1. Watch this Video

2. Study this Summary

1. Water’s Polarity and Hydrogen Bonding

Water is a polar molecule. It’s polarity comes from unequal electron sharing between oxygen and hydrogen, resulting in a partial negative charge the oxygen atom and partial positive charges near the hydrogen.
Hydrogen bonds are weak intermolecular bonds that form between oppositely charged sides of polar molecules. They are much weaker than covalent or ionic bonds but are essential in biological molecules like DNA, RNA, and proteins.

2. Key Properties of Water

Cohesion: Hydrogen bonds between water molecules enable water to stick to itself. This property contributes to water’s high heat of vaporization, high specific heat, and high surface tension.
Adhesion: Water molecules stick to other substances, such as cellulose in the conductive tubes that move water from the roots to the upper parts of plants (xylem). Adhesion supports processes like capillary action and transpiration in plants.
Surface Tension: Hydrogen bonds between water molecules create a “molecular net” on the surface of a body of water, enabling objects like paper clips and organisms like water striders to rest on water without sinking.

3. Acidity, Basicity, and pH

Note that pH won’t be directly tested on the AP exam, but understanding pH concepts is crucial for understanding biology and for AP Bio success.

Acidic Solutions: Contain more hydrogen ions (H⁺) than hydroxide ions (OH⁻). pH is below 7.
Basic Solutions: Contain more hydroxide ions (OH⁻) than hydrogen ions (H⁺). pH is above 7.

4. Biological Significance of Hydrogen Bonds

Hydrogen bonds are critical for the structure and function of biomolecules. For example:
- DNA: Hydrogen bonds hold complementary base pairs (adenine-thymine, guanine-cytosine) together.
- Proteins: Hydrogen bonding contributes to secondary and tertiary structures.
- Water Transport in Plants: Cohesion and adhesion enable water movement from roots to leaves via transpiration.
Temporary hydrogen bonds appear during a variety of processes, including
- DNA replication
- Transcription
- Protein synthesis
- Enzyme catalyzed reactions

3. Master these Flashcards

[qdeck qrecord_id=”sciencemusicvideosMeister1961-Water and Hydrogen Bonding, APBVP”]

[h]Water and Hydrogen Bonding

[i]

[q]Why is water considered a polar molecule?
[a]Water is polar because of unequal electron sharing between oxygen and hydrogen. Oxygen has a partial negative charge (δ⁻), and hydrogen has a partial positive charge (δ⁺).

[q]What are hydrogen bonds, and how do they compare to covalent and ionic bonds?
[a]Hydrogen bonds are weak intermolecular bonds formed between regions of molecules with opposite polarity (partial charges). They are much weaker than covalent or ionic bonds.

[q]Where can hydrogen bonds be found in biological molecules?
[a]Hydrogen bonds are found in DNA, RNA, and proteins. For example, they hold together nitrogenous base pairs like adenine and thymine in DNA.

[q]What is cohesion, how does it result from hydrogen bonding, and how does it affect water’s properties?
[a]Cohesion is the attraction between water molecules due to hydrogen bonding. It contributes to water’s high heat of vaporization, high specific heat, and high surface tension.

[q]What is adhesion, and what biological processes does it make possible?
[a]Adhesion is water’s ability to stick to other substances. It enables capillary action and transpiration, helping water move up plant stems.

[q]What is surface tension, and how is it created?
[a]Surface tension results from cohesive forces between water molecules, forming a “net” at the water’s surface that can support small objects.

[q]What distinguishes an acidic solution from a basic solution?
[a]An acidic solution has more hydrogen ions (H⁺) than hydroxide ions (OH⁻) and a pH below 7. A basic solution has more hydroxide ions (OH⁻) than hydrogen ions (H⁺) and a pH above 7.

[q]What is transpiration, and how does it depend on water’s properties?
[a]Transpiration is the movement of water from roots to the tops of trees. It relies on cohesion (water molecules sticking together) and adhesion (water sticking to plant cell walls).

[q] What’s happening in the diagram below

[a] The diagram shows five water molecules interacting through hydrogen bonds. Hydrogen bonds are intermolecular bonds that form between the partially positive (hydrogen) side of one water molecule and the partially negative (oxygen) side of another water molecule.

[q] Using the diagram below as an example, describe how hydrogen bonds can form between molecules besides water.

[a] Hydrogen bonds can form between partially positive and partially negatively charged regions of any molecule. In the example below, there are two hydrogen bonds. In one, a partially negatively charged oxygen in a carbonyl group in thymine binds with a partially positively charged hydrogen in an amine in adenine. In the second, a partially positively charged hydrogen in an amine in thymine binds with a partially negatively charged nitrogen in adenine.

