Biochemistry Overview: Membranes and Transport

<p>They consist of three fatty acids linked to glycerol. (B)</p> Signup and view all the answers

<p>They consist of two fatty acids and a polar group. (D)</p> Signup and view all the answers

<p>They lead to a more fluid state. (D)</p> Signup and view all the answers

<p>They interact with water, contributing to membrane fluidity. (A)</p> Signup and view all the answers

<p>They pack well and tend to be solid at room temperature. (C)</p> Signup and view all the answers

<p>Hydrophobic side chains facing outward towards the lipid tails (D)</p> Signup and view all the answers

<p>Having both hydrophilic and hydrophobic regions (A)</p> Signup and view all the answers

<p>A covalent bond between a protein and a lipid molecule (B)</p> Signup and view all the answers

<p>Facilitative diffusion (A), Simple diffusion (B)</p> Signup and view all the answers

<p>By utilizing various transport mechanisms (C)</p> Signup and view all the answers

<p>Phospholipase enzymes (A)</p> Signup and view all the answers

<p>It does not require an energy source (B)</p> Signup and view all the answers

<p>Concentration gradient (C)</p> Signup and view all the answers

<p>The interaction with the selectivity filter (D)</p> Signup and view all the answers

<p>Na+ ions cannot lose their hydration shell (B)</p> Signup and view all the answers

<p>It forms the selectivity filter for K+ ions (B)</p> Signup and view all the answers

<p>Phosphorylation of the regulatory domain (B)</p> Signup and view all the answers

<p>It requires energy derived from ATP hydrolysis (D)</p> Signup and view all the answers

<p>Only K+ interacts well with the selectivity filter (A)</p> Signup and view all the answers

<p>Ions must lose their water shell to enter the channel (B)</p> Signup and view all the answers

<p>It opens the channel by exposing the ATP binding domain (B)</p> Signup and view all the answers

<p>It hydrolyzes ATP to change conformation after binding Na+. (A)</p> Signup and view all the answers

<p>It relies on the sodium gradient to transport glucose into cells. (D)</p> Signup and view all the answers

<p>Transport of two compounds in the same direction. (C)</p> Signup and view all the answers

<p>By actively pumping Na+ out of the cell. (B)</p> Signup and view all the answers

<p>Production of protein pumps that actively expel antibiotics. (A)</p> Signup and view all the answers

<p>It uses the Na+ concentration difference to drive glucose uptake. (B)</p> Signup and view all the answers

<p>They hydrolyze ATP to facilitate drug expulsion. (D)</p> Signup and view all the answers

<p>It actively maintains a sodium gradient essential for glucose transport. (D)</p> Signup and view all the answers

<p>To keep wanted molecules inside and unwanted molecules outside (B)</p> Signup and view all the answers

<p>They have a linear chain of carbon atoms with hydrogen atoms (B)</p> Signup and view all the answers

<p>Unsaturated fatty acids contain double bonds that create kinks in the chain (C)</p> Signup and view all the answers

<p>They become more rigid and less flexible (D)</p> Signup and view all the answers

<p>Carbon-carbon single bonds (C)</p> Signup and view all the answers

<p>It consists of a linear chain of carbons with hydrogen atoms (C)</p> Signup and view all the answers

<p>It creates a kink that prevents tight packing (B)</p> Signup and view all the answers

<p>It prevents most water-soluble molecules from passing through (B)</p> Signup and view all the answers

<p>Carries K+ ions (A)</p> Signup and view all the answers

<p>It contains ATP binding cassettes on two domains. (B)</p> Signup and view all the answers

<p>They are produced by Brevibacillus brevis. (B)</p> Signup and view all the answers

<p>They increase ion permeability of the plasma membrane. (B)</p> Signup and view all the answers

<p>Valinomycin's affinity for K+ is 10000 times higher than that for Na+. (C)</p> Signup and view all the answers

<p>They use ATP for active transport mechanisms. (D)</p> Signup and view all the answers

