Cell Biology Lecture – Anatomy & Physiology Chapter 4

Vocabulary flashcards summarizing key cellular structures, transport processes, genetic mechanisms, and cell cycle events from the lecture notes.

Cholesterol

Waxy lipid embedded in animal cell membranes that adds stability and is a precursor for steroid hormones.

Prokaryote

Single-celled organism lacking a nucleus; includes bacteria and archaea.

Eukaryote

Cell type containing a true nucleus; found in animals, plants, fungi, and protists.

Plasma Membrane

Phospholipid bilayer with proteins that forms the cell’s outer barrier and controls transport.

Cytoplasm

Everything inside the plasma membrane except the nucleus; includes cytosol, organelles, and inclusions.

Nucleus

Largest cell structure that houses DNA and is enclosed by a double-membrane nuclear envelope.

Intracellular Fluid

Fluid located within the cell.

Extracellular Fluid

Fluid located outside the cell.

Integral Protein

Membrane protein that spans the bilayer and often functions in transport of ions or molecules.

Peripheral Protein

Protein loosely attached to the inner or outer surface of the membrane, often as an enzyme or anchor.

Marker Molecule

Membrane carbohydrate-linked molecule that enables cell recognition.

Glycoprotein

Protein with attached carbohydrate; functions in cell recognition and signaling.

Glycolipid

Lipid with attached carbohydrate; contributes to cell recognition.

Cadherin

Calcium-dependent adhesion molecule that links adjacent cells.

Integrin

Integral protein that connects the cytoskeleton to extracellular matrix molecules.

Nucleolus

Dense nuclear region that produces ribosomal RNA (rRNA).

Microvillus

Plasma-membrane extension that increases surface area for absorption.

Cilium

Short, hair-like projection that moves fluid or mucus across a cell surface.

Flagellum

Long, whip-like tail that propels a cell, e.g., human sperm.

Cytoskeleton

Network of protein filaments providing structural support, shape, and movement.

Microfilament

Thin actin filament involved in cell shape and muscle contraction.

Intermediate Filament

Rope-like filament providing tensile strength to cells.

Microtubule

Hollow tubulin cylinder that maintains shape and serves as a track for organelle movement.

Centrosome/Centriole

Organelle that organizes microtubules and forms spindle fibers during mitosis.

Ribosome

Non-membranous particle that synthesizes proteins; found free in cytosol or bound to RER.

Proteasome

Protein complex that degrades damaged or unneeded proteins.

Lysosome

Membranous organelle containing digestive enzymes for intracellular digestion.

Peroxisome

Organelle that breaks down fatty acids and neutralizes toxins with hydrogen peroxide.

Rough Endoplasmic Reticulum (RER)

Membranous network studded with ribosomes; synthesizes and transports proteins.

Smooth Endoplasmic Reticulum (SER)

Membranous network that synthesizes lipids, detoxifies drugs, and stores Ca²⁺.

Golgi Apparatus

Stack of flattened sacs that modifies, packages, and ships proteins and lipids.

Mitochondrion

Organelle that produces ATP through cellular respiration and contains its own DNA.

Simple Diffusion

Passive movement of small nonpolar molecules directly through the lipid bilayer down a gradient.

Facilitated Diffusion

Passive transport of larger or charged molecules via membrane proteins.

Channel-Mediated Diffusion

Ion movement through a water-filled protein channel; may be leak or gated.

Carrier-Mediated Diffusion

Transport in which a carrier protein binds a molecule, changes shape, and releases it across the membrane.

Osmosis

Passive movement of water across a semipermeable membrane toward higher solute concentration.

Osmolarity

Measure of solute particle concentration in a solution.

Tonicity

Effect of a solution on cell volume due to water movement.

Isotonic Solution

Solution with equal solute concentration to the cell; no net water movement.

Hypotonic Solution

Solution with lower solute outside the cell; water enters causing hemolysis.

Hypertonic Solution

Solution with higher solute outside the cell; water leaves causing crenation.

Primary Active Transport

ATP-powered transport that moves substances against their gradients, e.g., Na⁺/K⁺ pump.

Secondary Active Transport

Transport that uses energy from another substance’s gradient to move a molecule uphill.

Symporter

Secondary active transporter moving two substances in the same direction.

Antiporter

Secondary active transporter moving two substances in opposite directions.

Vesicular Transport

ATP-dependent movement of large substances via membrane-bound vesicles.

Endocytosis

Vesicular process that brings material into the cell.

Phagocytosis

“Cell eating” endocytosis of large particles like bacteria.

Pinocytosis

“Cell drinking” endocytosis of fluid and dissolved solutes.

Receptor-Mediated Endocytosis

Selective uptake using receptor binding before vesicle formation.

Exocytosis

Vesicular release of substances from the cell to the extracellular space.

Membrane Potential

Electrical charge difference across the plasma membrane.

Resting Membrane Potential

Stable voltage (≈ –70 mV in neurons) maintained by ion pumps and leak channels.

DNA

Double-stranded helix of nucleotides storing genetic information.

Transcription

Synthesis of mRNA from a DNA template in the nucleus.

Translation

Protein synthesis at a ribosome where mRNA codons specify amino acids.

Messenger RNA (mRNA)

RNA copy of a gene that carries coding information to ribosomes.

Transfer RNA (tRNA)

Adaptor molecule that delivers amino acids to the ribosome during translation.

Cell Cycle

Ordered sequence of events in cell growth and division.

Interphase

Non-dividing phase consisting of G₁, S, and G₂ where the cell grows and replicates DNA.

G1 Phase

Interphase stage of cell growth and organelle duplication.

S Phase

Interphase stage in which DNA is replicated.

G2 Phase

Interphase stage of final preparation for mitosis including protein synthesis.

Mitosis

Division of the nucleus into two identical nuclei.

Prophase

First mitotic stage where chromatin condenses and spindle fibers form.

Metaphase

Mitotic stage where chromosomes align at the cell’s equatorial plane.

Anaphase

Mitotic stage where sister chromatids separate and move to opposite poles.

Telophase

Mitotic stage where nuclear envelopes reform around separated chromosomes.

Cytokinesis

Division of the cytoplasm producing two daughter cells after mitosis.

Apoptosis

Programmed cell death that removes damaged or unnecessary cells.