Living cells constantly carry out various chemical reactions which are necessary for their proper functioning. These reactions are interlinked to one ...

Carbohydrates are polymers composed of molecules containing atoms of carbon, hydrogen and oxygen. One gram of carbohydrate can provide four kilo-calories ...

In cellular metabolism (the complete breakdown of glucose to extract energy),  glycolysis is the first step. Glycolysis takes place in the cytoplasm ...

So far, glycolysis has cost the cell two ATP molecules and produced two small, three-carbon sugar molecules. These molecules will proceed through the ...

Pyruvate is the end product of glycolysis, where glucose is oxidized to pyruvate, simultaneously reducing NAD+ to NADH. Two molecules of ATP are also ...

The energy released from the breakdown of the chemical bonds within nutrients can be stored either through the reduction of electron carriers or in the ...

Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is ...

Lipids also are sources of energy that power cellular processes. Like carbohydrates, lipids are composed of carbon, hydrogen, and oxygen, but these atoms ...

Sugar (a simple carbohydrate) metabolism (chemical reactions) is a classic example of the many cellular processes that use and produce energy. Living ...

Triglycerides are a form of long-term energy storage molecules. They are made of glycerol and three fatty acids. To obtain energy from fat, triglycerides ...

Cellular needs and conditions vary from cell to cell and change within individual cells over time. For example, the required enzymes and energetic demands ...

Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis ("steady state"). Examples ...