I would guess water, but I'm not 100% sure.
improved answer: water is a medium in which reactions take place, the answer to the most important energy source for a cell is discussable, the main way to intake energy is by breaking down glucose, but one might argue that starch and fats would be more important as they contain many glucose molecules. However glucose is actually broken down in two different cycles in which through a series of chemical alterations it is stripped of a single carbon at a time and the excess electrons are then stripped of excess energy to help form atp, ATP is the basic unit of fuel for life, Adenosine triphosphate looses a phosphorus atom to release a huge amount of energy to aid a cells chemical reactions
mitochondria
ATP
Yeast can use glucose as their primary energy source.
Animal cells use mitochondria to generate ATP, the primary energy source for the cell. This is through cellular respiration.
Glucose is considered a simple sugar. It is a primary energy source for the brain.
Atp
glucose
Glucose
Yeast can use glucose as their primary energy source.
primary
Carbohydrates are the body's primary and immediate source of energy.
Carbohydrates are the body's primary and immediate source of energy.
The term clean source of energy refers to only primary energy sources as wind or solar energy. Electricity, by definition, is not a primary energy source. It is a secondary energy source that is could be produced by a clean energy source as wind or any renewable primary energy source or produced by fossil energy source as oil, natural gas, or coal.
The energy source is the chemical energy stored in the cell.
A solar cell is not an energy source, but an energy converter. In the case of solar, the energy source is light, and the solar cell converts it from light energy to electrical energy.
The Sun is the primary source of all energy on Earth.
Animal cells use mitochondria to generate ATP, the primary energy source for the cell. This is through cellular respiration.
Carbohydrates are the primary energy source for herbivores (cows, horses, etc.). Proteins are the primary energy source for carnivores (dogs, cats, etc.).
The functions of carbohydrates are:1.Primary energy source for cells2.Structural material of plant cell walls