Anatomy & Physiology Basics: Cell Structure, Homeostasis, and Macromolecules

Anatomy

study of structure (what things are, where they are, what they're made of).

Physiology

study of function (how structures work).

Chemical level

atoms & molecules

Cellular level

organelles, cells

Tissue level

groups of similar cells

Organ level

2+ tissue types

Organ system level

multiple organs

Organism level

complete human

Tissues

epithelial, connective, muscle, nervous.

Organs

heart (muscle + connective + epithelial + neural tissue).

Homeostasis

Maintaining a stable internal environment.

Receptor

detects stimulus/change.

Control center

processes info, sends commands.

Effector

carries out response.

Negative feedback

opposes change → restores balance (ex: body temp regulation).

Positive feedback

amplifies change → rapid effect until event ends (ex: childbirth, blood clotting).

Atom

smallest stable unit of matter.

Proton (p⁺)

a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge.

Neutron (n⁰)

a subatomic particle with no charge found in nucleu of every atom except hydrogen, neutral,

Electron (e⁻)

a fundamental subatomic particle with a negative charge that orbits an atoms nucleus.

Atomic number

number of protons.

Atomic mass

actual mass of specific isotope. measured in atomic mass units (amu) or daltons

Atomic weight

equals average mass of an element, including different isotopes in proportion. very close to mass number of most common isotope.

Nucleus

center, contains protons & neutrons.

Isotopes

same number of protons but different number of neutrons

Cation

lost e⁻ → + charge.

Anion

gained e⁻ → - charge.

ionic bond

one of the most types of chemical bonds. created by electrical attraction between cations and anions. involve transfer of one or more electrons from one atom to another to achieve stability.

Covalent bond

electron sharing.

form molecules

Nonpolar

equal sharing (stable, no charge).

Polar

unequal sharing (H₂O).

Hydrogen bond

Attraction of the small positive charges on hydrogen
atoms (of a polar molecule) to negative charges on
atoms in other polar molecules
Can change shape
of molecules or pull
molecules together. (weakest)

strengths of chemical bonds

Ionic > Covalent > Hydrogen.

Decomposition (catabolism)

breaks bonds, releases energy.

Hydrolysis

uses water.

Synthesis (anabolism)

builds bonds, requires energy.

Dehydration synthesis

removes water.

Exchange

shuffles atoms.

Reversible

can proceed both directions, equilibrium.

States of matter

solid, liquid, gas.

Water

vital solvent, reactant, temperature regulator.

pH scale (0-14)

Acidic < 7 (more H⁺). Neutral = 7. Basic > 7 (more OH⁻). Normal blood pH = 7.35-7.45.

Acid

proton donor (H⁺ release).

Base

proton acceptor (OH⁻ release).

chemical reation

is a property of a substance indicating its tendency to undergo a chemical reaction and be transformed into other substances.

Organic compounds

always contain C + H (ex: carbs, lipids, proteins, nucleic acids).

Inorganic compounds

generally do not (ex: water, CO₂, salts).

Functional Groups

common attachments on carbon chains: Hydroxyl (-OH), Carboxyl (-COOH), Amino (-NH₂), Phosphate (-PO₄³⁻).

Carbohydrates

Ratio: ~1:2:1 (C:H:O). Function: energy source.

Monosaccharides

the basic building blocks of all carbohydrates, composed of a single sugar unit. ex(glucose).

Disaccharides

carbohydrates made of two linked simple sugar.ex (sucrose)

Polysaccharides

complex carbohydrates made of long chains of simple sugar ex(starch, glycogen.)

Proteins

Built from amino acids (20 types).

Amino acid structure

central carbon + H, amino group (-NH₂), carboxyl (-COOH), R group (variable).

pH and acidity

pH measures the acidity or alkalinity of a solution on a scale of 0 to 14, where lower pH values (below 7) indicate higher acidity, and higher values (above 7) indicate a higher base.

Functions of proteins

enzymes, structure, transport, defense.

Denaturation

loss of shape & function.

electron orbit

Electrons do not orbit the atomic nucleus like planets around a sun;instead, they exist as probability clouds or atomic orbitals

Types of lipids

fatty acids (sat/unsat), steroids, phospholipids/glycolipids.

DNA

double helix, bases A-T, C-G; stores genetic info.

RNA

single strand, bases A-U, C-G; helps build proteins.

Types of RNA

mRNA, tRNA, rRNA.

Enzymes

proteins that act as catalysts.

Activation energy

Lower activation energy.

Monomer

small building block.

Polymer

chain of monomers (via dehydration synthesis).

ATP (adenosine triphosphate)

Primary energy currency of the cell. Stores energy in high-energy phosphate bonds. Produced mainly in mitochondria.

reactants

atoms in the reacting substance