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.