Biology 1002B Lecture Notes - Lecture 7: Acetyl-Coa, Oxidative Phosphorylation, Electrochemical Gradient

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pinkserval403

27 Jan 2020

School

Western University

Department

Biology

Course

Biology 1002B

Professor

Tom Haffie Denis Maxwell

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Document Summary

Glycolysis: enzymes break down a molecule of glucose into two pyruvate molecules. Ca cycle: acetyl coenzyme a is formed from the oxidation of pyruvate, enters a metabolic cycle, where it is completely oxidized to carbon dioxide. Oxidative phosphorylation: nadh is synthesized by both glycolysis and the citric acid cycle is oxidized and electrons formed are passed along an electron transport chain. May then be used in the citric acid cycle: relative location of electron transport chain components relative to mitochondrial membrane, matrix, intermembrane space. We don"t need light, nadh has a very negative redox potential, readily gives electrons. Fes has greater affinity, will just take electrons away. Cannot oxidize proteins, molecules that are bound to proteins, proteins hold the molecules that under go redox reactions. Oxygen is the terminal electron accepter or aerobic respiration, because it has a very positive redox potential, greater affinity for electrons than anything else on the chain: uncoupling.

Related Questions

Q1:

Enzymes are essential for the conversion of organic molecules in biochemical pathways. Which of the following statements is incorrect?

Enzymes reduce the activation energy of chemical reactions.

Enzymes are catalysts and appear unchanged at the end of the reaction.

Enzymes change the equilibrium of a reaction.

Enzymes form a complex with the substrate.

Enzymes facilitate both the conversion of substrates into products and of products into substrates.

Q2:

NADH and NADPH are important energy carriers in biochemical pathways. Which of the following statements about these compounds is incorrect?

NADP+ is reduced by two electrons (involving 2 protons) from photosystem I to form NADPH + H+.

NADH is produced both during glycolysis and in the TCA cycle.

NADH feeds electrons into the respiratory chain of mitcohondria, which are ultimately used to form water.

In the absence of oxygen NADH produced during glycolysis is reoxidised by formation of lactate from pyruvate or by formation of ethanol from acetaldehyde (fermentation).

The majority of NADH produced during oxidation of glucose (in the presence of oxygen) is generated during glycolysis.

Q3:

The respiratory chain converts the reducing power of NADH into the production of ATP. Which of the following statements is incorrect?

Electrons are passed through the respiratory chain in a way to optimise the production of heat.

The complexes of the respiratory chain use the energy of redox reactions to pump protons across the inner mitochondrial membrane.

The ATP synthase uses the protonmotive force to synthesize ATP.

The principle of energy conversion by respiratory chain and ATP synthase is called âchemiosmosisâ.

The electrons from NADH are passed along the respiratory chain in a number of redox reactions mostly involving complexes

raspberrytortoise897

1)Pyruvate is one of the products of glycolysis that can be used by aerobic organisms to extract additional energy. Explain what happens to pyruvate after glycolysis, name the multi-enzyme complex that catalyzes this reaction, and name the cycle that the product feeds into.

2)Suppose you start with 1 molecule of glucose and go through glycolysis to produce 2 molecules of pyruvate. These 2 molecules of pyruvate are then converted into acetyl CoA which then go through the TCA cycle. Theoretically, how many total ATP can be formed through this process? (Account for NADH/FADH₂ produced). Show where each molecule of ATP is generated from.

3)Name the five types of membrane-bound electron carriers. All of the redox centers within the respiratory chain that accept and donate electrons are prosthetic groups except which?

4)Peroxisomes are the site of what? What properties do peroxisomes share with mitochondria?

Why does an electron have lower potential energy in an H-O bondthan in an O=O bond?

H has a higher electronegativity than O.

O=O is not stable.

O=O contains a double bond.

The electrons are closer to the oxygen atom in the H-O bond.

None of the answers are correct.

How is the energy from the electron transport chain used mostdirectly?

to form the bonds of a water molecule

to pump hydrogen ions across the mitochondrial inner membraneinto the mitochondrial intermembrane space

to join ADP with a phosphate

to decompose glucose into pyruvate

to rotate ATP synthase

Which process provides the energy needed to pump protons acrossthe mitochondrial membrane during oxidative phosphorylation?

the transfer of electrons in redox reactions

the breakdown of ATP to ADP

the rotation of the ATP synthase rotor

oxidation of isocitrate

None of the answers are correct.

What causes the ATP synthase rotor to spin?

the passing of electrons through ATP synthase

the movement of protons across the mitochondrial membrane

the movement of electrons across the mitochondrial membrane

the synthesis of ATP from ADP and a phosphate group

None of the answers are correct.

What of the following generates the proton-motive force duringoxidative phosphorylation?

buildup of NADH molecules at protein complex I

movement of H⁺ ions across the mitochondrial membraneduring electron transport

rotation of the ATP synthase rotor

joining of H⁺ ions with oxygen to form water

None of the answers are correct.

Suppose a microorganism invades a cell, causing damage to ATPsynthase. How would cellular respiration be affected?

Electrons could not be passed down the electron transportchain.

ADP could not be joined with a phosphate to form ATP.

Hydrogen ions could not be pumped into the mitochondrialintermembrane space.

The cell could not release any energy from the glucosemolecule.

Glucose could not be broken down into pyruvate.

Which molecules transport electrons from the citric acid cycleto the electron transport chain?

NADH and FADH₂

ATP and ADP

GTP and GDP

oxaloacetate and citric acid

None of the answers are correct.

Which type of reactions control the energy release from glucoseduring the citric acid cycle?

acid-base reactions

redox reactions

random reactions

All answers are correct.

None of the answers are correct.

What is the role of NAD⁺ in cellular respiration?

to receive electrons from the citric acid cycle and deliver themto the electron transport chain

to catalyze the synthesis of ATP from ADP

to accumulate in the mitochondrial intermembrane space tofacilitate ATP synthesis

to serve as a substrate to bind to acetyl-CoA at the beginningof the citric acid cycle

None of the answers are correct.

10.

Which molecule enters the citric acid cycle?

glucose

pyruvate

ATP

acetyl-CoA

None of the answers are correct.

apricotgoose897

Biology 1002B Lecture Notes - Lecture 7: Acetyl-Coa, Oxidative Phosphorylation, Electrochemical Gradient

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