Ap Biology Unit 2 Review*

Nucleus

A membrane-bound organelle that contains most of the cell's genetic material, playing a crucial role in growth, metabolism, and reproduction.

Plasmolysis

The shrinking of a plant cell due to water loss, causing the cell membrane to pull away from the cell wall.

Endocytosis

The process by which cells take in molecules or particles from outside the cell by engulfing them with their plasma membrane.

Cytoskeleton

A dynamic structure crucial for cell motility, division, and intracellular transport, composed of microtubules, microfilaments, and intermediate filaments.

Endoplasmic Reticulum (ER)

A network of membranous tubules within the cytoplasm of the cell, involved in protein synthesis, folding, and transport, as well as lipid synthesis.

Golgi Apparatus

A complex organelle that processes proteins and lipids synthesized by the endoplasmic reticulum, packaging them into vesicles for transport elsewhere.

Hypotonic Solution

A solution with a lower concentration of solutes than the cell, causing water to flow into the cell.

Flagella

Long, slender extensions of the cell membrane, used for locomotion in certain cells.

Prokaryotic Cells

Cells that lack a true nucleus and other membrane-bound organelles, typically small and simple in structure.

Exocytosis

The process by which cells release molecules to the outside by fusing vesicles with the plasma membrane.

Hypertonic Solution

A solution with a higher concentration of solutes than the cell, causing water to flow out of the cell.

Ribosomes

Small organelles found throughout the cytoplasm, on the endoplasmic reticulum, or attached to the nuclear membrane, responsible for protein synthesis.

Cell Wall

A rigid layer outside the cell membrane, providing structural support and protection to the cell, particularly in plant cells.

Phospholipid Bilayer

The structural basis of cell membranes, composed of two layers of phospholipid molecules, with hydrophobic tails facing inward and hydrophilic heads facing outward.

Water Potential

A measure of the tendency of water to move from one area to another, influenced by solute concentration and pressure.

Mitochondria

Organelles responsible for generating most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.

Centrosome

An organelle involved in the organization of microtubules, playing a key role in cell division.

Turgor Pressure

The pressure exerted by water against the cell wall of a plant cell, maintaining its rigidity and structure.

Isotonic Solution

A solution with the same concentration of solutes as the cell, resulting in no net movement of water into or out of the cell.

Lysosomes

Membrane-bound organelles containing digestive enzymes, responsible for cellular digestion and recycling of macromolecules.

Solute Potential

The contribution to water potential due to the presence of solutes, always negative or zero.

Membrane Potential

The electrical potential difference across a cell membrane, generated by the unequal distribution of ions.

Active Transport

The movement of molecules across a cell membrane against their concentration gradient, requiring energy input, typically in the form of ATP.

Surface Area-to-Volume Ratio

A measure of the cell's surface area relative to its volume, important for diffusion efficiency; larger cells have a lower ratio, making diffusion less efficient.

Endosymbiotic Theory

The theory that certain organelles, such as mitochondria and chloroplasts, originated from symbiotic relationships between ancient cells.

Vacuole

A membrane-bound organelle involved in storing materials such as water, salts, and waste products, particularly large in plant cells.

Cell Membrane

A selectively permeable barrier that separates the interior of the cell from its external environment, controlling the movement of materials in and out.

Chloroplasts

Organelles found in plant cells and some algae, responsible for photosynthesis, the process of converting light energy into chemical energy.

Eukaryotic Cells

Cells characterized by the presence of a true nucleus and other membrane-bound organelles, generally larger and more complex than prokaryotic cells.

Osmosis

The movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Pressure Potential

The contribution to water potential due to pressure exerted on the system, can be positive or zero.

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration, driven by thermal motion.