General Biology – Cell Structure and Function

30 vocabulary flashcards covering fundamental terms and structures related to cell biology.

Cell

Smallest unit of life; basic structural and functional unit of all organisms.

Codon

Sequence of three nucleotides in DNA or RNA that codes for a specific amino acid.

Permanent / Postmitotic Cells

Cells that can no longer regenerate once they have differentiated and been used (e.g., neurons).

Red Blood Cells

Blood cells that carry oxygen throughout the body via hemoglobin.

SAR11 (Mycoplasma)

One of the smallest known free-living bacterial cells found in nature.

Ostrich Egg

Largest single cell found in nature.

Cell Theory

Biological principle stating that all living things are made of cells, cells are the basic units of life, and all cells come from pre-existing cells.

Prokaryote

Unicellular organism (e.g., bacteria) lacking a nucleus and membrane-bound organelles.

Eukaryote

Cell type with a true nucleus and membrane-bound organelles; found in plants and animals.

Organelle

Specialized membrane-bound structure within eukaryotic cells that performs a specific function.

Cytoplasm

Everything inside a cell except the nucleus; includes cytosol and organelles.

Cell Membrane

Phospholipid bilayer that encloses the cell and regulates movement of substances in and out.

Diffusion

Passive movement of molecules from a region of high concentration to low concentration.

Osmosis

Diffusion of water across a semi-permeable membrane from high to low water concentration.

Nucleus

Control center of eukaryotic cells; houses DNA and nucleolus.

Ribosome

Small, non-membrane organelle that synthesizes proteins; can be free or bound to rough ER.

Endoplasmic Reticulum (ER)

Membranous network; Rough ER synthesizes proteins, Smooth ER makes lipids and hormones.

Golgi Apparatus

Organelle that modifies, packages, and distributes proteins and other molecules in vesicles.

Lysosome

Vesicle containing digestive enzymes that break down waste and cellular debris.

Mitochondrion

"Powerhouse" organelle where cellular respiration produces ATP energy.

Chloroplast

Plant cell organelle containing chlorophyll; converts sunlight into chemical energy (glucose).

Cell Wall

Rigid outer layer made of cellulose in plants and some bacteria; provides support and protection.

Vacuole

Membrane sac for storage; large central vacuole in plants, smaller multiple vacuoles in animals.

Cytoskeleton

Network of protein fibers that maintains cell shape and aids in movement.

Stem Cell Research

Study of undifferentiated cells capable of replacing damaged tissues in the body.

Semi-permeable

Property of a membrane that allows selective passage of certain molecules while blocking others.

ATP (Adenosine Triphosphate)

Primary energy currency of the cell produced mainly in mitochondria.

Brownian Motion

Random movement of microscopic particles in a fluid, observed by Robert Brown.

Chlorophyll

Green pigment inside chloroplasts that absorbs light energy for photosynthesis.

Flagella

Tail-like structures that propel certain cells, such as sperm or some bacteria.