Honors bio chapter one

how many elements exist naturally?

92

how many elements are essential for human life?

20-25

Compound

Substance formed when atoms of two or more different elements bonded into a fixed ratio

Molecules

made up of two or more atoms bonded together, which can. Be of the same OR different elements.`

What are the six most prominent elements found in the human body?

Carbon, Hydrogen, Nitrogen, Oxygen, Calcium, and Phosphorus

trace element

elements that are uncommon in your body but still necessary to function.

iodine

trace element that is needed in a hormone produced by the thyroid; a deficiency can lead to a swollen thyroid or pregnancy miscarriage.

fluoride

Trace element that is added to water supplies to help reduce the formation of cavities

atom

basic unit of a chemical element and the small building blocks that make up all matter.

proton

positively charged particle that defines the element, found in the nucleus, 1 AMU

neutron

no charge, found in nucleus, 1 AMU

electron

negative charge, found on electron shells, no mass

orbit

the fixed circular paths of an electron around the nucleus of an atom.

valence electron

An electron found in an atoms, outermost shell/orbit; these electrons are involved in forming chemical bonds with other atoms

Unicellular

made up of one cell

multicellular

made up of multiple cells

Homeostasis

is the self-regulating process by which an organism maintains a stable internal environment despite external changes. Element of a living thing

uses/needs energy

This is an element of a living thing; most living thins eat food to get this or sleep

DNA/genetic code.

The element of a living thing that is a genetic code that defines the features of something

evolution

Adapts to its surroundings over time, living thing

Reproduces

Can create more of the species, usually with a male and a female, living thing

grows and develops

develops tools and wit to navigate life, living thin

responds to environment

responds to the things around them to benefit off if it, living thing

Isotope

An atom of the same element that has different amounts or neutrons.

Radioactive isotope

This is an element that has a nucleus that decays spontaneously, which can damage molecules in cells, but also can help us date fossils or use as tracers in medicine.

Valence electron

These electrons are found on the outer shell of an atom, and they are what is involved in bonding.

Covalent bond

In this type of bond, electrons are shared between two elements. It occurs between two nonmetals (hydrogen and hydrogen.) this is the strongest bond

Ionic bond

In this type of bond, electrons are transferred between elements. It occurs between a metal and a nonmetal ( salt, NaCl)

Hydrogen bond

In this type of bond, Hydrogen bonds with Oxygen, nitrogen, fluorine, chlorine, sulfur, or carbon. (H2O/water). This bond is possible when the positively charged end of one polar molecule bonds to the negatively charged end of the other one. This is always hydrogen because it is left with a positive charge. This is the weakest bond.

Polar covalent bond

Hydrogen bonds are this. Forms when atoms are unevenly shared, resulting in charged molecules

Nonpolar covalent bonds

These form when electrons are shared equally.

Cohesion

Intermolecular force between like molecules (water)

Capillary action

The process of liquid flowing in a narrow space without the help of an outside force like gravity.

Adhesion

The attractive force that causes two substances to bond to each other.

Surface tension

Caused by cohesion, lack of pull from molecules above the surface causes the surface to have a strong inward pull toward the middle of the liquid, tightening the surface.

Why is ice less dense than water?

Hydrogen bonding pushes the molecules further apart

Why does water moderate bodily temperatures in living creatures

Due to the high numbers of hydrogen bonds that form, water is able to resist drastic changes in temperature

Positive side of water

The side with the two hydrogens

Negative side of water

The side with just oxygen

Neutral on the pH scale

7

Base

8+ pH

Acid

1-6.99 pH