Video: Cellular Biology and Membrane Transport - Vocabulary Flashcards

Vocabulary flashcards covering key concepts from cellular biology, membrane transport, organelles, signaling, and cellular communication as presented in the lecture notes.

Cellular biology

The study of cell structure and function, including how cells operate and interact to sustain life and how cellular processes relate to disease.

Cellular crosstalk

Communication between cells through signaling pathways that coordinates cellular functions and responses.

Solute

A dissolved substance within a solution.

Electrolyte

A dissolved substance that dissociates into ions and conducts electricity.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Nonelectrolyte

Substances that do not dissociate into ions in solution (e.g., glucose, urea, creatinine).

Passive transport

Movement of water and small, uncharged molecules across membranes without energy input.

Diffusion

Movement of a solute from an area of higher concentration to an area of lower concentration.

Facilitated diffusion

Passive transport via a protein carrier that moves solutes without energy expenditure.

Filtration

Movement of water and solutes through a membrane due to hydrostatic pressure.

Osmosis

Movement of water across a semipermeable membrane down its concentration gradient.

Osmotic pressure

Pressure required to oppose the osmotic movement of water.

Oncotic pressure

Osmotic pressure attributable to colloids (like plasma proteins) in the blood.

Osmolarity

Number of milliosmoles per liter of solution.

Osmolality

Number of milliosmoles per kilogram of water.

Isotonic

Having the same osmolality as body fluids or intracellular/extracellular fluid (around 285 mOsm/kg).

Hypertonic

Solution with a higher osmolality than body fluids (>294 mOsm/kg).

Hypotonic

Solution with a lower osmolality than body fluids (<285 mOsm/kg).

Mediator transport

Transport that is protein-mediated and can be passive or active.

Uniport

Transport of a single solute in one direction via a carrier.

Symport

Co-transport of two solutes moving in the same direction.

Antiport

Co-transport of two solutes moving in opposite directions.

Passive mediated transport

Transport that uses a carrier protein but does not require cellular energy.

Active transport

Movement of substances against their gradient that requires energy, often via pumps.

Sodium-potassium pump (Na+/K+-ATPase)

Ion pump that exchanges 3 Na+ out for 2 K+ in per ATP, maintaining gradients.

Endocytosis

Process of taking in substances by vesicle formation from the plasma membrane.

Pinocytosis

Cell drinking; ingestion of extracellular fluid and contents.

Phagocytosis

Engulfment of large particles by the cell through membrane extensions.

Exocytosis

Release of substances from vesicles by fusion with the plasma membrane.

Vesicle

Membrane-bound sac used for transport within or outside the cell.

Lysosome

Organelle containing hydrolases for intracellular digestion; primary and secondary forms.

Autophagy

Autodigestion of cellular components via lysosomes.

Golgi apparatus

Organelle that refines, processes, and traffics proteins to their destination.

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; site of protein synthesis.

Smooth endoplasmic reticulum (SER)

ER lacking ribosomes; site of lipid synthesis and metabolic processes.

Nucleus

Cellular organelle housing DNA, with features like the nuclear envelope and nucleolus.

Nuclear envelope

Membrane surrounding the nucleus.

Nucleolus

Nuclear region where ribosomal RNA synthesis occurs.

Chromatin

DNA-protein complex within the nucleus that packages genetic material.

Ribosomes

RNA-protein complexes that synthesize proteins; free or attached to RER.

Cristae

Folded inner mitochondrial membrane increases surface area for respiration.

Mitochondrion

Organelle responsible for cellular respiration and energy production.

Oxidative phosphorylation

Metabolic pathway in mitochondria that produces ATP using the electron transport chain.

Peroxisome

Organelle with oxidative enzymes; detoxifies compounds and metabolizes fatty acids.

Vaults

Ribonucleoprotein “truck” complexes that transport messenger RNA (mRNA).

Cytosol

Gel-like fluid portion of the cytoplasm; site of intermediary metabolism (about 55% of cell volume).

Cytoplasmic matrix

The cytosol and organelles within the cytoplasm.

Cytoskeleton

Network of microtubules, actin filaments, and intermediate filaments that maintains shape and enables movement.

Microtubules

Rigid, tubular structures that provide cell support and tracks for movement.

Actin (microfilaments)

Thin protein filaments involved in cell movement and shape.