[q json=”true” yy=”4″ dataset_id=”AP_Bio_Flashcards_2022|1ff66ba19f910″ question_number=”3″ unit=”1.Chemistry_of_Life” topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding”] Evaporative cooling is how humans cool themselves through sweating, and how dogs cool themselves through panting. With reference to water and hydrogen bonding, explain how evaporative cooling works.

[a] Because water molecules are polar, they have a high heat of vaporization: the energy required to transform a liquid into a gas. As a result, when water is converted into water vapor (which happens when sweat evaporates from human skin or from a dog’s tongue), it carries away a lot of heat energy, lowering the temperature of the body that it evaporated from. This is how evaporative cooling works, and it’s a key thermoregulatory adaptation in humans and other animals.

[/qdeck]

4. Tackle these Quizzes

4.1. Chemistry and Properties of Water

[qwiz random=”true” qrecord_id=”sciencemusicvideosMeister1961-Chemistry and Properties of Water, APBVP”]

[h]The Chemistry and Properties of Water
[i]

[q] In a water molecule, the region with a partially negative charge is near the [hangman] atom(s)

[c]b3h5Z2Vu[Qq]

[q] In a polar molecule (like water), electrons are shared [hangman] among the atoms in that molecule.

[c]dW5lcXVhbGx5[Qq]

[q] In a water molecule, the region with a partial positive charge is near the [hangman] atom(s)

[c]aHlkcm9nZW4=[Qq]

[q] Because water molecules are polar, they form [hangman] bonds with one another.

[c]aHlkcm9nZW4=[Qq]

[q] If you compared hydrogen, covalent, and ionic bonds, the weakest one would be the _________ bond.
[c]aHlkcm 9nZW4=

Cg==[Qq]

[c]Y292YWxlbnQ=[Qq]

[c]aW9uaWM=[Qq]

[f]RXhjZWxsZW50ISBJZiB5b3UgY29tcGFyZWQgaHlkcm9nZW4sIGNvdmFsZW50LCBhbmQgaW9uaWMgYm9uZHMsIHRoZSB3ZWFrZXN0IG9uZSB3b3VsZCBiZSB0aGUgaHlkcm9nZW4gYm9uZC4=[Qq]

[f]Tm8uIFRoZSB3ZWFrZXN0IG9mIHRoZSB0aHJlZSBib25kcyBpcyB0aGUgb25lIHRoYXQgb2NjdXJzIGJldHdlZW4gcG9sYXIgbW9sZWN1bGVzLiBXaGljaCBib25kIGlzIA==YmV0d2Vlbg==IG1vbGVjdWxlcyAoYXMgb3Bwb3NlZCB0byB3aXRoaW4gYSBtb2xlY3VsZSk=[Qq]

[q]Two bonds that are relevant to water are the covalent and the hydrogen bond. Which of these bonds is INSIDE a water molecule?
[c]aHlkcm9nZW4=

Cg==[Qq]

[c]Y292YW xlbnQ=[Qq]
[f]Tm8uIEh5ZHJvZ2VuIGJvbmRzIG9jY3VyIGJldHdlZW4gd2F0ZXIgbW9sZWN1bGVz

Cg==[Qq]

[f]RXhjZWxsZW50LiBDb3ZhbGVudCBib25kcyBvY2N1ciBiZXR3ZWVuIHRoZSBoeWRyb2dlbiBhbmQgb3h5Z2VuIGF0b21zIA==aW5zaWRlIGEgd2F0ZXIgbW9sZWN1bGUu[Qq]

[q]In this diagram, the dotted line between the two water molecules indicates a ___________ bond.[hangman]

[c]aHlkcm9nZW4=[Qq]

[q] In a molecule like methane, all of the electrons are shared equally among the atoms in the molecule. As a result, methane is a ___________.

[c]cG9sYXIgbW9sZWN1bGU=[Qq]

[c]bm9uLXBvbGFy IG1vbGVjdWxl[Qq]

[c]aW9uaWMgY29tcG91bmQ=[Qq]

[f]Tm8uwqBJbiBhIG1vbGVjdWxlIGxpa2UgbWV0aGFuZSwgYWxsIG9mIHRoZSBlbGVjdHJvbnMgYXJlIHNoYXJlZCBlcXVhbGx5IGFtb25nIHRoZSBhdG9tcyBpbiB0aGUgbW9sZWN1bGUuIEFzIGEgcmVzdWx0LCBtZXRoYW5lIGlzIGEgbm9uLXBvbGFywqBtb2xlY3VsZS4=[Qq]

