NUTR 3210 Lecture Notes - Lecture 1: Reactive Oxygen Species, Superoxide Dismutase, Glutathione Peroxidase

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20 Oct 2017

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Damage results when oxidants pull electrons from molecules like proteins, lipids and dna cellular damage: antioxidant molecules: are those that oppose the oxidizing action of oxidants (**free radicals) by acting as reducing agents (electron donor) Antioxidant enzymes (endogenous defense) = superoxide dismutase, glutathione peroxidase. Antioxidants (from the diet) = vitamin e, vitamin c. As a result the antioxidant donating an electron to the free radical, free radical preventing tissue damage. Types of reactive oxygen species (ros: most reactions of carbohydrate and lipid metabolism take place in the mitochondria (including the electron transport chain, etc) Eg: in synthesis of t3/t4, sod requires the minerals copper and zinc as cofactors: the enzymes glutathione peroxidase (gpx) converts h2o2 to h2o, gpx requires the mineral selenium, it also stops the production of free radicals in lipids. H2o2 can also form oh- with free e: they turn lipids and etc into free radicals, membranes are very sensitive to free radicals.

Related Questions

Can you answer the following questions:

1. Carbon monoxide is considered toxic because it acts on Complex IV. How would the addition of carbon monoxide to actively respiring mitochondria affect the relative oxidation-reduction states of all components of the electron-transport chain?

A) All four complexes would remain oxidized because they function as a multisystem complex.

B) Complexes I and III would be reduced, but complexes II and IV would be oxidized because the

electrons come from FADH2 oxidation, not NADH.

C) Complexes I, II, and III would be oxidized but Complex IV would remain reduced.

D) Complexes I, II, and III would be reduced and Complex IV would be oxidized.

E) All four complexes would remain reduced because they function as a multisystem complex.

2. Electrons are not very soluble in hydrophobic environments such as a bilipid membrane. What evidence is there that electrons move from complex to complex through the lipid membrane?

A) Cytochrome C is the electron carrier in the membrane and undergoes a head-over-heel flip to set up the proton gradient.

B) Cytochrome C is the electron carrier in the membrane and contains a cydrophoric porphyrin center.

C) CoQ is the electron carrier within the membrane and seems to be confined to the respirasome.

D) CoQ is the electron carrier within the membrane and it contains a hydrophobic porphyrin center.

E) FeS clusters are the carriers within the membrane and the electrons move from one cluster to the

next in a chain-like fashion.

3. What is the rationale for saying that âelectrons flow down the electron-transport chainâ?

A) Electrons flow from oxidized carriers to reduced carriers in discrete steps like a staircase.

B) Electrons flow from half-reactions with more positive redox potentials to more negative.

C) Electrons flow from reactions that continuously generate negative free energy values.

D) Electrons flow from the outer surface to the inner surface, a top down perception.

E) Because we think of electrons flowing like a liquid, the only direction electrons can flow is down.

Initial observations: before beginning Observations Observations after 30 minutes Chemical equation Element that is oxidized Element that is reduced Spectator ion Oxidizing agent Reducing agent www.HOLscience.com 16 Â©Hands-On Labs, Inc. Experiment Oxidation-Reduction Activity Series Questions A. Define oxidation, reduction, and oxidation number. Describe how oxidation and reduction affect the oxidation number of an element. B. Define oxidizing agent, reducing agent, and spectator ion. C. In the reaction of copper and silver nitrate, a new substance appeared in the test tube. Describe the physical appearance of the substance and identify its chemical formula. D. Given an activity series in which the most active metals are at the top of the list and the least active metals are at the bottom of the list, would copper be listed above silver or would silver be listed above copper? Support your answer with data from Data Table 1. E. Solid copper sulfide and silver nitrate react to form copper (II) nitrate and solid silver sulfide. Write a balanced chemical equation that describes the reaction. Identify the oxidation number of each element in the reaction. (You do not need to include the total contribution of charge.) Is this reaction a redox reaction or a non-redox reaction? Explain your answer. www.HOLscience.com 17 Â©Hands-On Labs, Inc. Experiment Oxidation-Reduction Activity Series Exercise 2: Creating an Activity Series Data Table 2. Redox Reactions of Copper, Lead, and Zinc Solid metal Well ID Solution Immediate observations 30 Minute Observations Cu A1 Pb(NO3 ) 2 A2 Zn(NO3 ) 2 Pb B1 CuSO4 B2 Zn(NO3 ) 2 Zn C1 CuSO4 C2 Pb(NO3 ) 2 Data Table 3. Potential Redox Reactions and Chemical Equations Metal and Metallic Solution Reaction Occurred? Chemical Equation Cu + Pb(NO3 ) 2 Cu + Zn(NO3 ) 2 Pb + CuSO4 Pb + Zn(NO3 ) 2 Zn + CuSO4 www.HOLscience.com 18 Â©Hands-On Labs, Inc. Experiment Oxidation-Reduction Activity Series Zn + Pb(NO3 ) 2 Questions A. List each of the metals tested in Exercise 2. Indicate the oxidation number when each element is pure and the oxidation number when each element is in a compound. B. Which of the metals in Exercise 2 was the strongest oxidizing agent? Was there an instance when this metal also acted as a reducing agent? Explain your answer using data from Data Table 3. C. Which of the metals in Exercise 2 was the strongest reducing agent? Was there an instance when this metal also acted as an oxidizing agent? Explain your answer using data from Data Table 3. D. How does ease of oxidation correlate with activity? Do highly active metals tend to donate electrons or accept electrons from other metals? E. Create an activity series for copper, lead, and zinc. Place the most active metal at the top of the list.

......Use the following to feel out the sentense: cycled, photosynthesis, cellular respiration, oxygen, carbon dioxide, ATP

During ____________ , mitochondria break down carbohydrates to produce energy that is used to make ____________ .

This process requires ____________ and carbohydrates, and produces ____________ and water.

During ____________ , chloroplasts use water and ____________ to create carbohydrates.

This process requires ____________ and water, which are byproducts from ____________ .

In turn, it produces ____________ and carbohydrates that are used in ____________ .

In this manner, the flow of energy is ____________ between chloroplasts and mitochondria.

..........use the following to feel out each sentense: from, oxidized, photosynthesis, cellular respiration, gains, to, loses, reduced.

During ____________ , hydrogen atoms are transferred ____________ water ____________ carbon dioxide as glucose forms.

Thus, during ____________ , carbon dioxide is ____________ , while water is ____________ . In other words, carbon dioxide ____________ electrons and water ____________ electrons.

During ____________ , glucose is ____________ as oxygen is ____________ , becoming water.

In each of these reactions, while one molecule loses electrons (is ____________ ), another gains electrons (is ____________ ); thus, each of these metabolic pathways includes redox reactions: coupled reduction and oxidation reactions.

..........use the following to feel out the sentenses: increase, conservation of energy, first of thermodynamics, input, decrease, laws of thermodynamics, secod law of thermodynamics, heat

The ____________ explain energy flow and energy conservation and can be applied to biological systems.

The ____________ states that energy cannot be created or destroyed, also known as the law of ____________ .

The ____________ states that energy is lost when it is converted from one form to another, often in the form of ____________ .

As cells go through transformations, they ____________ the total entropy of the universe, resulting in a ____________ in available energy.

For example, photosynthesis in plants requires an energy ____________ to turn carbon dioxide and water into sugar because there is a ____________ in entropy.

NUTR 3210 Lecture Notes - Lecture 1: Reactive Oxygen Species, Superoxide Dismutase, Glutathione Peroxidase

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