Cell Biology and Cellular Organization Flashcards

Comprehensive vocabulary flashcards covering cell theory, microscopy, organelles, membrane structure, transport mechanisms, cellular specialization, and levels of organization.

Cell Theory

The foundational biological concept stating that all life is cellular (made of cells), cells are the basic units of structure and function in life, and all cells come from pre-existing cells.

Transmission Electron Microscope (TEM)

A microscope used to view internal cell structures at $1000\times$ detail, producing black-and-white images of non-living (dead) specimens.

Scanning Electron Microscope (SEM)

A microscope designed to view the surface of cells at $1000\times$ detail, producing black-and-white images of non-living (dead) specimens.

Prokaryote

A generally smaller and less complicated cellular organism that lacks a nucleus, primarily represented by bacteria.

Eukaryote

A larger, more complex organism composed of cells with a true nucleus, including plants, animals, fungi, protists, and some single-celled organisms.

Nucleus

The cellular control center that contains the cell's $\text{DNA}$ and provides instructions for building proteins and other vital molecules.

Nuclear Envelope

A protective barrier surrounding the nucleus that contains pores allowing materials to move in and out.

Chromatin

A form of genetic material consisting of $\text{DNA}$ tied or bundled to proteins within the nucleus.

Chromosomes

Condensed structures of chromatin that form when a cell prepares to divide.

Nucleolus

The specialized structure within the nucleus responsible for constructing ribosomes.

Ribosome

A cellular machine that synthesizes proteins by assembling amino acids according to genetic instructions.

Smooth Endoplasmic Reticulum (SER)

A region of the endoplasmic reticulum lacking ribosomes, responsible for lipid synthesis and the detoxification of drugs.

Rough Endoplasmic Reticulum (RER)

A region of the endoplasmic reticulum studded with ribosomes, responsible for producing and processing proteins.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins and other materials for storage inside the cell or export outside the cell, functioning like a post office.

Lysosome

The cell's cleanup organelle, filled with enzymes to break down lipids, carbohydrates, proteins, and aged organelles.

Vacuole

A cellular storage structure for water, salts, proteins, and carbohydrates, which can occupy half or more of the volume in plant cells.

Mitochondria

The powerhouse of the cell that generates chemical energy ($\text{ATP}$) from food, containing its own $\text{DNA}$ inherited maternally from the ovum.

Chloroplast

An organelle found in plant cells that converts sunlight into chemical energy ($\text{ATP}$) and food.

Cytoplasm

The fluid medium of the cell in which organelles reside and are directed to move.

Cytoskeleton

A structural network of protein filaments, including microtubules and microfilaments, that maintains cell shape and internal organization.

Centriole

A specialized cellular structure that aids in organizing cell division.

Lipid Bilayer

A double-layered sheet of chain-structured lipids embedded with proteins that forms the core structure of the cell membrane.

Fluid Mosaic Model

A model describing the cell membrane as a dynamic, flexible structure composed of moving individual lipids, proteins, and cholesterol.

Cell Wall

A rigid outer boundary found in plants, algae, fungi, and prokaryotes composed of protein fibers and cellulose to provide shape, support, and protection.

Selectively Permeable

A property of biological membranes that allows specific substances to pass through while preventing others from entering or leaving.

Diffusion

The passive transport process wherein particles move from an area of higher concentration to lower concentration until equilibrium is reached, requiring no cellular energy.

Osmosis

The diffusion of water molecules across a semi-permeable membrane.

Isotonic

A solution condition where intracellular and extracellular solute concentrations are equal, maintaining cell volume.

Hypertonic

A condition where the extracellular solution has a higher solute concentration than inside the cell, causing water to leave and the cell to shrivel.

Hypotonic

A condition where the extracellular solution has a lower solute concentration than inside the cell, causing water to enter and potentially burst the cell.

Facilitated Diffusion

The passive movement of molecules from high to low concentration across the cell membrane through specialized transport proteins, requiring no energy.

Active Transport

The energy-dependent ($\text{ATP}$) movement of particles across a cell membrane against their concentration gradient.

Endocytosis

An active transport process in which the cell membrane wraps around external particles to bring them into the cell.

Exocytosis

An active transport process where membrane-bound vesicles fuse with the cell membrane to force particles out of the cell.

Phagocytosis

A specialized type of endocytosis where the cell membrane engulfs solid food particles.

Cell Specialization

The differentiation of cells in multicellular organisms to perform distinct tasks in order to maintain collective homeostasis.

Myosin

A specific protein forming overdeveloped cytoskeleton fibers in muscle cells that enables movement.

Guard Cells

Specialized plant cells that regulate gas and water exchange and protect against dehydration.

Tissue

An organized group of similar cells working together to perform a specific function, such as muscle, bone, or nerve tissue.

Organ

A group of different tissues combined to carry out a specialized function, such as the heart.

Organ System

A cooperative group of organs that perform unified physiological functions within an organism.

Cell Junctions

Cellular connections that provide physical strength to tissues and facilitate message relay between adjacent cells.

Receptors

Cellular structures that bind and accept specific chemical signals to trigger, accelerate, or slow down cellular activities.