Anatomy and Physiology: Intro, Chemistry, and Biological Molecules

Vocabulary flashcards covering introductory concepts in Anatomy and Physiology, chemical bonding, atomic structure, homeostasis, and major biological macromolecular groups.

Anatomy

The study of the structure of body parts and their relationship to one another, including the materials body parts are built from and the arrangement of those materials.

Physiology

The study of the function of body parts and how they work to carry out life-sustaining activities.

Levels of Structural Organization

The hierarchical organization of the human body, progressing from the chemical level to cellular level, tissue level, organ level, organ system level, and organismal level.

Tissue

A group of related cells working together to perform a specific function.

Organ

A collection of different types of tissues that work together to form a specific body structure.

Organ System

A group of organs that work closely together to perform complex physiological functions.

Homeostasis

The physiological process that oversees all necessary life functions to keep the internal environment of the body constant even if the external environment changes.

Set Point

The target value or normal range of function around which physiological systems fluctuate in dynamic steady state.

Stimulus

Any change in the internal or external environment that can be detected by a receptor.

Receptor

A body structure specialized to sense a specific stimulus from its environment and send an incoming signal to a controller.

Controller

A body structure that processes incoming stimulus signals from a receptor and decides how the body will respond by sending an outgoing signal to an effector.

Effector

A part of the body that receives outgoing signals from a controller and carries out a response to alter body function.

Negative Feedback Loop

The primary homeostatic mechanism in which the body's response counteracts or reduces the initial stimulus, moving the variable back toward the set point.

Positive Feedback Loop

A rare homeostatic mechanism in which the response reinforces or amplifies the initial stimulus, moving the variable farther away from the set point to complete a function quickly.

Atom

A single unit of matter consisting of a central nucleus surrounded by electron shells.

Proton

A positively charged subatomic particle located inside the nucleus of an atom.

Neutron

A neutral subatomic particle located in the nucleus that provides space between protons to prevent repulsive electrical forces from blowing up the nucleus.

Electron

A negatively charged subatomic particle that orbits the nucleus within specific electron shells.

Atomic Number

The total number of protons contained in the nucleus of an atom.

Atomic Mass

The total combined number of protons and neutrons in the nucleus of an atom.

Valence Shell

The outermost electron shell of an atom.

Valence Electron

An electron located in the outermost shell (valence shell) of an atom.

Octet-Duet Rule

A principle of chemistry stating that atoms are stable when their valence shell is full ($2$ electrons for the K shell; $8$ electrons for L, M, and N shells).

Ionic Bond

A chemical bond formed when one or more valence electrons are permanently transferred from a metal atom to a non-metal atom.

Covalent Bond

A chemical bond formed when one or more pairs of valence electrons are shared between non-metal atoms.

Bonding Orbital

A shared electron shell formed between atoms in a covalent bond.

Electronegativity

The ability of an atom's nucleus to attract shared electrons within a chemical bond.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally because the electronegativity difference between atoms is greater than $0.5$, creating partial charges.

Non-Polar Covalent Bond

A covalent bond in which electrons are shared equally because the difference in electronegativity between atoms is equal to or less than $0.5$.

Hydrogen Bond

A weak attraction, approximately $10\%$ as strong as a covalent bond, between a partial positive charge (usually hydrogen) on one molecule and a partial negative charge on another.

Hydrophilic

"Water-loving"; describes polar or ionic molecules that can readily dissolve in water.

Hydrophobic

"Water-fearing"; describes non-polar molecules that cannot dissolve in water.

Electrolyte

An ion dissolved in water that carries electrical signals through body fluids.

Monomer

A small individual molecule that serves as a building block for larger polymers.

Polymer

A long-chain molecule constructed from a repeated pattern of linked monomers.

Dehydration Synthesis

A chemical reaction that builds polymers by forming a covalent bond between two molecules while removing a water molecule.

Hydrolysis

A chemical reaction that breaks polymers down into monomers by splitting a covalent bond using a water molecule.

Protein

The most abundant biological molecule in the cell ($20\%\text{--}30\%$ of cell mass), formed as long-chain polymers of amino acids connected by peptide bonds.

Amino Acid

The monomer of proteins, consisting of a central alpha carbon, an amino group, a carboxyl (acid) group, a hydrogen atom, and one of $20$ unique side chains.

Peptide Bond

A specialized covalent bond formed between the carboxyl group of one amino acid and the amino group of an adjacent amino acid.

Primary Structure

The linear sequence of amino acids in a polypeptide chain.

Secondary Structure

The second level of protein structure, where the backbone forms coiled $\alpha$-helices or pleated $\beta$-sheets via hydrogen bonds.

Tertiary Structure

The three-dimensional folding of a protein formed when side chains interact to fold secondary structures into a compact globular shape.

Quaternary Structure

The structural level present when two or more polypeptide subunits combine to form a functional complex protein.

Denaturation

The loss of a protein's three-dimensional shape and biological function due to the disruption of its bonds by heat or acid.

Enzyme

A protein catalyst that speeds up specific chemical reactions without being consumed in the process.

Carbohydrate

A biological molecule with the formula $(CH_2O)_n$ used for cellular energy, cell surface identification, and structural support.

Monosaccharide

A single sugar monomer, including hexoses ($6$-carbon sugars like glucose, fructose, and galactose) and pentoses ($5$-carbon sugars like ribose and deoxyribose).

Disaccharide

A sugar dimer consisting of two monosaccharides linked by a covalent bond, such as sucrose, lactose, or maltose.

Polysaccharide

A carbohydrate polymer composed of three or more monosaccharides joined by covalent bonds.

Glycogen

The primary storage polysaccharide in humans, composed of branched glucose molecules stored in liver and muscle cells.

Nucleic Acid

A biological polymer composed of nucleotide monomers, such as DNA and RNA.

Nucleotide

The monomer of nucleic acids, consisting of a pentose sugar, a phosphate group ($PO_4$), and a nitrogenous base.

DNA (Deoxyribonucleic Acid)

A double-stranded helical nucleic acid located in chromosomes that carries instructions for building all cellular proteins.

ATP (Adenosine Triphosphate)

A nucleotide containing three phosphate groups that serves as the primary cellular energy currency to power transport, mechanical, and chemical work.

Lipid

A hydrophobic biological molecule made primarily from carbon and hydrogen atoms.

Hydrophobic Effect

The clumping property that causes non-polar hydrophobic lipid molecules to aggregate and separate from water.

Fatty Acid

A lipid component consisting of a non-polar hydrocarbon chain attached to an organic carboxyl acid group.

Triglyceride

A lipid composed of one glycerol bound to three fatty acid tails, serving as the main form of energy storage ($9\,\text{cal/g}$) and thermal insulation.

Phospholipid

An amphipathic lipid consisting of a glycerol backbone, two hydrophobic fatty acid tails, and a hydrophilic phosphate head group.

Amphipathic

Describing a molecule that possesses both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

Phospholipid Bilayer

A double-layered arrangement of phospholipids in which hydrophobic fatty acid tails face inward away from water and hydrophilic head groups face outward, forming cell and organelle membranes.

Steroid

A hydrophobic lipid molecule characterized by a structure of four fused carbon rings.

Cholesterol

The foundational steroid molecule in the body that serves as the structural precursor for all steroid hormones.