[f]WWVzLsKgSW4gYSBtb2xlY3VsZSBsaWtlIG1ldGhhbmUsIGFsbCBvZiB0aGUgZWxlY3Ryb25zIGFyZSBzaGFyZWQgZXF1YWxseSBhbW9uZyB0aGUgYXRvbXMgaW4gdGhlIG1vbGVjdWxlLiBBcyBhIHJlc3VsdCwgbWV0aGFuZSBpcyBhIA==bm9uLXBvbGFywqBtb2xlY3VsZS4=[Qq]

[f]Tm8uIElvbmljIGNvbXBvdW5kcyBhcmUgY29tcG91bmRzIHdoZXJlIGlvbmljIGJvbmRzIGhvbGQgdG9nZXRoZXIgY2hhcmdlZCBpb25zLg==[Qq]

[q] True or false: Non-polar molecules won’t form hydrogen bonds with one another

[c]VHJ1 ZQ==[Qq]

[c]RmFsc2U=[Qq]

[f]TmljZSBqb2IuIFRoZSBzdGF0ZW1lbnQgYWJvdmUgaXMgdHJ1ZTrCoE5vbi1wb2xhciBtb2xlY3VsZXMgd29uJiM4MjE3O3QgZm9ybSBoeWRyb2dlbiBib25kcyB3aXRoIG9uZSBhbm90aGVy[Qq]

[f]VGhhdCYjODIxNztzIG5vdCByaWdodC7CoE5vbi1wb2xhciBtb2xlY3VsZXMgd29uJiM4MjE3O3Q=IGZvcm0gaHlkcm9nZW4gYm9uZHMgd2l0aCBvbmUgYW5vdGhlcg==[Qq]

[x]

If you want more practice, please press the restart button below. Otherwise, continue below.
[restart]
[/qwiz]

4.2. Water and Hydrogen Bonding

[qwiz qrecord_id=”sciencemusicvideosMeister1961-Water and Hydrogen Bonding Quiz, APBVP”]

[h]Water and Hydrogen Bonding

[i]

[q json=”true” multiple_choice=”true” unit=”1.Chemistry of Life” topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding” dataset_id=”2019 AP Bio Dataset|1d1b7b86dbd4ad” question_number=”1″] The image below represents a spherical particle surrounded by a shell of water molecules. Based on the information in the image, the spherical particle must

[c]IGhhdmUgYSBwb3NpdGl2ZSBleHRlcmlvciBjaGFyZ2U=[Qq]

[f]IE5vLiBOb3RlIHRoZSBvcmllbnRhdGlvbiBvZiB0aGUgd2F0ZXIgbW9sZWN1bGVzIGluIHRoZSBpbWFnZSBhYm92ZS4gVGhlbiBzdHVkeSB0aGUgaW1hZ2UgYmVsb3cuIEluIHRoZSBpbWFnZSBiZWxvdywgdGhlIM60^Kw==IHJlcHJlc2VudHMgYSBwYXJ0aWFsIHBvc2l0aXZlIGNoYXJnZSwgYW5kIHRoZSDOtA==^JiM4MjExOw==IHJlcHJlc2VudHMgYSBwYXJ0aWFsIG5lZ2F0aXZlIGNoYXJnZS4gRmluYWxseSwgcmVtZW1iZXIgdGhhdCBvcHBvc2l0ZXMgYXR0cmFjdC4=

[Qq]

[c]IGhhdmUgYSBuZWdhdGl2ZS BleHRlcmlvciBjaGFyZ2Uu[Qq]

[f]IFRlcnJpZmljISBCZWNhdXNlIHdhdGVyIGhhcyBhIHBhcnRpYWxseSBwb3NpdGl2ZSBjaGFyZ2Ugb24gaXRzIGh5ZHJvZ2VuIHNpZGUsIHRoZSBzdXJyb3VuZGVkIHBhcnRpY2xlIG11c3QgaGF2ZSBhIG5lZ2F0aXZlIGV4dGVyaW9yIGNoYXJnZS4=[Qq]

[c]IGJlIGh5ZHJvcGhvYmlj[Qq]

[f]IE5vLiBJZiB0aGUgcGFydGljbGUgd2FzIGh5ZHJvcGhvYmljLCB0aGVuIHdhdGVyIG1vbGVjdWxlcyB3b3VsZG4mIzgyMTc7dCBiZSBpbnRlcmFjdGluZyB3aXRoIGl0IGF0IGFsbC4=

Cg==

SGVyZSYjODIxNztzIGEgaGludDogTm90ZSB0aGUgb3JpZW50YXRpb24gb2YgdGhlIHdhdGVyIG1vbGVjdWxlcyBpbiB0aGUgaW1hZ2UgYWJvdmUuIFRoZW4gc3R1ZHkgdGhlIGltYWdlIGJlbG93LiBJbiB0aGUgaW1hZ2UgYmVsb3csIHRoZSDOtA==^Kw==IHJlcHJlc2VudHMgYSBwYXJ0aWFsIHBvc2l0aXZlIGNoYXJnZSwgYW5kIHRoZSDOtA==^[Qq]– represents a partial negative charge. Finally, remember that opposites attract.

