are the four stages of aerobic respiration
- glycolysis
- link reaction
- krebs cycle
- oxidative phosphorylation
what occurs in glycolysis
the splitting of the 6 carbon glucose molecule into two 3- carbon pyruvate
what occurs in the link reaction
3 carbon pryvate molecules enter into a series of reactions which lead to the formation of acetylcoenzyme A a 2- carbon molecule
what occurs in the krebs cycle
the intro of acetylcoenzyme A into a cycle of oxidation reduction reaction that yield some ATP and a large quantity of reduced NAD and FAD
what occurs in oxidative phosphorylation
the use of the electrons, associated with reduced NAD and FAD, released from the krebs cycle to sythesise ATP with produced as a by- product
what is glycolysis
glycolysis is the initial stage of both aerobic and anaerobic respiration
where does glycolysis occurs
glycolysis occurs in the cytoplasm of all living cells and is the process which a hexose sugar - usually glucose- is split into two molecules of 3 - carbon molecule pyravate
what is the end product of glycolysis
pyravate
what are the four stages of glycolysis
- phosphorylation of glucose to glucose phosphate
- splitting of the phosphorylated glucose
- oxidation of triose phosphate
- the production of ATP
what occurs in the first stage of glycolysis
before it can be split into two, glucose must first be made reactive by the addition of two phosphate molecules (phosphorylation)
The phosphate molecules come from the hydrolysis of two ATP molecules to ADP. This provides energy to activate glucose and lowers the activation energy for the enzyme controlled reaction that follows
what occurs in the second stage of glycolysis
each glucose molecule is split into two 3- carbon molecules known as triose phosphate
what occurs in the third stage of glycolysis
hydrogen is removed from each of the triose phosphate molecules and transferred to a hydrogen - carrier molecule known as NAD to form reduced NAD
what occurs in the fourth stage of glycolysis
enzyme - controlled reaction convert each triose phosphate into another 3 - carbon molecule called pyravate
In the process, two molecules of ATP are regenerated from ADP
what is the energy yield from glycolysis
2 molecules of ATP
(four molecules of ATP are produced by two were used up in the initial phosphorylation of glucose and so the net increase is tow molecules)
2 molecueles of reduced NAD
2 molecules of pyravate
what does the reduced NAD produced in glycolysis have the potential to do
they have the potential to provide energy to produce more ATP
why does glycolysis provide indirect evidence for evolution
glycolysis provides indirect evidence for evolution
Enzymes for the glycolysis pathway are found in the cytoplasm of cells and so glycolysis does not require any organelle or membrane for it to take place
why can glycolysis occur without oxygen
no oxygen is needed so it can take place whether or not it is present
what happens to the pyravate in the absence of oxygen
in the absence of O2, the pyruvate produced by glycolysis can be converted into either lactate/ethanol during anaerobic respiration
This is necessary in order to re-oxidise NAD so that glycolysis can be continue
what happens to the pyravate in the krebs cycle
the pyravate molecules produced during glycolysis process has potential energy that can only be released in a process called the krebs cycle
before they can enter the krebs cycle they must be oxidised in a process known as the link reaction
what must happen to the pyruvate before it enters the krebs cycle
before they can enter the krebs cycle, these pyruvate molecules must first be oxidised in a procedure known as the link reaction