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1. The fluid mosaic model: membrane components in motion
One of the most important characteristics of membranes is their ability to control what passes through the membrane to enter or leave the cell (or a membrane-bound part within the cell). This is known as selective permeability (also semi-permeability).
But membranes can do even more. Here’s the verse from my Membranes! music video that describes some of these other functions:
But not just a guard, it sends signals in nerves
White blood cells use their membranes to eat germs like hors d’oeuvres,
Membranes have receptors, enzymes, and junctions,
So what kinds of structure can have all these functions?
As we saw in the previous tutorial, phospholipids make up the basic structure of the membrane. But additional membrane functions come from proteins, cholesterol, and carbohydrates that are embedded in the structure of the membrane, as shown below.
Using the numbered diagram below, let’s get a quick overview of some of the specific things that these membrane components do.
1a. Membrane Proteins
Proteins are classified by their position in the membrane.
- Any protein embedded in the phospholipid bilayer is called an integral protein. In the diagram at left, 1, 5, and 6 are integral proteins.
- If the protein passes all the way through the membrane, like 1 and 6 above, it’s a transmembrane protein.
- If the protein hangs on to the membrane, attached to the phospholipid heads (but not extending into the hydrophobic tails), then it’s a peripheral protein. Number 3 above is peripheral.
Here are some protein functions
- They act as channels or ports (6), allowing the cell to take in and let out molecules that can’t diffuse through the phospholipid bilayer portion of the membrane.
- They act as carriers, allowing the cell to perform active transport, moving molecules from low concentration to high concentration.
- They act as attachment points for the fibers of the cytoskeleton, allowing the cell to change its shape and move (3).
- They act as membrane-embedded enzymes. We’ll see these at work in essential cell processes like photosynthesis and cellular respiration.
- They act as receptors, receiving chemical messages (including hormones) and relaying these messages into the cytoplasm.
1b. Cholesterol, and Membrane Carbohydrates
Other key membrane components include cholesterol and membrane carbohydrates.
- Cholesterol (7) is a lipid that plays a key role in maintaining membrane integrity and fluidity. When cell membranes become too warm, cholesterol keeps the phospholipid bilayer intact. When cell membranes become too cold, cholesterol acts as an anti-freeze, keeping the membrane fluid.
- Membrane carbohydrates (8) play a key role in allowing the immune system to recognize a cell as belonging to the multicellular organism that it’s a part of (as opposed to some invading bacterium). You can think of these carbohydrates as little flags. They’re the key markers, for example, in the A, AB, B, and O blood type system.
1c. It’s all a fluid mosaic
Diagrams like these can leave you with the misunderstanding that membranes are fixed, kind of like a chocolate bar with almonds, with the almonds locked into place. In fact, the membrane is a dynamic fluid, with all of its parts in constant motion. This model of membrane structure is called the fluid mosaic model.
Use the flashcards below to master these membrane components.
2. Cell Membrane Structure Flashcards
[qdeck random = “true” style=”width: 528px; border: 2px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Cell Membrane Structure Flashcards (M8)”]
[h] Flashcards: Cell Membrane Structure
[i] If you haven’t used a set of flashcards on Learn-Biology.com before, here’s what you need to know.
- Click ‘Check Answer’ to see the answer to each card.
- If you know it, click ‘Got it.”
- If you don’t know it as well as you’d like, click ‘Need more practice,’ and that card will go to the bottom of the deck so you can practice it again.
- ‘Shuffle’ lets you shuffle the deck.
[!] Card 3+++++++++++++++++++++++++++++++++++[/!]
[q]Membranes allow certain molecules to pass through but not others. In other words, membranes are ________-_______________.
[textentry]
[a] Membranes allow certain molecules to pass through but not others. In other words, membranes are selectively-permeable. (note that semi-permeable means just about the same thing).
[!] Card 3+++++++++++++++++++++++++++++++++++[/!]
[q]Just for review (from the last tutorial). The arrangement of phospholipids shown below is called a phospholipid ________ [textentry]
[a]The arrangement of phospholipids shown below is called a phospholipid bilayer.
[!] Card 13+++++++++++++++++++++++++++++++++++[/!]
[q]The dynamic model of cell membrane structure which involves phospholipids, proteins, cholesterol, and carbohydrates in constant motion in the membrane is the _______-_______ model.[textentry]
[a]The dynamic model of cell membrane structure which involves phospholipids, proteins, cholesterol, and carbohydrates in constant motion in the membrane is the fluid mosaic model.
[!] Card 14+++++++++++++++++++++++++++++++++++[/!]
[q]In the diagram below, membrane proteins like the ones at 1, 5, and 6, all of which are embedded in the phospholipid bilayer, are known as_____________ proteins. [textentry]
[a]In the diagram below, membrane proteins like the ones at 1, 5, and 6, all of which are embedded in the phospholipid bilayer, are known as integral proteins.
[!] Card 15+++++++++++++++++++++++++++++++++++[/!]
[q]In the diagram below, membrane proteins like the ones at 1 and 6, both of which span the width of the phospholipid bilayer, are known as_____________ proteins. [textentry]
[a]In the diagram below, membrane proteins like the ones at 1 and 6, both of which span the width of the phospholipid bilayer, are known as transmembrane proteins.
[!] Card 16+++++++++++++++++++++++++++++++++++[/!]
[q]In the diagram below, the molecule shown at 7 is a lipid, but not a phospholipid. Its function is to stabilize the membrane at high temperatures and to keep it fluid at low temperatures. This molecule must be ________[textentry]
[a]In the diagram below, the molecule shown at 7 is a lipid, but not a phospholipid. Its function is to stabilize the membrane at high temperatures and to keep it fluid at low temperatures. This molecule must be cholesterol.
[!] Card 17+++++++++++++++++++++++++++++++++++[/!]
[q]Because of the way that it’s positioned in the membrane, you can tell that protein # 3 must be a _______ protein. [textentry]
[a]Because of the way that it’s positioned in the membrane (hanging off the bottom) you can tell that protein # 3 must be a peripheral protein.
[x]
If you want more practice, please press the restart button below. Otherwise, follow the links below.
[restart]
[/qdeck]
3. Quiz: Cell Membrane Structure
This quiz tests you on the diagram you just worked with above, plus this one:
- A – phospholipid molecule;
- A1 – hydrophilic phosphate head group of phospholipid;
- A2 – Fatty acid tail (x 2) of phospholipid;
- B – a phospholipid with a carbohydrate chain attached to it)
- C– a protein with a carbohydrate chain attached to it);
- D – carbohydrate chain of glycoprotein;
- E – cholesterol;
- F – protein;
- G – a protein channel (pore)
- H-I: Phospholipid bilayer
[qwiz random = “true;” style = ” border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Cell Membrane Structure Quiz (M8)”]
[h]Cell Membrane Structure Quiz
[i]
[q labels = “top”]
[l]phospholipid bilayer
[fx] No. Please try again.
[f*] Correct!
[l]phospholipid
head
[fx] No. Please try again.
[f*] Excellent!
[l]phospholipid
tail
[fx] No, that’s not correct. Please try again.
[f*] Good!
[l]protein channel
[fx] No, that’s not correct. Please try again.
[f*] Good!
[q labels = “top”]
[l]cholesterol
[fx] No. Please try again.
[f*] Good!
