What structures should be included in a plasma membrane drawing?
Phospholipids, peripheral proteins, integral proteins, glycolipids, glycoproteins, cholesterol
What are phospholipids, peripheral proteins, integral proteins, glycolipids, glycoproteins, and cholesterol?
Component of plasma membrane
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Flashcards for Biology 189 Unit 3 Study Guide
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What structures should be included in a plasma membrane drawing?
Phospholipids, peripheral proteins, integral proteins, glycolipids, glycoproteins, cholesterol
What are phospholipids, peripheral proteins, integral proteins, glycolipids, glycoproteins, and cholesterol?
Component of plasma membrane
Describe the fluid mosaic model.
Describes the cell membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.
What happens to a cell membrane if it gets too cold? Too hot?
If a cell membrane gets too cold, it may become rigid and less fluid. If it gets too hot, it may become too fluid and lose its structure.
What property allows some substances to cross more easily than others?
Selectively permeable
What type of transport doesn't require energy?
Passive transport
What type of transport requires energy?
Active transport
What is the movement of a substance from an area of high concentration to an area of low concentration?
Definition of Diffusion
What is the diffusion of water across a selectively permeable membrane?
Definition of Osmosis
What is a solution with a lower solute concentration compared to another solution?
Hypnotonic
What is a solution with a higher solute concentration compared to another solution?
Hypertonic
What is a solution with equal solute concentration compared to another solution?
Isotonic
Explain simple diffusion.
The movement of a substance from an area of high concentration to an area of low concentration without the help of membrane proteins.
What is the diffusion of water across a selectively permeable membrane?
Osmosis
What is turgor pressure?
The pressure exerted by the cell against the cell wall.
Explain facilitated diffusion.
The transport of substances across a cell membrane with the help of membrane proteins.
What is a membrane potential?
The voltage across a cell's plasma membrane.
What factors affect the rate of diffusion of a substance?
Concentration gradient, temperature, and the size of the molecule
Describe how a carrier protein channel functions.
A carrier protein binds to a specific molecule, changes shape, and releases the molecule on the other side of the membrane.
What does it mean for a carrier protein to be saturated?
All carrier protein binding sites are occupied, and the rate of transport reaches a maximum.
Explain primary active transport.
Active transport that uses ATP directly to move substances against their concentration gradients.
Explain co-transport.
A transport protein couples the movement of an ion down its electrochemical gradient to the uphill movement of another molecule or ion against a concentration gradient.
Describe two ways a gated protein channel functions.
Some gated protein channels open or close in response to electrical signals, while others respond to chemical signals.
How does receptor-mediated endocytosis differ from the other types of endocytosis?
Receptor-mediated endocytosis is more specific, involving receptor proteins binding to specific molecules, while the other types are less selective.
Explain exocytosis.
A process by which cells release substances to the extracellular environment by fusing vesicles with the plasma membrane.
Define potential energy.
Energy that matter possesses because of its location or structure.
Define kinetic energy.
Energy associated with motion.
Define catabolism.
A metabolic pathway that breaks down complex molecules into simpler ones, releasing energy.
Define anabolism.
A metabolic pathway that builds complex molecules from simpler ones, consuming energy.
Define chemical energy.
Potential energy available for release in a chemical reaction.
Define exergonic reaction.
A reaction that proceeds with a net release of free energy and is spontaneous.
Define endergonic reaction.
A reaction that absorbs free energy from its surroundings and is nonspontaneous.
Describe the types of endocytosis.
Phagocytosis, pinocytosis, and receptor-mediated endocytosis
If a reaction requires energy what is it called? What type of metabolism is it?
Endergonic, catabolism
If a reaction releases energy what is it called? What type of metabolism is it?
Exergonic, anabolism
Explain how catabolism and anabolism are linked.
Energy released during catabolism drives anabolism.
What is the first law of thermodynamics?
Energy cannot be created or destroyed, but it can be transferred and transformed.
What is the second law of thermodynamics?
Every energy transfer or transformation increases the entropy of the universe.
