Respiration Flashcards
What is cellular respiration?
Cellular respiration is the process of turning glucose into ATP.
‘To convert biochemical energy from nutrients into useable energy (ATP) and then release waste products.”
Respiration is a series of enzyme-controlled reactions that convert chemical potential energy (glucose) into cellular energy (ATP).
What are the two types of cellular respiration?
Aerobic and anaerobic.
What chemical pathways are involved in anaerobic respiration?
Glycolysis and Fermentation
What chemical pathways are involved in aerobic respiration?
Glycolysis, krebs cycle, and electron transport chain.
What is the equation for anaerobic respiration?
Glucose -> Lactic acid + ATP
What is the equation for aerobic respiration?
Glucose + Oxygen -> Carbon dioxide + Water + ATP
Where does respiration occur?
Inside mitochondria (small double membrane organelles)
What happens during glycolysis and where does it occur?
Glucose is split into two pyruvate. In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.
Occurs in the cytoplasm (cytosol).
What happens during the Krebs cycle and where does it take place?
Each pyruvate combines with a cofactor (Coenzyme-A). The resulting Acetyl-CoA enters the Krebs cycle where it is converted into carbon dioxide and hydrogen.
This occurs in the mitochondrial matrix (the internal fluid).
What happens during the electron transport chain process and where does it take place?
The hydrogens produced in the Krebs cycle are carried by NADH (an enzyme cofactor) through the electron transport chain - a series of reactions that take place on the surface of the cristae (folds of the inner mitochondrial membrane). The cristae provides a large surface area on which these reactions can occur.
Ultimately hydrogen combine with oxygen to produce water and large amounts of energy (ATP).
What is fermentation and where does it take place?
If no oxygen is available pyruvate is broken down into lactic acid (animals & bacteria) or alcohol (plants & yeast). The build up of these products can be toxic E.g. causes muscle fatigue in runners. This process occurs in the cytoplasm and generates much less energy (ATP) than the aerobic pathway.
When oxygen becomes available these products are generally converted back into pyruvate. This pathway provides a way to overcome a momentary shortage of oxygen (e.g. during intense exercise), but generates an “oxygen debt” that is repaid once oxygen becomes available.
Why are different numbers of mitochondria found in different cells?
Red blood cells -> no mitochondria as they have very low energy requirements due to only carrying out passive processes.
Skin cells -> A couple hundred mitochondria because they need to divide often but aren’t involved in movement so large amount of energy not required.
Liver cells -> 1000-2000 mitochondria because liver is involved in digestion and toxin removal which requires a lot of energy.
Heart muscle cells -> Contains 5000+ mitochondria because it is constantly moving and contracting. Movement requires a lot of energy and the heart pumps blood to every organ so it never stops.
What are mitochondria?
Mitochondria generate most of the chemical energy needed to power the cell’s biochemical reactions.
What is aerobic respiration?
Aerobic respiration is the process of reacting glucose with oxygen to produce ATP as energy for the cell, to enable it to carry out its life processes. (Carbon dioxide and water are waste products)
What is anaerobic respiration?
Anaerobic respiration or fermentation is a process which occurs when there is a limited amount of oxygen available within a cell. It produces a small amount of ATP, as well as various byproducts.
