AP Bio Unit 3 Water

Mastering Biology Questions

The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?

1. a covalent bond

2. an ionic bond

3. a van der Waals interaction

4. a hydrogen bond

4. a hydrogen bond

The partial negative charge in a molecule of water occurs because _____.

1. one of the hydrogen atoms donates an electron to the oxygen atom

2. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

3. the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms

4. the oxygen atom donates an electron to each of the hydrogen atoms

2. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

Which of the following is a property of liquid water? Liquid water _____.

1. has a specific heat that is lower than that for most other substances

2. is nonpolar

3. is less dense than ice

4. has a heat of vaporization that is higher than that for most other substances

4. has a heat of vaporization that is higher than that for most other substances

To act as an effective coolant in a car's radiator, a substance has to have the capacity to absorb a great deal of heat. You have a reference book with tables listing the physical properties of many liquids. In choosing a coolant for your car, which table would you check first?

1. heat of vaporization

2. density at room temperature

3. pH

4. specific heat

4. specific heat

Water has many exceptional and useful properties. Which is the rarest property among compounds?

1. Water is a solvent.

2. Solid water is less dense than liquid water.

3. Water has surface tension.

4. Water has a high heat capacity.

2. Solid water is less dense than liquid water.

Which type of bond must be broken for water to vaporize?

1. both polar covalent bonds and hydrogen bonds

2. polar covalent bonds

3. hydrogen bonds

4. ionic bonds

3. hydrogen bonds

Why does ice float in liquid water?

1. The high surface tension of liquid water keeps the ice on top.

2. The crystalline lattice of ice causes it to be denser than liquid water.

3. The ionic bonds between the molecules in ice prevent the ice from sinking.

4. Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water.

4. Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water.

Hydrophobic substances such as vegetable oil are _____.

1. nonpolar substances that repel water molecules

2. polar substances that repel water molecules

3. nonpolar substances that have an attraction for water molecules

4. polar substances that have an affinity for water

1. nonpolar substances that repel water molecules

One mole (mol) of glucose (molecular mass = 180 daltons) is _____.

1. 180 × 1023 molecules of glucose

2. 180 grams of glucose

3. 180 kilograms of glucose

4. 1 kilogram of glucose dissolved in 1 liter of solution

2. 180 grams of glucose

A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7?

1. 5 times

2. 10 times

3. 100 times

4. 1000 times

3. 100 times

Consider the following reaction at equilibrium: CO₂ + H₂O <—> H₂CO₃

What would be the effect of adding additional H₂CO₃?

1. The amounts of CO2 and H2O would decrease.

2. It would drive the equilibrium dynamics to the right.

3. Nothing would happen, because the reactants and products are in equilibrium.

4. It would drive the equilibrium dynamics to the left.

4. It would drive the equilibrium dynamics to the left.

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?

1. It is a strong acid that dissociates completely in water.

2. It is a strong base that dissociates completely in water.

3. It is a weak base.

4. It is a weak acid.

1. It is a strong acid that dissociates completely in water.

Which of the following statements is true about buffer solutions?

1. They maintain a constant pH when bases are added to them but not when acids are added to them.

2. They maintain a constant pH when acids are added to them but not when bases are added to them.

3. They maintain a relatively constant pH when either acids or bases are added to them.

4. They fluctuate in pH when either acids or bases are added to them.

3. They maintain a relatively constant pH when either acids or bases are added to them.

Increased atmospheric CO2 concentrations might have what effect on seawater?

1. Seawater will become more acidic, and carbonate concentrations will decrease.

2. Seawater will become more alkaline, and carbonate concentrations will decrease.

3. There will be no change in the pH of seawater, because carbonate will turn to bicarbonate.

4. Seawater will become more acidic, and carbonate concentrations will increase.

1. Seawater will become more acidic, and carbonate concentrations will decrease.

The _____ is the most efficient route of water movement in plants, while the _____ is the most select.

1. symplast apoplast

2. transmembrane: symplast

3. apoplast: transmembrane

4. apoplast: symplast

3. apoplast: transmembrane

The movement of water across biological membranes can best be predicted by _____.

1. level of active transport

2. prevailing weather conditions

3. water potentials

4. aquaporins

3. water potientials

If isolated plant cells with a water potential averaging -0.5 MPa are placed into a solution with a water potential of -0.3 MPa, which of the following would be the most likely outcome?