[c]IGJlIGEgbGlwaWQ=[Qq]

[f]IE5vLiBMaXBpZHMgYXJlIGVpdGhlciBlbnRpcmVseSBub25wb2xhciBvciBoYXZlIGxhcmdlIG5vbnBvbGFyIHJlZ2lvbnMuIEluIGVpdGhlciBjYXNlLCB3YXRlciBtb2xlY3VsZXMgd291bGRuJiM4MjE3O3QgYmUgYXR0cmFjdGVkIHRvIHRoZSBwYXJ0aWNsZSwgYXMgdGhleSBhcmUgaW4gdGhlIGRpYWdyYW0gYWJvdmUu

Cg==

[q json=”true” multiple choice=”true” unit=”1.Chemistry of Life” topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding” multiple_choice=”true” dataset_id=”2019 AP Bio Dataset|ec02698fc70d1″ question_number=”2″] The image below shows a paper clip on the surface of the water in a small cup.

Which of the following best explains why the paper clip doesn’t sink?

[c]IENvdmFsZW50IGJvbmRzIGJldHdlZW4gdGhlIHdhdGVyIG1vbGVjdWxlcyBhdCB0aGUgd2F0ZXItYWlyIGludGVyZmFjZSBhbmQgdGhlIHBhcGVyIGNsaXAgcHJldmVudCBpdCBmcm9tIHNpbmtpbmcu[Qq]

[f]IE5vLiBUaGUgYm9uZHMgYmV0d2VlbiB0aGUgd2F0ZXIgbW9sZWN1bGVzIGFyZSBub3QgY292YWxlbnQuIFN0dWR5IHRoZSBkaWFncmFtIGJlbG93OiB3aGF0IGtpbmQgb2YgYm9uZHMgYXJlIGNvbm5lY3RpbmcgdGhlIHdhdGVyIG1vbGVjdWxlcz8=

Cg==

[Qq]

[c]IEJvbmRpbmcgYmV0d2VlbiB0aGUgd2F0ZXIgbW9sZWN1bGVzIGFuZCB0aGUgYWlyIG1vbGVjdWxlcyBjcmVhdGVzIGEgbW9sZWN1bGFyIHdlYiB0aGF0IHN1cHBvcnRzIHRoZSBwYXBlciBjbGlwJiM4MjE3O3Mgd2VpZ2h0LCBwcmV2ZW50aW5nIGl0IGZyb20gc2lua2luZyBpbnRvIHRoZSB3YXRlci4=[Qq]

[f]IE5vLiBZb3UmIzgyMTc7cmUgcmlnaHQgYWJvdXQgdGhlcmUgYmVpbmcgYSBtb2xlY3VsYXIgd2ViIHRoYXQgcHJldmVudHMgdGhlIHBhcGVyIGNsaXAgZnJvbSBzaW5raW5nLCBidXQgaXQmIzgyMTc7cyBub3QgYmV0d2VlbiB0aGUgd2F0ZXIgYW5kIHRoZSBhaXIuwqAgV2hhdCBhcmUgdGhlIGJvbmRzIHNob3duIGluIHJlZCBpbiB0aGUgaW1hZ2UgYmVsb3c/

Cg==

[Qq]

[c]IEh5ZHJvZ2VuIGJvbmRzIGJldHdlZW4gdGhlIHdhdGVyIG 1vbGVjdWxlcyBjcmVhdGUgc3VyZmFjZSB0ZW5zaW9uLg==[Qq]

[f]IFdheSB0byBnby4gU3VyZmFjZSB0ZW5zaW9uIGVuYWJsZXMgdGhlIHBhcGVyIGNsaXAgdG8gcmVzdCB1cG9uIGEga2luZCBvZiBtb2xlY3VsYXIgd2ViIG9mIGh5ZHJvZ2VuIGJvbmRzIGJldHdlZW4gdGhlIHdhdGVyIG1vbGVjdWxlcyBvbiB0aGUgc3VyZmFjZS4gSGVyZSYjODIxNztzIGEgdmlzdWFsIHJlcHJlc2VudGF0aW9uIG9mIHdoYXQmIzgyMTc7cyBoYXBwZW5pbmcu

Cg==

[Qq]

