Respiration Flashcards
What is respiration?
Respiration is the process where cells breakdown glucose to produce ATP from glucose
What are the 2 types of respiration?
1) aerobic respiration = requires oxygen and fully breaks down glucose to produce carbon dioxide, water and many ATP. It involves mitochondria.
2) anaerobic respiration = does not require oxygen and glucose is not fully broken down . It does not involve mitochondria . Synthesises fewer ATP molecules
What is ATP? And what does it do
ATP is the immediate source of energy in a cell. A cell is unable to directly get energy from glucose. Therefore the energy released from glucose in respiration is used to produce ATP from ADP and Pi in a condensation reaction.
The energy stored as chemical energy in the phosphate bond and ATP synthase is the enzyme that catalyses the reaction. ATP is then used to carry the energy to where it is required where it can be hydrolysed back to ADP and Pi releasing the energy from the phosphate bond which supplies the energy required for the process. The enzyme used for this reaction is called ATP hydrolase.
What are useful features of ATP?
1) ATP only stores or releases small, manageable amounts of energy (30.5 Kj/mol)
2) it is a small soluble easily transported and broken down in cells it cannot pass out of a cell. It can be remade.
3) it can be used to transfer phosphates to other chemicals, this is known as phosphorylation
4) rapidly hrolysed to release energy
5) easily re-synthesised using entry from the breakdown of respiratory substrates eg glucose
What are coenzymes? Give 3 examples used in respiration
Molecules that some enzymes require in order to function. Co enzymes plan an important role in respiration and photosynthesis.
1) NAD - works with dehydrogenase enzymes in glycolysis, link reaction, Krebs cycle, and carries hydrogen from one molecule to another
2) FAD - involved in Krebs cycle
3) Coenzyme A - involved in links reaction and Krebs cycle
Why do metabolically active cells have high numbers of mitochondria?
To synthesise large amounts of ATP by oxidative phosphorylation
What is the role of the matrix of mitochondria?
Fluid filled and contains enzymes required for the link reaction + Krebs cycle eg NAD, FAD and Coenzyme A
What is the cristaes role in respiration?
Oxidative phosphorylation takes place here.
Provides a large surface area for ATP synthesis
What is the role of the outer membrane of mitochondria in respiration?
Controls the entry and exit of substances in and out of mitochondria
Eg pyruvate, O2, ADP moves in, ATP and O2 moves out
Define anabolic and catabolic reactions
Anabolic = metabolic reactions which build large molecules from small
Catabolic = metabolic reactions that hydrolyse large molecules into small
Describe phosphorylation and dephosphorylation
Phosphorylation = the addition of a phosphate group to a molecule
Eg ADP + Pi —> ATP
Dephosphorylation = the loss of a phosphate group from a molecule
Eg ATP —> ADP + Pi
Describe decarboxylation?
Loss of a carbon dioxide from a molecule
Describe substrate level phosphorylation
Producing ATP by addition of a phosphate group in the Krebs cycle and glycolysis
Describe oxidative phosphorylation
Producing ATP using a gradient of hydrogen ions
What is dehydrogenation?
The loss of hydrogen atoms from a molecule
