Cells and Cellular Components

Comprehensive vocabulary flashcards covering basic cell theory, plasma membrane structure, membrane transport mechanisms, and various cell organelles and their functions.

Cell Theory

The theory stating that cells are structural building blocks of plants and animals, are produced by the division of preexisting cells, and are the smallest structural units performing all vital functions.

Plasma Membrane

The outer boundary of the cell (skin) providing physical isolation, protecting the cell, regulating exchange with the environment, and connecting with other cells.

Phospholipid Bilayer

The structure of the plasma membrane consisting of hydrophilic heads oriented toward fluids and hydrophobic tails oriented inward.

Hydrophilic Heads

The polar part of phospholipid molecules that orientates towards the extracellular and intracellular fluid.

Hydrophobic Tails

The nonpolar part of phospholipid molecules that orientates inward away from watery environments.

Glycocalyx

Biological markers on the plasma membrane that determine 'self vs. non-self' recognition.

Cholesterol

A component of the plasma membrane that helps to stabilize the membrane structure.

Tight Junctions

Impermeable junctions formed by interlocking proteins encircling the cell to keep out enzymes, acids, microorganisms, and large molecules.

Desmosomes

Anchoring junctions associated with intermediate filaments that prevent cells from being pulled apart.

Gap Junctions

Permeable connections between cells consisting of hollow cylinder-shaped channels that allow chemical communication, found in smooth and cardiac muscle.

Passive Transport

Membrane transport that requires no energy, including simple diffusion, facilitated diffusion, and osmosis.

Active Transport

Membrane transport that uses $ATP$ to move solutes against a concentration gradient, requiring carrier proteins.

Simple Diffusion

The movement of substances directly through the phospholipid bilayer with the concentration gradient, such as $O_2$ diffusion from blood into tissue.

Facilitated Diffusion

A specialized form of diffusion where specific molecules, like glucose, bind to carrier proteins; it can be saturated and follows the concentration gradient.

Osmosis

The net movement of water through a selectively permeable membrane.

Isotonic Solution

A solution where there is no change in cell volume, typically characterized by $300\,mOsm$ of nonpenetrating solutes.

Hypertonic Solution

A solution that causes a cell to shrink, typically characterized by a higher concentration of solutes such as $400\,mOsm$.

Hypotonic Solution

A solution that causes a cell to swell, typically characterized by a lower concentration of solutes such as $200\,mOsm$.

Exocytosis

Vesicular transport process that moves large particles and fluid out of the cell.

Endocytosis

Vesicular transport process that moves large particles and fluid into the cell via phagocytosis or pinocytosis.

Cytoplasm

All the material located between the nucleus and the plasma membrane, containing cytosol and organelles.

Mitochondria

The “powerhouse of the cell” takes energy from nutrients, which provides $ATP$

Nucleus

The organelle containing genetic material ($DNA$),and houses and protects DNA. separated into euchromatin and heterochromatin, and surrounded by a nuclear envelope.

Nucleolus

A structure within the nucleus that serves as the site for ribosome production.

Rough Endoplasmic Reticulum (RER)

A membranous organelle studded with ribosomes that manufactures all secreted proteins.

Smooth Endoplasmic Reticulum (SER)

A membranous organelle responsible for lipid synthesis and calcium storage.

Golgi Apparatus

A stack of flat membranous sacs and vesicles that package proteins for transport.

Lysosomes

Vesicles containing digestive enzymes that break down non-usable or damaged organelles to be re-used by the cell.

Peroxisomes

Vesicles that can break down harmful chemicals as they containing oxidase and catalase that detoxify substances like alcohol and break down free radicals into $H_2O$ .

Ribosomes

Small dark bodies made of protein and $rRNA$ that serve as the site of protein synthesis.

Cytoskeleton

The internal framework of the cell consisting of microfilaments, intermediate filaments, and microtubules that supports organelles and allows motility.

Microtubules

Hollow tubes made of protein that radiate from the centrosome, anchor/move organelles, and form mitotic spindles.

Microfilaments

Protein filaments concentrated under the plasma membrane that provide strength and function in cell mobility and shape.

Intermediate Filaments

Proteins with high tensile strength that resist pulling forces on the cell and help form desmosomes.

Centrioles

A region containing two perpendicular _____ that directs the formation of the mitotic spindle and forms the bases of cilia/flagellum.

Cilia

Hair-like extensions on the free surface of the cell that move substances in one direction along the cell surface.

Flagellum

A single long extension, such as a sperm tail, used for cellular movement.

Chromatin

Condensed DNA found in the nucleus

Nuclear Membrane

filters selected substances to pass through and keep out the rest from the nucleus (like the cell membrane)