[l]integral protein
[fx] No. Please try again.
[f*] Excellent!
[l]membrane carbohydrate
[fx] No, that’s not correct. Please try again.
[f*] Good!
[l]peripheral protein
[fx] No, that’s not correct. Please try again.
[f*] Excellent!
[l]phospholipid bilayer
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]phospholipid head
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]phospholipid tail
[fx] No, that’s not correct. Please try again.
[f*] Good!
[l]protein channel
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]trans-membrane protein
[fx] No. Please try again.
[f*] Correct!
[q] In the diagram below, which number is pointing to the phospholipid bilayer?
[c]IDEgwqDCoA==[Qq][c]IDIgwqDCoA==[Qq][c]IDMgwqDCoA==[Qq][c]ID Q=
Cg==[Qq][f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC4gSGVyZSYjODIxNztzIGEgaGludDogdGhlIHRlcm0gJiM4MjIwO2JpbGF5ZXImIzgyMjE7IG1lYW5zICYjODIyMDt0d28gbGF5ZXJzLiYjODIyMTsgV2hhdCBsb29rcyBsaWtlIGl0JiM4MjE3O3MgbWFkZSBvZiB0d28gbGF5ZXJzPw==[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byBhIHBob3NwaG9saXBpZCBoZWFkLiBIZXJlJiM4MjE3O3MgYSBoaW50OiB0aGUgdGVybSAmIzgyMjA7YmlsYXllciYjODIyMTsgbWVhbnMgJiM4MjIwO3R3byBsYXllcnMuJiM4MjIxOyBXaGF0IGxvb2tzIGxpa2UgaXQmIzgyMTc7cyBtYWRlIG9mIHR3byBsYXllcnM/[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC7CoEhlcmUmIzgyMTc7cyBhIGhpbnQ6IHRoZSB0ZXJtICYjODIyMDtiaWxheWVyJiM4MjIxOyBtZWFucyAmIzgyMjA7dHdvIGxheWVycy4mIzgyMjE7IFdoYXQgbG9va3MgbGlrZSBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycz8=[Qq]
[f]IEV4Y2VsbGVudC4gTnVtYmVyIDQgaXMgcG9pbnRpbmcgdG8gdGhlIHBob3NwaG9saXBpZCBiaWxheWVyLg==
Cg==[Qq]
[q] In the diagram below, which number is pointing to the hydrophobic tail of a phospholipid?
[c]IDEgwq AgwqA=[Qq][c]IDIgwqAgwqA=[Qq][c]IDMgwqAgwqA=[Qq][c]IDQ=
Cg==[Qq][f]IFllcy4gTnVtYmVyIDEgaXMgcG9pbnRpbmcgdG8gdGhlIHRhaWwgb2YgYSBwaG9zcGhvbGlwaWQu[Qq]
[f]IE5vLsKgTnVtYmVyIDIgaXMgcG9pbnRpbmcgdG8gYSBwaG9zcGhvbGlwaWQgaGVhZC4gV2hhdCBsb29rcyBsaWtlIGEgdGFpbD8=[Qq]
[f]IE5vLsKgTnVtYmVyIDMgaXMgcG9pbnRpbmcgdG8gYSBwcm90ZWluIGNoYW5uZWwuwqBXaGF0IGxvb2tzIGxpa2UgYSB0YWlsPw==[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuIFdoYXQgbG9va3MgbGlrZSBhIHRhaWw/
Cg==[Qq]
[q] In the diagram below, which number is pointing to a protein channel?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAg wqDCoA==[Qq][c]IDQ=
Cg==[Qq][f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC4gSW4gdGhlIGNvbnRleHQgb2YgbWVtYnJhbmVzLCBhwqBjaGFubmVsIGlzIGEgc3RydWN0dXJlIHRoYXQgbGV0cyBtb2xlY3VsZXMgcGFzcyB0aHJvdWdowqAobGlrZSBhIGJyaWRnZSBvciBhIHR1bm5lbCkuIFdoYXQgbG9va3MgbGlrZSBhIGNoYW5uZWw/[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byBhIHBob3NwaG9saXBpZCBoZWFkLsKgSW4gdGhlIGNvbnRleHQgb2YgbWVtYnJhbmVzLCBhwqBjaGFubmVsIGlzIGEgc3RydWN0dXJlIHRoYXQgbGV0cyBtb2xlY3VsZXMgcGFzcyB0aHJvdWdowqAobGlrZSBhIGJyaWRnZSBvciBhIHR1bm5lbCkuIFdoYXQgbG9va3MgbGlrZSBhIGNoYW5uZWw/[Qq]
[f]IFllcy4gTnVtYmVyIDMgaXMgcG9pbnRpbmcgdG8gYSBwcm90ZWluIGNoYW5uZWwu[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuwqBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGHCoGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2jCoChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=
Cg==[Qq]
[q] In the diagram below, which number is pointing to the phospholipid bilayer?[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAg wqDCoA==[Qq][c]IDMgwqAgwqDCoA==[Qq][c]IDQgwqAgwqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIMKgIMKg[Qq][c]N8KgIMKgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ==
Cg==[Qq][f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0d28gdHJhbnNtZW1icmFuZSBwcm90ZWlucy4gVGhlIHBob3NwaG9saXBpZCBiaWxheWVyIGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IFllcy4gTnVtYmVyIDIgaXMgcG9pbnRpbmcgdG8gdGhlIHBob3NwaG9saXBpZCBiaWxheWVyLg==[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhIHBlcmlwaGVyYWwgcHJvdGVpbi4gVGhlIHBob3NwaG9saXBpZCBiaWxheWVyIGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHNpbmdsZSBwaG9zcGhvbGlwaWQuwqBUaGUgcGhvc3Bob2xpcGlkIA==YmlsYXllcg==IGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyBwb2ludGluZyB0byBhbiBpbnRlZ3JhbCBwcm90ZWluLiBUaGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIgaXMgdGhlIG1haW4gc3RydWN0dXJlIG9mIHRoZSBtZW1icmFuZSwgYW5kIGl0JiM4MjE3O3MgbWFkZSBvZiB0d28gbGF5ZXJzIG9mIHBob3NwaG9saXBpZHMsIHRoZSBsb3dlciBvbmUgd2l0aCBpdHMgaGVhZHMgZG93biwgYW5kIHRoZSB0b3Agb25lIHdpdGggaXRzIGhlYWRzIHVwLiBXaGF0IG51bWJlciBwb2ludHMgdG8gc29tZXRoaW5nIHRoYXQgZml0cyB0aGF0IGRlc2NyaXB0aW9uPw==[Qq]
