respiration Flashcards
why do organisms need energy
metabloic processes
for movement
cell divison
endo.exocytosis
keeping warm for endotherms
transmission of nrve impulses
structure of atp
adenine bonded to a sugar to 3 phosphate group
where is the high energy bond found within atp
phosphodiester bond between 2nd and 3rd phosphate group
what is formed within a breakdown of atp
adp + Pi
wht type of reaction is the breakdown of atp
hydrolysis
how is atp different to a dna nucleotide
atp only has an adenine bASE
ribose sugar but dna is deoxyribose
What is the role of the outer membrane in mitochondria?
Compartmentalises/separates the contents of the mitochondria from the rest of the cell.
why is the outer membrane of mitochondira important
So that ideal conditions for respiration can be maintained.
The inner membrane is folded to form finger like projections. What are these called?
Cristae
The inner membrane of mitochondria is similar to which membrane within a chloroplast?
Thylakoid
What is found within the inner membrane?
ETC and ATP synthase
The inner membrane is highly folded. Why this is a benefit?
Increases surface area so more ETC and ATP synthase.
The membrane also contains proteins for the ETC. What is an ETC?
Electron transport chain
Oxidative phosphorylation in mitochondria is similar to photophosphorylation in chloroplasts. These processes are involved in the formation of what compound?
ATP
What is the name of the enzyme that is involved in synthesising atp?
ATP Synthase
What is the space between the outer and inner membrane called?
Intermembrane space
Chemiosmosis (covered in photosynthesis) depends on the creation of proton concentration gradients. What sub-atomic particle provides the energy to maintain this gradient?
Electron
The matrix is the fluid filled space inside the mitochondria. Which 2 reactions take place here?
Link reaction and Kreb’s cycle
The matrix also contains mitochondrial DNA and lots of ribosomes. Explain why.
To synthesis some of the proteins necessary for aerobic respiration.Because mitochondria used to be free living bacteria.
Where does glycolysis take place
cytoplasm
what does lysis mean
splitting
What does glycolysis mean?
Splitting glucose
How many carbons does glucose contain?
6
What is phosphorylation?
The addition of a phosphate group.
How does glucose become hexose bisphosphate?
With the addition of two phosphate groups from two ATP.
How many carbons does hexose bisphosphate contain?
6
How many phosphates does hexose bisphosphate contain?
2
Hexose bisphosphate is split to form what 2 molecules?
Triose phosphate
How many carbons does each molecule of triose phosphate contain?
3
How many phosphates does each molecule of triose phosphate contain?
1
Triose phosphate then becomes triose bisphosphate. Adding a phosphate group is known as phosphorylation. Where does this extra phosphate come from?
A free inorganic phosphate in the cytoplasm.
Triose bisphosphate is then converted into what molecule?
pyruvate
How many carbons does pyruvate have
3
How many phosphates does pyruvate have
0
why does pyruvate have no phosphates
They have been joined to ADP to form ATP
How many molecules of ATP are created between triose bisphosphate and this pyruvate?
Two per molecule of triose bisphosphate.
Each triose bisphosphate molecule has a hydrogen atom removed (dehydrogenation). Is this oxidation or reduction?
oxidation
A coenzyme (NAD)is required to create pyruvate from triose bisphosphate. What is a coenzyme?
Coenzymes are organic cofactors which facilitate the binding of substrate to enzyme but do not bind permanently. Many coenzymes are vitamin derived, examples include NAD derived from niacin, which acts as a hydrogen acceptor.
The coenzyme, NAD gains this hydrogen atom and forms what molecule?
NADH (reduced NAD)
What is the difference between dehydrogenation and phosphorylation?
Dehydrogenation = removal of hydrogen atom, phosphorylation = removal of phosphate group.
How many ATP molecules are used at the start of glycolysis?
2
How many ATP molecules are created between triose phosphate and pyruvate?
2 per molecule of triose phosphate (4 per glucose)
What is the net gain in ATP within glycolysis?
2
. Glycolysis is an example of substrate level phosphorylation. This is different to photophosphorylation as Glycolysis does not require an ETC and ATP synthase to make ATP. Name another difference between the two processes.
Doesn’t involve coenzymes, doesn’t involve chemiosmosis
List the 3 products of glycolysis
ATP, NADH, pyruvate
Why is the production of reduced NAD important?
It is involved in oxidative phosphorylation
What molecules are required for glycolysis to take place?
NAD+, ADP, glucose
Describe the production of ATP by substrate-level phosphorylation in glycolysis
Phosphate groups are removed from triose phosphate and attached to ADP to from ATP
Where does the Krebs cycle takes place?
The matrix of mitochondria
How many carbons does an acetyl group have?
2
How many carbons does oxaloacetate have?
4
How is citrate formed?
Acetyl group combined with oxaloacetate
How many carbons does citrate have?
6
Oxidative decarboxylation takes place to convert Citrate (6C) into a 4C compound. Describe how oxidative carboxylation takes place.
NAD/FAD oxidises the molecule three times. Two carboxyl groups are removed.
How many molecules of reduced NAD are produced in the Krebs cycle per molecule of glucose?
6
Substrate level phosphorylation takes place within the Krebs cycle. What is substrate level phosphorylation?
The phosphorylation of ADP without the use of an electron transport chain or ATP synthases, the phosphate is removed directly from another molecule/substrate.
How many turns of the cycle are needed for one molecule of glucose?
