Respiration and ATP Flashcards
Describe the part played by the inner membrane of a mitochondrion in producing ATP
Electrons transferred down electron transport chain;
Provide energy to take protons/H+ into space between membranes;
Protons/H+ pass back, through membrane/into matrix/through ATPase;
Energy used to combine ADP and phosphate/to produce ATP;
A scientist investigated ATP production in a preparation of isolated mitochondria. He suspended the mitochondria in an isotonic solution and added a suitable respiratory substrate together with ADP and phosphate
explain why the scientist did not use glucose as the respiratory substrate.
Glucose is used/broken down during glycolysis;
Breakdown of glucose/glycolysis in cytoplasm/not in mitochondria;
Glucose cannot cross mitochondrial membrane/does not enter mitochondria;
Properties of ATP that make it a suitable source of energy
- Energy released in small/suitable amounts;
- Soluble;
- Involves a single/simple reaction;
ATP is useful in many biological processes. Explain why.
- Releases energy in small / manageable amounts;
- (Broken down) in a one step / single bond broken;
- Immediate energy compound/makes energy available rapidly;
- Phosphorylates/adds phosphate;
- Makes (phosphorylated substances) more reactive / lowers activation energy;
- Reformed/made again;
Describe how ATP is mad in the Mitocondria
. Substrate level phosphorylation / ATP produced in Krebs cycle;
- Krebs cycle/link reaction produces reduced coenzyme/reduced NAD/reduced FAD;
- Electrons released from reduced /coenzymes/ NAD/FAD;
- (Electrons) pass along carriers/through electron transport chain/through series of redox reactions;
- Energy released;
- ADP/ADP + Pi;
- Protons move into intermembrane space;
- ATP synthase;
Why It is important for plants to produce ATP in respiration in addition to photosythesis
- In the dark no ATP production in
photosynthesis; - Some tissues unable to photosynthesise/produce ATP;
- ATP cannot be moved from cell to cell/stored;
- Plant uses more ATP than produced in photosynthesis;
- ATP for active transport;
- ATP for synthesis (of named substance);
Humans synthesise more than their body mass of ATP each day. Explain why it is
necessary for them to synthesise such a large amount of ATP.
- ATP is unstable;
- ATP cannot be stored / is an immediate source of energy;
- Named process uses ATP ;
- ATP only releases a small amount of energy at a time;
DNP inhibits respiration by preventing a proton gradient being maintained across
membranes. When DNP was added to isolated mitochondria the following changes were observed
1. less ATP was produced
2.more heat was produced
3. the uptake of oxygen remained constant.
Explain how DNP caused these changes.
- Less H+ movement so less ATP produced;
- Heat released from electron transport.
- Oxygen used as final electron acceptor.
What measurement should the student take to calculate the rate of aerobic respiration in mm3 of oxygen g-1 h-1?
The diameter of the capillary tubing.
The distance the drop moves and time.
The mass of the woodlouse.
“The student CLOSED the tap. After thirty minutes the drop of coloured liquid had moved to the left. Explain why the drop of coloured liquid moved to the left.”
- Oxygen taken up/used (by woodlouse);
- Carbon dioxide (given out) is absorbed by
solution/potassium hydroxide; - Decrease/change in pressure;
What do NAD and FAD do?
NAD and FAD transfer hydrogen from one molecule to another. Meaning they can reduce (when you give hydrogen) or oxidise (when you take hydrogen) a molecule.
What are some examples of coenzymes used in respiration?
NAD, coemzyme A amd FAD.
When ATP diffuses to the part of the cell where it is needed, it is broken down into ADP and inorganic phosphate. What enzyme catalyses this reaction?
ATPase.
What is ATP synthesised from?
What enzyme catalyses the reaction?
ADP and inorganic phosphate
ATP synthase.
Why do humans need energy?
Humans need energy for biological processes such as muscle contraction, maintaining body temperature, active transport, DNA replication, sell division and finally protein synthesis.
Describe how ATP is made in mitochondria.
1.ATP is produced in Krebs cycle;
2. Krebs cycle/link reaction
produces a reduced
coenzyme A, 3 reduced
NAD and a reduced FAD.
3. Electrons are released from
reduced NAD and redeuced FAD.
4. (Electrons) pass through the electron
transport chain through series
of redox reactions.
5. Energy released and ADP synthesised from ADP + Pi;
7. Protons move into
intermembrane space via ATP synthase;
Glycolysis- 2 stages
- Phosphorylation. Glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP.
This creates 2 molecules of triose phosphate and 2 molecules of ADP. - Oxidation. Triose phosphate is oxidised, forming 2 molecules of pyruvate. NAD collects hydrogen ions, forming 2 reduced NAD. 4 ATP are produced but 2 were used up in stage 1 so net gain of ATP = 2.
Where does glycolysis occur?
in the cytoplasm of cells.
