Ap Bio Chapters 1-3

Front 1

Evaluate the following statement: Oxygen is not a greenhouse gas; therefore, gases containing oxygen, such as ozone, nitrous oxide, and carbon dioxide, are not greenhouse gases either

Back 1

Emergent properties of compounds are more than simply the sum of their parts.

Front 2

There are _____ naturally occurring elements

Back 2

There are 92 naturally occurring elements, and about 25 of these are essential to life.

Front 3

What is an example of a trace element?

Back 3

Copper (Cu) is a trace element. Copper accounts for less than 0.01% of living matter.

Front 4

What are the four most abundant elements found in living systems?

Back 4

hydrogen, oxygen, nitrogen, and carbon
These four elements make up about 96% of living matter

Front 5

Which of the following has negligible mass?

Back 5

electron, because the mass of an electron is only about 1/2,000 that of a proton or neutron, electrons are not considered when computing atomic mass.

Front 6

Which of the following subatomic particles has appreciable mass and lacks a charge?

Back 6

neutron, A neutron weighs about 1.7 x 10-24 grams (has a mass close to 1 dalton), and it is electrically neutral.

Front 7

The number of protons in an uncharged atom _____.

Back 7

equals the number of electrons

(The number of neutrons determines the isotope, not the number of protons. For example, the different isotopes of an element would have different numbers of neutrons, but each of the different isotopes would have the same number of protons and electrons.)

Front 8

Consider a hypothetical atom with an atomic number of 4 and a net electronic charge of +1. How many neutrons does this atom have?

Back 8

The answer cannot be determined from the information provided.
All the atoms of an element have the same number of protons, but some atoms have different numbers of neutrons than other atoms of the same element; therefore, the atoms have different mass numbers. Without the mass number (number of protons + neutrons), it is not possible to determine the number of neutrons.

Front 9

An uncharged atom of nitrogen (atomic number = 7) has _____.

Back 9

seven protons and seven electrons

Front 10

Isotopes of an element will always differ in _____.

Back 10

atomic mass
Atomic mass refers to the number of protons and neutrons in an atom. Atomic forms of an element with the same number of protons (atomic number) but different numbers of neutrons are isotopes of that element.

Front 11

A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective number of neutrons, protons, and electrons that this carbon isotope has is _____.

Back 11

8, 6, and 6
The atomic number, 6, is equal to the number of protons. Therefore, the number of electrons in an electrically neutral atom would also be 6. The number of neutrons must be 8 because the atomic mass is 14 (14 - 6 = 8).

Front 12

The most common form of calcium has 20 protons, 20 neutrons, and 20 electrons. Which of the following elements would be an isotope of calcium?

Back 12

an atom with 20 protons, 21 neutrons, and 20 electrons

Front 13

Phosphorus-32 (radioactive) has _____ than phosphorus-35 (normal).

Back 13

three fewer neutrons
The numbers 32 and 35 refer to mass number (number of protons plus neutrons). All the atoms of the same element have the same number of protons, but different isotopes of the same element have different numbers of neutrons. Because 35 - 32 = 3, P-32 has three fewer neutrons than P-35.

Front 14

Radioactive isotopes are useful in scientific research because _____.

Back 14

they can be used as tracers to follow particular atoms and molecules through metabolic pathways.
Because they are detectable in very small amounts, a few labeled molecules can be traced through an organism's body to see how they are used.

Front 15

Potassium (atomic number 19, mass number 40) and sodium (atomic number 11, mass number 23) have similar chemical properties and reactive behavior. This is because uncharged atoms of potassium and sodium _____.

Back 15

have different mass numbers and each has one electron in its outermost electron shell
Although potassium has 19 electrons and sodium has 11 electrons, each has only one electron in its outermost electron shell.

Front 16

The chemical characteristics or reactivity of an element depend mostly on the _____.

Back 16

number of electrons in its outermost shell
Only electrons are directly involved in the interactions between atoms, and the number of electrons in the outermost shell determines the chemical behavior or reactivity of an atom.

Front 17

Some groups of elements react chemically in similar ways. For example, the chemistry of sodium and the chemistry of lithium are similar. The chemistry of chlorine and the chemistry of iodine are also similar. These similarities in chemistry result when different elements have similar _____.

Back 17

numbers of outer-shell electrons

Front 18

How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)?

Back 18

six electrons

Front 19

For most atoms, a stable configuration of electrons is attained when the atom _____.

Back 19

has eight electrons in its outermost shell

Front 20

An atom that normally has _____ in its outer shell would not tend to form chemical bonds with other atoms.

Back 20

eight electrons
Eight electrons will leave no unpaired electrons in the valence shell. In this configuration atoms are chemically unreactive or inert.

Front 21

A sodium atom has a mass number of 23. Its atomic number is 11. How many electrons does it have if it is not an ion?

Back 21

11
The number of electrons will equal the number of protons in an electrically neutral atom.

Front 22

When the proton number and electron number are unequal, the atom or molecule _____.

Back 22

is an ion
When the proton number and electron number are unequal, the atom or molecule has a net positive (cation) or negative charge (anion).

Front 23

A covalent bond is likely to be polar if _____.

Back 23

one of the atoms sharing electrons is much more electronegative

Front 24

A polar covalent bond is a bond that _____.

Back 24

has shared electrons pulled closer to the more electronegative atom

Polar covalent bonds share electrons unequally, so that one part of the molecule has a partial negative region and one part a partial positive region.

Front 25

When one or more pairs of valence electrons are shared by two neutral atoms, what type of bond is formed?

Back 25

a covalent bond
Covalent bonds are formed between atoms that share one or more pairs of valence electrons.

Front 26

Copper has an atomic number of 29 and a mass number of 64. What would result if an uncharged copper atom lost two electrons?

Back 26

The atomic number would remain 29, the mass number would remain 64, and the atom would be a cation with a +2 charge.

Front 27

The compound CaSO4 ionizes into a calcium ion and a sulfate ion (SO4). Calcium has two electrons in its outer shell. Upon ionization, what would you expect the charge on the sulfate ion to be?

Back 27

-2

Front 28

Ionic bonds form as a result of _____.

Back 28

attraction between ions that have opposite charges
Oppositely charged ions attract each other electrically, forming an ionic bond.

Front 29

A hydrogen bond _____.

Back 29

is a weak chemical bond
-In a hydrogen bond the hydrogen has a partial positive charge.

Front 30

What is the role of van der Waals interactions in biological molecules?

Back 30

Although they are weak bonds, van der Waals interactions help to reinforce the three-dimensional shapes of large molecules.

Front 31

What is an example of a molecule that has the shape of a completed tetrahedron?

Back 31

methane (CH4)
-Molecules containing multiple carbon atoms have more complex overall shapes. (so it couldn't be glucose C6H12O6)

Front 32

Pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for this type of application?

Back 32

the molecule's shape

Front 33

A statement true about chemical reactions?

Back 33

They involve the making and breaking of chemical bonds.

Front 34

Describe a reversible reaction that has reached chemical equilibrium?

Back 34

The rate of the reverse reaction equals the rate of the forward reaction.

Front 35

Cells are surrounded by water, and cells themselves consist of about 70 to 95% water. As a result, _____.

Back 35

#35

Front 36

Water is a polar molecule. This means that _____.

Back 36

the opposite ends of the molecule have opposite electrical charges
When equally electronegative atoms bond, the electrons are shared equally between them, forming a nonpolar bond.

Front 37

The partial charges on a water molecule occur because of _____.

Back 37

the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule