Respiration Flashcards
The 2 stages in glycolysis are….
Phosphorylation
Oxidation
What are the 4 reactions in aerobic respiration
Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation (electron transport system)
What happens to the products of glycolysis
2 molecules of reduced NAD go to last stage (oxidative phosphorylation (ETS))
2 pyruvate molecules go into the matrix of the mitochondria for the link reaction
The link reaction converts …….. to …………
Pyruvate
Acetyl coenzyme A
The link reaction occurs …….. for every glucose molecule
Twice
2 molecules of pyruvate are made for every glucose molecule that enters glycolysis. Means link reaction and the third stage (krebs cycle) happen twice for every glucose molecule. So for each glucose molecule….
2 molecules of acetyl coA go into Krebs cycle
2 molecules of CO2 released as waste product of respiration
2 molecules of reduced NAD formed and go to the last stage (ETS)
In anaerobic respiration pyruvate is converted to ……….. Or ………
Ethanol and CO2 (in plants and yeast)
Lactic acid (in animals and some bacteria)
The production of ethanol or lactic acid (also called lactate) regenerates NAD. Means glycolysis can continue even when there isn’t much oxygen around, so a small amount of ATP can still be produced to keep some biological processes going
The Krebs cycle produces……..
Reduced coenzymes and ATP
The Krebs cycle involves a series of …………….. reactions, which take place in …………….. The cycle happens ……..
Oxidation-reduction reactions
Matrix of the mitochondria
Twice
ATP info
Energy released from glucose used to make ATP. Is made from the nucleotide base adenine combined with a ribose sugar and 3 phosphate groups. Carries energy around cell to where it’s needed. ATP is synthesised from ADP and Pi using energy from an energy releasing reaction, energy stored as chemical energy in the phosphate bond. Enzyme ATP synthase catalyses reaction. ATP diffuses to part of cell that needs energy. Here, broken down back into ADP and Pi. Chemical energy is released from phosphate bond and used by the cell. ATPase catalyses reaction. The ADP and Pi recycled and process starts again
Why is ATP such a good energy source
It stores or releases only a small manageable amount of energy at a time so no energy is wasted
Small, soluble so can easily transported around cell
Easily broken down as it only involves a single reaction so energy easily released
Can transfer energy to another molecule by transferring one of its phosphate groups. This makes the new substance more reactive by lowering its activation energy
ATP can’t pass out of the cell, so cell always has an immediate supply of energy
Reformed
What is a coenzyme
A molecule that aids the function of an enzyme, work by transferring a chemical group from one molecule to another
Examples of coenzymes used in respiration
NAD and FAD transfer hydrogen from one molecule to another, means they can reduce or oxidise a molecule
Coenzyme A transfers acetate between molecules
What is the role of oxygen in oxidative phosphorylation
It is the final electron acceptor. It combines with electrons and hydrogen ions to form water
Humans synthesise more than their body mass of ATP each day. Explain why it is necessary to synthesise such a large amount
ATP is unstable
can’t be stored as it is an immediate source of energy
ATP only releases a small amount of energy at a time
Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis
Photosynthesis can’t happen in dark as light is a limiting factor so no ATP produced
Some tissues are unable to photosynthesise
ATP can’t be moved from cell to cell/stored
Plants use more ATP than produced in photosynthesis
ATP is needed for active transport and synthesis
