All together

Plasma membrane

Serves an an external cell barrier

Mitochondria

Site of ATP synthesis; powerhouse of the cell.

Ribosomes

The sites of protein synthesis.

smooth ER

Site of lipid and steroid synthesis, lipid metabolism, and drug detoxification.

Golgi Apparatus

packages, modifies, and segregates proteins for secretion from the cell.

Peroxisomes

The enzymes detoxify toxic substances. Contains catalase.

Lysosomes

Site of intracellular digestion.

Microtubules

Support the cell and give it shape. Involved in intracellular and cellular movements.

Intermediate Filaments

Resist mechanical forces acting on the cell.

Microfilaments

Involved in muscle contraction and intracellular movement. Also helps form cytoskeleton.

Centrioles

Organize microtubule network. And form spindle and asters.

Cilia

Current that propels substances across cell surfaces.

Flagella

Propels the cell.

Microvilli

Increase surface area for absorption.

Nucleus

Controls center of the cell.

Cell

The smallest unit of life.

Plasma Membrane

The physical barrier that separates intracellular fluid from extracellular fluid and controls what enters and leaves the cell.

Selectively permeable

A characteristic of the plasma membrane that allows certain substances to cross more easily than others.

Glycocalyx

A coating formed by surface carbohydrates on the outer surface of the plasma membrane, which aids in cell recognition.

Phospholipid bilayer

The main structure of the plasma membrane, consisting of hydrophilic heads and hydrophobic tails.

Hydrophobic

Water-fearing; describes the tails of phospholipids that prevent water-soluble substances from crossing.

Hydrophilic

Water-loving; describes the heads of phospholipids that interact with water.

Carbohydrates

Molecules on the outer surface of the membrane that act as identity markers, allowing cells to recognize each other.

Integral proteins

Proteins embedded in the lipid bilayer that can extend across the membrane.

Peripheral proteins

Proteins that are anchored to the membrane's surface or to integral proteins.

Exocytosis

The process by which substances are expelled from the cell via vesicles that fuse with the plasma membrane.

Endocytosis

The process by which cells internalize substances by engulfing them in a vesicle.

Rough ER

Endoplasmic reticulum with ribosomes, involved in making membrane proteins and phospholipids.

Smooth ER

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

Vesicle

A small membrane-bound structure that transports substances within a cell.

Cytoplasm

The watery environment inside the cell where organelles are suspended.

Nucleus

The membrane-bound structure in a cell that contains genetic material.

Lysosomes

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

Ribosome

The sites of protein synthesis.

Secretory vesicles

Vesicles that transport proteins to the plasma membrane for secretion.

Free Ribosomes

Ribosomes that are not bound to any membrane; they synthesize soluble proteins in the cytoplasm.

Smooth Endoplasmic Reticulum

A membranous system free of ribosomes, involved in lipid and steroid synthesis, lipid metabolism, drug detoxification, and calcium storage.

Mitochondria

Organelles known as the power plants of the cell; they produce ATP from biomolecules through aerobic respiration.

ATP

Adenosine triphosphate; the energy currency of cells.

Cytoskeleton

An elaborate network of protein filaments in the cytosol that provides structural support and aids in movement.

Microfilaments

Thin, semi-flexible protein filaments made of actin that provide strength and support to the plasma membrane.

Intermediate Filaments

Tough, rope-like fibers that help cells withstand pulling forces.

Microtubules

Large, hollow tubes made of tubulin that determine cell shape and aid in intracellular transport.

Centrosome

The microtubule organizing center of the cell, consisting of a granular matrix and two centrioles.

Cilia

Small hairlike structures that aid in movement across cell surfaces and are composed of microtubules.

Flagella

Longer versions of cilia that propel cells, such as sperm.

Microvilli

finger-like projections; increase surface area; have a core of actin

microfilaments used for stiffening of projections

Nucleus

The control center of the cell that contains genetic material and regulates protein synthesis.

Nuclear Envelope

A double-membrane structure that encloses the nucleus and regulates substance passage.

Lysosomes

Membranous sacs containing enzymes for intracellular digestion.

