Metabolism and survival Flashcards
What 3 things can metabolic pathways have?
Metabolic pathways can have reversible steps, irreversible steps and alternative routes.
What 3 things are embedded in membranes?
Protein pores, pumps and enzymes are embedded in membranes.
What are metabolic pathways controlled by?
Metabolic pathways are controlled by the presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes.
When does induced fit occur?
Induced fit occurs when the active site changes shape to better fit the substrate after the substrate binds.
Some metabolic reactions are________and the presence of a substrate or the removal of a product will…….
Some metabolic reactions are reversible and the presence of a substrate or the removal of a product will drive a sequence of reactions in a particular direction.
Where do competitive inhibitors bind?
What does this prevent?
Competitive inhibitors bind at the active site preventing the substrate from binding.
How can competitive inhibition be reversed?
Competitive inhibition can be reversed by increasing substrate concentration.
Where do non-competitive inhibitors bind?
What does this prevent?
Non-competitive inhibitors bind away from the active site but change the shape of the active site preventing the substrate from binding.
Non-competitive inhibition (can/cannot) be reversed by increasing substrate concentration.
Non-competitive inhibition cannot be reversed by increasing substrate concentration.
When does feedback inhibition occur?
What does the end-product inhibit?
Feedback inhibition occurs when the end- product in the metabolic pathway reaches a critical concentration. The end-product then inhibits an earlier enzyme, blocking the pathway, and so prevents further synthesis of the end-product.
What is ATP required for during the energy investment phase of glycolysis?
What does this lead to during what stage?
ATP is required for the phosphorylation of glucose and intermediates during the energy investment phase of glycolysis. This leads to the generation of more ATP during the energy pay-off stage and results in a net gain of ATP.
In aerobic conditions, what is pyruvate broken down to?
What is formed?
In aerobic conditions, pyruvate is broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A.
In the citric acid cycle what does the acetyl group from acetyl coenzyme A combine with?
What does this form?
In the citric acid cycle the acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate.
During a series of enzyme controlled steps what is citrate gradually converted back into?
What does this result in?
During a series of enzyme controlled steps, citrate is gradually converted back into oxaloacetate which results in the generation of ATP and release of carbon dioxide.
Where does the citric acid cycle occur?
The citric acid cycle occurs in the matrix of the mitochondria.
What do Dehydrogenase enzymes do? What do they then pass them to and what does this form?
Where does this occur?
Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme NAD, forming NADH. This occurs in both glycolysis and the citric acid cycle.
What is passed to the electron transport chain on the inner mitochondrial membrane?
The hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane.
What is the electron transport chain?
The electron transport chain is a series of carrier proteins attached to the inner mitochondrial membrane.
What do the electrons do in the electron transport chain?
Electrons are passed along the electron transport chain releasing energy.
What does the energy released by electrons allow for hydrogen ions?
This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane.
What does the flow of these ions back through the membrane protein ATP synthase result in?
The flow of these ions back through the membrane protein ATP synthase results in the production of ATP.
What do hydrogen ions and electrons combine to form?
Finally, hydrogen ions and electrons combine with oxygen to form water.
Summarise Respiration
Glycolysis is the breakdown of glucose to pyruvate in the cytoplasm.
ATP is required for the phosphorylation of glucose and intermediates during the energy investment phase of glycolysis.
This leads to the generation of more ATP during the energy pay-off stage and results in a net gain of ATP.
In aerobic conditions, pyruvate is broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A.
In the citric acid cycle the acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate.
During a series of enzyme controlled steps, citrate is gradually converted back into oxaloacetate which results in the generation of ATP and release of carbon dioxide.
The citric acid cycle occurs in the matrix of the mitochondria.
Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme NAD, forming NADH. This occurs in both glycolysis and the citric acid cycle.
The hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane.
The electron transport chain is a series of carrier proteins attached to the inner mitochondrial membrane.
Electrons are passed along the electron transport chain releasing energy.
This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane.
The flow of these ions back through the membrane protein ATP synthase results in the production of ATP.
Finally, hydrogen ions and electrons combine with oxygen to form water.
In animal cells what is pyruvate converted to during fermentation?
In plants and yeast what is produced during fermentation?
In animal cells, pyruvate is converted to lactate in a reversible reaction.
In plants and yeast, ethanol and CO2 are produced in an irreversible reaction.
What 3 things can be measured to compare metabolic rates?
Measurement of oxygen consumption, carbon dioxide and heat production to compare metabolic rates.
How can metabolic rate be measured? What 4 things?
Metabolic rate can be measured using respirometers, oxygen probes, carbon dioxide probes and calorimeters.
What do birds and mammals have higher to reptiles and amphibians?
Birds and mammals have higher metabolic rates than reptiles and amphibians, which in turn have higher metabolic rates than fish.
What do organisms with high metabolic rate require more of?
Organisms with high metabolic rates require more efficient delivery of oxygen to cells.
What type of system do birds and mammals have?
How many atria and ventricles?
Birds and mammals have a complete double circulatory system consisting of two atria and two ventricles.
What type of system do Amphibians and most reptiles have?
How many atria and ventricles?
Amphibians and most reptiles have an incomplete double circulatory system consisting of two atria and one ventricle.
What type of system do fish have?
How many atrium and ventricles?
Fish have a single circulatory system consisting of one atrium and one ventricle.
What do Complete double circulatory systems enable?
How is there more efficient oxygen delivery to cells enabled?
Complete double circulatory systems enable higher metabolic rates to be maintained as there is no mixing of oxygenated and deoxygenated blood, and the oxygenated blood can be pumped out at a higher pressure. This enables more efficient oxygen delivery to cells.
What is the ability of an organism to maintain its metabolic rate affected by?
The ability of an organism to maintain its metabolic rate is affected by external abiotic factors.
What are 3 external abiotic factors which effect metabolic rate?
Abiotic factors — temperature, salinity and pH.
