Fundamentals of Human Biology - Homeostasis and Chemistry Vocabulary

Vocabulary flashcards covering key concepts, definitions, and chemical terminology from Chapters 1 and 2 of the Fundamentals of Human Biology lecture.

Homeostasis

The ability for the body to maintain a relatively stable internal environment despite changing external conditions.

Internal Variable

A chemical or physical property of the body that is monitored for homeostasis, such as blood temperature.

Setpoint

The desired value of an internal variable (for example, blood temperature between $97.7$ and $98.6\,^{\circ}F$).

Receptors

Structures that detect changes in the internal environment away from the setpoint.

Control Center

A structure, typically the brain or spinal cord such as the hypothalamus, that analyzes information from receptors and determines the response of effectors.

Effectors

Structures capable of carrying out a response, such as skeletal muscle contraction (shivering).

Negative Feedback Loops

Mechanisms where a receptor detects a change away from setpoint, alerting the control center to activate effectors in an attempt to negate and reverse the change and restore setpoint.

Positive Feedback Loops

Mechanisms where a receptor detects a change away from setpoint and the control center activates effectors to further move the internal variable away from setpoint, amplifying changes for processes like childbirth and blood clotting.

Salts

Ionic compounds composed of an anion and a cation, excluding Hydrogen ($H^+$) and Hydroxide ($OH^-$) ions, which dissociate into ions when dissolved.

Electrolytes

Ions that often arise from dissociated salts used to form specific solutions with characteristics like conduction and salinity/osmolarity.

Serous Membranes

Thin, double-layered membranes with serous fluid (mostly water) located between layers that enable various structures and organs to slide.

Electronegativity

The force an atomic nucleus exerts on each electron, which determines partial charges or polarity.

Hydrogen Bond

A weak attractive force between two partial charges.

Covalent Bond

A strong attractive force between two atoms that share an electron (co-valence).

Ionic Bond

A moderate attractive force between two oppositely charged atoms.

Monomers

Small molecules used to build larger biological macromolecules through dehydration synthesis.

Polymers

Larger repetitive chain molecules made of similar building blocks (monomers) connected together.

Dehydration Synthesis

The process by which polymers are made where a water molecule is removed to create molecular space for new bonds to form between molecules.

Hydrolysis

The chemical process where a covalent bond is broken while water is added to take up bonding sites.

Glycogenesis

The pathway where absorbed glucose is converted to glycogen in muscle or liver cells.

Glycogenolysis

The pathway where stored glycogen is hydrolyzed back into glucose for ATP production.

Triglycerides

Phenomenally energy-dense lipid molecules composed of $1$ glycerol and $3$ fatty acids, functioning in long-term energy storage, thermal insulation, and physical protection of internal organs.

Saturated Fatty Acid

A fatty acid in which all possible locations for hydrogen bonding are occupied by a hydrogen.

Unsaturated Fatty Acid

A fatty acid in which some possible locations for hydrogen bonding are not filled, replaced instead by a double covalent bond.

Hydrogenation

A process of industrially adding hydrogen to unsaturated fats.

Trans Fats

Partially hydrogenated fats that behave like saturated fats but are still unsaturated, causing severe disruption to blood lipid regulation.

Phospholipids

Lipids created by modifying triglycerides ($1$ glycerol + $2$ fatty acids + $1$ phosphate group) that are amphiphilic and essential for cell membranes.

Amphiphilic

Describing a molecule that contains both hydrophobic (water-fearing) tails and hydrophilic (water-loving) heads.

Cholesterol

The parent molecule of all steroids, produced only by animals, functioning in cell membrane structure, nervous system function, and hormone signaling.

Peptide Bonds

Special covalent bonds that connect pairs of amino acids together in a polypeptide chain.

Primary Structure

The linear sequence of amino acids in a polypeptide chain.

Secondary Structure

Conserved structural patterns held together by hydrogen bonds linking regions of the same polypeptide chain, specifically $\alpha$-helices and $\beta$-pleated sheets.

Tertiary Structure

The complex 3D shape of a protein, determined largely by its amino acid sequence and R group interactions.

Quaternary Structure

The protein structural level formed when two or more distinct polypeptide subunits join together into a functional complex.

Denaturation

The disruption of a protein's 3D shape—caused by changes in pH, temperature, or salinity—which disrupts its function.

Enzymes

Protein catalysts that increase the rate of chemical reactions and decrease energetic costs by binding specific substrates at an active site without being consumed.

Nucleotides

The monomers of nucleic acids, each composed of a nitrogenous base, a sugar, and one phosphate group.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid containing the genetic code, composed of nucleotides with bases Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).

RNA (Ribonucleic Acid)

A typically single-stranded nucleic acid that carries out genetic instructions from DNA to synthesize proteins, using bases Adenine (A), Guanine (G), Cytosine (C), and Uracil (U).

ATP (Adenosine Triphosphate)

A modified nucleotide that acts as cellular energy currency, storing energy in high-energy covalent bonds between its $2\text{nd}$ and $3\text{rd}$ phosphate groups.