Biology: Evolution and Metabolism

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the process through which energy is created in our cells?

Photosynthesis

Mitochondrial oxidative phosphorylation (correct)

Fermentation

Glycolysis

What are reactive oxygen species?

Molecules with one or more unpaired electron(s) (correct)

Molecules that cannot oxidize other molecules

Molecules with paired electrons

Stable and non-reactive molecules

What happens to oxidized molecules?

They become more stable

They are eliminated from the body

They become free radicals themselves (correct)

They become less reactive

What is a consequence of reactive oxygen species formation?

Toxic Liver Injury and other diseases Signup and view all the answers

Which of the following is NOT a source of reactive oxygen species?

Glycolysis Signup and view all the answers

What is the role of p66Shc in oxidative stress?

It translocates to the mitochondrial intermembrane space and associates with cytochrome c Signup and view all the answers

Which enzyme is involved in the formation of reactive oxygen species?

Monoamino oxidase Signup and view all the answers

What is a major consequence of reactive oxygen species formation in the body?

Cellular injury and disease Signup and view all the answers

What is the result of the reduction of oxygen to water in cellular metabolism?

Energy production Signup and view all the answers

What is a characteristic of reactive oxygen species?

Instability and high reactivity Signup and view all the answers

What is the function of superoxide dismutases (SODs) in the human body?

To catalyze the degradation of superoxide anions Signup and view all the answers

Which of the following antioxidants is responsible for scavenging free radicals to buffer against high levels of ROS?

Glutathione Signup and view all the answers

What is the function of catalase in the human body?

To catalyze the degradation of hydrogen peroxide Signup and view all the answers

What is the role of vitamin C in the human body?

To counteract superoxide, hydrogen peroxide, and hydroxyl radicals and singlet oxygen actions Signup and view all the answers

Which of the following antioxidants is responsible for trapping and scavenging superoxide, hydrogen peroxide, and hydroxyl radicals?

Vitamin E Signup and view all the answers

What is the function of glutathione peroxidases in the human body?

To remove peroxyl radicals from peroxides Signup and view all the answers

Which of the following antioxidants is related to low-density lipoproteins?

Coenzyme Q-10 Signup and view all the answers

What is the function of albumin, bilirubin, taurine, and hypotaurine in the human body?

To reduce the risk of the development of oxidative stress Signup and view all the answers

What is the function of the antioxidant defense system in the human body?

To maintain the normal physiological function Signup and view all the answers

Which of the following is an intramitochondrial metabolite?

Superoxide anion Signup and view all the answers

Study Notes

Reactive Oxygen Species (ROS)

We metabolize oxygen to produce energy through mitochondrial oxidative phosphorylation, which leads to the formation of oxygen free radicals.
ROS are molecules with one or more unpaired electrons, making them unstable and extremely reactive.
ROS can oxidize and modify nearby molecules, causing oxidized molecules to become free radicals themselves.

Effects of ROS

ROS contribute to various diseases and conditions, including:
- Toxic Liver Injury
- Nutritional Liver Disease
- Alcoholism
- Inflammation
- Rheumatoid Arthritis
- Atherosclerosis
- Some Parasitic Infections
- Some Lung Disorders
- Photosensitisation
- Reperfusion Injury
- Tumour Promotion
- Carcinogenesis

ROS-Inducing Compounds

Examples of compounds that induce ROS include:
- CCl4
- Aromatic nitro-compounds
- Aromatic amines
- Nitrosamines
- Hydrazines
- Quinones
- Adriamycin

Enzymes Affected by ROS

Enzymes affected by ROS include:
- Monoamino oxidase
- α-Ketoglutarae dehydrogenase
- Glycerol phosphate dehydrogenase
- p66shc (translocates to mitochondrial intermembrane space upon oxidative stress)

Types of ROS

Two main types of ROS:
- Superoxide anion (intramitochondrial metabolite)
- Hydrogen peroxide (cellular metabolite)

Antioxidant Defense System

The system includes endogenous and exogenous antioxidants that maintain normal physiological function.
Antioxidants can be:
- Enzymatic (e.g., SODs, Catalase, Glutathione peroxidases)
- Non-enzymatic (e.g., Glutathione, Vitamin C, Vitamin E, Coenzyme Q-10, Albumin, Bilirubin, Taurine, Hypotaurine)

Functions of Antioxidants

Antioxidants:
- Scavenge free radicals
- Protect cells from oxygen toxicity and lipid peroxidation
- Decrease lipid peroxidation
- Counteract ROS actions
- Prevent lipid peroxidation and reduce DNA damage
- Recycle other antioxidants
- Inhibit pro-oxidant capacity
- Reduce the risk of oxidative stress development

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the evolution of life on Earth, from the origins of multicellular organisms to extinction events, and learn about the process of energy production through mitochondrial oxidative phosphorylation.