1. Solutes would move out of the cells.

2. The pressure potential of the cells would increase.

3. Water would move out of the cells.

4. The cell walls would rupture, killing the cells.

2. The pressure potential of the cells would increase.

Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will _____.

1. have a faster rate of osmosis

2. have a lower water potential

3. have a faster rate of active transport

4. have a higher water potential

1. have a faster rate of osmosis

In plant roots, the Casparian strip _____.

1. provides energy for the active transport of minerals into the stele from the cortex

2. ensures that all water and dissolved substances must pass through a cell membrane before entering the stele

3. ensures that all minerals are absorbed from the soil in equal amounts

4. aids in the uptake of nutrients

2. ensures that all water and dissolved substances must pass through a cell membrane before entering the stele

What is the main force by which most of the water within xylem vessels moves toward the top of a tree?

1. osmosis in the root

2. evaporation of water through stoma

3. the force of root pressure

4. active transport of ions into the stele

1. evaporation of water through stoma; transpiration

Water potential is generally most negative in which of the following parts of a plant?

1. cells of the root cortex

2. xylem vessels in roots

3. mesophyll cells of the leaf

4. xylem vessels in leaves

3. mesophyll cells of the leaf

The opening of stomata is thought to involve _____.

1. movement of K+ from the guard cells

2. an increase in the solute concentration of the guard cells

3. decreased turgor pressure in guard cells

4. active transport of water out of the guard cells

2. an increase in the solute concentration of the guard cells

Which of the following is a correct statement about sugar movement in phloem?

1. Sugar is translocated from sinks to sources.

2. Only phloem cells with nuclei can perform sugar movement.

3. Movement can occur both upward and downward in the plant.

4. Diffusion can account for the observed rates of transport.

3. Movement can occur both upward and downward in the plant.

The force driving simple diffusion is _____, while the energy source for active transport is _____.

1. phosphorylated protein carriers; ATP

2. the concentration gradient; ADP

3. the concentration gradient; ATP

4. transmembrane pumps; electron transport

3. the concentration gradient; ATP

To maintain homeostasis freshwater fish must _____.

1. excrete large quantities of electrolytes

2. take in electrolytes through simple diffusion

3. excrete large quantities of water

4. consume large quantities of water

3. excrete large quantities of water

Terrestrial organisms lose water through evaporation. In what ecosystem might an entomologist find a good study organism to examine the prevention of water loss?

1. chaparral

2. wet rain forest

3. desert

4. prairie

3. desert

Which of the following animals generally has the lowest volume of urine production?

1. a salmon in fresh water

2. a marine bony fish

3. a vampire bat

4. a shark inhabiting the Mississippi River

2. marine bony fish

In animals, nitrogenous wastes are produced mostly from the catabolism of _____.

1. triglycerides and steroids

2. phospholipids and glycolipids

3. starch and cellulose

4. proteins and nucleic acids

4. proteins and nucleic acids

African lungfish, which are often found in small, stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

1. Urea takes less energy to synthesize than ammonia.

2. Urea makes lungfish tissue hypoosmotic to the pool.

3. Small, stagnant pools do not provide enough water to dilute the toxic ammonia.

4. The highly toxic urea makes the pool uninhabitable to potential competitors.

3. Small, stagnant pools do not provide enough water to dilute the toxic ammonia.

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?

1. The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys.

2. The renal artery and vein are the main pathways regulating how much is produced by the kidneys.

3. The kidneys require constant and abnormally high oxygen supply to function.

4. The kidneys require higher than normal levels of hormones.

1. The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys.

The transfer of fluid from the glomerulus to Bowman's capsule _____.

1. is very selective as to which subprotein-sized molecules are transferred

2. transfers large molecules as easily as small ones

3. is mainly a consequence of blood pressure in the capillaries of the glomerulus

4. results from active transport

3. is mainly a consequence of blood pressure in the capillaries of the glomerulus

Which process in the nephron is LEAST selective?

1. reabsorption

2. active transport

3. secretion

4. filtration

4. filtration

What is the difference between H⁺ concentration in an acidic solution such as lemon juice (pH 2) and a basic solution such as household bleach (pH 13)?

1. The H⁺ concentration of lemon juice is higher than the H⁺ concentration of household bleach by a factor of 11.

2. The H⁺ concentration of household bleach is higher than the H⁺ concentration of lemon juice by a factor of 10¹¹ (100 billion).

3. The H⁺ concentration of lemon juice is higher than the H⁺ concentration of household bleach by a factor of 10¹¹ (100 billion).