[f]IE5vISBOdW1iZXIgNiBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4gVGhlIHBob3NwaG9saXBpZCBiaWxheWVyIGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IE5vLiBOdW1iZXIgNyBpcyBwb2ludGluZyB0byBjaG9sZXN0ZXJvbC4gVGhlIHBob3NwaG9saXBpZCBiaWxheWVyIGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IE5vLiBOdW1iZXIgOCBpcyBwb2ludGluZyB0byBhIG1lbWJyYW5lIGNhcmJvaHlkcmF0ZS4gVGhlIHBob3NwaG9saXBpZCBiaWxheWVyIGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBOdW1iZXIgOcKgaXMgcG9pbnRpbmcgdG8gdGhlIGhlYWQgb2YgYSBwaG9zcGhvbGlwaWQuwqBUaGUgcGhvc3Bob2xpcGlkIA==YmlsYXllcg==IGlzIHRoZSBtYWluIHN0cnVjdHVyZSBvZiB0aGUgbWVtYnJhbmUsIGFuZCBpdCYjODIxNztzIG1hZGUgb2YgdHdvIGxheWVycyBvZiBwaG9zcGhvbGlwaWRzLCB0aGUgbG93ZXIgb25lIHdpdGggaXRzIGhlYWRzIGRvd24sIGFuZCB0aGUgdG9wIG9uZSB3aXRoIGl0cyBoZWFkcyB1cC4gV2hhdCBudW1iZXIgcG9pbnRzIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=
Cg==[Qq]
[q] In the diagram below, which number is pointing to a molecule of cholesterol?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAgwqDCoA==[Qq][c]IDQgwqAgwqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIMKgIMKg[Qq][c]N8KgIM KgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ==
[f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0d28gdHJhbnNtZW1icmFuZSBwcm90ZWlucy4gQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZCB0aGF0JiM4MjE3O3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLCBidXQgaXQmIzgyMTc7cyBub3QgYSBwaG9zcGhvbGlwaWQuIEVsaW1pbmF0ZSB0aGUgcHJvdGVpbnMgKGFsbCBzaGFkZWQgaW4gYmx1ZSksIGFuZCBzZWUgaWYgeW91IGNhbiBmaWd1cmUgb3V0IHRoZSBhbnN3ZXIu[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuwqBDaG9sZXN0ZXJvbCBpcyBhIGxpcGlkIHRoYXQmIzgyMTc7cyBlbWJlZGRlZCBpbiB0aGUgbWVtYnJhbmUsIGJ1dCBpdCYjODIxNztzIG5vdCBhIHBob3NwaG9saXBpZC4gRWxpbWluYXRlIHRoZSBwcm90ZWlucyAoYWxsIHNoYWRlZCBpbiBibHVlKSwgYW5kIHNlZSBpZiB5b3UgY2FuIGZpZ3VyZSBvdXQgdGhlIGFuc3dlci4=[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhIHBlcmlwaGVyYWwgcHJvdGVpbi4gQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZCB0aGF0JiM4MjE3O3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLCBidXQgaXQmIzgyMTc7cyBub3QgYSBwaG9zcGhvbGlwaWQuIEVsaW1pbmF0ZSB0aGUgcHJvdGVpbnMgKGFsbCBzaGFkZWQgaW4gYmx1ZSksIGFuZCBzZWUgaWYgeW91IGNhbiBmaWd1cmUgb3V0IHRoZSBhbnN3ZXIu[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC7CoENob2xlc3Rlcm9sIGlzIGEgbGlwaWQgdGhhdCYjODIxNztzIGVtYmVkZGVkIGluIHRoZSBtZW1icmFuZSwgYnV0IGl0JiM4MjE3O3Mgbm90IGEgcGhvc3Bob2xpcGlkLiBFbGltaW5hdGUgdGhlIHByb3RlaW5zIChhbGwgc2hhZGVkIGluIGJsdWUpLCBhbmQgc2VlIGlmIHlvdSBjYW4gZmlndXJlIG91dCB0aGUgYW5zd2VyLg==[Qq]
[f]IE5vLiBOdW1iZXIgNcKgaXMgcG9pbnRpbmcgdG/CoGFuIGludGVncmFsIHByb3RlaW4uwqBDaG9sZXN0ZXJvbCBpcyBhIGxpcGlkIHRoYXQmIzgyMTc7cyBlbWJlZGRlZCBpbiB0aGUgbWVtYnJhbmUsIGJ1dCBpdCYjODIxNztzIG5vdCBhIHBob3NwaG9saXBpZC4gRWxpbWluYXRlIHRoZSBwcm90ZWlucyAoYWxsIHNoYWRlZCBpbiBibHVlKSwgYW5kIHNlZSBpZiB5b3UgY2FuIGZpZ3VyZSBvdXQgdGhlIGFuc3dlci4=[Qq]
[f]IE5vLiBOdW1iZXIgNiBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4gQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZCB0aGF0JiM4MjE3O3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLCBidXQgaXQmIzgyMTc7cyBub3QgYSBwaG9zcGhvbGlwaWQuIEVsaW1pbmF0ZSB0aGUgcHJvdGVpbnMgKGFsbCBzaGFkZWQgaW4gYmx1ZSksIGFuZCBzZWUgaWYgeW91IGNhbiBmaWd1cmUgb3V0IHRoZSBhbnN3ZXIu[Qq]
[f]IFllcy4gTnVtYmVyIDfCoGlzIHBvaW50aW5nIHRvIGNob2xlc3Rlcm9sLg==[Qq]
[f]IE5vLiBOdW1iZXIgOMKgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqBDaG9sZXN0ZXJvbCBpcyBhIGxpcGlkIHRoYXQmIzgyMTc7cyBlbWJlZGRlZCBpbiB0aGUgbWVtYnJhbmUsIGJ1dCBpdCYjODIxNztzIG5vdCBhIHBob3NwaG9saXBpZC4gRWxpbWluYXRlIHRoZSBwcm90ZWlucyAoYWxsIHNoYWRlZCBpbiBibHVlKSwgYW5kIHNlZSBpZiB5b3UgY2FuIGZpZ3VyZSBvdXQgdGhlIGFuc3dlci4=[Qq]
[f]IE5vLiBOdW1iZXIgOcKgaXMgcG9pbnRpbmcgdG8gdGhlIGhlYWQgb2YgYSBwaG9zcGhvbGlwaWQuwqBDaG9sZXN0ZXJvbCBpcyBhIGxpcGlkIHRoYXQmIzgyMTc7cyBlbWJlZGRlZCBpbiB0aGUgbWVtYnJhbmUsIGJ1dCBpdCYjODIxNztzIG5vdCBhIHBob3NwaG9saXBpZC4gRWxpbWluYXRlIHRoZSBwcm90ZWlucyAoYWxsIHNoYWRlZCBpbiBibHVlKSwgYW5kIHNlZSBpZiB5b3UgY2FuIGZpZ3VyZSBvdXQgdGhlIGFuc3dlci4=
Cg==[Qq]
[q] In the diagram below, which number is pointing to a phospholipid head?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAgwqDCoA==[Qq][c]IDQgwqAgwqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIMKgIMKg[Qq][c]N8KgIMKgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ ==
[f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0d28gdHJhbnNtZW1icmFuZSBwcm90ZWlucy4gVGhlIHBob3NwaG9saXBpZHMgYXJlIHRoZSBtYWluIHN0cnVjdHVyYWwgbW9sZWN1bGVzIG1ha2luZyB1cCB0aGUgbWVtYnJhbmUuIFRoZSBwb2xhciAmIzgyMjA7aGVhZHMmIzgyMjE7IG9mIHRoZSBwaG9zcGhvbGlwaWRzIGZhY2UgdG93YXJkcyB0aGUgb3V0c2lkZSBvZiB0aGUgbWVtYnJhbmUgKHdoaWNoIG1lYW5zIHVwLCB0b3dhcmQgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQsIGFuZCBkb3duLCB0b3dhcmRzIHRoZSBjeXRvcGxhc20pLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==[Qq]
