HINT FOR NEXT TIME: Look carefully at the diagram.What’s the onl y thing that could be made of two layers?
The letter of a glycolipid (a short carbohydrate attached to a phospholipid)
Way to go! “B” is a glycolipid.
HINT FOR NEXT TIME: Look for a short polymer attached to the tails of a phospholipid.
The letter of a glycoprotein (a protein with a short carbohydrate attachment).
Very nice! “C” is a glycoprotein.
HINT FOR NEXT TIME: Look for a membrane protein with a short polymer extending from it. That polymer is a polysaccharide, and with the protein it makes a glycoprotein
The letter of a transmembrane protein (which isn’t also a channel).
Thumbs up! “D” is a transmembrane protein.
HINT FOR NEXT TIME: Look for a protein that’s going all the way through the membrane, but which doesn’t have an opening that would allow things to enter or leave the cell.
The letter for cholesterol.
That’s right! “E” is cholesterol.
HINT FOR NEXT TIME: Cholesterol is represented as four fused carbon rings, about the size of a phospholipid, embedded in the phospholipid bilayer.
A channel protein
Terrific! “F”is a channel protein.
HINT FOR NEXT TIME: Find a protein that goes all the way through the membrane, and which has a hole that would allow molecules to move across the membrane.
The letter for phospholipid heads
Outstanding! The phospholipid heads are at “F”
HINT FOR NEXT TIME: A phospholipid has a “head” and two fatty acid tails. Find a part of a molecule that’s connected to two tails. That’s the head.
The letter for phospholipid tails.
Superb! “H” represents the phospholipid tails.
HINT FOR NEXT TIME: A phospholipid has a “head” and two fatty acid tails. Find a molecule that has two “tails” coming out of it.
HINT FOR NEXT TIME: A phospholipid has a hydrophilic head and a hydrophobic portion referred to as a tail.What looks like a tail, and what looks like a head?
Hydrophobic tails
Good work! Those are the tails.
HINT FOR NEXT TIME: A phospholipid has a hydrophilic head and a hydrophobic portion referred to as a tail.What looks like a tail?
[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Membranes Click-on Challenge dataset|bee5350de1f0″ question_number=”4″ show_hotspots=”” unit=”2.Cell_Structure_and_Function” topic=”2.4-2.5.Plasma_Membranes”] Phospholipids in the membrane.
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In a bilayer, this part touches the cytoplasm, or the cell exterior.
Correct! In a bilayer, the head faces the water cell exterior, or the watery cytoplasmic interior.
HINT FOR NEXT TIME: Find the part of the phospholipid that’s hydrophilic and “likes” to interact with water.
In a bilayer, this part forms a hydrophobic, water-free zone.
Good work! The tails play that role in the bilayer.
HINT FOR NEXT TIME: You’re looking for the hydrophobic tails.
[q json=”true” hotspot_user_interaction=”label_prompt” dataset_id=”Membranes Click-on Challenge dataset|21deb4a351c945″ question_number=”5″ show_hotspots=”” unit=”2.Cell_Structure_and_Function” topic=”2.6-7,_2.9.Membrane_Transport”] Membrane Transport (click on the numbers)
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The number of a membrane channel
Yes! “5” is a membrane channel.
HINT FOR NEXT TIME: A membrane channel allows something to pass through as it flows down its concentration gradient.
The number of a membrane pump.
Way to go! “6” is a membrane pump.
HINT FOR NEXT TIME: A membrane pump moves a substance up a concentration gradient.
The number of the phospholipid bilayer.
Very Nice! “4” is the phospholipid bilayer.
HINT FOR NEXT TIME: The phospholipid bilayer forms the structural framework of the membrane. And bilayer means “two layers.”
The number of the arrow that represents facilitated diffusion.
That’s right. “2” is facilitated diffusion.
HINT FOR NEXT TIME: In facilitated diffusion,substances enter the cell as they diffusion through a protein channel.
The number of the arrow that represents simple diffusion.
Terrific! “1” represents simple diffusion.
HINT FOR NEXT TIME: In simple diffusion, substances diffuse right through the phospholipid bilayer.
The number for the arrow that represents active transport.
Superb! “3” represents active transport.
HINT FOR NEXT TIME: In active transport, the cell pumps substances up a concentration gradient.