Chapter 3: Cells and Cytology – Vocabulary Flashcards

Vocabulary terms from Chapter 3 notes on cells, cytology, and the plasma membrane, including cell components, membrane proteins, cell shapes, and basic concepts of cell size and osmotic tonicity.

Plasma membrane (cell membrane)

Outer boundary of the cell; phospholipid bilayer containing lipids and proteins that is semipermeable and regulates what enters and leaves the cell.

Cytoplasm

Intracellular region inside the cell containing cytosol, organelles, cytoskeleton, and inclusions.

Nucleus

Membrane-bound organelle that houses DNA and controls cellular activities; the cell’s genetic blueprint.

DNA (deoxyribonucleic acid)

Genetic material stored in the nucleus; blueprint for protein synthesis and cell function.

Intracellular fluid

Fluid inside the cell (cytosol and organelles’ interiors).

Extracellular fluid

Fluid outside the cell; includes interstitial fluid, blood plasma, lymph, and CSF.

Interstitial fluid (tissue fluid)

Extracellular fluid in the tissue spaces surrounding cells.

Cytoskeleton

Network of protein filaments that maintains cell shape, provides support, and aids in movement.

Organelles

Membrane-bound structures within the cytoplasm with specialized functions (e.g., mitochondria, Golgi apparatus).

Phospholipid bilayer

Two-layer arrangement of phospholipids forming the core structure of the plasma membrane; hydrophilic heads face water, hydrophobic tails face inward.

Cholesterol (in membrane)

Membrane lipid that helps stabilize membrane structure and fluidity.

Glycolipids

Lipids with carbohydrate chains on the outer surface of the membrane; contribute to the glycocalyx.

Glycocalyx

Carbohydrate coating on the cell surface formed by glycolipids and glycoproteins; serves as a cell identity/recognition marker.

Transmembrane proteins

Proteins that span the entire phospholipid bilayer; provide channels or receptors and often have both hydrophilic and hydrophobic regions.

Peripheral proteins

Membrane proteins attached to the membrane’s inner or outer surfaces; often interact with cytoskeleton or extracellular matrix.

Receptors

Membrane proteins that bind signaling molecules and trigger cellular responses, possibly activating second messengers.

Enzymes (membrane-bound)

Proteins that catalyze reactions at the membrane and can lower activation energy for chemical processes.

Channel proteins

Proteins forming pores that allow specific ions, water, or small molecules to cross the membrane.

Leak channels

Always-open channels that permit continuous movement of ions or water across the membrane.

Ligand-gated channels

Channels opened by a chemical messenger (ligand) binding to a receptor.

Voltage-gated channels

Channels opened by a change in membrane potential (voltage) across the membrane.

Carriers (transporters)

Membrane proteins that bind solutes and move them across the membrane; may require energy (active transport).

Cell identity markers

Membrane glycoproteins/glycolipids that identify the cell type to other cells and the immune system.

Cell adhesion molecules (CAMs)

Membrane proteins that mediate binding between cells or between cells and the extracellular matrix.

Surface-area-to-volume ratio

Relationship where volume grows faster than surface area as the cell diameter increases; affects nutrient/waste exchange and cell viability.

Tonicity (osmotic effect)

Osmotic property of a solution that affects cell volume; hypotonic can cause swelling/lysis, hypertonic can cause shrinkage.

Hypotonic solution

Solution with lower solute concentration than the cell interior; water enters the cell, which can lead to swelling or rupture.

Hypertonic solution

Solution with higher solute concentration than the cell interior; water leaves the cell, causing shrinkage.

Cell shapes (squamous, cuboidal, columnar, polygonal, stellate, spheroid, discoidal, fusiform, fibrous)

Descriptors of common cell shapes: squamous (flat), cuboidal (cube-like), columnar (tall), polygonal (many sides), stellate (star-shaped), spheroid (rounded), discoidal (disc-shaped), fusiform (spindle-shaped), fibrous (thread-like).