[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byB0aGUgZW50aXJlIHBob3NwaG9saXBpZCBiaWxheWVyLiBUaGUgcG9sYXIgJiM4MjIwO2hlYWRzJiM4MjIxOyBvZiB0aGUgcGhvc3Bob2xpcGlkcyBmYWNlIHRvd2FyZHMgdGhlIG91dHNpZGUgb2YgdGhlIG1lbWJyYW5lICh3aGljaCBtZWFucyB1cCwgdG93YXJkIHRoZSBleHRyYWNlbGx1bGFyIGZsdWlkLCBhbmQgZG93biwgdG93YXJkcyB0aGUgY3l0b3BsYXNtKS4gV2l0aCB0aGF0IGluIG1pbmQsIHNlZSBpZiB5b3UgY2FuIGZpbmQgYSBwaG9zcGhvbGlwaWQgaGVhZC4=[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhwqBwZXJpcGhlcmFsIHByb3RlaW4uwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIHBvbGFyICYjODIyMDtoZWFkcyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBvdXRzaWRlIG9mIHRoZSBtZW1icmFuZSAod2hpY2ggbWVhbnMgdXAsIHRvd2FyZCB0aGUgZXh0cmFjZWxsdWxhciBmbHVpZCwgYW5kIGRvd24sIHRvd2FyZHMgdGhlIGN5dG9wbGFzbSkuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC4gVGhlIHBvbGFyICYjODIyMDtoZWFkcyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBvdXRzaWRlIG9mIHRoZSBtZW1icmFuZSAod2hpY2ggbWVhbnMgdXAsIHRvd2FyZCB0aGUgZXh0cmFjZWxsdWxhciBmbHVpZCwgYW5kIGRvd24sIHRvd2FyZHMgdGhlIGN5dG9wbGFzbSkuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLiBOdW1iZXIgNcKgaXMgcG9pbnRpbmcgdG/CoGFuIGludGVncmFsIHByb3RlaW4uwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIHBvbGFyICYjODIyMDtoZWFkcyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBvdXRzaWRlIG9mIHRoZSBtZW1icmFuZSAod2hpY2ggbWVhbnMgdXAsIHRvd2FyZCB0aGUgZXh0cmFjZWxsdWxhciBmbHVpZCwgYW5kIGRvd24sIHRvd2FyZHMgdGhlIGN5dG9wbGFzbSkuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLiBOdW1iZXIgNiBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4gVGhlIHBob3NwaG9saXBpZHMgYXJlIHRoZSBtYWluIHN0cnVjdHVyYWwgbW9sZWN1bGVzIG1ha2luZyB1cCB0aGUgbWVtYnJhbmUuIFRoZSBwb2xhciAmIzgyMjA7aGVhZHMmIzgyMjE7IG9mIHRoZSBwaG9zcGhvbGlwaWRzIGZhY2UgdG93YXJkcyB0aGUgb3V0c2lkZSBvZiB0aGUgbWVtYnJhbmUgKHdoaWNoIG1lYW5zIHVwLCB0b3dhcmQgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQsIGFuZCBkb3duLCB0b3dhcmRzIHRoZSBjeXRvcGxhc20pLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==
[f]IE5vLiBOdW1iZXIgN8KgaXMgcG9pbnRpbmcgdG8gY2hvbGVzdGVyb2wuwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIHBvbGFyICYjODIyMDtoZWFkcyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBvdXRzaWRlIG9mIHRoZSBtZW1icmFuZSAod2hpY2ggbWVhbnMgdXAsIHRvd2FyZCB0aGUgZXh0cmFjZWxsdWxhciBmbHVpZCwgYW5kIGRvd24sIHRvd2FyZHMgdGhlIGN5dG9wbGFzbSkuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLiBOdW1iZXIgOMKgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIHBvbGFyICYjODIyMDtoZWFkcyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBvdXRzaWRlIG9mIHRoZSBtZW1icmFuZSAod2hpY2ggbWVhbnMgdXAsIHRvd2FyZCB0aGUgZXh0cmFjZWxsdWxhciBmbHVpZCwgYW5kIGRvd24sIHRvd2FyZHMgdGhlIGN5dG9wbGFzbSkuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IFllcy4gTnVtYmVyIDnCoGlzIHBvaW50aW5nIHRvIHRoZSBoZWFkIG9mIGEgcGhvc3Bob2xpcGlkLg==
Cg==[Qq]
[q] In the diagram below, which number is pointing to a peripheral protein?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAg wqDCoA==[Qq][c]IDQgwqAgwqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIMKgIMKg[Qq][c]N8KgIMKgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ==
[f]IE5vLiBOdW1iZXIgMSBwb2ludHMgdG8gdHdvIHRyYW5zbWVtYnJhbmUgcHJvdGVpbnMuIFBlcmlwaGVyYWwgcHJvdGVpbnMgaGFuZyBvbnRvIHRoZSBwaG9zcGhvbGlwaWQgaGVhZHMgb2YgdGhlIGJpbGF5ZXIsIHdpdGhvdXQgcGVuZXRyYXRpbmcgaW50byB0aGUgbWlkZGxlLCBoeWRyb3Bob2JpYyBwb3J0aW9uLiBHaXZlbiB0aGF0IGluIHRoaXMgZGlhZ3JhbSB0aGUgcHJvdGVpbnMgYXJlIHNoYWRlZCBibHVlLCB3aGljaCBudW1iZXIgaXMgcG9pbnRpbmcgdG8gc29tZXRoaW5nIHRoYXQgZml0cyB0aGF0IGRlc2NyaXB0aW9uPw==[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byB0aGUgZW50aXJlIHBob3NwaG9saXBpZCBiaWxheWVyLsKgUGVyaXBoZXJhbCBwcm90ZWlucyBoYW5nIG9udG8gdGhlIHBob3NwaG9saXBpZCBoZWFkcyBvZiB0aGUgYmlsYXllciwgd2l0aG91dCBwZW5ldHJhdGluZyBpbnRvIHRoZSBtaWRkbGUsIGh5ZHJvcGhvYmljIHBvcnRpb24uIEdpdmVuIHRoYXQgaW4gdGhpcyBkaWFncmFtIHRoZSBwcm90ZWlucyBhcmUgc2hhZGVkIGJsdWUsIHdoaWNoIG51bWJlciBpcyBwb2ludGluZyB0byBzb21ldGhpbmcgdGhhdCBmaXRzIHRoYXQgZGVzY3JpcHRpb24/[Qq]
[f]IFllcy4gTnVtYmVyIDMgaXMgcG9pbnRpbmcgdG8gYcKgcGVyaXBoZXJhbCBwcm90ZWluLg==[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC7CoFBlcmlwaGVyYWwgcHJvdGVpbnMgaGFuZyBvbnRvIHRoZSBwaG9zcGhvbGlwaWQgaGVhZHMgb2YgdGhlIGJpbGF5ZXIsIHdpdGhvdXQgcGVuZXRyYXRpbmcgaW50byB0aGUgbWlkZGxlLCBoeWRyb3Bob2JpYyBwb3J0aW9uLiBHaXZlbiB0aGF0IGluIHRoaXMgZGlhZ3JhbSB0aGUgcHJvdGVpbnMgYXJlIHNoYWRlZCBibHVlLCB3aGljaCBudW1iZXIgaXMgcG9pbnRpbmcgdG8gc29tZXRoaW5nIHRoYXQgZml0cyB0aGXCoGRlc2NyaXB0aW9uIG9mIGEgcGVyaXBoZXJhbCBwcm90ZWluPw==[Qq]