What happens to all the products of glycolysis?
- The 2 molecules of reduced NAD go to LAST STAGE (oxidative phosphorylation)
- The two pyruvate molecules go into the matrix of the mitochondria for link reaction.
2.What happens in the link reaction?
- Pyruvate is decarboxylated - one carbon atom is removed from pyruvate in the form of CO2.
- NAD is reduced - it collects hydrogen from pyruvate, changing pyruvate into acetate.
- Acetate is combined with coenzyme A to form… ACETYL COENZYME A.
Is any ATP produced in the Link Reaction?
NO
What happens in anaerobic respiration?
Pyruvate is converted to ethanol (in plants). Or lactate (in animal cells).
The production of lactate/ethanol
regenerates NAD. SO glycolysis can continue even when thereis not much oxygen around and so a small amount of ATP can still be produced.
- The Krebs Cycle.
It produces reduces coenzymes and ATP.
where does krebs cycle take place?
Matrix
What happens in krebs
Acetyl co enzyme A from the link reaction combines with a 4C carbon to form a 6C compound + coenzyme A goes back to the link reaction for re use.
Decarboxylation and Dehydrogenation occurs. What are they?
Decarboxylation is when a CO2 is removed. Dehydration occurs when a H is removed for reduced NAD. Now that a CO2 has been removed..a 5C compound is formed. Substrate level phosphorylation occurs
Substrate phoshorylation
When a phosphate molecule is transferred from 1 molecule to another. So ATP is generated from ADP and inorganic phosphate.
Hydrogenation occurs again
3 times! twice with NAD to produce reduced NAD and once with FAD to produce reduced FAD. Decarboxylation also occurs so… a 4C compound is formed
Where does the 3 reduced NAD and 1 reduced FAD from the Krebs Cycle go?
Oxidative Phosphorylation.
in oxidative phosphorylation?
- Electrons move along the electron transport chain, losing energy at each carrier.
- The energy is used by electron carriers to pump protons from the mitochondrial matrix into the inter-membrane space.
- The conc. of protons is now higher in the inter-membrane space than in the mitochondrial matrix, which forms an electro-chemical gradient, a concentration gradient of ions.
- Protons move down the electro-chemical gradient back into the mitochondrial matrix, via ATP synthase.
- This movement drives the synthesis of ATP from ADP and inorganic phosphate.
- The movement of H protons across a membrane which generates ATP is called chemiosmosis.
- in the mitochondrial matrix, at the end of the transport chain, the protons, electrons and oxygen combine to form water.
What is the final electron acceptor?
oxygen
why does respiration produce more ATP per molecule of glucose in the presence of oxygen ?
only glycolysis occurs without oxygen
oxygen final electron acceptor
oxidative phosphorylation
how is puruvate transported into the matrix of mitochondria
Active transport
does link oxidise or reduce pyruvate
oxidise
what are coenzymes
molecules some enzymes require in order to funtion
how does NAD coenzyme work
dehydrogenase enzymes - catalyse removal hydrogen ions from substrates and transfer to other molecules - hydrogen carriers in oxidative phosphorylation
what is produced in glycolysis
2 ATP
2 NADH
Products of link
2 NADH
2CO2
Krebs
2 ATP
4 CO2
6 NADH
2 FADH
how much ATP is produced per glucose molecule
38
Why do organisms need E
METABOLISM- all reactions E
MOVEMENT- within organism ( circulation blood) movement of organism (locomotion)
A.T ions against conc gradient in plasma membrane
MAINTANCE, REPAIR + DIVISION CELLS
PRODUCTION OF SUBSTANCES - enzymes hormones
MAINTENACE BT- endotherms
5 Things ATP source of energy for
METABOLIC PROCESSES- build macromolecules from basic units
MOVEMENT- muscle contraction- E filaments slide past each other - shorten length muscle fibre
A.T- change shape proteins plasma membrane- ions move against conc gradient
SECRETION - lysosomes necc secretion cell products
ACTIVATION MOLECULES- phosphate molecule transferred from ATP another molecule more reactive- lowers EA- allowing enzyme catalysed reactions take place more easily
How ATP makes enzyme catalysed reactions take place more readily
ATP provides phosphate attach another molecule- more reactive lower EA
Enzymes work lowering EA - enzymes less work to do function more readily
Why ATP immediate E source
Rapid release E
Single step
Transferred directly to reaction requiring it
How chloroplasts adapted function capturing sunlight
THYLAKIOD MEMBRANE- LARGE SA
attachment chlorophyll, electron carriers and enzymes
NETWORK PROTEINS GRANA
holds chlorophyll precise mannor- MAX ABSORPTION LIGHT
GRANAL MEMBRANES ENZYMES ATTATCHED- manufacture ATP
CHLORPLASTS CONTAIN DNA + RIBOSOMES- quickly easily manufacture proteins needed LDR
