Fundamental Biology I – Chapter 2: Cells & Biological Organization

Vocabulary flashcards covering key terms from Chapter 2: cell theory, cell types, organelles, microscopy, and levels of biological organization.

Cell

The smallest structural and functional unit of an organism capable of performing all life processes.

Cell Theory

Concept that all organisms are composed of cells, cells are the basic units of structure and function, and all cells arise from pre-existing cells.

Modern Cell Theory

Expanded cell theory stating that cells carry genetic information (DNA), perform all basic chemical reactions of life, and their activities depend on organelles.

Prokaryotic Cell

Simple cell lacking a nucleus and membrane-bound organelles; DNA resides in an unbound region called the nucleoid.

Eukaryotic Cell

Complex cell with a true nucleus enclosed by a nuclear envelope and numerous membrane-bound organelles.

Plasma Membrane

Selective phospholipid bilayer that forms the outer boundary of every cell.

Cytosol

Semi-fluid substance inside the cell in which organelles and other components are suspended.

Chromosome

Structure composed of DNA and associated proteins that carries genetic information.

Ribosome

Cellular particle made of rRNA and proteins that synthesizes polypeptides.

Nucleoid

Region in prokaryotes where the chromosome (DNA) is found, not enclosed by a membrane.

Organelle

Specialized subcellular structure with a specific function, e.g., mitochondrion, Golgi apparatus.

Nucleus

Membrane-bound organelle that houses chromosomes and nucleoli in eukaryotic cells.

Rough Endoplasmic Reticulum (RER)

ER studded with ribosomes; synthesizes proteins destined for secretion or membranes.

Smooth Endoplasmic Reticulum (SER)

ER lacking ribosomes; synthesizes lipids, detoxifies drugs, stores Ca²⁺, and metabolizes carbohydrates.

Golgi Apparatus

Stacks of flattened sacs that modify, sort, and package proteins and lipids for transport.

Mitochondrion

Double-membrane organelle that performs cellular respiration to produce ATP.

Chloroplast

Photosynthetic organelle in plants and algae containing chlorophyll and thylakoid membranes.

Lysosome

Membrane sac of hydrolytic enzymes that digests macromolecules and worn-out organelles in animal cells.

Peroxisome

Single-membrane organelle that breaks down fatty acids and detoxifies compounds, producing then degrading H₂O₂.

Cytoskeleton

Network of microfilaments, intermediate filaments, and microtubules providing support, transport, and motility.

Centrosome

Microtubule-organizing center containing a pair of centrioles in animal cells.

Cell Wall

Rigid layer outside the plasma membrane of plants, fungi, and many prokaryotes; provides support and protection.

Central Vacuole

Large plant organelle storing water, ions, and waste; maintains turgor pressure.

Plasmodesmata

Channels through plant cell walls that connect cytoplasm of adjacent cells for communication.

Fimbriae

Hair-like appendages on bacteria used for attachment to surfaces.

Capsule

Sticky outer layer of polysaccharide or protein that protects bacteria and aids adhesion.

Flagella

Long whip-like structures that propel cells such as sperm or bacteria.

Light Microscope (LM)

Instrument that uses visible light and lenses to magnify specimens up to ~1000×.

Electron Microscope (EM)

Microscope that uses electron beams to achieve much higher resolution than light microscopes.

Scanning Electron Microscope (SEM)

EM that scans a specimen’s surface, producing detailed 3-D images.

Transmission Electron Microscope (TEM)

EM that transmits electrons through thin sections to reveal internal cell structures.

Magnification

Factor by which the apparent size of an image is increased compared to the actual object.

Resolution

Measure of the clarity of an image; minimum distance two points can be separated and still distinguished.

Contrast

Difference in brightness between parts of the specimen; enhances visibility of structures.

Surface Area-to-Volume Ratio

Relationship dictating that smaller cells have more surface area relative to volume, enhancing material exchange.

Tissue

Group of similar cells working together to perform a specific function.

Epithelial Tissue

Animal tissue that covers surfaces and lines cavities, providing protection and absorption.

Connective Tissue

Animal tissue that supports, binds, and transports; includes bone, blood, and cartilage.

Muscle Tissue

Animal tissue specialized for contraction and movement; types: skeletal, cardiac, smooth.

Nervous Tissue

Animal tissue comprising neurons and glial cells, responsible for communication and control.

Meristematic Tissue

Plant tissue with actively dividing cells located in apical, lateral, and intercalary meristems.

Parenchyma

Living, thin-walled plant cells involved in storage and photosynthesis.

Collenchyma

Plant cells with unevenly thickened walls providing flexible support.

Sclerenchyma

Dead plant cells with thick, lignified walls offering rigid support.

Xylem

Complex plant tissue that transports water and minerals upward from roots.

Phloem

Complex plant tissue that transports organic nutrients throughout the plant.

Organ

Structure composed of two or more tissue types working together for specific functions.

Organ System

Group of organs that coordinate to perform major bodily functions (e.g., digestive system).