BIO 171 A&P I Week 3 Flashcards

Acids

Proton donors that release $H^+$ in solution, increasing the concentration of $H^+$ and making the solution more acidic.

Bases

Proton acceptors that accept $H^+$ in solution, decreasing the concentration of $H^+$ and making the solution less acidic or more basic/alkaline.

Hydrogen Ion ($H^+$)

A positively charged ion formed when a hydrogen atom loses its single electron, leaving behind only a proton.

pH

Potential of hydrogen; a scale measuring acidity or alkalinity where values from $0$ to $6.99$ are acidic and values from $7.01$ to $14$ are basic/alkaline.

Acidosis

The physiological condition that occurs when blood pH falls below $7.35$.

Alkalosis

The physiological condition that occurs when blood pH rises above $7.45$.

Chemical Level

The lowest level of structural organization, where atoms bond to form molecules with three-dimensional structures.

Element

A pure substance that cannot be broken down any further.

Atomic Number

The number of protons in an atom of an element, which determines the element's placement on the periodic table.

Atomic Mass

The mass of both protons and neutrons in the atomic nucleus, reflecting the heaviness of an element's atoms relative to other atoms.

Periods

Rows on the periodic table representing the energy levels being filled by electrons.

Atom

The smallest particle that can exist as an element, consisting of a central nucleus (protons and neutrons) and orbiting electrons.

Isotopes

Atoms of the same element that have the same atomic number (number of protons) but different atomic mass numbers due to a different number of neutrons.

Radioactive Isotope

An unstable isotope (such as Carbon 14) that undergoes radioactive decay, releasing particles and energy over time.

Half-Life

The time required for half of the radioactive atoms in a nucleus to break down and become stable.

Physical Half-Life

The time taken for half of the radioactive atoms in the nuclei to decay through radioactive processes ($t_{1/2}$).

Biological Half-Life

The time taken for the body to eliminate half of a substance through natural processes.

Effective Half-Life

The time required for radioactivity to be reduced by half, representing a combination of physical half-life and biological half-life.

Alpha Particles

Subatomic decay products consisting of $2$ protons and $2$ neutrons (essentially a helium nucleus).

Beta Particles

High-speed subatomic particles (electrons) released during decay that can be blocked by aluminum foil.

Gamma Rays

High-energy radiation originating from the atomic nucleus that can harm DNA and cause cell tumors or cancer.

Triiodothyronine ($T_3$)

A thyroid hormone that plays a crucial role in regulating metabolism, heart function, muscle control, and brain development.

Thyroxine ($T_4$)

The main hormone produced by the thyroid gland, which is converted in the body to the more active $T_3$ form.

Hypothyroidism

A condition caused by low levels of $T_3$ and $T_4$, resulting in low ATP production, cold intolerance, and weight gain.

Obligate Glucose Aerobes

Cells or organs, such as neurons in the brain, that have an absolute requirement for glucose and oxygen to function.

Thyrotropin-Releasing Hormone (TRH)

A releasing hormone secreted by the hypothalamus that stimulates the anterior pituitary gland.

Thyroid Stimulating Hormone (TSH)

A hormone secreted by the anterior pituitary that stimulates the thyroid gland to produce and release $T_3$ and $T_4$.

Mole

An amount of substance containing Avogadro's number ($6.023 \times 10^{23}$) of particles, with a mass in grams equal to its atomic mass.

Covalent Bonds

Chemical bonds formed by the sharing of valence electrons between atoms, serving as stored chemical or electrical energy.

Polar Covalent Bonds

Covalent bonds resulting from the unequal sharing of electrons between atoms with different electronegativities, causing partial positive and partial negative charges.

Nonpolar Covalent Bonds

Covalent bonds formed by the equal sharing of electrons between two atoms with identical or equal electronegativity.

Ionic Bonds

Electrostatic attractions between positively and negatively charged ions resulting from the complete transfer of valence electrons.

Cation

A positively charged ion created when an atom loses one or more electrons.

Anion

A negatively charged ion created when an atom gains one or more electrons.

Electronegativity

The attraction or pull that an atom exerts on its shared electrons.

Hydrogen Bonds

Weak electrostatic attractions occurring between molecules, specifically between a partial positive hydrogen atom and a partial negative atom.

Cohesion

The attraction between water molecules due to hydrogen bonding.

Adhesion

The attraction between water molecules and a substance other than water.

Surface Tension

The inward pulling force created by cohesive forces at the surface of water.