LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses Adenosine triphosphate or ATP is the energy “currency” or carrier of the cell. When cells require an input of energy, they use ATP. An ATP nucleotide…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses In studying energy, scientists use the term system to refer to the matter and its environment involved in energy transfers, such as an ecosystem. Even single…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses Although cells and organisms require free energy to survive, they cannot spontaneously create energy, as stated in the Law of Conservation of Energy. Energy is available…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses All living systems, from simple cells to complex ecosystems, require free energy to conduct cell processes such as growth and reproduction. Organisms have evolved various strategies…
Figure 6.1 A hummingbird needs energy to maintain prolonged periods of flight. The bird obtains its energy from taking in food and transforming the nutrients into energy through a series of biochemical reactions. The flight muscles in birds are extremely efficient in…
Components and Structure The modern understanding of the plasma membrane is referred to as the fluid mosaic model. The plasma membrane is composed of a bilayer of phospholipids, with their hydrophobic, fatty acid tails in contact with each other. The…
LEARNING OBJECTIVES By the end of this section, you will be able to: Connection for AP® Courses Diffusion, osmosis, and active transport are used to transport fairly small molecules across plasma cell membranes. However, sometimes large particles, such as macromolecules, parts…
LEARNING OBJECTIVES By the end of this section, you will be able to: Connection for AP® Courses If a substance must move into the cell against its concentration gradient, the cell must use free energy, often provided by ATP, and carrier…
LEARNING OBJECTIVES By the end of this section, you will be able to: Connection for AP® Courses Preventing dehydration is important for both plants and animals. Water moves across plasma membranes by a specific type of diffusion called osmosis. The concentration…
LEARNING OBJECTIVES In this section, you will explore the following questions: Connection for AP® Courses Like an art mosaic, the plasma membrane consists of several different components. Phospholipids (which we studied in previously) form a bilayer; the hydrophobic, fatty acid tails…