<p>Alternating amino acids and esters. (A), A mixture of D- and L-amino acids. (D)</p> Signup and view all the answers

<p>It is resistant to multiple antibiotics, limiting treatment options. (A)</p> Signup and view all the answers

<p>It modulates membrane fluidity by filling gaps created by unsaturated fatty acids. (B)</p> Signup and view all the answers

<p>Saturated fatty acids make the membrane less fluid and require higher temperatures to remain fluid. (C)</p> Signup and view all the answers

<p>They possess a sugar in the polar head group. (A)</p> Signup and view all the answers

<p>A bilayer with tails facing each other and heads facing outward. (A)</p> Signup and view all the answers

<p>Tm determines the balance between gel-like and fluid states in membranes. (D)</p> Signup and view all the answers

<p>Electrostatic interactions of head groups with water and ions, along with the hydrophobic effect. (A)</p> Signup and view all the answers

<p>They adjust lipid composition to include longer and more saturated lipids. (C)</p> Signup and view all the answers

<p>They are held together by weak interactions but can be easily deformed. (D)</p> Signup and view all the answers

<p>The ion must dissociate from its water shell. (B)</p> Signup and view all the answers

<p>It involves interactions with K+ ions through specific oxygen atoms. (A)</p> Signup and view all the answers

<p>ATP hydrolysis. (A)</p> Signup and view all the answers

<p>Na+ ions have weaker interactions and do not dehydrate. (D)</p> Signup and view all the answers

<p>It triggers conformational changes necessary for the channel to open. (B)</p> Signup and view all the answers

<p>It requires significant energy to lose water interactions. (B)</p> Signup and view all the answers

<p>Na+ has a smaller ionic radius than K+. (B)</p> Signup and view all the answers

<p>It separates the internal environment from the external environment. (B)</p> Signup and view all the answers

<p>The linear chain structure with carbon and hydrogen. (B)</p> Signup and view all the answers

<p>They possess one or more double bonds between carbon atoms. (A)</p> Signup and view all the answers

<p>It restricts the rotation around the bond, creating a kink. (C)</p> Signup and view all the answers

<p>It is primarily composed of lipids and proteins. (A)</p> Signup and view all the answers

<p>The presence of double bonds in the carbon chain. (B)</p> Signup and view all the answers

<p>It selectively allows certain molecules to enter and exit the cell. (C)</p> Signup and view all the answers

<p>Single carbon-carbon bonds allowing rotation. (A)</p> Signup and view all the answers

<p>It has hydrophobic side chains that face outward. (A)</p> Signup and view all the answers

<p>They are covalently bound to lipid molecules. (B)</p> Signup and view all the answers

<p>As either requiring energy or not, as well as by the mechanism of transport. (A)</p> Signup and view all the answers

<p>It is a random process that does not require energy. (B)</p> Signup and view all the answers

<p>It can reside on the surface or within the membrane forming channels. (D)</p> Signup and view all the answers

<p>They facilitate the controlled release of these proteins from the membrane. (A)</p> Signup and view all the answers

<p>Active transport requires ATP hydrolysis, while passive does not. (D)</p> Signup and view all the answers

<p>They can pass through the membrane by simple diffusion. (B)</p> Signup and view all the answers

<p>Flippases require ATP and are selective. (B)</p> Signup and view all the answers

<p>Phosphatidylcholine (PC) and sphingomyelin (SM) (B)</p> Signup and view all the answers

<p>Lipid rafts are enriched in cholesterol and glycosphingolipids. (C)</p> Signup and view all the answers

<p>Via the selective action of flippases. (C)</p> Signup and view all the answers

<p>They diffuse randomly in the plane of the membrane. (C)</p> Signup and view all the answers

<p>The energetic favorability of separating long, stiff lipids. (B)</p> Signup and view all the answers

<p>They catalyze the flipping of lipids between membrane leaflets. (A)</p> Signup and view all the answers

<p>To maintain a concentration gradient for Na+ and K+ across the membrane (B)</p> Signup and view all the answers

