Biology 1301 Midterm
About 25 of the 92 natural elements are essential to life. Which 4 of these 25 elements
make up approximately 96% of living matter? - ANS-carbon, hydrogen, nitrogen, and
oxygen
Atoms that vary in the number of neutrons found in the nuclei are called - ANS-isotopes
Why is each element unique and different from other elements with respect to its
chemical properties? - ANS-Each element has a unique number of protons
Carbon-12 is the most common elemental form of carbon and has mass number of 12.
However, the atomic mass of carbon can also be 13 & 14 daltons. Why? - ANS-Some
carbon atoms in nature have more neutrons
When an acid like HCl is added to a solution, the pH should - ANS-increase
In general, which of these bonds in the weakest - ANS-hydrogen
Each carbon molecule can bond with how many hydrogen atoms - ANS-4
A suggested and testable explanation for an event is called a - ANS-hypothesis
The smallest unit of biological structure that meets the functional requirements for
"living" is a - ANS-cell
A group of individuals of the same species living in the same area such as the crickets
in your backyard or the students in this room is called a - ANS-population
A covalent bond is one in which - ANS-outer-shell electrons of two atoms are shared so
as to satisfactorily fill the outer electron shell of both atoms
What results from an unequal sharing of electrons between atoms, such as found in
H2O? - ANS-a polar covalent bond
Liquid water's high specific heat is mainly a consequence of the - ANS-absorption and
release of heat when hydrogen bonds release and form
, Why does ice float in liquid water? - ANS-Hydrogen bonds stabilize and keep the
molecules of the ice farther apart than the water molecules of liquid water
One of the buffers that contributes to pH stability of human blood is carbonic acid
(H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-)
and a hydrogen ion (H+).
Thus, H2CO3<---> HCO3- + H+
If the pH of the blood drops becoming more acidic, one would expect - ANS-the HCO3-
to act as a base and remove excess H+ with the formation of H2CO3-.
The study of plants is called - ANS-botany
The attraction of water molecules to other polar substances such as that of cellulose in
paper towels or a cotton towel is known as - ANS-adhesion
In the molecule of CO2 there is an equal sharing of electrons between the 'C' and 'O'
molecules, thus the bond that forms is known as a - ANS-non-polar covalent bond
Explain what a theory is - ANS-A tested and confirmed explanation of observations or
phenomena (ex: theory of gravity)
Explain what the octet rule is and how it applies to chemical bonds - ANS-Inner most
orbital shell has a maximum of 2 electrons but the next two shells can have 8 electrons.
Atoms either share (covalent bonds) or gain/lose electrons to fill 8 electrons in the
orbital shell
The element present in all organic molecules is - ANS-carbon
Which two functional groups are always found in amino acids? - ANS-carboxyl and
amino
Which of the following is not a polymer? - ANS-glucose
What is the chemical reaction mechanism by which cells make polymers from
monomers? - ANS-dehydration reactions
Which of the following is true of both starch and cellulose? - ANS-They are both
polymers of glucose
About 25 of the 92 natural elements are essential to life. Which 4 of these 25 elements
make up approximately 96% of living matter? - ANS-carbon, hydrogen, nitrogen, and
oxygen
Atoms that vary in the number of neutrons found in the nuclei are called - ANS-isotopes
Why is each element unique and different from other elements with respect to its
chemical properties? - ANS-Each element has a unique number of protons
Carbon-12 is the most common elemental form of carbon and has mass number of 12.
However, the atomic mass of carbon can also be 13 & 14 daltons. Why? - ANS-Some
carbon atoms in nature have more neutrons
When an acid like HCl is added to a solution, the pH should - ANS-increase
In general, which of these bonds in the weakest - ANS-hydrogen
Each carbon molecule can bond with how many hydrogen atoms - ANS-4
A suggested and testable explanation for an event is called a - ANS-hypothesis
The smallest unit of biological structure that meets the functional requirements for
"living" is a - ANS-cell
A group of individuals of the same species living in the same area such as the crickets
in your backyard or the students in this room is called a - ANS-population
A covalent bond is one in which - ANS-outer-shell electrons of two atoms are shared so
as to satisfactorily fill the outer electron shell of both atoms
What results from an unequal sharing of electrons between atoms, such as found in
H2O? - ANS-a polar covalent bond
Liquid water's high specific heat is mainly a consequence of the - ANS-absorption and
release of heat when hydrogen bonds release and form
, Why does ice float in liquid water? - ANS-Hydrogen bonds stabilize and keep the
molecules of the ice farther apart than the water molecules of liquid water
One of the buffers that contributes to pH stability of human blood is carbonic acid
(H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-)
and a hydrogen ion (H+).
Thus, H2CO3<---> HCO3- + H+
If the pH of the blood drops becoming more acidic, one would expect - ANS-the HCO3-
to act as a base and remove excess H+ with the formation of H2CO3-.
The study of plants is called - ANS-botany
The attraction of water molecules to other polar substances such as that of cellulose in
paper towels or a cotton towel is known as - ANS-adhesion
In the molecule of CO2 there is an equal sharing of electrons between the 'C' and 'O'
molecules, thus the bond that forms is known as a - ANS-non-polar covalent bond
Explain what a theory is - ANS-A tested and confirmed explanation of observations or
phenomena (ex: theory of gravity)
Explain what the octet rule is and how it applies to chemical bonds - ANS-Inner most
orbital shell has a maximum of 2 electrons but the next two shells can have 8 electrons.
Atoms either share (covalent bonds) or gain/lose electrons to fill 8 electrons in the
orbital shell
The element present in all organic molecules is - ANS-carbon
Which two functional groups are always found in amino acids? - ANS-carboxyl and
amino
Which of the following is not a polymer? - ANS-glucose
What is the chemical reaction mechanism by which cells make polymers from
monomers? - ANS-dehydration reactions
Which of the following is true of both starch and cellulose? - ANS-They are both
polymers of glucose
