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Questions and Answers
What role do aquaporins play in cellular processes?
What role do aquaporins play in cellular processes?
Which feature is characteristic of ion channels?
Which feature is characteristic of ion channels?
What distinguishes a symporter from a uniporter?
What distinguishes a symporter from a uniporter?
What characteristics favor a molecule diffusing through the plasma membrane?
What characteristics favor a molecule diffusing through the plasma membrane?
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What function does an active transporter perform in the cell?
What function does an active transporter perform in the cell?
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What characterizes saturated fatty acids?
What characterizes saturated fatty acids?
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Which statement about triglycerides is correct?
Which statement about triglycerides is correct?
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What is the structure of phospholipids?
What is the structure of phospholipids?
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What is the primary function of ion channels?
What is the primary function of ion channels?
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What distinguishes active transport from passive transport?
What distinguishes active transport from passive transport?
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What best describes aquaporins?
What best describes aquaporins?
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What type of fatty acids are considered more favorable for health?
What type of fatty acids are considered more favorable for health?
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What is a characteristic of facilitated diffusion?
What is a characteristic of facilitated diffusion?
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What is the role of cholesterol in cell membranes?
What is the role of cholesterol in cell membranes?
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What does membrane compartmentalization achieve within a cell?
What does membrane compartmentalization achieve within a cell?
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Study Notes
Lipids, Membranes and Transport
- Lipids are hydrophobic molecules, insoluble in water, and are formed from fatty acids.
- Fatty acids have a long hydrocarbon chain and a carboxyl group.
- Hydrocarbon chains are non-polar.
- Saturated fatty acids have no double bonds, are solid at room temperature, and are important for cell membranes.
- Unsaturated fatty acids have one or more double bonds.
- Cis-unsaturated fatty acids have hydrogens on the same side of the double bond and are generally healthier.
- Trans-unsaturated fatty acids have hydrogens on opposite sides of the double bond.
- Triglycerides are formed from three fatty acids and glycerol.
- Animal fats contain triglycerides primarily made of saturated fatty acids.
- Plant fats contain triglycerides primarily made of unsaturated fatty acids.
- Triglycerides are hydrophobic and completely insoluble in water.
- Phospholipids have a glycerol backbone attached to two fatty acids and a polar head (e.g., phosphocholine).
- Phospholipids are amphipathic, meaning they have both a polar head and a non-polar tail.
- Steroids are made of cholesterol.
- Cholesterol is important for cell membrane rigidity and is a precursor for the synthesis of hormones.
- Vitamin D is a steroid structure.
Cell Partitions
- Cell partitions separate different parts of the cell.
- Compartmentalization may be used to raise the concentration of a substance, or to separate organelles with unique functions.
- Partitions are important for cellular signalling.
Phospholipid Membranes
- Phospholipid membranes have hydrophilic heads on the outside and hydrophobic tails on the inside.
- They are impermeable to large or charged molecules.
Diffusion
- Diffusion is the passive movement of a molecule down its concentration gradient.
Osmosis
- Osmosis is the passive movement of water molecules down their water potential gradient.
Active Transport
- Active transport moves molecules against their concentration gradient, requiring energy (ATP).
Facilitated Diffusion
- Facilitated diffusion moves molecules across membranes that can't independently move.
- Facilitated diffusion may occur due to size or charge restrictions.
Ion Channels
- Ion channels are proteins that form pores or channels in the membrane.
- Ion channels can be opened and closed by various mechanisms and don't use energy.
- They are selective for specific ions.
Carrier Molecules
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Uniporters: carry one molecule in one direction
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Symporters: carry two different molecules in the same direction
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Antiporters: carry two different molecules in opposite directions
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Carrier molecules may use concentration gradients to power movement.
Aquaporins
- Aquaporins are water channels that allow for osmotic movement of water.
- They are made of four subunits, each with a pore.
Moodle Recap Quiz
- Ion channels are simple pores in the membrane that are selectively permeable and are controlled.
- Carriers bind to molecules and change shape to transport them across membranes. Aquaporins are involved in osmosis.
- Molecules diffuse more easily through membranes if they are small and nonpolar.
- Antiporters, active transporters, symporters are used in pumps like the sodium-glucose pump. Uniporters carry a single molecule.
- Plasm membranes have two layers of phospholipids.
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Description
Explore the fascinating world of lipids, their structure, and their vital role in biological membranes. This quiz covers essential topics such as fatty acids, triglycerides, and the differences between saturated and unsaturated fats. Understand how lipid composition affects cell membrane structure and function.