[f]IE5vLiBOdW1iZXIgNcKgaXMgcG9pbnRpbmcgdG/CoGFuIGludGVncmFsIHByb3RlaW4uwqBQZXJpcGhlcmFsIHByb3RlaW5zIGhhbmcgb250byB0aGUgcGhvc3Bob2xpcGlkIGhlYWRzIG9mIHRoZSBiaWxheWVyLCB3aXRob3V0IHBlbmV0cmF0aW5nIGludG8gdGhlIG1pZGRsZSwgaHlkcm9waG9iaWMgcG9ydGlvbi4gR2l2ZW4gdGhhdCBpbiB0aGlzIGRpYWdyYW0gdGhlIHByb3RlaW5zIGFyZSBzaGFkZWQgYmx1ZSwgd2hpY2ggbnVtYmVyIGlzIHBvaW50aW5nIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhlwqBkZXNjcmlwdGlvbiBvZiBhIHBlcmlwaGVyYWwgcHJvdGVpbj8=[Qq]
[f]IE5vLiBOdW1iZXIgNiBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4gUGVyaXBoZXJhbCBwcm90ZWlucyBoYW5nIG9udG8gdGhlIHBob3NwaG9saXBpZCBoZWFkcyBvZiB0aGUgYmlsYXllciwgd2l0aG91dCBwZW5ldHJhdGluZyBpbnRvIHRoZSBtaWRkbGUsIGh5ZHJvcGhvYmljIHBvcnRpb24uIEdpdmVuIHRoYXQgaW4gdGhpcyBkaWFncmFtIHRoZSBwcm90ZWlucyBhcmUgc2hhZGVkIGJsdWUsIHdoaWNoIG51bWJlciBpcyBwb2ludGluZyB0byBzb21ldGhpbmcgdGhhdCBmaXRzIHRoZSBkZXNjcmlwdGlvbiBvZiBhIHBlcmlwaGVyYWwgcHJvdGVpbj8=[Qq]
[f]IE5vLiBOdW1iZXIgN8KgaXMgcG9pbnRpbmcgdG8gY2hvbGVzdGVyb2wuwqBQZXJpcGhlcmFsIHByb3RlaW5zIGhhbmcgb250byB0aGUgcGhvc3Bob2xpcGlkIGhlYWRzIG9mIHRoZSBiaWxheWVyLCB3aXRob3V0IHBlbmV0cmF0aW5nIGludG8gdGhlIG1pZGRsZSwgaHlkcm9waG9iaWMgcG9ydGlvbi4gR2l2ZW4gdGhhdCBpbiB0aGlzIGRpYWdyYW0gdGhlIHByb3RlaW5zIGFyZSBzaGFkZWQgYmx1ZSwgd2hpY2ggbnVtYmVyIGlzIHBvaW50aW5nIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhlwqBkZXNjcmlwdGlvbiBvZiBhIHBlcmlwaGVyYWwgcHJvdGVpbj8=[Qq]
[f]IE5vLiBOdW1iZXIgOMKgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqBQZXJpcGhlcmFsIHByb3RlaW5zIGhhbmcgb250byB0aGUgcGhvc3Bob2xpcGlkIGhlYWRzIG9mIHRoZSBiaWxheWVyLCB3aXRob3V0IHBlbmV0cmF0aW5nIGludG8gdGhlIG1pZGRsZSwgaHlkcm9waG9iaWMgcG9ydGlvbi4gR2l2ZW4gdGhhdCBpbiB0aGlzIGRpYWdyYW0gdGhlIHByb3RlaW5zIGFyZSBzaGFkZWQgYmx1ZSwgd2hpY2ggbnVtYmVyIGlzIHBvaW50aW5nIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhlwqBkZXNjcmlwdGlvbiBvZiBhIHBlcmlwaGVyYWwgcHJvdGVpbj8=[Qq]
[f]IE5vLiBOdW1iZXIgOcKgaXMgcG9pbnRpbmcgdG8gdGhlIGhlYWQgb2YgYSBwaG9zcGhvbGlwaWQuwqBQZXJpcGhlcmFsIHByb3RlaW5zIGhhbmcgb250byB0aGUgcGhvc3Bob2xpcGlkIGhlYWRzIG9mIHRoZSBiaWxheWVyLCB3aXRob3V0IHBlbmV0cmF0aW5nIGludG8gdGhlIG1pZGRsZSwgaHlkcm9waG9iaWMgcG9ydGlvbi4gR2l2ZW4gdGhhdCBpbiB0aGlzIGRpYWdyYW0gdGhlIHByb3RlaW5zIGFyZSBzaGFkZWQgYmx1ZSwgd2hpY2ggbnVtYmVyIGlzIHBvaW50aW5nIHRvIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhlwqBkZXNjcmlwdGlvbiBvZiBhIHBlcmlwaGVyYWwgcHJvdGVpbj8=
Cg==[Qq]
[q] In the diagram below, which number is pointing to a protein channel?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAgwqDCoA==[Qq][c]IDQgwqAgwqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIM KgIMKg[Qq][c]N8KgIMKgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ==
[f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0d28gdHJhbnNtZW1icmFuZSBwcm90ZWlucy4gQSBjaGFubmVsIGlzIGEgc3RydWN0dXJlIHRoYXQgbGV0cyBtb2xlY3VsZXMgcGFzcyB0aHJvdWdoIChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=[Qq]
[f]IE5vLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuwqBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGHCoGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2jCoChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhIHBlcmlwaGVyYWwgcHJvdGVpbi4gSW4gdGhlIGNvbnRleHQgb2YgbWVtYnJhbmVzLCBhIGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2ggKGxpa2UgYSBicmlkZ2Ugb3IgYSB0dW5uZWwpLiBXaGF0IGxvb2tzIGxpa2UgYSBjaGFubmVsPw==[Qq]
[f]IE5vLiBOdW1iZXIgNCBpcyBwb2ludGluZyB0byB0aGUgdGFpbCBvZiBhIHBob3NwaG9saXBpZC7CoEluIHRoZSBjb250ZXh0IG9mIG1lbWJyYW5lcywgYcKgY2hhbm5lbCBpcyBhIHN0cnVjdHVyZSB0aGF0IGxldHMgbW9sZWN1bGVzIHBhc3MgdGhyb3VnaMKgKGxpa2UgYSBicmlkZ2Ugb3IgYSB0dW5uZWwpLiBXaGF0IGxvb2tzIGxpa2UgYSBjaGFubmVsPw==[Qq]
[f]IE5vLiBOdW1iZXIgNSBpcyBwb2ludGluZyB0byBhbiBpbnRlZ3JhbCBwcm90ZWluIChidXQgb25lIHRoYXQmIzgyMTc7cyBub3QgYSB0cmFuc21lbWJyYW5lIHByb3RlaW4pLiBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGEgY2hhbm5lbCBpcyBhIHN0cnVjdHVyZSB0aGF0IGxldHMgbW9sZWN1bGVzIHBhc3MgdGhyb3VnaCAobGlrZSBhIGJyaWRnZSBvciBhIHR1bm5lbCkuIFdoYXQgbG9va3MgbGlrZSBhIGNoYW5uZWw/[Qq]
[f]IEV4Y2VsbGVudCEgTnVtYmVyIDYgaXMgcG9pbnRpbmcgdG8gYSBwcm90ZWluIGNoYW5uZWwu[Qq]
[f]IE5vLiBOdW1iZXIgN8KgaXMgcG9pbnRpbmcgdG8gY2hvbGVzdGVyb2wuwqBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGHCoGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2jCoChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=[Qq]
[f]IE5vLiBOdW1iZXIgOMKgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGHCoGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2jCoChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=[Qq]
[f]IE5vLiBOdW1iZXIgOcKgaXMgcG9pbnRpbmcgdG8gdGhlIGhlYWQgb2YgYSBwaG9zcGhvbGlwaWQuwqBJbiB0aGUgY29udGV4dCBvZiBtZW1icmFuZXMsIGHCoGNoYW5uZWwgaXMgYSBzdHJ1Y3R1cmUgdGhhdCBsZXRzIG1vbGVjdWxlcyBwYXNzIHRocm91Z2jCoChsaWtlIGEgYnJpZGdlIG9yIGEgdHVubmVsKS4gV2hhdCBsb29rcyBsaWtlIGEgY2hhbm5lbD8=
Cg==[Qq]
[q] In the diagram below, which number is pointing to a phospholipid tail?
