AP Bio Chapter 6-10

Cell

smallest unit of life that can perform all necessary functions of life

Prokaryotic cell

cell without a nucleus or membrane-bound organelles

Eukaryotic cell

cell containing a nucleus and membrane-bound organelles

Bacteria

prokaryotic organisms belonging to one of the three domains of life

Archaea

prokaryotic organisms distinct from bacteria in genetics and biochemistry

Eukarya

domain containing organisms with eukaryotic cells

Nucleus

membrane-bound organelle containing most of a eukaryotic cell's DNA

Nuclear envelope

double membrane surrounding the nucleus

Nuclear pore

opening in the nuclear envelope that regulates movement into and out of the nucleus

Nucleolus

region where ribosomal RNA is produced and ribosome subunits are assembled

Chromatin

DNA associated with proteins inside the nucleus

Chromosome

condensed DNA-protein structure carrying genetic information

Ribosome

structure that synthesizes proteins by translating mRNA

Free ribosome

ribosome in cytosol that makes proteins used inside the cell

Bound ribosome

ribosome attached to rough ER that makes proteins for secretion or membranes

Cytoplasm

everything inside the cell between plasma membrane and nucleus

Cytosol

fluid portion of the cytoplasm

Organelle

specialized cell structure that performs a specific function

Plasma membrane

selectively permeable membrane surrounding the cell

Cell wall

rigid external structure that supports and protects certain cells

Flagellum

long cellular structure used for movement

Cilia

short hair-like structures used for movement

Rough endoplasmic reticulum

membrane network with ribosomes that synthesizes and modifies proteins

Smooth endoplasmic reticulum

membrane network involved in lipid synthesis detoxification and calcium storage

Golgi apparatus

modifies sorts and packages proteins and lipids

Transport vesicle

membrane-bound sac that transports materials between organelles or to the membrane

Lysosome

organelle containing enzymes that digest macromolecules and cellular waste

Vacuole

membrane-bound compartment used for storage and other functions

Central vacuole

large plant-cell vacuole that stores water and helps maintain turgor pressure

Peroxisome

organelle involved in oxidation reactions and breakdown of fatty acids and toxins

Mitochondrion

organelle where most cellular respiration and ATP production occur

Chloroplast

plant organelle where photosynthesis occurs

Thylakoid

flattened membrane sac where light-dependent reactions occur

Granum

stack of thylakoids inside a chloroplast

Stroma

fluid surrounding thylakoids where the Calvin cycle occurs

Endomembrane system

membranes involved in protein and lipid production modification transport and digestion

Vesicle

small membrane-bound sac used for storage or transport

Cytoskeleton

protein network that maintains cell shape and organizes movement

Microtubule

cytoskeletal fiber involved in cell shape transport cilia flagella and chromosome movement

Microfilament

thin actin fiber involved in cell shape movement and muscle contraction

Intermediate filament

cytoskeletal fiber providing mechanical strength

Motor protein

protein that uses ATP to move along cytoskeletal fibers

Centrosome

region that organizes microtubules and helps form the mitotic spindle

Surface-area-to-volume ratio

ratio of membrane area available for exchange to cell volume

Compartmentalization

separation of cellular processes into specialized compartments

Phospholipid

molecule with a hydrophilic phosphate head and hydrophobic fatty-acid tails

Phospholipid bilayer

double layer of phospholipids forming the basic membrane structure

Hydrophilic

attracted to water

Hydrophobic

repelled by water

Amphipathic

containing both hydrophilic and hydrophobic regions

Fluid mosaic model

model describing the membrane as a fluid phospholipid bilayer with proteins

Integral protein

protein embedded within the membrane

Transmembrane protein

protein that crosses the entire membrane

Peripheral protein

protein loosely attached to the membrane surface

Glycoprotein

protein with an attached carbohydrate

Glycolipid

lipid with an attached carbohydrate

Cholesterol

lipid that helps regulate membrane fluidity and stability

Membrane fluidity

ability of membrane components to move laterally

Selective permeability

ability of a membrane to allow some substances through more easily than others

Concentration gradient

difference in concentration between two regions

Electrochemical gradient

combined concentration and electrical gradient affecting ion movement

Passive transport

movement across a membrane without cellular energy

Diffusion

net movement of particles from high to low concentration

Facilitated diffusion

passive transport through membrane proteins

Channel protein

membrane protein forming a passageway for specific substances

Carrier protein

membrane protein that changes shape to transport substances

Aquaporin

channel protein that facilitates water movement

Osmosis

diffusion of water across a selectively permeable membrane

Tonicity

ability of a solution to cause a cell to gain or lose water

Isotonic

solution with equal effective solute concentration to the cell

Hypertonic

solution with greater effective solute concentration than the cell

Hypotonic

solution with lower effective solute concentration than the cell

Plasmolysis

shrinking of a plant cell membrane away from the wall due to water loss

Turgor pressure

pressure of water against a plant cell wall

Active transport

movement against a concentration or electrochemical gradient using energy

Sodium-potassium pump

ATP-powered protein that pumps Na+ out and K+ into cells

Proton pump

protein that uses energy to move H+ across a membrane

Electrogenic pump

transport protein that creates a voltage across a membrane

Cotransport

transport of two substances using the gradient of one to drive the other

Secondary active transport

transport using energy stored in an ion gradient

Membrane potential

electrical difference across a membrane

Exocytosis

vesicles fuse with the membrane and release contents outside the cell

Endocytosis

membrane folds inward to bring material into the cell

Phagocytosis

endocytosis of large particles or cells

Pinocytosis

nonspecific uptake of extracellular fluid

Receptor-mediated endocytosis

selective uptake using membrane receptors

Ligand

molecule that binds specifically to a receptor

Tight junction

junction that prevents leakage between adjacent animal cells

Desmosome

junction that anchors neighboring animal cells together

Gap junction

channel connecting animal cells that allows ions and small molecules to pass

Plasmodesmata

channels connecting neighboring plant cells

Extracellular matrix

network outside animal cells providing structural support and signaling

Cell adhesion molecule

membrane protein involved in cell attachment

Cell signaling

process by which cells receive and respond to information

Signal transduction

conversion of an external signal into a cellular response

Signal molecule

molecule carrying information between or within cells

Receptor

protein that detects a specific signal molecule

Intracellular receptor

receptor located inside the cell

Membrane receptor

receptor located in the plasma membrane

G-protein-coupled receptor

membrane receptor that activates a G protein after ligand binding