2
Name the coenzymes used within the Krebs cycle
NAD and FAD (and could make an argument for CoA)
What is dehydrogenation?
.
The removal of hydrogen atoms
- Which compounds in the Krebs cycle carry out dehydrogenation?
NAD and FAD
- Describe the role of coenzymes within the Krebs cycle.
CoA delivers the acetyl group at the start of the cycle.
NAD & FAD oxidise and dehydrogenate compounds as the cycle progresses.
- ATP can be produced in various ways. Each stage of respiration contributes to the production of ATP. Describe the production of ATP by substrate-level phosphorylation in different stages of respiration with reference to the number of ATP molecules produced.
Glycolysis – Two phosphate groups are removed from each triose bisphosphate molecule to phosphorylate two ADP to form two ATP.
Kreb’s cycle – one phosphate group is removed from a 4C compound to phosphorylate one ADP to form one ATP.
- What is the role of NAD in Glycolysis?
To oxidise/dehydrogenate triose bisphosphate forming pyruvate.
- What is the role of NAD within the Link reaction?
To oxidise/dehydrogenate pyruvate forming acetyl
- Which coenzyme can synthesise more ATP?
NAD
- When a coenzyme is reduced what has it gained?
An electron (and also a proton/hydrogen atom)
- Name this type of reaction
Redox reaction
- What has happened to its substrate?
It has been oxidised
- What is the role of coenzyme A in the link reaction?
To bind to acetyl
- How many ATP does 1x reduced NAD make?
3
- How many ATP 8x reduced NAD make?
24
- How many ATP would 4x reduced NAD and 2 reduced FAD make?
16
- What are cristae?
Folds/projections of the inner membrane in mitochondria which increase the surface area.
- What are embedded within the cristae?
Electron carriers (ETC) and ATP synthase
- Hydrogen atoms are made up of what subatomic particles?
Proton and electrons
- Which molecules bring hydrogen to the inner membrane?
NADH and FADH2
- Hydrogen is split into a H+ and a high energy electron. Where does the high energy electron go?
Reduces the electron carrier.
- Energy is released as the high energy electron moves through the ETC. What is the energy used for by the carrier proteins?
Pump protons/H+ across the inner membrane from the matric to the intermembrane space.
- Why can’t H+ diffuse back across the inner membrane without a channel protein?
It is charged so cannot pass through the phospholipid bilayer.
- What type of diffusion is used to move protons (H+) back across the membrane?
Facilitated diffusion
- Facilitated diffusion is a passive process however where does the energy required to synthesise ATP come from?
Protons moving down the electrochemical gradient/proton motive force
- What happens to pH levels within the intermembrane if there is a buildup of H+?
.
Decreases
1
- At what stage of respiration is oxygen involved?
Oxidative Phosphorylation
1
- What is the role of oxygen within this stage?
Final electron acceptor
- How is water formed at the end of the electron transport chain?
Oxygen combines with four electrons and four H+./ Half an oxygen molecule combines with two electrons and two H+.
- What properties of the mitochondrial inner membrane allow chemiosmosis to occur?
The phospholipid bilayer is impermeable to H+.
It contains ATP synthase/channel proteins through which H+ can pass.
- Describe two quantitative changes in region P which occur as a result of oxidative phosphorylation.
The pH decreases
The concentration of H+ increases
- Outline the processes involved in the generation of ATP through chemiosmosis.
- H+ move through ATP synthases
- Down an (electrochemical) gradient.
- ATP synthase combines ADP + Pi
- What happens to reduced NAD and FAD after they have been oxidised and lost their hydrogen atom?
They can then be used again in glycolysis, link reaction and Kreb’s cycle.
- Explain why the link reaction and the Krebs cycle stop if ATP synthase is inactivated?
- ETC stops
- NADH and FADH2 cannot be oxidized
- NAD and FAD not regenerated
- Oxidative decarboxylation in the Link reaction and Krebs Cycle
- Chronic fatigue syndrome (CFS) is a condition in which symptoms vary from individual to individual. It is thought that a number of different malfunctioning processes can contribute to this condition in an individual. CFS can affect every system in the body and is identified by symptoms that include fatigue, muscle weakness and aching muscles. It has been suggested that, in the cells of people with CFS, pyruvate may not be transferred into the mitochondria efficiently. Outline the consequences of an inefficient transfer of pyruvate into mitochondria and link this to the symptoms of CFS stated above.
- Less pyruvate transported into the mitochondria
- Less link reactions and Krebs cycle occurring
- Less NAD and FAD produced
- Less electrons delivered to the ETC
- Less H+ pumped
- Less Chemiosmosis
- Less ATP
- ATP is required as energy source for e.g. muscle contraction
- What are the other products of the Krebs Cycle?
NADH, FADH2, ATP - Outline the differences in the two ways by which ATP is produced in respiration.
Oxidative phosphorylation involves ETC and ATP synthase
Substrate level phosphorylation involves removing the phosphate group from a substrate
NADH, FADH2, ATP
- Outline the differences in the two ways by which ATP is produced in respiration.
Oxidative phosphorylation involves ETC and ATP synthase
Substrate level phosphorylation involves removing the phosphate group from a substrate.
- How many molecules of ATP are made in Glycolysis?
4/2 net)
- How many molecules of ATP are made in the Link Reaction?
0
- How many molecules of ATP are made in the Krebs Cycle?
1
- How many molecules of ATP can be made per molecule of reduced NAD?
3
- How many molecules of ATP can be made per molecule of reduced FAD?
2