[c]IDEgwqAgwqDCoA==[Qq][c]IDIgwqAgwqDCoA==[Qq][c]IDMgwqAgwqDCoA==[Qq][c]IDQgwqAg wqDCoA==[Qq][c]NcKgIMKgIA==[Qq][c]NsKgIMKgIMKg[Qq][c]N8KgIMKgIMKg[Qq][c]OCDCoCDCoA==[Qq][c]OQ==
[f]IE5vLiBOdW1iZXIgMSBpcyBwb2ludGluZyB0byB0d28gdHJhbnNtZW1icmFuZSBwcm90ZWlucy4gVGhlIHBob3NwaG9saXBpZHMgYXJlIHRoZSBtYWluIHN0cnVjdHVyYWwgbW9sZWN1bGVzIG1ha2luZyB1cCB0aGUgbWVtYnJhbmUuIFRoZSBub24tcG9sYXIgJiM4MjIwO3RhaWxzJiM4MjIxOyBvZiB0aGUgcGhvc3Bob2xpcGlkcyBmYWNlIHRvd2FyZHMgdGhlIGluc2lkZSBvZiB0aGUgbWVtYnJhbmUsIGF3YXkgZnJvbSB0aGUgY3l0b3BsYXNtIG9yIHRoZSBleHRyYWNlbGx1bGFyIGZsdWlkLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==[Qq]
[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBOdW1iZXIgMiBpcyBwb2ludGluZyB0byB0aGUgZW50aXJlIHBob3NwaG9saXBpZCBiaWxheWVyLiBUaGUgbm9uLXBvbGFyICYjODIyMDt0YWlscyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBpbnNpZGXCoG9mIHRoZSBtZW1icmFuZSwgYXdheSBmcm9tIHRoZSBjeXRvcGxhc20gb3IgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLiBOdW1iZXIgMyBpcyBwb2ludGluZyB0byBhwqBwZXJpcGhlcmFsIHByb3RlaW4uIFRoZSBwaG9zcGhvbGlwaWRzIGFyZSB0aGUgbWFpbiBzdHJ1Y3R1cmFsIG1vbGVjdWxlcyBtYWtpbmcgdXAgdGhlIG1lbWJyYW5lLiBUaGUgbm9uLXBvbGFyICYjODIyMDt0YWlscyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBpbnNpZGXCoG9mIHRoZSBtZW1icmFuZSwgYXdheSBmcm9tIHRoZSBjeXRvcGxhc20gb3IgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IFllcy4gTnVtYmVyIDQgaXMgcG9pbnRpbmcgdG8gdGhlIHRhaWwgb2YgYSBwaG9zcGhvbGlwaWQu[Qq]
[f]IE5vLiBOdW1iZXIgNcKgaXMgcG9pbnRpbmcgdG/CoGFuIGludGVncmFsIHByb3RlaW4uIFRoZSBwaG9zcGhvbGlwaWRzIGFyZSB0aGUgbWFpbiBzdHJ1Y3R1cmFsIG1vbGVjdWxlcyBtYWtpbmcgdXAgdGhlIG1lbWJyYW5lLiBUaGUgbm9uLXBvbGFyICYjODIyMDt0YWlscyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBpbnNpZGXCoG9mIHRoZSBtZW1icmFuZSwgYXdheSBmcm9tIHRoZSBjeXRvcGxhc20gb3IgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vISBOdW1iZXIgNiBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4gVGhlIHBob3NwaG9saXBpZHMgYXJlIHRoZSBtYWluIHN0cnVjdHVyYWwgbW9sZWN1bGVzIG1ha2luZyB1cCB0aGUgbWVtYnJhbmUuIFRoZSBub24tcG9sYXIgJiM4MjIwO3RhaWxzJiM4MjIxOyBvZiB0aGUgcGhvc3Bob2xpcGlkcyBmYWNlIHRvd2FyZHMgdGhlIGluc2lkZSBvZiB0aGUgbWVtYnJhbmUsIGF3YXkgZnJvbSB0aGUgY3l0b3BsYXNtIG9yIHRoZSBleHRyYWNlbGx1bGFyIGZsdWlkLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==[Qq]
[f]IE5vLiBOdW1iZXIgN8KgaXMgcG9pbnRpbmcgdG8gY2hvbGVzdGVyb2wuIFRoZSBwaG9zcGhvbGlwaWRzIGFyZSB0aGUgbWFpbiBzdHJ1Y3R1cmFsIG1vbGVjdWxlcyBtYWtpbmcgdXAgdGhlIG1lbWJyYW5lLiBUaGUgbm9uLXBvbGFyICYjODIyMDt0YWlscyYjODIyMTsgb2YgdGhlIHBob3NwaG9saXBpZHMgZmFjZSB0b3dhcmRzIHRoZSBpbnNpZGXCoG9mIHRoZSBtZW1icmFuZSwgYXdheSBmcm9tIHRoZSBjeXRvcGxhc20gb3IgdGhlIGV4dHJhY2VsbHVsYXIgZmx1aWQuIFdpdGggdGhhdCBpbiBtaW5kLCBzZWUgaWYgeW91IGNhbiBmaW5kIGEgcGhvc3Bob2xpcGlkIGhlYWQu[Qq]
[f]IE5vLiBOdW1iZXIgOMKgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIG5vbi1wb2xhciAmIzgyMjA7dGFpbHMmIzgyMjE7IG9mIHRoZSBwaG9zcGhvbGlwaWRzIGZhY2UgdG93YXJkcyB0aGUgaW5zaWRlwqBvZiB0aGUgbWVtYnJhbmUsIGF3YXkgZnJvbSB0aGUgY3l0b3BsYXNtIG9yIHRoZSBleHRyYWNlbGx1bGFyIGZsdWlkLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==[Qq]
[f]IE5vLiBOdW1iZXIgOcKgaXMgcG9pbnRpbmcgdG8gdGhlIGhlYWQgb2YgYSBwaG9zcGhvbGlwaWQuwqBUaGUgcGhvc3Bob2xpcGlkcyBhcmUgdGhlIG1haW4gc3RydWN0dXJhbCBtb2xlY3VsZXMgbWFraW5nIHVwIHRoZSBtZW1icmFuZS4gVGhlIG5vbi1wb2xhciAmIzgyMjA7dGFpbHMmIzgyMjE7IG9mIHRoZSBwaG9zcGhvbGlwaWRzIGZhY2UgdG93YXJkcyB0aGUgaW5zaWRlwqBvZiB0aGUgbWVtYnJhbmUsIGF3YXkgZnJvbSB0aGUgY3l0b3BsYXNtIG9yIHRoZSBleHRyYWNlbGx1bGFyIGZsdWlkLiBXaXRoIHRoYXQgaW4gbWluZCwgc2VlIGlmIHlvdSBjYW4gZmluZCBhIHBob3NwaG9saXBpZCBoZWFkLg==
Cg==[Qq]
[q]In the diagram below, which letter represents a membrane carbohydrate?