<p>Phosphatidylethanolamine (PE) (C)</p> Signup and view all the answers

<p>Sodium ions create a gradient that drives glucose transport against its gradient (D)</p> Signup and view all the answers

<p>An antiporter transports compounds in opposite directions (C)</p> Signup and view all the answers

<p>Multi-drug resistance against antibiotics (B)</p> Signup and view all the answers

<p>It changes conformation and then releases Na+ (C)</p> Signup and view all the answers

<p>It returns the protein to its original conformation (C)</p> Signup and view all the answers

<p>They pump therapeutic drugs out of the cancer cells (D)</p> Signup and view all the answers

<p>It facilitates the coupling of glucose uptake to Na+ transport (C)</p> Signup and view all the answers

A fatty acid is a linear chain of carbons with hydrogens and a carboxylic acid group at one end.

Saturated fatty acids have only single bonds, while unsaturated fatty acids have at least one double bond between carbon atoms.

Plasma membranes are made up of lipids and proteins.

The hydrophobic core of the membrane prevents most water-soluble molecules from passing through.

Eukaryotic cells have internal compartments, each surrounded by membranes.

Membranes control what enters and exits the cell or specific compartments within.

Fatty acids with one or more double carbon bonds; usually cis configuration.

Fatty acids in which the carbons are bonded to the maximum number of hydrogens; no double bonds.

Essential fatty acids are needed by the body but cannot be produced. Must be consumed.

A fat molecule that stores energy, consisting of glycerol with three fatty acids attached.

Phospholipids have a glycerol backbone, two fatty acid tails, and a polar head group.

Fatty acids with a double bond at a particular position counting from the omega end (the methyl end).

A way to name fatty acids based on the number of carbons and double bonds, and the position of the double bonds.

A protein embedded within the cell membrane, often with hydrophobic regions interacting with the lipid bilayer.

A helical region in a membrane protein that has both hydrophilic and hydrophobic sections, allowing it to interact with both the membrane and aqueous environments.

A lipid anchor that attaches some proteins to the membrane, composed of a phospholipid, oligosaccharide, and phosphoethanolamide.

Movement of molecules across a membrane from a high concentration to a low concentration, without requiring energy.

Transport of molecules across a membrane with the help of a membrane protein, down their concentration gradient, without requiring energy.

Membrane proteins that act like doors, opening or closing to allow specific molecules to pass through the membrane, often regulated by signals.

Membrane proteins that use energy to move molecules across the membrane against their concentration gradient.

Movement of molecules across the membrane without requiring energy, driven by concentration gradients.

The ability of an ion channel to allow passage of specific ions while blocking others, based on size and charge. This is achieved by a selectivity filter, which dehydrates the ion and requires strong interactions with channel proteins.

A potassium (K+) channel is designed to specifically transport K+ ions, preventing the passage of smaller sodium (Na+) ions. This is due to the selectivity filter that allows strong interactions with K+ but not with Na+, leading to dehydration of K+ within the channel.

The KcsA potassium channel is a tetrameric structure, meaning it consists of four subunits. The selectivity filter, composed of the TVGYG amino acid sequence, lies in the middle of the channel. This filter interacts with K+ ions through oxygen atoms, allowing their passage while excluding Na+ ions.

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride (Cl-) channel activated by both a ligand and phosphorylation. It requires phosphorylation of its regulatory domain by protein kinase A (PKA) and subsequent ATP binding. This leads to channel opening and Cl- diffusion out of the cell.

The difference in concentration of a substance across a membrane. Molecules naturally move from a region of high concentration to a region of low concentration, driven by the concentration gradient.

The combined effect of both concentration gradient and membrane potential on the movement of ions across a membrane. The electrical potential difference also influences the movement of charged ions.

A type of active transport where the energy required to move molecules against their gradient is directly obtained from ATP hydrolysis.

Uses the energy stored in the concentration gradient of one molecule to move another molecule across the membrane.

A primary active transporter that pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell.

A membrane protein that transports two different molecules in opposite directions.

