Fundamental Macromolecules and Concepts
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Biochemistry › Fundamental Macromolecules and Concepts
Which of the following statements about water is incorrect?
Because of hydrogen bonding, water has a low heat of vaporization.
Water has a tetrahedral structure when considering lone pairs and a bent molecular structure when not considering lone pairs.
Water has the potential to form a maximum of 4 hydrogen bonds.
Ice is a hexagonally packed network of water molecules and is less dense than water.
Explanation
Because of hydrogen bonding, water has a low high heat of vaporization. In other words, it takes more energy to free up water molecules from a hydrogen-bonded liquid state to a gaseous state.
What percentage of the human body is composed of interstitial water?
15%
5%
65%
60%
90%
Explanation
Interstitial water is the fluid on the outside of cells, and surrounds the cells of the human body. While estimates vary, the best answer is that 15% of the entire human body is composed of interstitial water. Overall, about 60% of the body (42L) is composed of water. Additionally, about two-thirds of the total body water is intracellular water. Finally, about 5% of the entire body is composed of plasma.
Remember that these percentages are estimates, and vary by individual. Sex and muscle mass are two factors that can significantly alter these estimates.
Which of the following statements about water is incorrect?
Because of hydrogen bonding, water has a low heat of vaporization.
Water has a tetrahedral structure when considering lone pairs and a bent molecular structure when not considering lone pairs.
Water has the potential to form a maximum of 4 hydrogen bonds.
Ice is a hexagonally packed network of water molecules and is less dense than water.
Explanation
Because of hydrogen bonding, water has a low high heat of vaporization. In other words, it takes more energy to free up water molecules from a hydrogen-bonded liquid state to a gaseous state.
What percentage of the human body is composed of interstitial water?
15%
5%
65%
60%
90%
Explanation
Interstitial water is the fluid on the outside of cells, and surrounds the cells of the human body. While estimates vary, the best answer is that 15% of the entire human body is composed of interstitial water. Overall, about 60% of the body (42L) is composed of water. Additionally, about two-thirds of the total body water is intracellular water. Finally, about 5% of the entire body is composed of plasma.
Remember that these percentages are estimates, and vary by individual. Sex and muscle mass are two factors that can significantly alter these estimates.
Which of the following statements about water is incorrect?
Because of hydrogen bonding, water has a low heat of vaporization.
Water has a tetrahedral structure when considering lone pairs and a bent molecular structure when not considering lone pairs.
Water has the potential to form a maximum of 4 hydrogen bonds.
Ice is a hexagonally packed network of water molecules and is less dense than water.
Explanation
Because of hydrogen bonding, water has a low high heat of vaporization. In other words, it takes more energy to free up water molecules from a hydrogen-bonded liquid state to a gaseous state.
A biochemist is studying two metabolic reactions at constant temperature and pressure. Reaction 1 is found to have a G value of
. Reaction 2 has a
G value of
. Which statement is true about these reactions?
None of the other answers are true
Reaction 1 proceeds at a faster rate than reaction 2
Reaction 1 proceeds at a slower rate than reaction 2
Reaction 1 and reaction 2 proceed at equally fast rates
Reaction 1 and reaction 2 proceed at equally slow rates
Explanation
The G values given in the question relate to the reactions' thermodynamics. A negative
G value means that a reaction is thermodynamically spontaneous. A spontaneous reaction can occur without further energy input. This does not tell us anything about the reaction's rate (kinetics). A spontaneous reaction may be slow or it may be fast.
A biochemist is studying two metabolic reactions at constant temperature and pressure. Reaction 1 is found to have a G value of
. Reaction 2 has a
G value of
. Which statement is true about these reactions?
None of the other answers are true
Reaction 1 proceeds at a faster rate than reaction 2
Reaction 1 proceeds at a slower rate than reaction 2
Reaction 1 and reaction 2 proceed at equally fast rates
Reaction 1 and reaction 2 proceed at equally slow rates
Explanation
The G values given in the question relate to the reactions' thermodynamics. A negative
G value means that a reaction is thermodynamically spontaneous. A spontaneous reaction can occur without further energy input. This does not tell us anything about the reaction's rate (kinetics). A spontaneous reaction may be slow or it may be fast.
What percentage of the human body is composed of interstitial water?
15%
5%
65%
60%
90%
Explanation
Interstitial water is the fluid on the outside of cells, and surrounds the cells of the human body. While estimates vary, the best answer is that 15% of the entire human body is composed of interstitial water. Overall, about 60% of the body (42L) is composed of water. Additionally, about two-thirds of the total body water is intracellular water. Finally, about 5% of the entire body is composed of plasma.
Remember that these percentages are estimates, and vary by individual. Sex and muscle mass are two factors that can significantly alter these estimates.
A biochemist is studying two metabolic reactions at constant temperature and pressure. Reaction 1 is found to have a G value of
. Reaction 2 has a
G value of
. Which statement is true about these reactions?
None of the other answers are true
Reaction 1 proceeds at a faster rate than reaction 2
Reaction 1 proceeds at a slower rate than reaction 2
Reaction 1 and reaction 2 proceed at equally fast rates
Reaction 1 and reaction 2 proceed at equally slow rates
Explanation
The G values given in the question relate to the reactions' thermodynamics. A negative
G value means that a reaction is thermodynamically spontaneous. A spontaneous reaction can occur without further energy input. This does not tell us anything about the reaction's rate (kinetics). A spontaneous reaction may be slow or it may be fast.
Is water an acid or a base?
Both
Acid
Base
It is impossible to predict.
Explanation
Water, , is an amphoteric substance--it can act as either an acid or a base. In certain circumstances, water can act as a Bronsted-Lowry acid by donating a proton.
As seen above, donated one of its hydrogen atoms, becoming
.
In other cases, water can act as a Bronsted-Lowry base by accepting a proton.
As seen above, accepted a hydrogen atom to become
.
Therefore, water can act as either an acid or a base depending on the situation. There are other amphoteric substances, but water is definitely the most common.