Biology Chapter 2

Question 1

Element

Answer 1

A material that is matter, that is made up of only one type of atom (it cannot be broken down into any other type of atom.)

Question 2

Atom

Answer 2

Atoms are the smallest unit of matter that still retains the property of that element.

Question 3

pH

Answer 3

H stand for Hydrogen (don’t need this for the test)
The pH scale utilized in measuring the relative acidity or alkalinity of a solution. The scale, ranging from 0-14, quantifies the concentration of hydrogen ions in a solution. The lower the pH number, the more acid the solution; the higher the number, the more basic the solution.

Question 4

Atomic Weight

Answer 4

The average mass of atoms of an element, calculated using the relative abundance of isotopes in a naturally-occurring element. It is the weighted average of the masses of naturally-occurring isotopes.
Also Known As: Atomic Mass
Examples: The atomic mass of carbon is 12.011; the atomic mass of hydrogen is 1.0079

Question 5

Atomic Number

Answer 5

The number of protons in the nucleus of an atom. Gold has 79 protons in its nucleus and thus the atomic number is 79. All elements are ordered on the periodic table according to atomic number.

Question 6

Molecule

Answer 6

An entity consisting of defined number of atoms covalently bonded together in a defined spatial relationship.

Question 7

Base

Answer 7

Any substance that accepts hydrogen ions in solution. A base has a number higher that 7 on the pH scale.

Question 8

Proton

Answer 8

A base consistent of an atom, found in the nucleus of the atom and having positive electrical charge. Elements are defined by the number of protons in their nucleus.

Question 9

Neutron

Answer 9

One of three primarily constituents of an atom, processing no electrical charge and found in the atom’s nucleus. Isotopes are defined by the number of neutrons in an atom.

Question 10

Electron

Answer 10

With protons the neutrons, one os three basic constitutions of an atom. Electrons carry a negative electrical charge and are distributed in a atom at a distance from the nucleus.

Question 11

Ionic Bond

Answer 11

A linking in which two or more ions are bonded to each other by virtue of their opposite charge.

Question 12

Covalent Bond

Answer 12

A type of bond in which two or more atoms are linked through a sharing of electrons.

Question 13

Hydrophilic

Answer 13

The property, possessed by some compounds, of being to able to form chemical bounds with water molecules. Table salt (NaCI) is hydrophilic and this will readily dissolve in water.

Question 14

Acid

Answer 14

An acid is a chemical species that donates protons or hydrogen ions and/or accepts electrons.
Examples: Arrhenius acid, Lewis acid, hydrochloric acid

Question 15

Orbital

Answer 15

Electron cloud having an energy state described by given values of the n, ℓ, and mℓ quantum numbers. An orbital can contain two electrons with paired spins and is often associated with a specific region of an atom.
Examples: The electrons in the 2px orbital of an atom are generally found within a dumbbell-shaped cloud about the x-axis.

Question 16

Chemical Bond

Answer 16

General term for a bond created when electrons of two atoms interact and rearrange into a new form that allows the atoms to become attracted to each other. Ionic, covalent, and hydrogen bonds are all chemically bound.

Question 17

Ion

Answer 17

An atom or molecule which has gained or lost one or more of its valence electrons, giving it a net positive or negative electrical charge.
Examples: alpha particle He2+, hydroxide OH-

Question 18

Shell

Answer 18

An electron shell is a set of atomic electrons grouped together by their quantum energy levels.

Question 19

Solvent

Answer 19

The component of a solution that is present in the greatest amount. It is the substance in which the solute is dissolved.
Examples: The solvent for seawater is water. The solvent for air is nitrogen.

Question 20

Matter

Answer 20

Anything that occupies space and has mass.

Question 21

Hydrophobic

Answer 21

The property, prepossessed by some compounds, of being unable to form chemical bonds with water molecules. Oil of hydrophilic and this will not readily dissolve in water.

Question 22

Nonpolar Covalent Bond

Answer 22

A type of covalent bond in which electrons are shared equally between atoms.

Question 23

Polar Covalent Bond

Answer 23

A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. This causes the molecule to have a slight electrical dipole moment where one end is slightly positive and the other is slightly negative.

Polar bonds are the dividing line between pure covalent bonding and pure ionic bonding.

Question 24

Solute

Answer 24

The substance in which a solute is dissolved in water.

Question 25

Compound

Answer 25

A compound is a chemical species that is formed when two or more atoms join together chemically, with covalent or ionic bonds.

Question 26

Mixture

Answer 26

Two or more substances which have been combined such that each substance retains its own chemical identity.

Question 27

Solution

Answer 27

A homogeneous mixture of two or more substances. In Biology, solution often consists of a solute dissolved in water, which produces an aqueous solution.

Question 28

Salt

Answer 28

Sometimes 'salt' simply refers to table salt, which is sodium chloride. Usually the term is applied to an ionic compound produced by reacting an acid with a base.

Question 29

Buffer

Answer 29

A physiological system that functions to keep pH within normal limits in an organism. Buffering system generally utilized weak acids or bases to neutralize any sudden infusion of acid or base.

Question 30

Isotope

Answer 30

An Isotope has the same number of protons and electrons as the normal element, but a different number of neutrons.

Question 31

Radioisotope

Answer 31

Unstable isotopes that emits radiation energy.

Question 32

Why do we need to know some Chemistry in order to understand biology?

Answer 32

You can't have biology without chemistry. Biological organisms including just a single cell is basically a bag of chemical reactants. Everything that occurs in living organism is a chemical reaction.

Question 33

Describe the characteristics of the various subatomic particles that make up an atom. Draw a model of an atom with the various subatomic particles.

Answer 33

Particles that are smaller than the atom are called subatomic particles. The three main subatomic particles that form an atom are protons, neutrons, and electrons...

Question 34

What is an Isotope? What are radioisotopes? What are three different ways that they are used in biology (research or medicine)?

Answer 34

Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element. A radioactive isotope. 1. Archaeological Dating. Carbon-14 is often used to find the age of a substance many years old. 4. Pest Control: Some radioactive isotopes are used to control med flies in homes. 3. Smoke detectors: Americium is often used in smoke detectors because it is very sensitive to burning carbon dioxide.

Question 35

What are the three types of chemical bonds that can form between atoms and how are they formed? What type of bond forms between the hydrogen and oxygen atoms within a water molecule? What type of bond form between water molecules?

Answer 35

Ionic Bond, Covalent bond, Polar covalent bond. Covalent Bonds. Covalent Bonds.

Question 36

Describe the special properties of water are important biologically. What characteristics of water molecules allow these properties to exist?

Answer 36

Look Up

Question 37

Why are atoms like carbon and oxygen so highly reactive?

Answer 37

Because the are missing electrons.

Question 38

Describe the pH scale. How does it work (i.e. what ions are involved, how do the concentrations of these ions change as you go through the scale)? Give an example of a strong acid, a strong base, a weak acid, and a weak base.

Answer 38

it shows the acidic in things, where 7 is in the middle(water.) Strong, limn juice, weak, wate.

Question 39

What is a buffer? How do they work? Why are buffers important in living organisms?

Answer 39

Resistant to extreme changes in pH. Its like a bumper on a car, is protects the car from getting damaged. It breaks down the acidic in your stomach so the acidic wont break down your small intestine.