cellular respiration Flashcards
what is cellular respiration?
combination of biochemical pathways that release energy from glucose
why is glucose the most common source of energy? what is the energy from glucose used for? how is this energy used? what respiration uses glycolysis
Glucose is most common source of energy
Other substances must be first converted into glucose
Energy released is used to make the coenzyme ATP
Energy is released when the high energy bond between ADP and Pi is broken
Aerobic and anaerobic respiration both involve glycolysis
where does glycolysis occur? how much energy? what happens to glucose? energy carriers? what is the equation?
Cytosol
Net production of 2 ATP
Glucose (6 carbon ) is broken into 2 pyruvate or pyruvic acid (3 carbons)
The energy released is transferred to ATP and NADH which act as energy carriers
Glucose + 2 ADP + 2 Pi + 2NAD+ ——> 2 pyruvate + 2 ATP + 2NADH
what happens with aerobic respiration? what are the stages? what is the equation?
Involves oxygen
Stages: glycolysis, Krebs cycle and electron transport chain
Cellular respiration (aerobic): C6H12O6 + 6O2 ——> 6CO2 + 6H2O (30-32 ATP)
what is the mitochondria involved in? what happens? what is the structure?
Sites of Krebs cycle and electron transport chain
Pyruvate passes into mitochondria and is broken into carbon dioxide and water
Folded inner membrane is called cristae
Inside this membrane is the mitochondrial matrix
what is the origin of the mitochondria? what evidence is there?
Endosymbiotic theory
Have ribosomes and DNA
reproduce by binary fission
DNA is circular like bacterial DNA
Ribosomes are similar to those in bacteria
what is the Krebs cycle? where does it occur? what happens?
Second stage (critic acid cycle)
Mitochondrial matrix
Pyruvate diffuses into mitochondria and is then taken by active transport into the matrix
Pyruvate is converted into acetyl coenzyme A (2 carbons) 1 carbon dioxide is also made
Acetyl coenzyme A is the substrate for the first reactions that make up the Krebs cycle
In one turn of the Krebs cycle, 2 Carbon dioxides are made, so 6 for one glucose
Each turn also produces 3 NADH, 1 FADH2 and 1 ATP
what happens in the electron transport chain?
Moves protons and electrons across the membrane as a system for making ATP
Oxygen is needed because it picks up electrons at the end of the chain
Energy-carrying molecules from Krebs cycle become NAD+ and FAD again
The H+ move into the intermembraneous space and the electrons are transferred
The energy obtained from this process is used to make ATP
At the end, hydrogen ions, electrons and oxygen make water
Makes 26-28 ATP
how much ATP is made in each stage of aerobic respiration?
2 ATP from glycolysis
2 ATP from Krebs cycle
26-28 ATP from electron transport chain
what is anaerobic respiration? where does it occur? what is it?
No or little oxygen
Occurs in cytosol after glycolysis
Fermentation occurs
what is the importance of fermentation?
Product builds up, slowing reaction and causing a build up of reactants
For the reaction to continue the products of each stage must be dealt with
With no oxygen, pyruvate would accumulate so fermentation must occur
Also glycolysis needs NAD+ which would not be formed without oxygen unless fermentation existed
Fermentation removes pyruvate and provides NAD+
how does fermentation occur in animals?
Lactic acid fermentation
Lactic acid is produced
Lactic acid can be removed from the cell to prevent build up so that pyruvate can continue to be processed
Lactic acid is produced and circulated to tissues that convert it Bach to pyruvate to enter aerobic respiration
how does fermentation occur in plants (yeast)?
Ethanol fermentation
Pyruvate is broken into ethanol and carbon dioxide
NADH becomes NAD+
Alcohol diffuses out of cell so that reactions can continue
energy output of aerobic and anaerobic respiration
30-32 ATP
2 ATP
how does temperature affect rate of cellular respiration?
Enzymes are affected which affects rate of cellular respiration
Too hot- denature
Too cold- kinetic energy is low
