AP Bio: Biochemistry

Where are valence electrons found?

In the outermost orbital of an atom.

How many electrons do most elements what?

8 electrons

What is an ion?

A non-neutral atom.

What charge do most atoms have?

Neutral charge because the # of electron = # of protons.

What are the main elements of life?

CHON

What is the main source of biomass in ecosystems?

Carbon

Carbon is used to produce every what?

Biomolecule

Organisms utilize nitrogen to produce what?

Proteins and nucleic acids

Phosphorus is used to build what?

Nucleic acids and certain types of phospholipids

Electronegativity

The measurement of how strongly atoms attract binding/valence electrons to themselves.

What is electronegativity determined by?

How many electrons are in the valence shell

The closer to eight electrons an element has…

The more electronegative the element is.

What are the most electronegative elements?

Fluorine, oxygen, and nitrogen.

Electropositivity

A measurement of the ability of elements to donate electrons and form positive ions.

How many electrons do electropositive elements have in their valence shells?

1 or 2 electrons

Hydrogen bonds

Weak attraction between a hydrogen bonded to an oxygen, nitrogen, or fluorine and another O, N, or F atoms.

Why can hydrogen bonds only occur withO, N, and F?

Because they are very electronegative, attracting to

Covalent bonds

Occurs when two atoms share electrons.

Ionic bonds

Transfer of valence electrons from a metal to a non-metal.

Polar molecules

Occurs when there is unequal sharing of electrons across a covalent bond.

What causes a polar molecule to occur?

When a very electronegative element is bonded to a very small or electropositive element.

What charge do polar bonds have?

Overall neutral charge, but ALSO have partially positive and negative charges on the poles.

What determines the functions of a molecule?

The structure, shape, and chemical properties.

Energy that appears as lost was probably…

Given off as heat.