cellular respiration

need help on a few dont questions......

give 2 reasons why respiration occurs in many small steps each step catalysed by a particular enzyme?


ummm missing word...:

in most organisms this product (pyruvate) then enters the 2nd phase of cellular respiration known as the krebs cycle which occurs in specific organelles, .............., under aerobic conditions.

thank u

ooo, thanks! sori bout this but a bit more help needed.........

in the respiratory process, energy is released and is used to synthesise enery rich molecules of........... from ............ thereby storing energy for future use.

Are these two gaps ATP and ADP?

the final stage in the electron carrier system is completed in the presence of oxygen and is catalysed by the haem-containing enzyme.............?


where is most of the ATP made? is it in the perimitochondiral space or matrix?

appreciate the help

yep they are ATP and ADP

ATP synthase?

most ATP is made via oxidative phosphorylation that occurs in/around intermembranal space of cristae

No, ATP synthase is the enzyme that catalyses Oxidative phosphorylation, not the electron transport chain.

And the ATP is actually made in the matrix, on the heads of the ATP synthase, although the enzyme itself extends into the Inner mitochondrial membrane and intermembranal space.

Ohhh I see, sorry I wasn't sure, thought it meant the final synthesis of ATP.

Yes, I meant to say near the inner membrane not in the intermembranal space. It's probably better to specify that it is synthesised by ATPase that is in the membrane though isn't it? Rather than just say "matrix" because that could mean anywhere.

missing word is mitochondria.

2 reasons: (I'm giving one reason for each half of the sentence)
1) If it was in one big step the body would not be able to use the energy given out efficiently
2) Each step is catalysed by a particular enzyme because enzymes are specific and can't usually catalyse more than one reaction.

I think that if it happened in one big step, excess energy would be produced and given off as heat, which would kill the cell, wouldn't it?
We are doing this topic atm in bio is evry1 doin it?

Maybe, but the question specifies two choices - matrix or perimitochondrial space. To me that is suggesting that it expects you to know that ATPase is found in the membrane, but it wants to know on which side of the membrane the ATP is actually made!

thank u so much for evry1's help. i'm finding it very difficult to get to grips with this topic...i have another question, if anyone could help me.

liver cells were homogenised - mitochondria + cytoplasm seperated. the mitochondria was incubated in a medium containing glucose and some in pyruvate. the amount of CO2 was monitored. Experiement was repeated using the cytoplasm. O2 was made available for both of them.

1. explain why carbon dioxide is not produced by the cytoplasm when incubated with glucose or pyruvate.

2. explain why CO2 is produced by mitochondria from pyruvate but NOT from glucose.

is the first question something to do with the fact that decarboxylase enzyme is not available in the cytoplasm....occurs during the link reaction?

and the second queston because, glucose has 6carbons which is too big n needs 2 be broken down first?