Topic 2 - Cells

Biol 186

Cell

The basic unit of life, which all organisms are made of.

Prokaryotes

Simple cells that do not have a nucleus; their DNA is organized in a nucleoid.

Eukaryotes

More complex cells that contain organelles, including a nucleus.

Plasma membrane

The barrier between the inside and outside of a cell.

DNA

The genetic material that carries information for cell function and organization.

Ribosomes

Cellular machinery responsible for protein synthesis.

Cytosol

The fluid contained within the cell, excluding organelles.

Unicellular organisms

Organisms made up of a single cell.

Multicellular organisms

Organisms made up of multiple cells.

Microscope

An instrument used to study cells.

Light microscope

A microscope that uses visible light to observe small objects.

Electron microscope

A microscope that uses electron beams to achieve higher magnification.

Centrifugation

A process used to separate organelles from cells.

Nucleoid

The region in prokaryotes where DNA is located, lacking a membrane.

Protein synthesis

The process by which cells produce proteins using ribosomes.

Cell size

Relates to cell function; limited by the ratio of surface area to volume.

Surface area to volume ratio

A critical factor influencing the movement of substances in and out of cells.

Golgi apparatus

An organelle that synthesizes, modifies, and ships macromolecules.

Lysosome

A digestive compartment in cells that contains hydrolytic enzymes.

Peroxisome

An organelle involved in lipid catabolism and detoxification processes.

Endoplasmic reticulum (ER)

An organelle involved in protein and lipid synthesis; two types are rough and smooth ER.

Smooth ER

Endoplasmic reticulum without ribosomes, involved in lipid synthesis and detoxification.

Rough ER

Endoplasmic reticulum with ribosomes, involved in protein synthesis.

Mitochondria

Organelles that serve as the powerhouses of the cell, converting nutrients into energy.

Chloroplasts

Organelles in plant cells that conduct photosynthesis.

Cytoskeleton

A network of fibers that maintains cell shape and stability.

Microtubules

The thickest component of the cytoskeleton, composed of tubulin.

Actin filaments

The thinnest filaments of the cytoskeleton, made of actin proteins.

Intermediate filaments

Cytoskeletal elements with a diameter between microtubules and actin filaments.

Extracellular matrix

A collection of extracellular molecules secreted by cells that provide structural and biochemical support.

Cell wall

A rigid outer layer in plant cells composed of cellulose, providing structural support.

Plasmodesmata

Cytosolic bridges between neighboring plant cells, allowing communication.

Tight junctions

Cell junctions that prevent the leakage of extracellular fluid across epithelial cells.

Desmosomes

Strong cell junctions that connect adjacent cells in tissues under mechanical stress.

Gap junctions

Channels that allow small molecules and ions to pass between adjacent cells.

Centriole

A structure involved in cell division, found within the centrosome.

Chromatin

The complex of DNA and proteins found in the nucleus during interphase.

Nuclear envelope

A double membrane that encloses the nucleus, containing nuclear pore complexes.

Nuclear pore complex

Structures that regulate entry and exit of molecules into and out of the nucleus.

Chromosomes

Tightly coiled structures of chromatin that contain genetic information.

Phagocytosis

A process by which cells engulf large particles for digestion.

Contractile vacuoles

Organelles in unicellular organisms that help discharge excess water.

Vacuoles

Membrane-bound structures in cells, used for storage and maintaining turgor pressure.

Hydrolytic enzymes

Enzymes that catalyze the breakdown of complex molecules in lysosomes.

Dynamic cytoskeleton

The ability of the cytoskeleton to continually remodel and adapt.

Protein sorting

The process by which proteins are designated to their appropriate cellular destinations.

Cellular respiration

The metabolic process that converts nutrients into energy within mitochondria.

Photosynthesis

The process by which chloroplasts convert light energy, CO2, and water into glucose and oxygen.

Prokaryotes

Unicellular organisms without a nucleus, including bacteria and archaea.

Eukaryotes

Organisms whose cells contain a nucleus and membrane-bound organelles.

Microscopy

The use of a microscope to see objects that are too small to be seen by the naked eye.

