APBIO: Unit 2: Cell Structure and Function (copy)

Structure–Function

A central theme in AP Biology that explains how the build of a cell aids its functions.

Eukaryotic Cells

Cells that include animals, plants, fungi, and protists, characterized by internal membranes forming membrane-bound organelles.

Prokaryotic Cells

Cells found in Bacteria and Archaea, lacking membrane-bound organelles and generally smaller.

Nucleus

The largest organelle in a eukaryotic cell, storing hereditary information (DNA) and directing cell activities.

Ribosomes

Sites of protein synthesis made of rRNA and proteins, organized as large and small subunits.

Endoplasmic Reticulum (ER)

A continuous channel throughout the cytoplasm providing support and transport functions, divided into rough ER and smooth ER.

Golgi Apparatus

Modifies, processes, and sorts products received from the ER, acting as the cell’s packaging and distribution center.

Lysosomes

Contain digestive enzymes to break down old organelles, debris, or ingested materials, functioning optimally in an acidic interior.

Vacuoles

Fluid-filled sacs in plant cells for storing water, food, waste, salts, or pigments, crucial for maintaining turgor pressure.

Mitochondria

Organelles that convert energy from organic molecules into ATP, containing their own DNA and ribosomes.

Chloroplasts

Organelles in plants and algae that conduct photosynthesis, containing chlorophyll and their own DNA.

Peroxisomes

Specialized compartments that break down fatty acids and detoxify harmful substances, producing hydrogen peroxide as a byproduct.

Cytoskeleton

A dynamic network of protein fibers that determine cell shape, facilitate movement, and organize cellular materials.

Cell Junctions

Membrane adhesion proteins that form junctions between adjacent animal cells for communication and structural integrity.

Cell Walls

Structures providing support and protection in plants (cellulose), fungi (chitin), and bacteria (peptidoglycan); absent in animal cells.

Membrane Composition

The plasma membrane is primarily composed of a phospholipid bilayer with embedded proteins and carbohydrates.

Fluid Mosaic Model

Describes the plasma membrane as fluid and a mosaic, where lipids and proteins move laterally, creating a dynamic structure.

Selective Permeability

The ability of the plasma membrane to regulate the entry and exit of substances based on their properties.

Active Transport

The process requiring energy to move substances against their concentration gradient.

Endocytosis

The process of engulfing material to form vesicles or vacuoles, including types like phagocytosis and pinocytosis.

Exocytosis

The process of exporting materials through vesicle fusion with the plasma membrane.

Internal Transport

A system powered by the cytoskeleton and motor proteins that assists vesicle and organelle movement within cells.

Endosymbiotic Theory

The theory suggesting that mitochondria and chloroplasts originated from prokaryotes that formed a mutualistic relationship with host cells.

Surface Area-to-Volume Ratio (SA:V)

A critical concept where increasing cell size leads to a decreased ratio that can limit material exchange efficiency.