[c]IFRoZSBkZW5zaXR5IG9mIHRoZSBtZXRhbCBpbiB0aGUgcGFwZXIgY2xpcCBpcyBsZXNzIHRoYW4gdGhlIGRlbnNpdHkgb2Ygd2F0ZXIu[Qq]

[f]IE5vLiBJZiB5b3Ugd2VyZSB0byBwdXNoIHRoZSBwYXBlciBjbGlwIGJlbG93IHRoZSBzdXJmYWNlIG9mIHRoZSB3YXRlciwgaXQgd291bGQgc2luay4gVGhhdCB0ZWxscyB5b3UgdGhhdCB0aGUgZGVuc2l0eSBvZiB0aGUgcGFwZXIgY2xpcCBpcyBncmVhdGVyIHRoYW4gdGhlIGRlbnNpdHkgb2YgdGhlIHdhdGVyLiBTZWUgaWYgeW91IGNhbiBmaWd1cmUgb3V0IHdoYXQmIzgyMTc7cyBnb2luZyBvbiBpbiB0aGUgaW1hZ2UgYmVsb3cu

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”1.Chemistry of Life” topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding” dataset_id=”2019 AP Bio Dataset|c069acea10c30″ question_number=”3″] The diagram below shows part of a structure called xylem, which is found in the stems of certain plants. Note that the water molecules shown are vastly out of scale. Which of the following explanations of the interactions between water molecules and the cell walls of the xylem is correct?

[c]IEJlY2F1c2Ugd2F0ZXIgaXMgbm9ucG9sYXIgYW5kIHRoZSB3YWxscyBvZiB0aGUgeHlsZW0gYXJlIHBvbGFyLCB3YXRlciBjYW4gZm9ybSBoeWRyb2dlbiBib25kcyB3aXRoIHRoZSB4eWxlbSB3YWxscy4=[Qq]

[f]IE5vLiB3YXRlciBpcyBhIHBvbGFyIG1vbGVjdWxlLCB3aXRoIHBhcnRpYWwgcG9zaXRpdmUgY2hhcmdlcyBvbiB0aGUgaHlkcm9nZW4gYXRvbXMgYW5kIGEgcGFydGlhbCBuZWdhdGl2ZSBjaGFyZ2Ugb24gdGhlIG94eWdlbiBhdG9tLiBOb3RlIHRoZSBib25kcyBzaG93biBiZXR3ZWVuIHRoZSB3YXRlciBtb2xlY3VsZXMgYW5kIHRoZSB3YWxscyBvZiB0aGUgeHlsZW0uIEhvdyBjb3VsZCBzdWNoIGJvbmRzIGZvcm0/

Cg==

[Qq]

[c]IEJlY2F1c2UgYm90aCB3YXRlciBhbmQgdGhlIHh5bGVtIHdhbGxzIGFyZSBub25wb2xhciwgaHlkcm9waG9iaWMgaW50ZXJhY3Rpb25zIGVuYWJsZSB0aGUgdHdvIHRvIGJvbmQgdG9nZXRoZXIu[Qq]

Cg==

[Qq]

[c]IEJlY2F1c2UgYm90aCB3YXRlciBhbmQgdGhlIHh5bGVtIHdhbGxzIGFyZSBwb2xhciwgaHlkcm9nZW4gYm 9uZHMgY2FuIGZvcm0gYmV0d2VlbiB0aGUgd2F0ZXIgbW9sZWN1bGVzIGFuZCB0aGUgeHlsZW0gd2FsbHMu[Qq]

[f]IEV4Y2VsbGVudCEgVGhlIHdhbGxzIG9mIHRoZSB4eWxlbSBoYXZlIGEgcGFydGlhbGx5IG5lZ2F0aXZlIGNoYXJnZSBhbmQgY2FuIGZvcm0gaHlkcm9nZW4gYm9uZHMgd2l0aCB0aGUgcGFydGlhbGx5IHBvc2l0aXZlIHJlZ2lvbnMgb2Ygd2F0ZXIgbW9sZWN1bGVzLg==[Qq]

[c]IFdoaWxlIHdhdGVyIGlzIHBvbGFyLCB0aGUgd2FsbHMgb2YgdGhlIHh5bGVtIGFyZSBub25wb2xhci4gVGhpcyBhbGxvd3Mgd2F0ZXIgbW9sZWN1bGVzIHRvIGJpbmQgd2l0aCBvbmUgYW5vdGhlciwgYnV0IG5vdCB0byB0aGUgd2FsbHMgb2YgdGhlIHh5bGVtLg==[Qq]

