respiration(change name ) Flashcards
how does photosynthesis work
photosynthesis transfers energy in the form of sunlight in to the chemical energy of carbohydrates. instead cells use ATP as their immediate energy source . the formation of ATP from the breakdown of glucose takes place during the process of cellular repiration depending on whether oxygen is involved or not
what are the stages of aerobic respiration
- glycolysis - the splitting of glucose into 2 pyruvate molecules
-link reaction - the pyruvate molecules enter into a series of reactions which leads to the formation of the acetyl coenzyme A
krebs cycle - the introduction of acetyl coenzyme A into a cycle of oxidation -reduction reactions that yield some ATP and a large quantity of NAD and FAD
-oxidative phosphorylation - the use of the electrons associated with reduced NAD and FAD released from the krebs cycle to synthesis ATP with water as a by product
what is glycolysis
glycolysis is the initial stage of both aerobic and anaerobic respiration. it occurs in the cytoplasm of all living cells and is the process by which glucose is split into two molecules of pyruvate
it has 2 stages , phosphorylation - addition of phosphate groups as ATP-> ADP + Pi
oxidation and reduction - addition and loss of hydrogen respectively (for glycolysis)
what is NAD
NAD transfers electrons from one molecule to another within cells . it exists in two forms reduced NAD (NADH) and NAD+ (without hydrogen)
what are mitcondria
mitocondria are the site of aerobic repsiration , producing the vast majority of ATP molecules used by the cell to release energy
why do mitocondria have a double membrane
they have a double membrane which determine the molecules that can pass into and out of the mitocondrion
what is the actual process of glycolysis
1) glucose is phosphorylated by the addition of two phosphate molecules to produce phosphorylated glucose. the phosphate groups come from the hydrolysis of two ATP molecules to ADP. this also provides the energy to activate glucose
2) each glucose molecule is split into 2 triose phosphate( 3 carbon molecule)
3) each triose phosphate molecule is oxidised to remove a hydrogen molecule which is transferred to NAD to produce NADH ( reduced NAD), each triose phopshate is then converted into pyruvate which releases 2 molecules of ATP per molecule and reduced NAD per molecule therefore 2 reduced NAD produced
what is the summary for glycolysis
- net gain of 2 ATP molecules
-2 molecules of reduced NAD - 2 molecules of pyruvate
what is the link reaction
after glycolysis these pyruvate molecules posess potential energy that can only be released in a process called the krebs cycle . but before they can enter the cycle these pyruvate molecules must first be oxidised in the ink reaction. both the krebs cycle and link reaction takes place inside the mitocondria
what happens in the link reaction
reduced NAD and pyruvate in the cytoplasm actively transported into the matrix of the mitoncdria
what happens in the link reaction
the pyruvate is oxidised to acetate . the 3 carbon pyruvate loses a carbon dioxide molecule to form acetate ( a 2 carbon molecule) and also hydrogen which goes to NAD to form reduced NAD. the acetate combines with coenzyme A to produce acetylcoenzyme A ( a 2 carbon molecule )
what is the overall equation for the link reaction
pyruvate + NAD + coenzyme A -> acetyl coenzyme A + reduced NAD + Co2
how many times does the link reaction occur
twice ( two pyruvate molecules produced per glucose molecule) therefore in total 2 acetylcoenzyme A produced , 2 co2 produced and 2 reduced NAD produced
what is the krebs cycle
involves a series of oxidation- reduction reactions that take place in the matrix of the mitocondria
what happens in the krebs cycle
1) the 2 carbon acetylcoenzyme A from the link reaction combines with a 4 carbon molecule to produce a 6 carbon molecule
2) this coenzyme A is released
3)then in a series of reactions this 6 carbon molecule loses 2 carbon dixoides and hydrogens to produce a 4 carbon molecule , reduced NAD , 2 carbon dioxide and reduced FAD and ATP