Light microscopy

A technique using visible light to magnify samples, allowing observation of unstained and stained samples.

Electron microscopy

A technique that uses electrons to provide high-resolution images of specimens.

Cell fractionation

A technique for separating cellular components while preserving individual functions.

Differential centrifugation

A method to separate cellular components based on size and density using varying speeds of centrifugation.

Plasma membrane

The lipid bilayer that forms the outer boundary of a cell, controlling the movement of substances in and out.

Ribosomes

Molecular machines that synthesize proteins by translating messenger RNA.

Cytosol

The fluid component of the cytoplasm in which cell organelles are suspended.

Cilia

Short, hair-like structures on the surface of some cells that aid in movement.

Flagella

Long, whip-like structures that propel cells through fluid environments.

Cytoskeleton

A network of protein filaments and tubules that provides structure and shape to the cell.

Endoplasmic reticulum (ER)

An organelle involved in protein and lipid synthesis, including rough (RER) and smooth (SER) types.

Golgi apparatus

A cell organelle that modifies, sorts, and packages proteins and lipids for secretion.

Lysosome

An organelle containing digestive enzymes that break down waste materials and cellular debris.

Vacuoles

Storage compartments in cells that hold various substances, including nutrients and waste products.

Mitochondria

Organelles known as the powerhouse of the cell, generating ATP through cellular respiration.

Chloroplasts

Organelles found in plant cells that conduct photosynthesis.

Cell wall

A rigid layer found outside the plasma membrane in plant cells, providing structural support.

Nuclear envelope

A double membrane that surrounds the nucleus and separates it from the cytoplasm.

Nucleus

The control center of the cell, containing genetic material.

Chromatin

A complex of DNA and proteins found in the nucleus, which condenses to form chromosomes.

Microtubules

Cylindrical structures composed of tubulin that form part of the cytoskeleton.

Microfilaments

Fine, thread-like proteins made of actin that support the cell's shape.

Intermediate filaments

Cytoskeletal components that provide mechanical support for the cell.

Peroxisomes

Organelles that contain enzymes for oxidation reactions, breaking down fatty acids and toxic substances.

Endosymbiont theory

The hypothesis that mitochondria and chloroplasts originated as free-living prokaryotes engulfed by ancestral eukaryotic cells.

Homeostasis

The ability of a cell or organism to maintain internal stability despite external changes.

Signal transduction

The process by which a cell responds to external signals via a series of molecular events.

Phagocytosis

A form of endocytosis in which a cell engulfs large particles or other cells.

Exocytosis

The process by which vesicles fuse with the plasma membrane to release their contents outside the cell.

Cellular respiration

The metabolic process that converts glucose into ATP, using oxygen and producing carbon dioxide.

Photosynthesis

The process by which plants and some microorganisms convert light energy into chemical energy.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell, used for cellular processes.

Hydrolytic enzymes

Enzymes found in lysosomes that catalyze the breakdown of complex molecules.

Collagen

A key structural protein found in the extracellular matrix of animals.

Extracellular matrix (ECM)

A network of proteins and carbohydrates outside the cell that provides structural and biochemical support.

Tight junctions

Cell junctions that prevent leakage of materials between adjacent cells.

Desmosomes

Cell junctions that anchor cells together, providing structural integrity.

Gap junctions

Channels that allow direct communication between adjacent cells.

Plant cell components

Features unique to plant cells, such as chloroplasts, a rigid cell wall, and large vacuoles.

Animal cell components

Features of animal cells, which lack a cell wall and chloroplasts but contain centrioles.

Nucleosome

A structural unit of a chromosome, consisting of a segment of DNA wound around a core of histone proteins.

Transcription

The process of copying a segment of DNA into RNA.

Translation

The process by which ribosomes synthesize proteins based on the sequence of mRNA.

Membrane proteins

Proteins embedded in the plasma membrane that perform various functions including transport and signaling.

Aquaporins

Membrane proteins that facilitate the transport of water across cell membranes.

Cytoplasm

The gel-like substance within a cell, excluding the nucleus, in which organelles are suspended.