anp ch2 (copy)

ch2 assessment

Which of the following statements accurately describes electrons?

They are in orbitals outside the nucleus and have a negative charge.

Two atoms that differ only in the number of neutrons they contain are known as

isotopes.

An ion is an atom or group of atoms that has

\
lost or gained an electron.

When elements found in column VIA of the periodic table become ions, they usually have a charge of

–2.

MgCl2 fully dissociates into Mg2+ and Cl- ions when mixed with water. Therefore, the bonds between Mg2+ and Cl- in MgCl2 can be described as

ionic.

In the formation of an ionic bond between Na and Cl to form common table salt, sodium (Na) _____ an electron and chlorine (Cl) _____ an electron.

loses; gains

A double covalent bond involves

the sharing of two pairs of electrons.

C6H12O6 is an example of a ______ formula.

\
molecular

Hydrogen bonds form between molecules containing _________ bonds; the hydrogen bond is between a hydrogen atom of one molecule and a partially _________ charged atom of another.

polar covalent; negatively

Chemical barriers composed of phospholipid bilayers form within biological systems because

hydrophobic exclusion results in the close positioning of the nonpolar tails.

In a water molecule, each oxygen can form up to _____ hydrogen bonds with other water molecules.

2

Compared to a solution with a pH of 7, a solution with a pH of 4 is

more acidic and has a 1,000-fold increase in \[H+\].

To neutralize a base, a(n) ________ must be added.

acid

When a protein of 50 nanometers is mixed with water, the opaque result is called a(n)

colloid.

Given that the mass of an oxygen atom is 16 amu and that of a hydrogen atom is 1 amu, 1 mole of water would be equal to

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18 grams.

ATP is a nucleotide that is composed of

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adenine, ribose, and three covalently bonded phosphate groups.

Like most functional groups, carboxyl groups are

polar and therefore increase a biomolecule's solubility in water.

A protein consists of

more than 200 amino acids.

The first amino acid put in place when a protein is being synthesized at a ribosome is

methionine.

Amino acids such as alanine contain hydrocarbons as side groups, and these amino acids engage in hydrophobic interactions with each other. Such amino acids are

nonpolar.

An element's atomic number is determined by the number of __________ in one atom of that element.

protons

Which of the following has the smallest mass?

An electron

Ionic bonds involve

electrostatic interactions between anions and cations.

Fatty acids in soap have a polar end and a nonpolar end. Which of the following best describes these molecules?

Amphipathic

Water contains two hydrogen atoms bound to one oxygen atom; "H2O" is therefore water's

molecular formula

What is the number of covalent bonds that an atom of nitrogen can form within a molecule?

3

The hydrogen bonds in a sample of water result in ________ cohesion and a _____ heat of vaporization.

increased; high

A technician is asked to make up a solution of physiological saline and is told that it should be a 0.9% NaCl solution using the mass/volume percent measurement of concentration.  If the technician is making 100 milliliters of solution, how much NaCl should be included?

0\.9 grams

The most common lipids in the body are

triglycerides, and they are used for energy storage in adipose.

Which list contains all four types of amino acids?

Charged, polar, nonpolar, and those with special functions

When two or more polypeptide chains come together to give a protein its ultimate shape, that structure is described as the _________ structure.

quaternary