AP BIO UNIT 2 PART 1

A set of vocabulary flashcards covering cell types, endomembrane and energy organelles, cytoskeleton components, surface area to volume dynamics, and the structure of the cell membrane.

Cells

The basic structural and functional units of every organism.

Prokaryotes

Unicellular organisms belonging to Bacteria and Archaea that lack membrane-bound organelles, have DNA located in a nucleoid region, and are smaller than eukaryotes.

Eukaryotes

Organisms including protists, fungi, animals, and plants that contain membrane-bound organelles and house their DNA inside a membrane-enclosed nucleus.

Endomembrane Organelles

A group of cellular membranes and organelles consisting of the nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles/vacuoles, and plasma membrane.

Energy Organelles

Organelles dedicated to metabolic energy transformations, specifically mitochondria and chloroplasts.

Compartmentalization

The separation of cellular spaces by membranes to create distinct environments for metabolic reactions, increasing surface area and preventing competing reactions from interfering.

Nucleus

The organelle containing chromosomes (genetic information), enclosed by a double-membrane envelope with pores that regulate the entry and exit of cellular materials.

Nucleolus

The dense region within the nucleus where ribosomal RNA ($rRNA$) is synthesized and combined with proteins to produce large and small ribosomal subunits.

Ribosomes

Non-membranous complexes composed of ribosomal RNA and proteins that translate mRNA instructions into polypeptide chains to synthesize proteins.

Free Ribosomes

Ribosomes suspended in the cytosol that typically synthesize proteins intended to function within the cytosol (such as intracellular enzymes).

Endoplasmic Reticulum (ER)

An extensive network of membranous sacs and tubes that synthesizes membranes and compartmentalizes the cell to isolate newly synthesized proteins from cytosolic enzymes.

Rough ER

The portion of the endoplasmic reticulum studded with bound ribosomes on its surface, specialized for protein synthesis and membrane creation.

Smooth ER

The portion of the endoplasmic reticulum devoid of ribosomes, specialized for synthesizing lipids, metabolizing carbohydrates, and detoxifying the cell.

Golgi Complex

An organelle composed of flattened membranous sacs called cisternae that receives, modifies, sorts, adds molecular tags to, and packages materials into transport vesicles.

Cisternae

Individual, flattened membranous sacs that comprise the Golgi complex; each cisterna is physically separate and not connected to adjacent ones.

Cis Face

The receiving side of the Golgi complex that accepts transport vesicles carrying materials from the rough ER.

Trans Face

The shipping side of the Golgi complex that dispatches finished materials within transport vesicles out to the cytosol or to the plasma membrane for secretion.

Cytosol

The semi-fluid, liquid portion of the cell interior in which organelles and cell components are suspended.

Cytoplasm

Everything located within the boundary of the plasma membrane, including the organelles and the cytosol.

Lysosomes

Membranous sacs of hydrolytic enzymes found in animal cells that catalyze hydrolysis reactions to digest and break down macromolecules into simpler units.

Autophagy

A process where lysosomes hydrolyze and recycle the cell's own damaged or surplus organic material.

Peroxisomes

Membrane-bound metabolic compartments that catalyze oxidation reactions producing hydrogen peroxide ($H_2O_2$) and contain enzymes that break $H_2O_2$ down into water.

Food Vacuole

A cellular sac formed via phagocytosis (cell eating) that merges with lysosomes for nutrient digestion.

Contractile Vacuole

A specialized organelle that maintains water and osmolar balance in freshwater unicellular organisms by pumping excess water out of the cell.

Central Vacuole

A large plant organelle containing cell sap, ions, and water that provides mechanical support by maintaining turgor pressure.

Endosymbiont Theory

The theory stating that an ancestral eukaryotic host engulfed a prokaryotic cell, which persisted as an endosymbiont and evolved into modern mitochondria and chloroplasts.

Cristae

Infoldings of the inner mitochondrial membrane that divide the mitochondrion into internal compartments and greatly increase surface area for cellular respiration.

Mitochondrial Matrix

The compartment enclosed by the inner mitochondrial membrane containing mitochondrial DNA, ribosomes, and enzymes that drive cellular respiration, the Krebs cycle, and ATP synthesis.

Chloroplasts

Double-membrane photosynthetic organelles found in plants and algae that contain chlorophyll and serve as the site of photosynthesis.

Thylakoids

Flattened membranous sacs inside chloroplasts where light-dependent reactions occur, organized into multi-layered stacks called grana.

Stroma

The fluid-filled space surrounding thylakoids within the chloroplast; houses chloroplast DNA, ribosomes, and enzymes that drive the Calvin cycle.

Cytoskeleton

A dynamic network of protein fibers running throughout the cytoplasm that provides mechanical and structural support, anchors organelles, and enables cell and vesicle motility.

Microtubules

Hollow, rod-like cytoskeletal cylinders constructed of the protein tubulin that grow from centrosomes, anchor organelles, aid in motility (cilia/flagella), and separate chromosomes.

Microfilaments

Thin, solid cytoskeletal rods made of actin protein that maintain cell shape, interact with myosin to produce contractile force, and form the cleavage furrow during cell division.

Intermediate Filaments

Permanent, tough cytoskeletal fibers composed of varying protein subunits that preserve cell shape, anchor the nucleus and organelles, and form the nuclear lamina.

Surface Area-to-Volume Ratio

The mathematical relationship ($SA:V$) determining cellular exchange efficiency; cells require a high ratio to adequately import nutrients, release wastes, and dissipate thermal energy.

Glycoproteins

Membrane proteins bonded to carbohydrate sugar chains that extend outside the cell to function as cellular identification markers against foreign invaders.