[f]IE5vLiBZb3UmIzgyMTc7cmUgcmlnaHQgYWJvdXQgd2F0ZXIsIHdoaWNoIGlzIGEgcG9sYXIgbW9sZWN1bGUuIEJ1dCBub3RlIHRoZSBib25kcyBiZXR3ZWVuIHdhdGVyIGFuZCB0aGUgd2FsbHMgb2YgdGhlIHh5bGVtLiBIb3cgY291bGQgc3VjaCBib25kcyBmb3JtPw==

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”1.Chemistry of Life” topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding” dataset_id=”2019 AP Bio Dataset|1500bbeece4507″ question_number=”4″] Water has a high heat capacity due to its ability to form hydrogen bonds. Which of the following would be an accurate statement about the heat capacity of the molecules shown below?

[c]IE1ldGhhbmUgd291bGQgaGF2ZSBhIGxvd2VyIGhlYXQgY2FwYWNpdHkgdGhhbiBtZXRoYW5vbCBiZW NhdXNlIGl0IGNhbuKAmXQgZm9ybSBoeWRyb2dlbiBib25kcywgd2hpbGUgbWV0aGFub2wgY2FuLg==[Qq]

[f]IEV4Y2VsbGVudC4gVGhlIHN0cnVjdHVyZSBvZiBtZXRoYW5lIG1ha2VzIGl0IGNvbXBsZXRlbHkgbm9ucG9sYXIsIHdoaWNoIGlzIHdoeSBpdCYjODIxNztzIHVuYWJsZSB0byBmb3JtIGh5ZHJvZ2VuIGJvbmRzLCBnaXZpbmcgaXQgYSB2ZXJ5IGxvdyBoZWF0IGNhcGFjaXR5LiBUaGUgaHlkcm94eWwgZnVuY3Rpb25hbCBncm91cCAo4oCUT0gpIG9uIG1ldGhhbm9sIGlzIHBvbGFyLCBzbyBtZXRoYW5vbCA=Y2FuIGZvcm0gaHlkcm9nZW4gYm9uZHMsIGdpdmluZyBtZXRoYW5vbCBhIGhpZ2hlciBoZWF0IGNhcGFjaXR5IHRoYW4gbWV0aGFuZS4=[Qq]

[c]IE1ldGhhbmUgd291bGQgaGF2ZSB0aGUgc2FtZSBoZWF0IGNhcGFjaXR5IGFzIG1ldGhhbm9sIGJlY2F1c2UgdGhleSBib3RoIGhhdmUgZm91ciBoeWRyb2dlbiBhdG9tcy4=[Qq]

[f]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Y2FuIGZvcm0gaHlkcm9nZW4gYm9uZHMuIEtub3dpbmcgdGhhdCwgaG93IHdvdWxkIHRoZSBoZWF0IGNhcGFjaXR5IG9mIG1ldGhhbmUgY29tcGFyZSB0byB0aGF0IG9mIG1ldGhhbm9sPw==[Qq]

[c]IE1ldGhhbm9sIHdvdWxkIGhhdmUgYSBsb3dlciBoZWF0IGNhcGFjaXR5IHRoYW4gbWV0aGFuZSBiZWNhdXNlIGl0IGNhbuKAmXQgZm9ybSBoeWRyb2dlbiBib25kcywgd2hpbGUgbWV0aGFuZSBjYW4gZm9ybSBmb3VyLg==[Qq]

[c]IEJvdGggbWV0aGFuZSBhbmQgbWV0aGFub2wgd291bGQgaGF2ZSBhIGhpZ2hlciBoZWF0IGNhcGFjaXR5IHRoYW4gd2F0ZXIgYmVjYXVzZSB0aGV5IGZvcm0gbW9yZSBoeWRyb2dlbiBib25kcy4=[Qq]

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”1.Chemistry of Life” dataset_id=”2019 AP Bio Dataset|2170e2518d885a” question_number=”5″ topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding”] Which of the following is responsible for holding water molecules together as they get pulled up through the stem of a plant?

[c]IHN1cmZhY2UgdGVuc2lvbg==[Qq]

[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIHRoaW5raW5nIGFib3V0IHRoaXMgdGhlIHJpZ2h0IHdheS4gU3VyZmFjZSB0ZW5zaW9uIGlzIHdoYXQmIzgyMTc7cyBnZW5lcmF0aW5nIHNvbWUgb2YgdGhlIG5lZ2F0aXZlIHByZXNzdXJlIChhbHNvIGtub3duIGFzIHRlbnNpb24pIHRoYXQgc3Vja3Mgd2F0ZXIgdXAgZnJvbSB0aGUgcm9vdCwgdGhyb3VnaCB0aGUgc3RlbSwgYW5kIHVwIHRvIHRoZSBsZWF2ZXMuIEJ1dCB3aGF0JiM4MjE3O3Mga2VlcGluZyB0aG9zZSB3YXRlciBtb2xlY3VsZXMgdG9nZXRoZXI/[Qq]

