THE PRINCIPLES OF BIOLOGY EXAM
1 QUESTIONS WITH COMPLETE
ANSWERS
Which one is in orbit? - ANSWER-Electrons orbit a tightly packed nucleus of protons
and neutrons
What is an element and how is it defined? - ANSWER-An element (a kind of atom) is
a pure substance that cannot be reduced to any simpler set of other substances. An
element is defined by its number of protons which is referred to as its atomic number
What is an isotope? - ANSWER-An isotope is an element that has a different number
of neutrons
-Are the same element with different numbers of neutrons but the same number of
protons
What is the most common element that has three isotopes? - ANSWER-Hydrogen
How many protons and neutrons are there in carbon? - ANSWER-In its basic state,
carbon has 6 protons and 6 neutrons but carbon also has isotopes (added neutrons)
carbon-13, and carbon-14, is a radioactive isotope (carbon dating). Carbon 12 is the
most common one.
Carbon Isotopes
1. C12 (most common, and most stable)
2. C13
3. C14
What is Ion? - ANSWER-An atom with a charge
What are three kinds of chemical bonds? - ANSWER-1. Covalent-Two atoms come
together (they share outer electrons)
2. Ionic- Attraction between Ions (they give outer electrons away or receive them)
3. Hydorgen-Attraction between polar molecules
Define the one that is the strongest and most common - ANSWER-The covalent
bond
All atoms bond with other atoms in order to fill... - ANSWER-Outer orbital, they do
this to create the most stable state, and fill outer orbital first. This is a basic fact
about chemical reactions.
What is the maximum for all orbitals except the first? - ANSWER-The first is 2, then
the rest are 8
-The pattern/rule, lowest orbital first because they have the least amount of distance
and energy
, Define a molecule and give an example - ANSWER-Molecules are atoms with
chemicals bonds bounded together in a specific ratio like H20 and C02 which are
chemical formulas. Water would be an example this.
Define a polar molecule and give in example - ANSWER-A polar molecule is where
the bonding structure is not symmetrical. Water would be an example because the
charge is distributed asymmetrically (unevenly) so there will be negative charge on
one end and a positive charge on the other. (resulting in a zero charge overall)
What is an ion, and an ionic bond? - ANSWER-An atom where the number of
electrons does not equal the number of protons.
Anion-negative charge
Cation-postive charge
Ionic bond-Two ions are attracted to each other (and they are giving or receiving
electrons)
Define the weakest bond - ANSWER-Hydrogen Bond-Because the slightly positive
hydrogen end of a polar molecule bonds weakly with the slightly negative end of a
water molecule
What two things make up a solution? - ANSWER-1. Solute
2. Solvent
Example-Saltwater salt is the solute (dissolves) and water is the solvent (does the
dissolving)
What is heavy water? - ANSWER-Known as deuterium oxide. The hydrogen atom in
the water molecule is replaced by a deuterium atom which is simply a hydrogen
isotope (one proton, one electron, one neutron). Heavy water has a higher freezing
and boiling point than regular water. The addition of the neutron is what causes the
water to be "heavier".
Why is water such a good solvent? - ANSWER-It's a polar molecule pulling apart
other molecules by surrounding them and pulling them apart
Why does ice float? - ANSWER-It expands when it freezes (about 5%). Its density
lowers because its volume grows.
Mass divided by Volume= Density
-It does this because the bonds can't break apart anymore so they "lock" together
Good for the ecosystem:
-Ice floats and freezes from the top down therefore not killing the wildlife underneath
also creating a layer of insolation
-It also seeps into rocks and break them apart so it helps with erosion
Give two other characteristics of water - ANSWER-1. It has a great heat capacity to
absorb and retain heat
-moderates climate
-takes longer to heat because you are having to break apart its bonds
2. It has great cohesion which allows it to have surface tension
-It sticks together
1 QUESTIONS WITH COMPLETE
ANSWERS
Which one is in orbit? - ANSWER-Electrons orbit a tightly packed nucleus of protons
and neutrons
What is an element and how is it defined? - ANSWER-An element (a kind of atom) is
a pure substance that cannot be reduced to any simpler set of other substances. An
element is defined by its number of protons which is referred to as its atomic number
What is an isotope? - ANSWER-An isotope is an element that has a different number
of neutrons
-Are the same element with different numbers of neutrons but the same number of
protons
What is the most common element that has three isotopes? - ANSWER-Hydrogen
How many protons and neutrons are there in carbon? - ANSWER-In its basic state,
carbon has 6 protons and 6 neutrons but carbon also has isotopes (added neutrons)
carbon-13, and carbon-14, is a radioactive isotope (carbon dating). Carbon 12 is the
most common one.
Carbon Isotopes
1. C12 (most common, and most stable)
2. C13
3. C14
What is Ion? - ANSWER-An atom with a charge
What are three kinds of chemical bonds? - ANSWER-1. Covalent-Two atoms come
together (they share outer electrons)
2. Ionic- Attraction between Ions (they give outer electrons away or receive them)
3. Hydorgen-Attraction between polar molecules
Define the one that is the strongest and most common - ANSWER-The covalent
bond
All atoms bond with other atoms in order to fill... - ANSWER-Outer orbital, they do
this to create the most stable state, and fill outer orbital first. This is a basic fact
about chemical reactions.
What is the maximum for all orbitals except the first? - ANSWER-The first is 2, then
the rest are 8
-The pattern/rule, lowest orbital first because they have the least amount of distance
and energy
, Define a molecule and give an example - ANSWER-Molecules are atoms with
chemicals bonds bounded together in a specific ratio like H20 and C02 which are
chemical formulas. Water would be an example this.
Define a polar molecule and give in example - ANSWER-A polar molecule is where
the bonding structure is not symmetrical. Water would be an example because the
charge is distributed asymmetrically (unevenly) so there will be negative charge on
one end and a positive charge on the other. (resulting in a zero charge overall)
What is an ion, and an ionic bond? - ANSWER-An atom where the number of
electrons does not equal the number of protons.
Anion-negative charge
Cation-postive charge
Ionic bond-Two ions are attracted to each other (and they are giving or receiving
electrons)
Define the weakest bond - ANSWER-Hydrogen Bond-Because the slightly positive
hydrogen end of a polar molecule bonds weakly with the slightly negative end of a
water molecule
What two things make up a solution? - ANSWER-1. Solute
2. Solvent
Example-Saltwater salt is the solute (dissolves) and water is the solvent (does the
dissolving)
What is heavy water? - ANSWER-Known as deuterium oxide. The hydrogen atom in
the water molecule is replaced by a deuterium atom which is simply a hydrogen
isotope (one proton, one electron, one neutron). Heavy water has a higher freezing
and boiling point than regular water. The addition of the neutron is what causes the
water to be "heavier".
Why is water such a good solvent? - ANSWER-It's a polar molecule pulling apart
other molecules by surrounding them and pulling them apart
Why does ice float? - ANSWER-It expands when it freezes (about 5%). Its density
lowers because its volume grows.
Mass divided by Volume= Density
-It does this because the bonds can't break apart anymore so they "lock" together
Good for the ecosystem:
-Ice floats and freezes from the top down therefore not killing the wildlife underneath
also creating a layer of insolation
-It also seeps into rocks and break them apart so it helps with erosion
Give two other characteristics of water - ANSWER-1. It has a great heat capacity to
absorb and retain heat
-moderates climate
-takes longer to heat because you are having to break apart its bonds
2. It has great cohesion which allows it to have surface tension
-It sticks together
