AP Bio Penguins Unit 2 Review: Cell Structure and Function

Comprehensive vocabulary flashcards covering cellular organelles, membrane structure, transport mechanisms, and water potential terminology based on the AP Biology Unit 2 review.

Ribosomes

Non-membrane bound structures made of ribosomal RNA ($rRNA$) and proteins that synthesize proteins during translation according to mRNA sequences.

Rough ER

A part of the endoplasmic reticulum studded with ribosomes that is directly attached to the nucleus; it functions in synthesizing membrane proteins or secretory proteins.

Smooth ER

A region of the endoplasmic reticulum without ribosomes responsible for detoxification and the synthesis of lipids, including steroids.

Golgi Complex

A membrane-bound organelle made of cisternae that packages and modifies materials for trafficking or secretion via transport vesicles.

Mitochondria

Organelles with double membranes where the inner membrane (cristae) is highly folded to increase the surface area for oxidative phosphorylation and the Krebs cycle to synthesize $ATP$.

Lysosomes

Membrane-bound sacs containing hydrolytic enzymes used for intracellular digestion, such as breaking down food vacuoles or misformed organelles.

Vacuoles

Membrane-bound sacs used for storage; examples include central vacuoles for turgor pressure in plants, contractile vacuoles for water regulation, and food vacuoles from phagocytosis.

Chloroplasts

Organelles found in photosynthetic organisms containing thylakoid membranes; they synthesize sugars and capture light energy for photosynthesis.

Endomembrane System

A connected system of membranes including the nuclear envelope, ER, Golgi, lysosomes, and vacuoles that works to package, transport, and modify materials.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts originated from prehistoric prokaryotes, supported by their double membranes, circular DNA, and ability to replicate via binary fission.

Surface Area to Volume Ratio

A critical cell measurement where a larger ratio (found in smaller cells) allows for the most efficient exchange of nutrients and elimination of waste.

Phospholipid Bilayer

A membrane structure featuring hydrophilic phosphate heads facing the aqueous exterior/interior and hydrophobic fatty acid tails facing the interior of the membrane.

Cholesterol

A steroid molecule embedded in the phospholipid bilayer that acts as a temperature buffer to maintain membrane fluidity.

Fluid Mosaic Model

A model describing the plasma membrane's dynamic nature and its various components, such as phospholipids, proteins, glycolipids, and glycoproteins.

Simple Diffusion

A form of passive transport where small, nonpolar molecules like $O_2$, $N_2$, and $CO_2$ move directly across the membrane down their concentration gradient.

Facilitated Diffusion

Passive transport of polar or charged materials across the membrane using specific transport proteins without requiring energy.

Aquaporins

Specific channel proteins that allow for the facilitated diffusion of water molecules across the hydrophobic plasma membrane.

Active Transport

The movement of molecules against their concentration gradient (low to high) using carrier proteins and an input of energy ($ATP$).

Sodium-Potassium Pump

An active transport mechanism that pumps three sodium ($Na^+$) ions out of the cell and two potassium ($K^+$) ions into the cell using $ATP$.

Exocytosis

The bulk transport process of moving materials produced within the cell out toward the extracellular environment via vesicle fusion.

Phagocytosis

A type of endocytosis referred to as 'cellular eating' where a cell engulfs large particles or food items from the environment into a vacuole.

Hypotonic Solution

A solution with a low solute concentration and high free water; causes water to flow into cells, potentially leading to osmotic lysis in animal cells.

Hypertonic Solution

A solution with a high solute concentration and low free water; causes water to flow out of cells, leading to crenation (shriveling) or plasmolysis.

Water Potential ($\Psi$)

The measure of the potential for water to move, calculated as the sum of pressure potential ($\Psi_p$) and solute potential ($\Psi_s$).

Solute Potential formula

Represented as $\Psi_s = -iCRT$, involving the ionization constant ($i$), concentration ($C$), molar gas constant ($R$), and temperature in Kelvin ($T$).