Cell Structure Vocabulary Flashcards

Vocabulary flashcards based on lecture notes covering cell structure, microscopy skills, organelles, life processes, eukaryotic differences, atypical cells, and endosymbiosis.

Cell Theory

A central biological theory stating that all living things are made of cells, the cell is the basic unit of life, and cells only arise from pre-existing cells.

Inductive Reasoning

A form of reasoning that draws general conclusions from many specific observations.

Deductive Reasoning

A form of reasoning that makes specific predictions based on an established theory.

Magnification Formula

The mathematical relationship used to calculate magnification, defined as $\text{Magnification} = \frac{\text{drawing size}}{\text{actual size}}$.

Immunofluorescence

An advanced light microscopy technique using specially-modified fluorescent antibodies that bind to specific cell structures to make them visible.

Electron Microscope

A microscope that uses electrons instead of light to form images, offering superior magnification and resolution compared to light microscopes, though samples must be dead.

Cryogenic Electron Microscopy

A microscopy technique in which a sample is frozen before imaging, keeping individual atoms still to allow visualization of large molecules like proteins and viruses.

Freeze-Fracture Microscopy

A technique where a sample is frozen and fractured to break open cell membranes, allowing detailed study of membrane structure.

Prokaryotic Cells

Smaller cells that lack internal membranes and a nucleus, encompassing bacteria and archaeans.

Eukaryotic Cells

Generally larger cells containing internal membrane-bound organelles, such as a nucleus, encompassing plants, animals, fungi, and protists.

Bacterial Cell Wall

A structure found outside the plasma membrane in bacteria, composed of peptidoglycan, that provides structural support and protection.

Peptidoglycan

The specific substance that makes up the cell wall of eubacteria.

Plasma Membrane

A thin outer boundary composed of a double layer of phospholipids and embedded proteins that controls which substances pass into or out of the cell.

Cytoplasm

The water-based fluid space enclosed by the plasma membrane that serves as the medium for metabolic reactions and surrounds internal structures.

Naked DNA

DNA that is not associated with histone proteins, characteristic of prokaryotic cells, mitochondria, and chloroplasts.

Nucleoid Region

The region within a prokaryotic cell that contains the main, large circular loop of naked DNA.

Plasmids

Small loops of naked DNA found in prokaryotic cells that exist separately from the main chromosome.

70S Ribosomes

Smaller ribosomes found in prokaryotes, as well as inside mitochondria and chloroplasts, responsible for protein synthesis.

80S Ribosomes

Larger ribosomes found in eukaryotic cells, which can float free in the cytoplasm or be bound to the rough endoplasmic reticulum.

Nucleus

A double-membraned organelle in eukaryotic cells containing pores and linear chromosomes composed of DNA bound to histone proteins.

Histone Proteins

Proteins bound to eukaryotic DNA that help package linear DNA into chromosomes.

Mitochondria

Double-membraned eukaryotic organelles with a highly folded inner membrane that perform aerobic cellular respiration to provide energy.

Rough Endoplasmic Reticulum

A network of interconnected membranes studded with bound ribosomes involved in producing proteins destined for membranes or export from the cell.

Smooth Endoplasmic Reticulum

A network of interconnected tubules lacking ribosomes that synthesizes membrane components such as phospholipids and cholesterol and detoxifies toxins like ethanol.

Golgi Apparatus

An organelle composed of a series of flattened membrane sacs that receives vesicles from the rough ER, modifies proteins, and repackages them for export.

Microvilli

Highly folded projections of the plasma membrane in certain animal cells that increase surface area to speed up transport across the membrane.

Vesicles

Small membrane-bound sacs used within eukaryotic cells to transport, store, or secrete materials.

Vacuoles

Membrane-bound sacs, typically larger than vesicles, used to contain water and recently-consumed food.

Lysosomes

Specialized vesicles containing digestive enzymes used to break down food or old organelles.

Microfilaments

Cytoskeletal components made of actin filaments that provide tensile strength to eukaryotic cells.

Microtubules

Cytoskeletal components that provide compressive strength to eukaryotic cells and serve as tracks for motor proteins to move organelles and vesicles.

Metabolism

All the enzyme-catalysed chemical reactions occurring within a cell or living organism, such as respiration.

Response

The life process involving the sensing of environmental changes and interacting with the environment.

Homeostasis

The maintenance and regulation of constant internal cell conditions, such as water and pH.

Movement

The process by which living things carry out small-scale and large-scale changes in position.

Growth

The life function where living organisms grow or change size and shape.

Reproduction

The production of offspring by living organisms, either sexually or asexually.

Excretion

The removal of metabolic waste products from a cell or organism.

Nutrition

Obtaining energy and materials by either synthesizing organic molecules or absorbing organic matter.

Contractile Vacuoles

Specialized vacuoles in unicellular organisms like Paramecium used to regulate water balance as part of homeostasis.

Chitin

The specific substance that forms the cell walls of fungal cells.

Cellulose

The carbohydrate material that forms the cell walls of plant cells.

Large Central Vacuole

A prominent vacuole in plant cells used for storage and for providing structural support through hydrostatic pressure.

Chloroplasts

Photosynthetic organelles present in plant cells that contain thylakoids and double membranes to perform photosynthesis.

Red Blood Cells

Atypical eukaryotic cells that eliminate their nucleus and mitochondria during development to fit through narrow capillaries measuring $8\,\mu\text{m}$ to $10\,\mu\text{m}$.

Aseptate Fungal Hyphae

Long, thin fungal cells that lack dividing walls (septa), resulting in continuous multi-nucleated structures.

Phloem Sieve Tube Elements

Specialized plant vascular cells measuring $7\,\mu\text{m}$ to $19\,\mu\text{m}$ that discard their nucleus to form an open tube for sap transport.

Plasma Membrane Infolding

The evolutionary process by which the plasma membrane folded inward to form internal compartmentalized membranes like the nucleus and ER.

Endosymbiotic Theory

The theory stating that eukaryotic organelles like mitochondria and chloroplasts originated from free-living prokaryotes that were taken in by larger host cells.

Cell Differentiation

The process in multicellular organisms where cells develop specialized tissues through different patterns of gene expression.