AP Biology Unit 2: Comprehensive Study Notes

Ribosomes

Cellular machinery responsible for protein synthesis; composed of rRNA and protein.

Free Ribosomes

Ribosomes that float in the cytosol and synthesize proteins for use within the cytosol.

Bound Ribosomes

Ribosomes attached to the Rough ER that synthesize proteins for membranes, organelles, or export.

Rough ER

Network of membrane tubes studded with ribosomes; involved in protein synthesis and processing.

Smooth ER

Network of membrane tubes lacking ribosomes; synthesizes lipids and detoxifies drugs.

Golgi Complex

Series of flattened membranous sacs (cisternae) involved in modifying, sorting, and packaging proteins.

Mitochondria

Organelles that produce ATP through cellular respiration; known as the powerhouse of the cell.

Cristae

Folds of the inner mitochondrial membrane, increasing surface area for ATP production.

Chloroplasts

Organelles that conduct photosynthesis; contain thylakoids and stroma.

Thylakoids

Membrane-bound sacs in chloroplasts where light-dependent reactions of photosynthesis occur.

Lysosomes

Membrane-enclosed sacs containing hydrolytic enzymes for digestion and recycling within the cell.

Vacuoles

Large membrane-bound vesicles; maintain turgor pressure in plants and store substances.

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

A ratio critical for cell function, indicating efficiency in material exchange.

High SA:V Ratio

Desirable for cells, allowing efficient diffusion of materials.

Low SA:V Ratio

Undesirable; results in limited nutrient exchange and waste accumulation.

Compartmentalization

The presence of membrane-bound organelles creating separate environments within the cell.

Prokaryotes

Single-celled organisms that generally lack internal membrane-bound organelles.

Eukaryotes

Organisms with highly compartmentalized cells, including plants, animals, fungi, and protists.

Endosymbiotic Theory

Theory explaining the origin of eukaryotic cells from prokaryotic cells through symbiotic relationships.

Binary fission

The process by which mitochondria and chloroplasts reproduce independently.

Circular DNA

Type of DNA present in mitochondria and chloroplasts, resembling that of bacteria.

Cell Wall

Rigid structure providing support, found in plants, fungi, and some prokaryotes, unlike the cell membrane.

Normal Cell Membrane

The plasma membrane present in all cells, regulating transport and maintaining the cell's environment.

Protein Modification

The process of adding molecular tags and ensuring correct folding of proteins in the Golgi complex.

Autophagy

The process by which lysosomes digest macromolecules and recycle cellular components.

Turgor Pressure

Pressure exerted by the fluid in the large central vacuole that helps maintain plant structure.

Hydrolytic Enzymes

Enzymes contained in lysosomes that break down macromolecules.

Metabolic Efficiency

The concentration of enzymes and substrates in one area, improving the speed and output of metabolic processes.