Mastering Biology 2

Front 1

An example of a stimulus that a plant would respond to is:

Back 1

Plants can respond only to certain stimuli in the environment, such as sunlight

Front 2

Which of the following things would be considered complex AND organized?

Back 2

red blood cell in the human body

Front 3

DNA is a molecule that directly allows a living thing to:

Back 3

store information.

Front 4

The process of homeostasis is:

Back 4

how organisms maintain a relatively constant internal environment.
Correct. Homeostasis is the maintenance of a relatively constant internal environment even in changing external environments.”

Front 5

Living systems need energy to:

Back 5

replace worn-out parts and build new parts.





help maintain a relatively constant internal environment.





grow larger.

Front 6

The complexity of living systems:

Back 6

is also highly organized.

Front 7

Identify a characteristic that is representative of some, but not all, life-forms.

Back 7

movement over great distances

Front 8

The innermost electron shell of an atom can hold up to _____ electrons.

Back 8

2 This is the maximum number of electrons that can occupy the innermost electron shell.

Front 9

Which of these relationships is true of an uncharged atom?

Back 9

The number of protons is equal to the number of electrons.
In this situation the number of positive charges is equal to the number of negative charges

Front 10

What determines the types of chemical reactions that an atom participates in?

Back 10

the number of electrons in the outermost electron shell

Front 11

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

Back 11

6 This is an atom of carbon, an element with 6 protons. Atomic number is the number of protons in an atom

Front 12

Which of these refers to atoms with the same atomic number but different atomic masses?

Back 12

These atoms are isotopes.
Atoms with the same atomic number and different atomic masses are referred to as isotopes.

Front 13

Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?

Back 13

10 Atomic mass is equal to the number of protons plus the number of neutrons (19-9 = 10).

Front 14

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?

Back 14

The atomic number is equal to the number of protons.

Front 15

What type of bond is joining the two hydrogen atoms?

Back 15

covalent
A covalent bond is one in which electron pairs are shared.

Front 16

A(n) _____ refers to two or more atoms held together by covalent bonds.

Back 16

molecule
A molecule is defined as two or more atoms held together by covalent bonds.

Front 17

This atom can form up to _____ single covalent bond(s).

Back 17

4

There are four electrons in the outermost electron shell.

Front 18

A(n) _____ bond joins these two oxygen atoms.

Back 18

double covalent
The oxygen atoms are sharing two pairs of electrons

Front 19

Atoms with the same number of protons but with different electrical charges _____.

Back 19

are different ions
Ions are charged atoms.

Front 20

In salt, what is the nature of the bond between sodium and chlorine?

Back 20

ionic
Sodium and chlorine ions are attracted to each other

Front 21

An ionic bond involves _____.

Back 21

an attraction between ions of opposite charge

Front 22

Each water molecule is joined to _____ other water molecules by ____ bonds.

Back 22

four ... hydrogen
As can be seen in the illustration on page 1 of the activity titled "The Polarity of Water" a water molecule is joined to four other water molecules by hydrogen bonds.

Front 23

The unequal sharing of electrons within a water molecule makes the water molecule _____.

Back 23

polar
The electrons spend more time with the oxygen of the water molecule than with the hydrogens of water. Thus, the oxygen has a net negative charge and the hydrogens have a net positive charge.

Front 24

The tendency of an atom to pull electrons toward itself is referred to as its _____.

Back 24

electronegativity

Front 25

In this molecule, what type of bond is found between the oxygen and hydrogens?

Back 25

polar covalent
While oxygen shares electrons with hydrogen, the electrons spend more time with the oxygen than with the hydrogens.

Front 26

Which bonds are weakest?

Back 26

Hydrogen Bonds are weaker than covalent bonds because they do not involve sharing of electrons, and they are weaker than ionic bonds because they involve the attraction of partial (not full) opposite charges.

Front 27

Why isn't this insect drowning?

Back 27

The high surface tension of water allows the insect to remain on the surface.

Front 28

What name is given to the bond between water molecules?

Back 28

hydrogen
A hydrogen atom with a net positive charge is attracted to an oxygen atom with a net negative charge

Front 29

In a neutral solution the concentration of _____.

Back 29

hydrogen ions is equal to the concentration of hydroxide ions

Front 30

What are an atoms subatomic particles?

Back 30

protons, neutrons and electrons

Front 31

6 CO2 + 6 H2OC6H12O6 + 6 O2 The equation shows a ______ that leads to the change in composition in matter

Back 31

chemical reaction

Front 32

6 CO2 + 6 H2OC6H12O6 + 6 O2
In the equation, CO2 is the____

Back 32

reactant

Front 33

6 CO2 + 6 H2OC6H12O6 + 6 O2
In the equation C6H12O6 is the ______

Back 33

product

Front 34

6 CO2 + 6 H2OC6H12O6 + 6 O2
In O2 the type of bond that holds the oxygen together is _______

Back 34

a non-polar covalent bond

Front 35

Four elements combine to make about 96% of the mass of the human body. Which of the following elements is one of the four?

Back 35

Carbon atoms serve as the backbone for all biological molecules. The four elements that make up over 96% of the mass of a human body are hydrogen, oxygen, nitrogen, and carbon

Front 36

In an atom with a neutral overall charge, the number of protons is equal to the _________.

Back 36

number of electrons
Each electron has a negative charge and each proton has a positive charge. Thus, in a neutral atom, the number of electrons is equal to the number of protons.

Front 37

The simplest unit of matter that still retains the properties of an element is a(n) _____.

Back 37

atom

Front 38

Substances that contain two or more elements in a fixed ratio are called _____.

Back 38

compounds
When elements combine in fixed ratios and are joined together by chemical bonds, they form compounds. On Earth, compounds are much more common than elements.

Front 39

Carbon-12 and carbon-13 are different in the number of their _____.

Back 39

neutrons
Carbon-12 and carbon-13 are isotopes. Isotopes differ only in the number of their neutrons.

Front 40

What is the term for atoms that are electrically charged as a result of gaining or losing electrons?

Back 40

ion Ions are atoms that are electrically charged as a result of gaining or losing electrons

Front 41

Which of these is a type of chemical bond that involves the sharing of electrons?

Back 41

covalent Covalent bonds involve sharing a pair of electrons.

Front 42

What type of bond joins neighboring water molecules?

Back 42

Hydrogen bonds form weak attractions between neighboring water molecules.

Front 43

The four most common elements found in living things are

Back 43

carbon, oxygen, nitrogen, and hydrogen

Front 44

An atom with a positive charge has ______.

Back 44

more protons than electrons

Front 45

An uncharged atom of gold has an atomic number of 79 and an atomic mass of 197. This atom has ______ protons, ______ neutrons, and ______ electrons.

Back 45

79... 118... 79

Front 46

How do radioactive isotopes differ from isotopes?

Back 46

Radioactive isotopes are unstable; isotopes are stable.

Front 47

The second electron shell of an atom can hold a maximum of ______ electron(s).

Back 47

8

Front 48

Nitrogen has an atomic number of 7; therefore, it has ______ electrons in its outermost electron shell.

Back 48

5

Front 49

The bond between oppositely charged ions is a(n) ______ bond.

Back 49

ionic

Front 50

What name is given to bonds that involve the sharing of electrons?

Back 50

covalent

Front 51

Why is water considered a polar molecule?

Back 51

The oxygen end of the molecule has a slight negative charge, and the hydrogen end has a slight positive charge.

Front 52

Adjacent water molecules are joined by ______ bonds.

Back 52

hydrogen

Front 53

Relative to a pH of 6, a pH of 4 has a ______.

Back 53

100 times higher H+ concentration