AP studyguide Flashcards
Where does cellular respiration occur?
In the mitochondria.
What kind of energy do cells harvest?
Why do they harvest this energy?
Chemical energy stored in organic molecules.
To generate ATP
What is a major source of fuel for animals?
starch
what does starch break down into?
glucose
What is the cellular respiration formula?
C6H12O6 + 6O2 ———> 6CO2 + 6H2O + energy (ATP and heat)
What does oxidation mean?
Loss of electrons.
what does reduction mean?
gain of electrons
What does the oxidation of glucose do?
What is energy to be used in?
Transfers e- to a lower energy state, releasing energy
ATP synthase
What path will most electrons follow during cellular respiration?
A “downhill” exergonic path.
Glucose ———> NADPH ———> ETC———> Oxygen
What has to happen in order to harvest energy?
Glucose is broken down into steps.
Describe what happens to electrons in energy harvest.
Electrons are taken from glucose at different steps.
Each e- travels with a proton (H+).
What do dehydrogenases do?
Take 2 e- and 2 protons from glucose.
What are dehydrogenases?
Oxidizing agent for glucose.
What is the second step for electrons in energy harvest?
Transfers 2 e- and 1 proton to the coenzyme NAD+.
What does NAD+ reduce to? What does the NADH do?
NADH.
Stores the energy.
What happens to the other proton?
● energy harvest
what does NADH do?
It’s released into the surrounding solution as H+.
Carries e- to the electron transport chain.
What is the electron transport chain (ETC)?
A sequence of membrane proteins that shuttle electrons down a series of
redox reactions.
What does this chain release?
Energy used to make ATP.
What does the ETC do?
Transfers e- to O2 to make H2O; Releases energy.
Who is the final electron acceptor?
O2
What are the 3 stages of cellular respiration?
- Glycolysis.
- Pyruvate oxidation and the citric acid cycle.
- Oxidation phosphorylation (ETC and chemiosmosis).
Glycolysis——> Pyruvate Oxidation ——> Citric Acid Cycle ——> ETC and Chemiosmosis\
What is glycolysis known for?
Being the starting point of cellular respiration.
Where does glycolysis occur?
In the cytosol.
What does glycolysis split?
Splits glucose (6C) into 2 pyruvates (3C).
What are the 2 stages of glycolysis?
- Energy investment stage.
- Energy payoff stage.
What happens in the energy investment stage?
The cell uses ATP to phosphorylate compounds of glucose.
How is energy produced in the energy payoff stage?
Produced by substrate level phosphorylation.
What is the net energy yield per 1 glucose?
● 2 ATP.
● 2 NADH.
What happens to the pyruvate if oxygen is present?
What happens to the pyruvate if oxygen is present?
What is pyruvate oxidized into?
Acetyl coA.
What is Acetyl coA used for?
Used to make citrate in the citric acid cycle.
What is produced in this stage?
● 2 CO2.
● 2 NADH.
What is the citric acid cycle also known as?
The krebs cycle
Where does the citric acid cycle occur?
In the mitochondrial matrix.
What does the citric acid cycle do?
Turns acetyl coA into citrate.
What happens as a result as well?(citric acid cycle)
● CO2 is released.
● ATP synthesized.
● Electrons transferred to NADH and FADH2.
What are the inputs in the citric acid cycle?
2 acetyl coA.
What are the outputs in the citric acid cycle?
● 2 ATP.
● 6 NADH.
● 4 CO2.
● 2 FADH2.
What does oxidation phosphorylation consist of?
● Electron transport chain.
● Chemiosmosis.
What does the ETC consist of?
collection of proteins
What happens to the etc proteins as the electrons “fall”?
Proteins alternate between reduced (accepts e-) and oxidized (donates e-)
state.
What does the cristae do in the ETC?
Increases the surface area for the reactions to occur.
The ETC DOESN’T do what?
Doesn’t produce ATP directly.
What does ETC do instead?
Helps manage the release of energy by creating several small steps for “fall”
of electrons.
Who is the final electron acceptor?
Oxygen.
What does each oxygen do?
Pairs with 2H+ and 2e- to form H2O.
What is one major function of the ETC?
To create a photon (H+) gradient across the membrane.
What happens as proteins shuttle electrons along the ETC?
● They also pump H+ into their inner membrane space.
● It uses the exergonic flow of electrons from NADH and FADH2.
What will this H+ gradient power?
How will it power cellular work?^^
● Chemiosmosis.
● By using hydrogen ions.
What is ATP synthase?
● The enzyme that makes ATP and ADP + P.
Where does ATP synthase get its energy from?
The H+ gradient across the membrane.
What do H+ ions do? (ATP synthase)
What does this activate?^^
● Flow down their gradient through ATP synthase.
● (ATP synthase acts as a rotor; when H+ binds, the rotor spins).
● Activates catalytic site to turn ADP + P into ATP.
What is produced in chemiosmosis?
About 26-28 ATP per glucose.
What are the inputs of glycolysis?
1 glucose.
What are the outputs of glycolysis?
● 2 pyruvates.
● 2 ATP
● 2 NADH.
What are the inputs of pyruvate oxidation?
● 2 pyruvate.
What are the outputs of pyruvate oxidation?
● 2 acetyl coA
● 2 CO2
● 2 NADH.
What are the inputs of the citric acid cycle?
● 2 acetyl coA.
What are the outputs of the citric acid cycle?
● 4 CO2.
● 2 ATP.
● 6 NADH.
● 2 FADH2.
What are the inputs for oxidation phosphorylation?
10 NADH and 2 FADH2.
What are the outputs for oxidative phosphorylation?
26-28 ATP.
What is the TOTAL ATP produced?
30-32 ATP
What does oxygen do in cellular respiration?
It drives electrons down the ETC because it is the final electron acceptor.
How do organisms produce ATP in the absence of oxygen?
● Anaerobic respiration.
● Fermentation.
What does anaerobic respiration do?
Generates ATP using an ETC in the absence of oxygen.
Where does anaerobic respiration occur?
In prokaryotic organisms that live in environments with NO OXYGEN.
Who are the final electron acceptors?
● Sulfates.
● Nitrates.
What does fermentation do?
Generates ATP WITHOUT an ETC.
What is fermentation?
An extension of glycolysis.
What does fermentation do?
● Recycles NAD+.
● HAS NO OXYGEN.
Where does fermentation occur?
In the cytosol.
What are the 2 types of fermentation?
● Alcohol fermentation.
● Lactic acid fermentation.
What happens in alcohol fermentation?
● Pyruvate is converted into ethanol.
What happens in lactic acid fermentation?
● Pyruvate is reduced directly by NADH to form lactate.
What do muscles do?
Produce lactate, which goes into the blood, and is broken down back to
glucose in the liver.
What happens when lactate is in the blood?
It lowers the pH.
What happens if lactate builds up and is unable to be broken down?
It can lead to lactic acidosis.
What is lactic acidosis?
Excessively low blood pH.
