Question

1. why do cells (animal cells, plant cells, any type of cells) need simple sugars?
2. why is glucose important for these cells as a simple sugar (whats it used for)?

Explanation:

Cells need simple sugars (like glucose) as they are a primary energy source. Through cellular respiration, cells break down simple sugars to release energy (in the form of ATP) that powers various cellular processes such as growth, repair, and maintaining homeostasis. Glucose, being a common simple sugar, is crucial as it can be easily metabolized. It enters cells via specific transporters. In glycolysis (the first step of cellular respiration), glucose is converted into pyruvate, generating some ATP. Then, in aerobic respiration (if oxygen is available), further steps (like the Krebs cycle and oxidative phosphorylation) occur in mitochondria (in eukaryotic cells) to produce a large amount of ATP. Even in anaerobic conditions (like in some bacteria or in muscle cells during intense exercise), glucose can be metabolized (though less efficiently) via fermentation to still provide some energy. Also, glucose can be used in other metabolic pathways. For example, in plants, excess glucose can be converted into starch for storage or into cellulose for cell - wall synthesis. In animals, glucose can be stored as glycogen in the liver and muscles.

Answer:

Cells need simple sugars as an energy source. Glucose is important as it is metabolized (via cellular respiration or fermentation) to produce ATP for cellular processes and can also be used in other metabolic pathways (like storage or synthesis of structural components).