Describe how the structure of a virus aids in its ability to infect cells.

capsid proteins interlock with a receptor site on the host cell. the capsid protein and host cell receptor interlock like a puzzle piece. viruses vary in shape to attack the various types of receptors on cells. the shapes of viruses include polyhedral, helical, enveloped, and complex. once the virus attaches to the host cell, it invades the cell and hijacks the dna of the cell.

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.