[c]IGhlYXQgb2YgdmFwb3JpemF0aW9u[Qq]

[f]IE5vLiBUaGUgaGVhdCBvZiB2YXBvcml6YXRpb24gaXMgdGhlIGFtb3VudCBvZiBlbmVyZ3kgcmVxdWlyZWQgdG8gdHVybiBhIGxpcXVpZCBpbnRvIGEgZ2FzLiBZb3UmIzgyMTc7cmUgbG9va2luZyBmb3IgdGhlIG5hbWUgb2YgdGhlIGludGVyYWN0aW9uIGJldHdlZW4gd2F0ZXIgbW9sZWN1bGVzIHRoYXQga2VlcHMgdGhlbSBpbiBhbiB1bmJyb2tlbiBjaGFpbiBhcyB0aGV5IGdldCBwdWxsZWQgdXAgdGhlIHN0ZW0gZHVyaW5nIHRyYW5zcGlyYXRpb24u[Qq]

[c]IGNvaG VzaW9u[Qq]

[f]IEZhYnVsb3VzLiBUaGUgZm9yY2UgdGhhdCYjODIxNztzIGtlZXBpbmcgd2F0ZXIgbW9sZWN1bGVzIHRvZ2V0aGVyIGlzIGNvaGVzaW9uLg==[Qq]

[c]IGFkaGVzaW9u[Qq]

[f]IE5vLiBBZGhlc2lvbiBpcyB0aGUgZm9yY2UgdGhhdCBlbmFibGVzIHdhdGVyIG1vbGVjdWxlcyB0byBhZGhlcmUgdG8gdGhlIHNpZGVzIG9mIHRoZSB0dWJlcyAoY2FsbGVkIHh5bGVtKSB0aGF0IHRoZXkmIzgyMTc7cmUgYmVpbmcgcHVsbGVkIHVwIHRocm91Z2guIFdoYXQgZm9yY2UgZW5hYmxlcyB0aGUgd2F0ZXIgbW9sZWN1bGVzIHRvIHN0aWNrIHRvZ2V0aGVyPyBIZXJlJiM4MjE3O3MgYSBoaW50OiB5b3UmIzgyMTc7cmUganVzdCBvbmUgc3lsbGFibGUgYXdheSBmcm9tIHRoZSBhbnN3ZXIu[Qq]

[c]IHRyYW5zcGlyYXRpb24=[Qq]

[f]IE5vLiBUcmFuc3BpcmF0aW9uIGlzIHRoZSBwcm9jZXNzIHRoYXQgYWxsb3dzIG1vdmVzIHdhdGVyIHRocm91Z2ggcGxhbnRzLiBJdCBkZXBlbmRzIG9uIHRoZSBwcm9wZXJ0aWVzIG9mIHdhdGVyLCBhbmQgdGhlIHByb3BlcnR5IHRoYXQgeW91JiM4MjE3O3JlIGxvb2tpbmcgZm9yIGlzIHRoZSBuYW1lIG9mIHRoZSBpbnRlcmFjdGlvbiBiZXR3ZWVuIHdhdGVyIG1vbGVjdWxlcyB0aGF0IGtlZXBzIHRoZW0gaW4gYW4gdW5icm9rZW4gY2hhaW4u

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”1.Chemistry of Life” dataset_id=”2019 AP Bio Dataset|216e2ecfc2045a” question_number=”6″ topic=”1.1.Structure_of_Water_and_Hydrogen_Bonding”] The process of transpiration, which pulls water up from the roots through the plant’s stem and out through the leaves, only works because water molecules stay connected to the walls of the xylem as they get pulled up through the stem of a plant. What’s the name of the force behind that connection?

[c]IGNvaGVzaW9u[Qq]

[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIHZlcnkgY2xvc2UgKG9ubHkgYSBzeWxsYWJsZSBhd2F5KS4gQ29oZXNpb24gZGVzY3JpYmVzIGhvdyB3YXRlciBtb2xlY3VsZXMgc3RpY2sgdG8gb25lIGFub3RoZXIuIFdoYXQgZGVzY3JpYmVzIGhvdyB3YXRlciBzdGlja3MgdG8gb3RoZXIgbW9sZWN1bGVzPw==[Qq]

[c]IHN1cmZhY2UgdGVuc2lvbg==[Qq]

