Respiration Pathways Flashcards
Concert of molecules working together small, stepwise reactions in a specific sequence
Pathways
Anabolic and catabolic reactions sum up all reactions needed to maintain life
Pathways
Energy is needed to drive endergonic reactions
Pathways
An organic 6-carbon molecule
Glucose
The process of extracting energy from organic molecules (like glucose)
Aerobic respiration
C6H12O6 + 6O2 + 6H2O —> 6CO2 + 12H2O + ATP
Aerobic respiration breaks down the sugar
Organic carbon returns to its inorganic form
C6H12O6 is oxidized to 6CO2
Purpose of respiration ?
to gradually release the energy tied up in the bonds of glucose
What does aerobic require?
Oxygen
What consists aerobic respiration?
4 or 5 smaller pathways
It completely oxidizes glucose to capture cellular energy (ATP)
Aerobic respiration
It occurs in organisms requiring oxygen to survive
Aerobic
It occurs in the mitochondrion
Aerobic
What is the name of the inner mitochondrion membrane?
Cristae
What is the name of the inner compartment of the mitochondrion?
Matrix
It transfers energy
Respiration
It occurs in cells having mitochondria
Respiration
This type of respiration is exergonic
Aerobic
*The overall breakdown of glucose molecules is exergonic (releases energy)
When energy is released, oxidation reduction reactions do…. (2 things)
- shuffle electrons around with the help of coenzymes FAD and NAD+
- produced ATP
ATP is produced by.. (2 things)
- substrate-level-phosphorylation
- chemiosmosis
Energy potential of coenzymes used to make ATP… (2)
- NAD+ (oxidized form) or NADH (reduced) will provide energy to make 3 ATPs
- FAD (oxidized form) or FADH2 (reduced form) will provide energy to make 2 ATPs
Critical factor for the maintenance of respiration.
The reaction is reversible, coenzymes are recycled
NAD+ NADH + H+
FAD FADH2
What binds to NAD+ and the substrate?
Enzymes that use NAD+ as a cofactor for oxidation reactions
What is binding to the enzymes that use NAD+ as a cofactor for oxidation reactions?
NAD+ and the substrate
2 electrons and a proton are transferred to NAD+, forming NADH. A second proton is donated to the solution.
Oxidation-reduction reaction
What happens in an oxidation-reduction reaction?
2 electrons and a proton are transferred to NAD+ forming NADH. A second electron is donated to the solution.
3 steps of oxidation?
1-Enzymes bind NAD+ and the susbtrate
2-2 electrons and a proton are transferred to NAD+ froming NADH and a second proton is donated to the solution
3-NADH diffuses away and can then donate electrons to other molecules.
What are the 5 pathways of aerobic respiration?
- Glycolysis
- Pyruvate oxidation
- Krebs cycle
- Electron transport chain
- Chemiosmosis (oxidative phosphorylation)
How many pathways make up the process of respiration?
5 small (1 in the cytoplasm and 4 in the mitochondrion)
What pathway occurs inthe cytoplasm?
Glycolysis
Where does pyruvate oxidation occur?
Mitochondiral inner membrane
How are the electrons transported to the electron transport chain?
via NADH
What is the citric acid cycle?
Krebs cycle
Why can’t glycolysis occur in the mitochondrion?
Too big to enter
Where do the electrons come from to feed the ETC?
Glycolysis
Conversion of Pyruvate
Many from Krebs
Does it take oxygen for glycolysis to occur?
It occurs with or without O2
Glycolysis occurs in 3 phases… What are they?
1- energy investment (need 2 ATP)
2- cleavage into 2-3 C molecules (2 G3P)
3- energy producing (makes 4 ATP)
What are the three conditions for glycolysis?
NAD+ must be present
Doesn’t need oxygen
Occurs in cytoplasm
What will NADH do?
Transfer electrons to ETC and it has the potential to make 3 ATPs
In the first glycolysis phase (energy investment), what happens to glucose?
Priming glucose: glucose is phosphorylated at both ends using 2 ATPs
In the second glycolysis phase (cleavage), what happens to the sugar?
The sugar is split into 2 3-carbon sugars called G3P
What are G3P?
when sugar is split into 2 * 3-carbon sugars
Into what is the G3P converted?
Into 2 pyruvate
In the third glycolysis phase (energy acquisition), energy is harvested by what?
Substrate-level-phosphorylation
What is substrate-level-phosphorylation?
ADP picks up phosphate from sugar producing 4 ATP
What are the glycolysis products per glucose?
2 pyruvate, 2 net ATP, 2 NADH
*NO CO2 IS RELEASED
What happens to pyruvate when there is a presence of oxygen?
It will move into the mitochondrion to undergo aerobic respiration
What happens to pyruvate when there is NO presence of oxygen?
It will ferment in the cytoplasm by fermentation (a form of anaerobic respiration)
When no oxygen, what happens?
cell runs out of oxygen and shuts down mitochondria
Where does oxidation of pyruvate occur?
inner mitochondrial membrane in eukaryotess
What does pyruvate do during oxidization? (3 things)
Converts 3-C pyrhuvate to 2-C acetyl
Produces 1 NADH for every pyruvate
First 2 CO2 are released from original glucose (1 per pyruvate)
What are the products per pyruvate?
1 CO2 given off as waste
1 NADH will make ATP in ETC
1 acetyl-CoA
*per glucose means multiply all by 2
What is the ratio of by pyruvate products and by glucose products?
Per glucose: multiply all pyruvate products by 2
Where does the Krebs cycle occur?
Matrix of mitochondria
This cycle completes glucose oxidation.
Krebs cycle
What does the Krebs cycle produce per pyruvate?
