Plasma Membranes, Transport and Enzymes - Chapter 5

A collection of 35 flashcards based on Chapter 5 lecture notes focused on plasma membranes, transport processes, and enzymes.

Membrane

A great barrier and semi-permeable structure that keeps out many polar molecules.

Phospholipid

A molecule with a hydrophilic head and hydrophobic tails; the fundamental building block of cellular membranes.

Hydrophilic

Water-attracting; pertains to the head of phospholipids.

Hydrophobic

Water-repelling; pertains to the tails of phospholipids.

Integral Proteins

Proteins that span the entire membrane and are embedded within it.

Peripheral Proteins

Proteins that are attached to the surface of the membrane but do not penetrate it.

Facilitated Diffusion

A process by which specific molecules are transported across a cell membrane via protein channels.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tonicity

A measure of the effective osmotic pressure gradient, defined by the concentration of non-permeable solutes.

Active Transport

The movement of ions or molecules across a membrane against their concentration gradient, requiring energy.

Endocytosis

A process where the cell engulfs materials from the outside environment into a vesicle.

Exocytosis

A process where materials are expelled from a cell through the fusion of a vesicle with the plasma membrane.

Diffusion

The passive movement of molecules from an area of high concentration to an area of low concentration.

Channel Protein

A type of integral protein that forms a channel to allow specific molecules to pass through the membrane.

Solute

A substance that is dissolved in a solvent to create a solution.

Acquaporin

Special protein channels that facilitate the transport of water across cell membranes.

Concentration Gradient

A difference in the concentration of a substance across a space.

Equilibrium

The state in which the concentrations of a substance are equal in two areas, resulting in no net movement.

Vesicle

A small structure within or outside the cell, enclosed by a lipid bilayer.

Potential Energy

The stored energy available for use; can be found in chemical bonds.

Kinetic Energy

The energy of motion; it is energy in action.

Exergonic Reactions

Chemical reactions that release energy, with products having less energy than reactants.

Endergonic Reactions

Reactions that require an input of energy, having products with more energy than reactants.

ATP (Adenosine Triphosphate)

The main energy carrier in cells, providing energy for various cellular processes.

Enzyme

A biological catalyst that reduces the activation energy of a chemical reaction.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Substrate

The reactant on which an enzyme acts.

Competitive Inhibitor

A molecule that binds to the active site of an enzyme, preventing the substrate from binding.

Non-competitive Inhibitor

A molecule that binds to an enzyme regardless of whether the substrate is bound, altering enzyme function.

Feedback Inhibition

A regulation mechanism whereby the end product of a metabolic pathway inhibits an earlier step.

Phagocytosis

The process by which a cell engulfs large particles or microorganisms.

Pinocytosis

The process by which a cell takes in liquid from the surrounding environment.

Law of Conservation of Energy

A principle stating that energy cannot be created or destroyed, only transformed.

Biological Catalyst

A substance, typically a protein, that accelerates a chemical reaction without being consumed.

Hydrocarbon Chains

Long chains of carbon and hydrogen atoms found in fatty acids.

Saturated Fatty Acid

A type of fatty acid where all carbon atoms are bonded to the maximum number of hydrogen atoms.

Unsaturated Fatty Acid

A type of fatty acid containing one or more double bonds between carbon atoms.