Golgi Apparatus

A stacked structure that modifies, packages, and segregates proteins for secretion or internal use.

Homeostasis

The ability of the body to maintain relatively stable internal conditions in spite of changes in the outside environment.

Receptor

A sensor that detects a change in the variable.

Control Center

The structure that receives information about the variable, compares it to the homeostatic value, and determines a response.

Afferent Pathway

The pathway that takes information about the variable to the control center.

Efferent Pathway

The pathway that takes information from the control center to the structure(s) that carries out the response.

Effector

A structure that carries out the response.

Set Point

The level (or range of levels) at which a variable is to be maintained; the homeostatic value.

Negative feedback mechanism

A series of steps that causes a variable to change in the direction opposite to that of the initial change.

Positive feedback mechanism

Response enhances or exaggerates the original stimulus, causing greater imbalance.

Metabolism

All chemical reactions that occur in cells; the sum of catabolism and anabolism.

Excretion

Removal of wastes from metabolism and digestion.

Digestion

Breakdown of food; absorption of nutrients into blood.

Cardiovascular System

Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc.; the heart pumps blood.

Nervous System

The fast-acting control system of the body, responding to internal and external changes.

Endocrine System

Glands that secrete hormones regulating processes such as growth, reproduction, and metabolism.

Integumentary System

Forms the external body covering, protects deeper tissues, synthesizes vitamin D, and houses receptors.

Skeletal System

Protects and supports body organs and provides framework for muscle movement.

Muscular System

Allows manipulation of the environment and locomotion, maintains posture, and produces heat.

Lymphatic System

Picks up fluid leaked from blood vessels and returns it to blood; involves immunity.

Respiratory System

Keeps blood supplied with oxygen and removes carbon dioxide through gas exchange in lungs.

Digestive System

Breaks down food into absorbable units and eliminates indigestible food as feces.

Homeostatic Imbalance

Disturbances that increase risk of serious diseases and contribute to changes associated with aging.

Protein

Organic molecule broken down into amino acids (by breaking the peptide bonds that hold amino acids together).

Nucleic acid

Organic molecule that stores genetic info; DNA & RNA.

Water

Makes up most of our body, universal solvent.

Lipid

Organic molecule used for long-term energy storage.

Carbohydrate

Organic molecule used for quick energy; often '-ose' suffix (e.g., sucrose).

Organic molecule

Contains carbon; includes protein, lipid, nucleic acid, carbohydrate.

Inorganic compound

Acid/base, salt/electrolyte (e.g., NaCl), water.

Enzyme

Protein that speeds up metabolic reactions by lowering activation energy; involved in most reactions in body; often '-ase' suffix (e.g., lactase).

Acidic solution

Has a high concentration of H+; low pH.

Basic (alkaline) solution

Has a low concentration of H+ (and lots of OH-); high pH.

Polymer

Any chain of monomers.

Monomer

Any building block of polymers.

Polysaccharide

Long carbohydrate like starches, including glycogen (glucose chain).

Disaccharide

a sugar formed when two monosaccharides are joined by a glycosidic bond

Monosaccharide

Single sugar molecule (e.g., glucose); building block of carbohydrates.

Polypeptide

Long chain of amino acids; one or more of these folded up make a protein.

Peptide

Short chain of amino acids; product of partially digested proteins.

Amino acid

Monomer of proteins/polypeptides; 20 of them, which are all vital for life.

Triglyceride

Glycerol backbone with three fatty acid chains.

Fatty acid

3 of these are in triglycerides; mostly carbon & hydrogen.

Nucleotide

Building block of nucleic acids.

Dehydration synthesis

Reaction that occurs when polymers are built; water is released (after forming from H + OH).

Hydrolysis

Reaction that occurs when polymers are broken apart; uses water, which breaks into H and OH.

Integral proteins

Proteins that are embedded in the lipid bilayer of the membrane, functioning as transport proteins, enzymes, or receptors.

Peripheral proteins

Proteins located on the surface of the membrane or attached to other proteins, serving roles such as enzymes and motor proteins.

Transport proteins

Membrane proteins that facilitate the movement of substances across the membrane.