3 NADH
1 FADH2
1 ATP
What does the Krebs cycle release per pyruvate?
2 CO2
After glycolysis, pyruvate oxidation, and the Krebs cycle, glucose has been oxidized to what?
4 ATP
10 NADH (go to ETC)
2 FADH2 (go to ETC)
6 CO2 per glucose is given off as waste
What is the electron transport chain (ETC)?
A series of membrane-bound electron carriers
Where is located the ETC?
in the cristae of eukaryotic cells
What does the ETC?
Pumps hydrogen ions into inner membrane space and accepts electrons from NADH and FADH2
From which phases is CO2 released?
fermentation
pyruvate oxidation
krebs cycle
Is there any CO2 coming off of glycolysis?
NO
What is recycled by the krebs cycle?
Oxaloacetate
What does ETC need as the final electron acceptor?
Oxygen (O2)
What is the difference between net and total?
Net: cell benefits 2 ATP
Total: 4 ATP made
What is the energy used to pumps H+ across the membrane?
Electron energy that got lost with each transfer of electrons
What is established in the intermembrane space?
Proton H+ gradient
What type of reaction is Cellular Respiration?
Exergonic
Is cellular respiration aerobic or anaerobic?
Aerobic
What gas does cellular respiration consume? What gas does it send out as waste?
Consumes oxygen
Sends out carbon dioxide
Where does cellular respiration occur?
Mitochondrion
What is the chemical equation for Cellular Respiration?
C₆H₁₂O₆ + 6O₂→ 6CO₂ + 6H₂O + heat + ATP
What is the function of cellular respiration?
Breaks down glucose molecules and stores that energy in ATP
Roughly how many ATP are made in the process of cellular respiration (per molecule of glucose)?
38
How much energy from ATP is lost as heat?
40%
How much energy from ATP is used for body maintenance?
75%
Is oxidation a loss or gain of electrons?
Loss
Is reduction a loss or gain of electrons?
Gain
Name the enzyme that is involved in the regulation of redox reactions.
Dehydrogenase
What is the second stage of cellular respiration?
Citric Acid Cycle or Krebs Cycle
Where does citric acid cycle take place?
Matrix
What is the third stage of cellular respiration?
Oxidative Phosphorylation (ETC)
What is the main function of glycolysis and the citric acid cycle?
to supply Oxidative Phosphorylation with electrons
The cell transfers energy by shuttling _____ from molecule to molecule.
Electrons
Energy released in the electron transport chain is used to pump ______ ions across a membrane.
hydrogen
ATP is made by adding ______ to an inorganic phosphate.
ADP
Oxidative ________ involved an electron transport chain and a process called chemiosmosis.
Phosphorylation
A sequence of electron carriers forms the electron ______ chain.
Transport
_______ is the loss of an electron.
Oxidation
A molecule such as glucose is oxidized when it ______ an electron
Loses
_______ is short for “oxidation-reduction”
Redox
Oxygen is ________ in cellular respiration.
Reduced
A coenzyme called ______ is used to carry electrons in redox reactions.
NAD⁺
Most cells make most of their ATP via a process that involves an electron transport chain and a process called ______.
Chemiosmosis
A ______ enzyme strips hydrogen atoms from organic molecules.
Dehydrogenase
ATP ______ are protein complexes hat use energy from a gradient of ion concentration to make ATP.
Synthesis
NADH delivers electrons to an electron ______ at the beginning of the electron transport chain.
Carrier
Glucose is _______ in cellular respiration.
Oxidized
NAD⁺ picks up electrons and hydrogen, forming _______.
NADH
Steps in glycolysis that produce ATP and Pyruvate.
Energy payoff phase
Reduced as glucose is oxidized.
NAD⁺
The steps in glycolysis that consume energy.
Preparatory phase
“Splitting of sugar”
Glycolysis
When an enzyme transfers a phosphate from a substrate to ADP.
Substrate-level phosphorylation
This is not involved in glycolysis.
Oxygen
Fermentation enables cells to make ATP in the absence of ______
Oxygen
For every molecule of glucose consumed, glycolysis produces two molecules of pyruvic acid, two molecules of ATP, and two molecules of ______.
NADH
What are the waste products of Alcohol Fermentation?
Ethanol & carbon dioxide & NAD+
How many ATP does fermentation make?
2
This causes muscle fatigue and sorenese.
Lactic acid
Most* protons diffuse into the matrix through
ATP synthase
A membrane-bound enzyme that uses the energy of the proton gradient to synthesize ATP from ADP + Pi
ATP synthase
In theory, 38 ATP per glucose for _____
Bacteria
In theory, 36 ATP per glucose for _____
Eukaryotes
Regulation of respiration is by ____.
Feedback inhibition
In Aerobic respiration in mito: final electron receptor is _______.
Oxygen
In Fermentation in cytoplasm: final electron acceptor is an organic molecule like ____ and _____.
Acetaldehyde
Pyruvate
It regenerates NAD+ by reducing organic molecules in the cytoplasm.
Fermentation
Glycolysis NEEDS ___.
NAD+
What happens with electrons during lactic acid fermentation?
They are transferred from NADH to pyruvate to produce lactic acid
Amino acid is ______ to remove the amino group.
Deaminated
Amino acid is deaminated to remove the amino group and the remainder is converted to a molecule that enters glycolysis or the KRebs cyle. What is the type of reaction?
Catabolic reaction of proteins
Fats are broken down to fatty acids and glycerol. Fatty acids are converted to acetyl groups by b-oxidation. What is the type of reaction?
Catabolic reaction of fats
What prepares fat for Krebs Cycle?
Oxidation of neutral fat
