AP Bio CH 3 and 4

Open Ended

What is the difference between a covalent bond and a hydrogen bond?

Open Ended

This graph shows 2 cities that are both about the same latitude. How would you explain their seasonal differences?

How would you explain the differences in temperature from the previous slide?

Bozeman montana (surrounded by mountains) and Seattle, WA coastal – High specific heat of water surrounding seattle resists changes in temperature; harder to pull the molecules of water apart due to its polar nature

Fill in the Blanks

Water is a polar molecule, meaning that its overall charge is unevenly distributed. In water, the oxygen region of the molecule has a partial ___ charge and each hydrogen has a partial ___ charge.

Multiple Choice

What makes a molecule polar?

• Equal sharing of valence electrons
• Unequal sharing of valence electrons
• Stealing of electrons
• Temporary charges that come and go

Multiple Choice

 Small insects can walk across the surface of calm water. Their feet push the surface of the water down slightly, somewhat like a person walking across a trampoline, but they do not break the surface. What is the best explanation for why this happens?

• The insects are light enough so that they do not break the hydrogen bonds holding the water molecules together
• The insects actually use their wings to hover slightly above the water's surface and they only skim it with their feet
• The insects' feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water's surface
• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

Multiple Choice

Which of the following best describes the difference between covalent bonding and hydrogen bonding in water molecules?

• Covalent bonds occur between atoms within a water molecule, while hydrogen bonds occur between different water molecules.

• Covalent bonds are weaker than hydrogen bonds.

• Hydrogen bonds occur within a water molecule, while covalent bonds occur between water molecules.

• Both covalent and hydrogen bonds occur only between water molecules.

Multiple Choice

The fact that ice floats on liquid water is due to the fact that water's solid is ___________ than it's liquid form

• less polar
• more polar
• less dense
• more dense

Fill in the Blanks

Surface tension in water is primarily the result of

between water molecules.

Open Ended

Describe how cohesion and adhesion contribute to the transport of water in plants.

Multiple Choice

Which of the following best describes the difference between temperature and heat as explained in the slides?

• Temperature is the amount of heat in a substance, while heat is the average kinetic energy of molecules.

• Temperature is a measure of average kinetic energy of molecules, while heat is thermal energy in transfer from one body to another.

• Temperature is the same as heat, both measure energy in a substance.

• Temperature is measured in calories, while heat is measured in degrees Celsius.

Multiple Select

Which of the following statements about water's high specific heat are correct?

• It allows large bodies of water to store heat and moderate climate.

• It means water heats up and cools down very quickly.

• It helps organisms resist rapid temperature changes.

• It is unrelated to hydrogen bonding.

Multiple Choice

Why does ice float on liquid water?

• Because ice is denser than liquid water.

• Because hydrogen bonds in ice keep molecules farther apart, making ice less dense than liquid water.

• Because ice contains more air bubbles. The air bubbles move the molecules of water further apart and therefore cause the ice to float.

• Because water molecules in ice are closer together than in liquid water.

Open Ended

Explain how the polarity of water molecules contributes to their ability to dissolve different types of solutes.

Multiple Choice

Which of the following best describes the role of water as a solvent in biological systems?

• Water dissolves only ionic compounds like salt.

• Water dissolves both ionic and polar compounds due to its polarity.

• Water dissolves only nonpolar molecules like oil.

• Water cannot dissolve large molecules like proteins.

Multiple Select

Which of the following are characteristics of hydrophobic substances?

• They are nonpolar.

• They form hydrogen bonds with water.

• They dissolve easily in water.

• They tend to repel water.

Multiple Choice

Which of the following best describes the difference between an acid and a base according to the information provided?

• Acids increase the hydrogen ion concentration, while bases decrease it.

• Acids decrease the hydrogen ion concentration, while bases increase it.

• Both acids and bases increase the hydrogen ion concentration.

• Acids and bases have no effect on hydrogen ion concentration.

Fill in the Blanks

Compared with a basic solution of pH 9, the same volume of acidic acid at pH 4 has

times as many hydrogen ions?

Multiple Choice

Which of the following statements about buffers is correct?

• Buffers minimize changes in pH by accepting or donating hydrogen ions.

• Buffers only work in acidic solutions.

• Buffers work by consistently increasing the concentration of hydrogen ions in a solution.

• Buffers are only found in laboratory settings.

Multiple Choice

What property of water is most important for the cohesion and adhesion described in living systems?

• Hydrogen bonding

• Ionic bonding

• Covalent bonding

• Van der Waals forces

Open Ended

Reflecting on today's lesson, what is one question you still have about how latitude affects seasonal temperature differences?