3. The H⁺ concentration of lemon juice is higher than the H⁺ concentration of household bleach by a factor of 10¹¹ (100 billion).

Identify all correct statements about the ionization of water.

1. Dissociation of water is reversible.

2. Dissociation of water produces equal numbers of OH- and H+.

3. Dissociation of water is not reversible.

4. Dissociation of water produces equal masses of OH- and H+.

5. Water ionizes to form hydroxide and hydronium ions.

6. Water ionizes to form peroxide and hydronium ions.

1. Dissociation of water is reversible

2. Dissociateion of water produces equal numbers of OH^- and H⁺

5. Water ionizes to form hydroxide and hydronium ions.

Which property of water allows a water strider to walk on water?

1. adhesion of water molecules to other kinds of molecules

2. the formation of covalent bonds between water molecules

3. water’s high surface tension

3. water’s high surface tension

Which property of water allows a paper towel to pick up a puddle of water?

1. water’s high surface tension

2. water’s high heat of vaporization

3. adhesion of water molecules to other kinds of molecules

3. adhesion of water molecules to other kinds of molecules

Which property of water allows dogs to cool themselves by panting?

1. water’s high heat of vaporization

2. water’s high surface tension

3. the formation of covalent bonds between water molecules

1. water’s high heat of vaporization

Select the accurate statement about water potential.

1. Adding solutes to water increases water potential.

2. Free water moves from a region of lower water potential to a region of higher water potential.

3. Water in a turgid cell has positive pressure potential.

3. Water in a turgid cell has positive pressure potential.

A plant cell is placed in distilled water, as shown in the figure. There is a net uptake of water by osmosis, causing the cell to become turgid. Select the correct statement about this setup, after the cell is fully turgid.

1. The pressure potentials (Ψ_P) of the cell and its surroundings are the same.

2. Because the cell contains more solutes than the distilled water that surrounds it, the solute potential (Ψ_S) of the cell is higher than the solute potential of distilled water.

3. The water potentials (Ψ) of the cell and its surroundings are the same.

3. The water potentials (Ψ) of the cell and its surroundings are the same.

Select the correct mechanism of stomatal opening and closing.

1. The radial orientation of cellulose microfibrils in the cell walls of guard cells causes them to bow outward and open the stomatal pore when turgid.

2. Light stimulates proton pumps in the plasma membrane of the guard cells, causing them to lose K+ and become flaccid.

3. The cell walls of guard cells are thickened on the side of the stomatal opening and the thinner walls bow outward when the guard cells become turgid, to close the stomata.

1. The radial orientation of cellulose microfibrils in the cell walls of guard cells causes them to bow outward and open the stomatal pore when turgid.

Select the correct statement about variation in stomatal density.

1. Stomatal density is fully under genetic control.

2. Stomatal density increases with increasing atmospheric CO2 level.

3. Stomatal density is developmentally plastic.

3. Stomatal density is developmentally plastic.

If a plant’s stomata are closed and no transpiration is occurring, which of the following predictions is accurate?

1. Without transpiration, the plant will be water deficient.

2. Without transpiration, less water will be absorbed from the soil.

3. Without transpiration, the plant’s cells will become flaccid.

2. Without transpiration, less water will be absorbed from the soil.

Select the correct statement about osmolarity.

1. If two solutions are separated by a selectively permeable membrane, water flows by osmosis from a hyperosmotic solution to a hypoosmotic one.

2. The contents of an animal cell are hyperosmotic.

3. Osmolarity measures the moles of solute per liter of solution.

3. Osmolarity measures the moles of solute per liter of solution.

Select the correct statement about osmoregulation.

1. The less the gradient between an animal’s internal osmolarity and its external osmolarity (that of its surroundings), the higher the cost of osmoregulation.

2. All marine invertebrates are stenohaline.

3. All osmoconformers are marine animals.

3. All osmoconformers are marine animals.

Where and when does osmolarity of the filtrate increase?

1. As the filtrate moves up to the cortex in the ascending limb of the loop

2. As the filtrate moves through the proximal tubule

3. As the filtrate moves down the descending limb of the loop of Henle

3. As the filtrate moves down the descending limb of the loop of Henle

Select the correct statement describing the osmolarity of mammalian urine.

1. Mammalian urine is always hyperosmotic to blood.

2. The osmolarity of mammalian urine may vary over time.

3. The osmolarity of mammalian urine varies little between species

2. The osmolarity of mammalian urine may vary over time.