What is entropy and how is it related to the second law?
A measure of disorder or randomness. It is related to the second law because every energy transfer increases entropy.
Define catalyst.
A chemical agent that speeds up a reaction without being consumed by the reaction.
Define enzyme.
A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.
Define ribozyme.
An RNA molecule that functions as an enzyme, catalyzing reactions during RNA splicing.
Define reactant.
A starting material in a chemical reaction.
Define product.
A final material in a chemical reaction.
Define energy barrier.
The amount of energy that reactants must absorb before a chemical reaction will start
Define transition state.
The state or configuration through which the reactants must pass as they are converted to products in a chemical reaction.
Define activation energy.
The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.
Define substrate.
The reactant on which an enzyme works.
Define active site.
The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.
Define enzyme-substrate complex.
A complex formed when an enzyme binds to its substrate.
Define induced fit.
The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.
Define cofactor.
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis.
Define coenzyme.
An organic molecule serving as a cofactor.
Define rate of reaction.
The measure of how quickly a reaction occurs.
What does an enzyme do to a reaction?
An enzyme speeds up a reaction by lowering the activation energy.
Explain four ways an enzyme can lower the activation energy for a reaction.
By orienting substrates correctly, straining substrate bonds, providing a favorable microenvironment, and covalently bonding to the substrate.
Define metabolic pathway.
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.
Define homeostasis.
The steady-state physiological condition of the body.
Define irreversible inhibition.
A inhibitor that attaches to the enzyme by covalent bonds
Define reversible inhibition.
A inhibitor that attaches to the enzyme by weak bonds
Define allosteric regulation.
The binding of a molecule to a protein that affects the function of the protein at a different site.
Define feedback inhibition.
A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.
Describe the two types of reversible inhibition
Competitive inhibition and noncompetitive inhibition.
Explain allosteric regulation.
A regulatory molecule binds to a protein at one site and affects the protein’s function at another site.
What conditions can affect enzyme activity?
Temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.
What is a metabolic pathway?
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.
Explain how a pathway can be regulated.
Regulating enzyme activity
What does ATP stand for?
Adenosine Triphosphate
What does ADP stand for?
Adenosine Diphosphate
What does AMP stand for?
Adenosine Monophosphate
Why is ATP used as the currency of the cell?
It's readily available and easily regenerated.
What is feedback inhibition?
Metabolic control where the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.
Describe OIL RIG.
Oxidation Is Loss, Reduction Is Gain.
Define Endergonic.
A reaction that proceeds with a net input of free energy; they are nonspontaneous.
Define Exergonic.
A reaction that proceeds with a net release of free energy and is spontaneous.
Define Catabolism.
A metabolic pathway that breaks down complex molecules into simpler ones, releasing energy.
Define Anabolism.
A metabolic pathway that builds complex molecules from simpler ones, consuming energy.
Define Reduction.
The addition of electrons to a substance.
Define Oxidation.
The loss of electrons from a substance.
Define Redox.
A chemical reaction involving the transfer of one or more electrons from one reactant to another.
Define Substrate level phosphorylation.
The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.
Define Oxidative phosphorylation.
The production of ATP using energy derived from the redox reactions of an electron transport chain.
Define Chemiosmosis.
An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP.
Define Proton motive force.
The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis.
How are reduction and oxidation linked?
Oxidation and reduction always occur together because electrons are transferred from one molecule to another.
How does chemiosmosis work? What does it rely on?
Chemiosmosis uses the energy stored in a proton gradient to drive ATP synthesis. It relies on the electron transport chain to create the proton gradient.
What does NAD stand for?
Nicotinamide adenine dinucleotide
What forms can NAD exist in?
NAD+ and NADH.
What does FAD stand for?
Flavin adenine dinucleotide
What forms can FAD exist in?
FAD and FADH2
Where in cellular respiration is FAD found?
Citric Acid Cycle
How are chemiosmosis and proton motive force different?
Chemiosmosis is the process that uses the proton motive force to generate ATP. The proton motive force is the potential energy stored in the proton gradient.