A membrane protein that transports two different molecules in the same direction.

A secondary active transporter that uses the Na+ gradient to move glucose into the cell.

Bacteria or cancer cells can develop resistance to drugs by producing pumps that actively remove the drugs from the cell.

A specific multi-drug resistance protein found in Staphylococcus aureus. It functions as an ABC transporter, using energy from ATP to pump out a variety of drugs.

A type of membrane protein that uses energy from ATP to transport molecules across cell membranes. They are commonly involved in drug resistance.

The difference in concentration of ions (like Na+ and K+) across a cell membrane. Cells actively maintain these gradients to function properly.

Substances that make cell membranes permeable to ions. Some antibiotics act as ionophores, disrupting the ion balance and killing bacteria.

An ionophore that transports K+ ions out of the cell. It has a higher affinity for K+ compared to Na+, making it selective for potassium.

Antibiotics produced by bacteria, acting as ionophores. They consist of peptides with a unique amino acid composition.

A rare type of amino acid found in some peptides and antibiotics. These amino acids are mirror images of standard L-amino acids.

A thin outer layer of a cell that acts as a barrier between the cell's interior and its environment. It controls the movement of molecules in and out of the cell.

The middle region of the plasma membrane composed of fatty acid tails, which repel water and prevent most water-soluble molecules from passing through.

A long chain of carbon atoms linked together, with hydrogen atoms attached, and a carboxylic acid group at one end.

Lipids with a sugar molecule attached to their polar head group, like inositol or galactose.

A type of phospholipid that has an amino-alcohol core instead of glycerol and a choline head group.

A type of glycosphingolipid that has both an amino-alcohol core (like sphingomyelin) and a sugar head group.

Cholesterol has a rigid, hydrophobic sterol core made of 4 rings and a short tail. It has a small, hydrophilic OH group.

Cholesterol fills gaps in the membrane caused by unsaturated fatty acids, regulating membrane fluidity.

A spherical structure formed by hydrophobic tails of lipids pointing inward and hydrophilic heads facing outward in a watery environment.

A spherical vesicle formed by a phospholipid bilayer, with the hydrophobic tails facing each other and polar heads facing the aqueous environment.

The ability of a membrane to move and deform easily, due to the dynamic arrangement of its components.

Think of a protein tethered to the membrane by a fatty chain like a boat anchored to the seafloor.

Lipids rarely switch from one layer of the membrane to the other.

Enzymes that help lipids change layers. Flippases are specific and require energy, while Scramblases are random.

The two layers of the membrane have different compositions due to flippases, creating a functional difference.

The membrane is a fluid of lipids with proteins scattered like tiles in a mosaic, able to diffuse freely.

Thicker, more organized areas in the membrane, enriched in cholesterol and certain proteins, that act as platforms for specific interactions.

Lipid rafts influence cell signaling, membrane trafficking, and protein sorting by concentrating specific molecules.

Lipid rafts form due to favorable interactions between specific lipids, like cholesterol and long chain fatty acids.

A membrane protein that pumps sodium ions (Na+) out of the cell and potassium ions (K+) into the cell, against their concentration gradients, using energy from ATP hydrolysis.

Secondary active transport is a common mechanism used by cells to transport nutrients, ions, and other essential molecules across their membranes.

A symporter moves two compounds in the same direction across the membrane, while an antiporter moves them in opposite directions.

A growing problem where bacteria have evolved mechanisms to resist the effects of antibiotics, making infections harder to treat.

A potassium (K+) channel is specifically designed to transport K+ ions, preventing the passage of smaller sodium (Na+) ions. This is because the selectivity filter interacts strongly with K+ ions, allowing them to dehydrate and pass through.

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride (Cl-) channel activated by a ligand and phosphorylation. It requires phosphorylation by protein kinase A (PKA) and subsequent ATP binding to open.

Movement of molecules from a region of high concentration to a region of low concentration, driven by the concentration gradient. This can be simple or facilitated by a transport protein.