Intermediate filaments

Cytoskeletal components providing mechanical strength.

Centrioles

Cylindrical structures that organize spindle fibers during cell division.

Plasma membrane

Phospholipid bilayer that encloses the cell, governs transport, and mediates signaling.

Amphipathic

Molecules that have both hydrophilic and hydrophobic parts.

Lipid rafts

Membrane microdomains rich in cholesterol and sphingolipids that organize signaling.

Caveolae

Small, cholesterol-rich invaginations of the plasma membrane formed by caveolin.

Integral proteins

Membrane proteins embedded in the lipid bilayer.

Peripheral proteins

Membrane proteins attached to the surface of the bilayer.

Transmembrane proteins

Proteins that span the lipid bilayer, often acting as receptors or channels.

Receptors

Proteins that bind ligands and trigger cellular responses.

Transporters

Proteins that mediate movement of substances across membranes.

Enzymes

Proteins that catalyze biochemical reactions at the cell surface or inside.

Surface markers

Proteins on the cell surface used for cellular recognition.

Adhesion molecules

Proteins that mediate cell-cell and cell-matrix adhesion.

Desmosomes

Anchoring junctions that hold cells together under stress.

Tight junctions

Seals between cells preventing diffusion of substances.

Gap junctions

Channels that directly connect neighboring cells for intercellular communication.

Basement membrane

Thin ECM layer underlying many tissues, providing support and filtration.

Extracellular matrix (ECM)

Meshwork of collagen, elastin, fibronectin, and other molecules that support tissues.

Fibroblasts

Cells that synthesize and remodel the extracellular matrix.

Junctional complex

Group of junctions (desmosomes, tight junctions, gap junctions) forming a communication barrier and connectivity.

Proteolytic cascade

Series of proteolytic events that lead to processes like apoptosis, coagulation, and complement activation.

Apoptosis (caspase-mediated pathway)

Programmed cell death involving a cascade of caspase enzymes.

Receptors

Membrane, cytoplasmic, or nuclear proteins that bind ligands and trigger cellular responses.

Ligand

Molecule that binds to a receptor to initiate signaling.

Adenylyl cyclase

Enzyme that converts ATP to cyclic AMP (cAMP) upon receptor activation.

cAMP

A second messenger produced from ATP; activates downstream signaling.

Second messengers

Intracellular molecules (e.g., cAMP, IP3, DAG, Ca2+) that relay signals inside the cell.

IP3 (inositol triphosphate)

Second messenger that mobilizes intracellular Ca2+.

DAG (diacylglycerol)

Second messenger that activates protein kinase C at the membrane.

Ca2+ (calcium)

Second messenger that regulates numerous cellular processes.

Protein kinase cascade

Sequential activation of kinases that amplifies a signal through phosphorylation.

Phosphorylation

Addition of a phosphate group to a protein, usually altering activity.

Kinase

Enzyme that transfers phosphate groups from ATP to target proteins.

MAPK cascade

Mitogen-activated protein kinase signaling pathway leading to changes in gene expression.

Transcription factors

Proteins that regulate gene expression by binding DNA.

Receptor tyrosine kinase (catalytic receptor)

Enzyme-linked receptor with intrinsic kinase activity that phosphorylates tyrosines.

Channel-linked receptor

Ligand-gated ion channel receptor that opens an ion channel upon binding.

G-protein linked receptor

Seven-transmembrane receptor that activates G proteins to propagate signals.

Insulin receptor

A catalytic (tyrosine kinase) receptor that binds insulin and triggers signaling for glucose uptake.

Hormonal signaling

Long-range signaling via hormones transported in the bloodstream.

Paracrine signaling

Local signaling to nearby cells through secreted factors.

Autocrine signaling

Signaling that targets the secreting cell itself.

Neurohormonal signaling

Hormone release by neurons into the bloodstream to act on distant targets.

Neurotransmitters

Chemical messengers released by neurons to communicate across synapses.

Contact-dependent signaling

Signaling requiring direct cell-cell contact via membrane-bound receptors or gap junctions.

Action potential

Rapid, short-lasting electric impulse across a neuron's membrane.

Resting membrane potential (RMP)

Baseline electrical potential across the plasma membrane when a cell is at rest.

Depolarization

Reduction of the membrane’s difference in charge, making the inside less negative.