Figure 4.1 A hummingbird needs energy to maintain prolonged flight. The bird obtains its energy…

In contrast to these methods of moving material into a cell is the process of…

Endocytosis is a type of active transport that moves particles, such as large molecules, parts…

We have discussed simple concentration gradients—differential concentrations of a substance across a space or a…

Active transport mechanisms require the use of the cell’s energy, usually in the form of…

A cell’s plasma membrane defines the boundary of the cell and determines the nature of…

Despite their fundamental similarities, there are some striking differences between animal and plant cells Animal…

Ribosomes Ribosomes are the cellular structures responsible for protein synthesis. When viewed through an electron microscope,…

Vesicles and vacuoles are membrane-bound sacs that function in storage and transport. Vacuoles are somewhat…

In animal cells, the lysosomes are the cell’s “garbage disposal.” Digestive enzymes within the lysosomes aid the…