Anatomy 12

Ion

An atom with an electrical charge

Positive ion

Forms when an atom LOSES an electron

Negative ion

Forms when an atom GAINS an electron

Ionic Bond

Metal + Nonmetal. One atom STEALS an electron from another.

Covalent Bond

Nonmetal + Nonmetal. Atoms SHARE electrons.

Acid

Has a pH lower than 7

Base

Has a pH higher than 7

Polar Molecule

A molecule with an uneven charge

Why is water polar?

Oxygen is "greedy" and pulls negative electrons away from the Hydrogens.

Oxygen in water

Has a slightly NEGATIVE charge.

Hydrogen in water

Has a slightly POSITIVE charge.

Hydrogen Bond

The connection between the negative Oxygen of one water molecule and the positive Hydrogen of a DIFFERENT water molecule.

Cohesion

Water molecules stick to EACH OTHER (creates surface tension).

Adhesion

Water molecules stick to OTHER SURFACES (like a plant stem).

Universal Solvent

Water's polarity acts like a magnet to pull apart and dissolve other substances.

Temperature Buffer

Water takes a lot of energy to heat up or cool down, which keeps our body temperature stable.

Homeostasis

Keeps its internal environment stable and balanced.

Stimulus

A change in the environment that your body notices

Response

What your body does to fix the change

Negative Feedback Loop

REVERSES the change to bring the body back to normal. Stops the stimulus.

Negative Feedback Examples

Sweating when hot, shivering when cold, blood sugar control.

Positive Feedback Loop

INCREASES the change until a major event happens. Pushes body further from normal.

Positive Feedback Examples

Contractions during childbirth, blood clotting.

Dehydration Synthesis

BUILDS larger molecules from smaller ones by REMOVING a water molecule.

Hydrolysis

BREAKS large molecules into smaller ones by ADDING a water molecule.