ATP and respiration Flashcards
When is ATP produced
made when energy is available from respiration and the light dependant reactions of photosynthesis.
how and why is controlled release of energy required
glucose is Brocken down in controlled steps by enzymes.
This allows small amounts of energy to be released to prevent against over heating by uncontrolled release. And is released gradually to phosphorylate ADP to ATP.
what enzyme causes brekadown of ATP to ADP
ATPase
What reaction is endergonic -energy used
to produce ATP
what enzyme causes phosphorylation of ADP to ATP
ATP synthetase.
Where is ATP producede in organisms
either- cristae /inner membrane of mitochondria.
or on the thylakoid membranes of chlorplasts.
what is chemiosmosis
flow of protons down an electrochemical gradient through ATP synthetase .
describe chemiosmosis in ATP flow
ATP is produced as protons (H+) flow across the inner membrane down their electrochemical gradient to a lower conc. They move via the enzyme ATP synthetase in stalked particles. The down=ward movement releases energy used to form ATP.
Explain the proton gradient/pump process.
H+ pumped from one side to a another- creating a proton gradient.
The energy to pump the protons come from energy being released from electrons flowing down a series of electron carriers in an electron transport chain. Each carrier is at a lower energy level than previous.
protons then flow back across membrane down their electrochemical gradient via ATP synthetase.
describe substrate phosphorylation
phosphate groups transferred directly from phosphate compounds e.g in cytoplasm during glycolysis and Krebs cycle.
describe oxidative phosphorylation
occurs in mitochondria during aerobic respiration as electrons are transported down the electron transport chain.- requires oxygen.
advantages of ATP
-easily hydrolysed by 1 enzyme ATPase to release energy -is efficient
-rleseases energy in useable amounts.
-inert-no osmotic effects
-easily transported across membranes and into cytoplasm
- readily formed by phosphorylation.
how is mitochondria adapted for respiration
-intermembrane spaces is small to quickly accumulate protons.
-matrix has appropriate enzymes and PH for krebs cycle.
- inner membranes contain ETC and ATP synthetase for oxidative phosphorylation.
-cristae highly folded to increase surface area.
-outer membrane contains transport proteins for shuttling pyruvate into mitochondria.
where does glycolysis occur
cytoplasm
describe process of glycolysis (4 marks)
glucose is phosphorylated creating a glucose diphosphate. The hexose diphosphate (glucose diphosphate) then splits as it becomes unstable by phosphorylation into triose phosphate -3c sugar.
hydrogens is removed from triose phosphate , which allows =NAD to become reduced (NADH)
-pyruvate is then formed and 2 ATP is formed by substrate level phosphorylation.
what are the products of glycolysis
-2 ATP
-2 NADH
-2 pyruvate
what happens to the pyruvate after created in glycolysis
moves into mitochondria by diffusion down a conc gradient into matrix. This leads to link reaction which allows the conc gradient to be maintained.
describe the process of the link reaction (3 marks)
-pyruvate decarboxylated and dehydrogenated, NADH produced
-all that remains of each pyruvate is a 2 carbon acetate molecule which combined with coenzyme A producing acetyl coenzyme A.
what are the products of link recation
-Acetyl conzyme A
-c02
-NADH
where does the krebs cycle occur
matrix or mitochondria
describe the process of krebs cycle (6 marks)
-Each acetyl CO A (2C) combines with a 4C molecule producing a 6C molecule. Tjhis regenerates the CO A and cycle begins again. The 6C compound is dehydrogentaed to rpoduce NADH and decarbolylated to prouduce C02 and a 5 carbon intermediate. Compounds used in krebs cycle containc ompoiunds used in other processes.
This 5C carbon compound is dehydrogenates to produce 2x NADH and one FADH. It is also decarboxylated to produce a 4c carbon molecule.
what are the overall products of the krebs cycle from one acetyl coenzyme A
-2x C02.
-3x NADH
-1x FADH
importance of krebs cycle
-coenzyme has to be regenerated to allow the continuity of link reaction.
-4c molecule needs to be regenerated to accept the 2c carbon compound entering the Krebs cycle.
-intermediate compounds can be used elsewhere e.g to make fatty acids.
-the FADH and NADH are formed to enter the electron transport chain to produce more ATP by oxidative phosphorylation.
what is the final stage of respiration
oxidative phosphorylation
