Biochemistry

Question 1

matter

Answer 1

anything that takes up space and has mass.

Question 2

element

Answer 2

a substance that cannot be broken down into other substances by chemical reactions. There are 92 of these found in nature. gold, copper, carbon, and oxygen are all examples.

Question 3

compound

Answer 3

a substance consisting of two or more different elements combined in a fixed ratio. Examples include sodium chloride (NaCl), and water (H2O).

Question 4

essential elements

Answer 4

elements an organism needs to live a healthy life and reproduce easily. These elements may vary by domain.

Question 5

Trace elements

Answer 5

elements required by an organism is minute (very small) quantities

Question 6

Toxic Elements

Answer 6

Some elements are toxic to organisms. One example is arsenic being very toxic to humans.

Question 7

Atom

Answer 7

the smallest unit of matter that still retains the properties of an element.

Question 8

subatomic particles

Answer 8

particles of matter that makeup atoms, each with a specific role.

Question 9

neutrons

Answer 9

a subatomic particle with a neutral charge (or no charge). These particles are found in the nucleus of the atom. These particles are approximately one dalton in mass.

Question 10

proton

Answer 10

a subatomic particle with a positive charge. These particles are found in the nucleus of the atom. These particles are approximately one dalton in mass.

Question 11

electron

Answer 11

a subatomic particle with a negative charge. These particles are found surrounding the nucleus. These particles have a mass that is approximately 1/2000 of a dalton.

Question 12

Atomic nucleus

Answer 12

a dense core at the center of the atom packed with protons and neutrons.

Question 13

dalton

Answer 13

a unit of measurement equal to one atomic mass unit.

Question 14

atomic number

Answer 14

The number of protons found in an element. This number is unique to each specific element. Written as a subscript to the left of the symbol for the element.

Question 15

mass number

Answer 15

In daltons, the sum of the number of protons and neutrons in the nucleus of the atom. This number can be given in daltons or atomic mass units (amu). Subtracting the atomic number from this number allows the number of neutrons to be deduced. This number is written as a superscript to the left of the element’s symbol. This number is an approximation of the total mass of the atom.

Question 16

Isotopes

Answer 16

Atoms of an element which have a different number of neutrons, thus having a different atomic mass or mass number. Carbon-14 is one example.

Question 17

radioactive isotope

Answer 17

an isotope which is unstable or radioactive. The nucleus of these isotopes decays spontaneously, giving off particles and energy.

Question 18

radioactive tracers

Answer 18

radioactive isotopes can be used to follow atoms through the process of metabolism.

Question 19

Energy

Answer 19

the capacity to cause change (normally by doing work.)

Question 20

potential energy

Answer 20

is the energy that matter possesses because of its location or structure.

Question 21

Electron shells

Answer 21

An electron’s energy level is correlated with its average distance from the nucleus. Each shell has a characteristic average distance and energy level.

Question 22

Valence Electrons

Answer 22

the electrons found in the outermost shell of the atom. The number of these electrons determines the behavior of the atom.

Question 23

ion

Answer 23

an atom or molecule with an electric charge

Question 24

cation

Answer 24

an ion with a positive charge

Question 25

anion

Answer 25

an ion with a negative charge

Question 26

ionic bond

Answer 26

the attraction between cations and anions

Question 27

Hydrogen bonds

Answer 27

a noncovalent attraction between a hydrogen atom and an electronegative atom.

Question 28

Van der Waals Interactions

Answer 28

individually weak attractions that occur only when atoms and molecules are very close to each other.

Question 29

chemical equilibrium

Answer 29

when two chemical reactions offset one another equally.

Question 30

polar molecule

Answer 30

a molecule in which there is an unequal sharing of electrons.

Question 31

cohesion

Answer 31

when water molecules attract to one another

Question 32

adhesion

Answer 32

when water molecules attract to