[f]IE5vLiBIZXJlIGFyZSB0d28gdGhpbmdzIHRvIGtub3cgYWJvdXQgdGhpcyBxdWVzdGlvbi4gMSkgU3VyZmFjZSB0ZW5zaW9uIGlzIHdoYXQgaGFwcGVucyBhdCB0aGUgd2F0ZXIvYWlyIGludGVyZmFjZSBvZiBhIGJvZHkgb2Ygd2F0ZXIuIEl0JiM4MjE3O3MgdGhlIGZvcmNlIHRoYXQgbGV0cyB5b3UgZmxvYXQgYSBwYXBlcmNsaXAgb24gdGhlIHN1cmZhY2Ugb2YgYSBjdXAgb2Ygd2F0ZXIuIDIpIA==WHlsZW0=IGFyZSB0aGUgdGhpbiB0dWJlcyBpbiB0aGUgcm9vdHMsIHN0ZW1zLCBhbmQgbGVhdmVzIG9mIHBsYW50cyB0aHJvdWdoIHdoaWNoIHdhdGVyIGZsb3dzIHVwIGR1cmluZyB0cmFuc3BpcmF0aW9uLiBZb3UmIzgyMTc7cmUgbG9va2luZyBmb3IgdGhlIG5hbWUgb2YgdGhlIHByb3BlcnR5IHRoYXQgZGVzY3JpYmVzIGhvdyB3YXRlciBtb2xlY3VsZXMgJiM4MjIwO3N0aWNrJiM4MjIxOyB0byBvdGhlciBwb2xhciBtb2xlY3VsZXMgKHN1Y2ggYXMgdGhvc2UgbWFraW5nIHVwIHRoZSB3YWxscyBvZiB0aGUgeHlsZW0pLg==[Qq]

[c]IGhlYXQgb2YgdmFwb3JpemF0aW9uLg==[Qq]

[f]IE5vLiBUaGUgaGVhdCBvZiB2YXBvcml6YXRpb24gaXMgdGhlIGFtb3VudCBvZiBlbmVyZ3kgcmVxdWlyZWQgdG8gdHVybiBhIGxpcXVpZCBpbnRvIGEgZ2FzLiBZb3UmIzgyMTc7cmUgbG9va2luZyBmb3IgdGhlIG5hbWUgb2YgdGhlIHByb3BlcnR5IHRoYXQgZGVzY3JpYmVzIGhvdyB3YXRlciBtb2xlY3VsZXMgJiM4MjIwO3N0aWNrJiM4MjIxOyB0byBvdGhlciBwb2xhciBtb2xlY3VsZXMgKHN1Y2ggYXMgdGhvc2UgbWFraW5nIHVwIHRoZSB3YWxscyBvZiB0aGUgeHlsZW0pLg==[Qq]

[c]IGFkaG VzaW9u[Qq]

[f]IEV4Y2VsbGVudCEgQWRoZXNpb24gaXMgY29ycmVjdC4gV2F0ZXIgbW9sZWN1bGVzIGFkaGVyZSB0byB0aGUgd2FsbHMgb2YgdGhlIHh5bGVtIGR1cmluZyB0cmFuc3BpcmF0aW9uLiBBbG9uZyB3aXRoIGNvaGVzaW9uLCB0aGF0JiM4MjE3O3MgaG93IHRoZXNlIHdhdGVyIG1vbGVjdWxlcyBjYW4gZ2V0IHB1bGxlZCB1cCB0aGUgbGVuZ3RoIG9mIGEgcGxhbnQmIzgyMTc7cyBzdGVtLg==[Qq]

[c]IGV2YXBvcmF0aW9u[Qq]

[f]IE5vLiBFdmFwb3JhdGlvbiBpcywgdWx0aW1hdGVseSwgZ2VuZXJhdGluZyB0aGUgdGVuc2lvbiB0aGF0JiM4MjE3O3MgcHVsbGluZyB3YXRlciBtb2xlY3VsZXMgdXAgdGhlIHN0ZW0gb2YgYSBwbGFudC4gQnV0IHlvdSYjODIxNztyZSBsb29raW5nIGZvciB0aGUgbmFtZSBvZiB0aGUgcHJvcGVydHkgdGhhdCBkZXNjcmliZXMgaG93IHdhdGVyIG1vbGVjdWxlcyAmIzgyMjA7c3RpY2smIzgyMjE7IHRvIG90aGVyIHBvbGFyIG1vbGVjdWxlcyAoc3VjaCBhcyB0aG9zZSBtYWtpbmcgdXAgdGhlIHdhbGxzIG9mIHRoZSB4eWxlbSku[Qq]

[x][restart]

[/qwiz]

What’s next?

Please proceed to this next tutorial: Biochemistry Basics for AP Bio