这页已由机器翻译。其他页面可能仍然显示为英文。
View in English
早期地球代谢过程的可能非生物反应框架
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
相关概念视频
4.7K
A phase I reaction is a biochemical process that introduces a functionally reactive polar group to a substance. This transformation predominantly occurs in the liver, facilitated by the cytochrome P450 system of hemoproteins situated in the lipophilic endoplasmic reticulum of cells. The metabolite generated through this process can have varying polarities. If it is sufficiently polar, it can be easily excreted in the urine due to its water compatibility. However, if the metabolite is nonpolar,...
4.9K
Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...
131.5K
Overview
Metabolism represents all of the chemical activity in a cell, including reactions that build molecules (anabolism) and those that break molecules down (catabolism). Anabolic reactions require energy, whereas catabolic reactions provide it. Thus, metabolism describes how cells transform energy through a variety of chemical reactions, which are often made more efficient with the help of enzymes.
Metabolism Is the Sum of All of the Chemical Reactions That Take Place in an Organism
75.3K
Oxidation–Reduction Reactions
Earth’s atmosphere contains about 20% molecular oxygen, O2, a chemically reactive gas that plays an essential role in the metabolism of aerobic organisms and in many environmental processes that shape the world. The term oxidation was originally used to describe chemical reactions involving O2, but its meaning has evolved to refer to a broad and important reaction class known as oxidation–reduction (redox) reactions.
Some redox reactions involve the...
101.0K
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
In the 1920s, the scientists Oparin and Haldane proposed the idea that simple...
12.0K
According to Newton's law of gravitation, the gravitational force on a body is proportional to its mass. According to Newton's second law of motion, the acceleration produced by an external force is inversely proportional to the force. Hence, the acceleration of an object under an external force of gravitation is independent of its mass.
The acceleration of an object close to the Earth, because of the Earth's gravitational pull, is called the acceleration due to gravity. It is...