[c]IEHCoCDCoCDCoA==[Qq][c]IETCoC DCoA==[Qq][c]RSDCoCDCoCDCoCA=[Qq][c]SC1JIMKgIMKgIA==[Qq][c]Rw==
Cg==[Qq][f]Tm8uIEEgaXMgcG9pbnRpbmcgdG8gYSBwaG9zcGhvbGlwaWQuIE1lbWJyYW5lIGNhcmJvaHlkcmF0ZXMgYXJlIHVzdWFsbHkgc2hvcnQsIGJyYW5jaGVkIHBvbHlzYWNjaGFyaWRlcy4gTG9vayBjbG9zZWx5IGFuZCBzZWUgaWYgeW91IGNhbiBmaW5kIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbi4=[Qq]
[f]WWVzLiBEIGlzIHBvaW50aW5nIHRvIGEgbWVtYnJhbmUgY2FyYm9oeWRyYXRlLg==[Qq]
[f]Tm8uIEUgaXMgcG9pbnRpbmcgdG8gYSBtb2xlY3VsZSBvZiBjaG9sZXN0ZXJvbC4gTWVtYnJhbmUgY2FyYm9oeWRyYXRlcyBhcmUgdXN1YWxseSBzaG9ydCwgYnJhbmNoZWQgcG9seXNhY2NoYXJpZGVzLiBMb29rIGNsb3NlbHkgYW5kIHNlZSBpZiB5b3UgY2FuIGZpbmQgc29tZXRoaW5nIHRoYXQgZml0cyB0aGF0IGRlc2NyaXB0aW9uLg==[Qq]
[f]Tm8uIEgtSSBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuIE1lbWJyYW5lIGNhcmJvaHlkcmF0ZXMgYXJlIHVzdWFsbHkgc2hvcnQsIGJyYW5jaGVkIHBvbHlzYWNjaGFyaWRlcy4gTG9vayBjbG9zZWx5IGFuZCBzZWUgaWYgeW91IGNhbiBmaW5kIHNvbWV0aGluZyB0aGF0IGZpdHMgdGhhdCBkZXNjcmlwdGlvbi4=[Qq]
[f]Tm8uIEfCoGlzIHBvaW50aW5nIHRvIGEgcHJvdGVpbiBjaGFubmVsLiBNZW1icmFuZSBjYXJib2h5ZHJhdGVzIGFyZSB1c3VhbGx5IHNob3J0LCBicmFuY2hlZCBwb2x5c2FjY2hhcmlkZXMuIExvb2sgY2xvc2VseSBhbmQgc2VlIGlmIHlvdSBjYW4gZmluZCBzb21ldGhpbmcgdGhhdCBmaXRzIHRoYXQgZGVzY3JpcHRpb24u
Cg==[Qq]
[q]In the diagram below, which letter represents a protein channel?
[c]IEHCoCDCoCDCoA==[Qq][c]IETCoCDCoA==[Qq][c]RSDCoCDCoCDCoCA=[Qq][c]SC1JIMKgIMKgIA==[Qq][c]Rw ==
Cg==[Qq][f]Tm8uIEEgaXMgcG9pbnRpbmcgdG8gYSBwaG9zcGhvbGlwaWQuIEEgcHJvdGVpbiBjaGFubmVsIGlzIGxpa2UgYSBwb3JlIG9yIGEgdHVubmVsLiBJdCBhbGxvd3MgbW9sZWN1bGVzIHRvIHBhc3MgdGhyb3VnaC4gV2hhdCwgaW4gdGhpcyBkaWFncmFtLCBsb29rcyBsaWtlIGEgdHVubmVsPw==[Qq]
[f]Tm8uIEQgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuwqDCoEEgcHJvdGVpbiBjaGFubmVsIGlzIGxpa2UgYSBwb3JlIG9yIGEgdHVubmVsLiBJdCBhbGxvd3MgbW9sZWN1bGVzIHRvIHBhc3MgdGhyb3VnaC4gV2hhdCwgaW4gdGhpcyBkaWFncmFtLCBsb29rcyBsaWtlIGEgdHVubmVsPw==[Qq]
[f]Tm8uIEUgaXMgcG9pbnRpbmcgdG8gYSBtb2xlY3VsZSBvZiBjaG9sZXN0ZXJvbC4gQSBwcm90ZWluIGNoYW5uZWwgaXMgbGlrZSBhIHBvcmUgb3IgYSB0dW5uZWwuIEl0IGFsbG93cyBtb2xlY3VsZXMgdG8gcGFzcyB0aHJvdWdoLiBXaGF0LCBpbiB0aGlzIGRpYWdyYW0sIGxvb2tzIGxpa2UgYSB0dW5uZWw/[Qq]
[f]Tm8uIEgtSSBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuwqDCoEEgcHJvdGVpbiBjaGFubmVsIGlzIGxpa2UgYSBwb3JlIG9yIGEgdHVubmVsLiBJdCBhbGxvd3MgbW9sZWN1bGVzIHRvIHBhc3MgdGhyb3VnaC4gV2hhdCwgaW4gdGhpcyBkaWFncmFtLCBsb29rcyBsaWtlIGEgdHVubmVsPw==[Qq]
[f]WWVzLiBHwqBpcyBwb2ludGluZyB0byBhIHByb3RlaW4gY2hhbm5lbC4=
Cg==[Qq]
[q]In the diagram below, which letter represents cholesterol?
[c]IEHCoCDCoCDCoA==[Qq][c]IETCoCDCoA==[Qq][c]RSDCoCDC oCDCoCA=[Qq][c]SC1JIMKgIMKgIA==[Qq][c]Rw==
Cg==[Qq][f]Tm8uIEEgaXMgcG9pbnRpbmcgdG8gYSBwaG9zcGhvbGlwaWQuwqBDaG9sZXN0ZXJvbCBpcyBhIGxpcGlkLiBJdCYjODIxNztzIHVzdWFsbHkgcmVwcmVzZW50ZWQgYXMgYSBncm91cCBvZiBmdXNlZCByaW5ncyBlbWJlZGRlZCBpbiB0aGUgbWVtYnJhbmUuIFdoYXQsIGluIHRoaXMgZGlhZ3JhbSwgZml0cyB0aGF0IGRlc2NyaXB0aW9uPw==[Qq]
[f]Tm8uIEQgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuIMKgQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZC4gSXQmIzgyMTc7cyB1c3VhbGx5IHJlcHJlc2VudGVkIGFzIGEgZ3JvdXAgb2YgZnVzZWQgcmluZ3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLiBXaGF0LCBpbiB0aGlzIGRpYWdyYW0sIGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]WWVzLiBFIGlzIHBvaW50aW5nIHRvIGEgbW9sZWN1bGUgb2YgY2hvbGVzdGVyb2wu[Qq]
[f]Tm8uIEgtSSBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIGJpbGF5ZXIuIMKgQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZC4gSXQmIzgyMTc7cyB1c3VhbGx5IHJlcHJlc2VudGVkIGFzIGEgZ3JvdXAgb2YgZnVzZWQgcmluZ3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLiBXaGF0LCBpbiB0aGlzIGRpYWdyYW0sIGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]
[f]Tm8uIEfCoGlzIHBvaW50aW5nIHRvIGEgcHJvdGVpbiBjaGFubmVsLsKgQ2hvbGVzdGVyb2wgaXMgYSBsaXBpZC4gSXQmIzgyMTc7cyB1c3VhbGx5IHJlcHJlc2VudGVkIGFzIGEgZ3JvdXAgb2YgZnVzZWQgcmluZ3MgZW1iZWRkZWQgaW4gdGhlIG1lbWJyYW5lLiBXaGF0LCBpbiB0aGlzIGRpYWdyYW0sIGZpdHMgdGhhdCBkZXNjcmlwdGlvbj8=
Cg==[Qq]
[q]In the diagram below, which letter represents a phospholipid?
[c]IEHCoCDC oCDCoA==[Qq][c]IETCoCDCoA==[Qq][c]RSDCoCDCoCDCoCA=[Qq][c]SC1JIMKgIMKgIA==[Qq][c]Rw==
Cg==[Qq][f]WWVzLiBBIGlzIHBvaW50aW5nIHRvIGEgcGhvc3Bob2xpcGlkLg==[Qq]
[f]Tm8uIEQgaXMgcG9pbnRpbmcgdG8gYSBtZW1icmFuZSBjYXJib2h5ZHJhdGUuIMKgWW91IGNhbiBpZGVudGlmeSBwaG9zcGhvbGlwaWRzIGluIHNldmVyYWzCoHdheXM6IDEpIHRoZXkgbWFrZSB1cCB0aGUgbWFpbiBzdHJ1Y3R1cmUgb3IgZnJhbWV3b3JrIG9mIHRoZSBtZW1icmFuZS4gMikgVGhleSYjODIxNztyZSBvcmdhbml6ZWQgaW50byBhIGJpbGF5ZXIsIHdpdGjCoHRoZSB0YWlscyBmYWNpbmcgaW53YXJkIGFuZCB0aGUgaGVhZHMgZmFjaW5nIG91dHdhcmQuIDMpIFRoZXkgaGF2ZSBhICYjODIyMDtoZWFkJiM4MjIxOyBhbmQgYSAmIzgyMjA7dGFpbC4mIzgyMjE7[Qq]
[f]Tm8uIEUgaXMgcG9pbnRpbmcgdG8gYSBtb2xlY3VsZSBvZiBjaG9sZXN0ZXJvbC7CoFlvdSBjYW4gaWRlbnRpZnkgcGhvc3Bob2xpcGlkcyBpbiBzZXZlcmFswqB3YXlzOiAxKSB0aGV5IG1ha2UgdXAgdGhlIG1haW4gc3RydWN0dXJlIG9yIGZyYW1ld29yayBvZiB0aGUgbWVtYnJhbmUuIDIpIFRoZXkmIzgyMTc7cmUgb3JnYW5pemVkIGludG8gYSBiaWxheWVyLCB3aXRowqB0aGUgdGFpbHMgZmFjaW5nIGlud2FyZCBhbmQgdGhlIGhlYWRzIGZhY2luZyBvdXR3YXJkLiAzKSBUaGV5IGhhdmUgYSAmIzgyMjA7aGVhZCYjODIyMTsgYW5kIGEgJiM4MjIwO3RhaWwuJiM4MjIxOw==[Qq]
[f]Tm8sIGJ1dCB5b3UmIzgyMTc7cmUgY2xvc2UuIEgtSSBpcyBwb2ludGluZyB0byB0aGUgcGhvc3Bob2xpcGlkIA==YmlsYXllcg==LiDCoEZpbmQgd2hhdCYjODIxNztzIHBvaW50aW5nIHRvIGEgc2luZ2xlIHBob3NwaG9saXBpZCBtb2xlY3VsZS4=[Qq]
[f]Tm8uIEfCoGlzIHBvaW50aW5nIHRvIGEgcHJvdGVpbiBjaGFubmVsLsKgWW91IGNhbiBpZGVudGlmeSBwaG9zcGhvbGlwaWRzIGluIHNldmVyYWzCoHdheXM6IDEpIHRoZXkgbWFrZSB1cCB0aGUgbWFpbiBzdHJ1Y3R1cmUgb3IgZnJhbWV3b3JrIG9mIHRoZSBtZW1icmFuZS4gMikgVGhleSYjODIxNztyZSBvcmdhbml6ZWQgaW50byBhIGJpbGF5ZXIsIHdpdGjCoHRoZSB0YWlscyBmYWNpbmcgaW53YXJkIGFuZCB0aGUgaGVhZHMgZmFjaW5nIG91dHdhcmQuIDMpIFRoZXkgaGF2ZSBhICYjODIyMDtoZWFkJiM4MjIxOyBhbmQgYSAmIzgyMjA7dGFpbC4mIzgyMjE7
Cg==[Qq]
[q]Membranes allow certain molecules to pass through but not others. In other words, membranes are [hangman] [hangman].
[c]c2VsZWN0aXZlbHk=[Qq]
[c]cGVybWVhYmxl
Cg==[Qq]
[q]Just for review (from the last tutorial). The arrangement of phospholipids shown below is called a phospholipid [hangman].
[c]YmlsYXllcg==
Cg==[Qq]
[q]The dynamic model of cell membrane structure which involves phospholipids, proteins, cholesterol, and carbohydrates in constant motion in the membrane is the [hangman] [hangman] model.
[c]Zmx1aWQ=[Qq]
[c]bW9zYWlj
Cg==[Qq]
[q]In the diagram below, membrane proteins like the ones at 1, 5, and 6, all of which are embedded in the phospholipid bilayer, are known as [hangman] proteins.
[c]aW50ZWdyYWw=
Cg==[Qq]
[q]In the diagram below, membrane proteins like the ones at 1 and 6, both of which span the width of the phospholipid bilayer, are known as [hangman] proteins.
[c]dHJhbnNtZW1icmFuZQ==
Cg==[Qq]
[q]In the diagram below, the molecule shown at 7 is a lipid, but not a phospholipid. Its function is to stabilize the membrane at high temperatures and to keep it fluid at low temperatures. This molecule must be [hangman].
[c]Y2hvbGVzdGVyb2w=
Cg==[Qq]
[q]Because of the way that it’s positioned in the membrane, you can tell that protein #3 must be a [hangman] protein.
[c]cGVyaXBoZXJhbA==[Qq]
[x]
[restart]
[/qwiz]
Next
- Transport across cell membranes (the next tutorial in this series)
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