Module 3 Flashcards
Phospholipid Bilayer
A two-layered structure of the cell membrane with hydrophilic heads pointing outward toward the aqueous environment and hydrophobic tails oriented inward away from water.
Passive Transport
The movement of substances across a cell membrane that does not require energy.
Active Transport
The movement of substances across a cell membrane against an electrochemical gradient, requiring an input of energy.
Secondary Active Transport
Active transport that uses the energy of an electrochemical gradient to drive the movement of ions or molecules against their concentration gradients.
Diffusion
The net movement of molecules from areas of higher to lower concentration as a result of their random thermal motion.
Plasmolysis
Plant cell will pull away from surrounding cell wall.
Osmosis
The net movement of a solvent, such as water, across a selectively permeable membrane towards the side of higher solute concentration.
Osmotic Pressure
The pressure needed to prevent water from moving from one solution into another by osmosis.
Crenation
Animal cells will shrivel and die.
Isotonic
Equal concentrations on either side of the membrane.
Hypotonic Solution
One with a solute concentration lower than that inside the cell.
Hypertonic Solution
The solute concentration is higher than that inside the cell.
Cytoplasm
The entire contents of the cell minus the nucleus.
Cytosol
The region outside the organelles but inside the plasma membrane.
Endomembrane System (EMS)
The system of interconnected organelles within the cell that includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, the cell membrane, and the vesicles that move between them.
Nuclear Envelope
The cell structure, composed of two membranes, inner and outer, that defines the boundary of the nucleus.
Nuclear Pores
A protein channel in the nuclear envelope that allows molecules to move into and out of the nucleus and is thus essential for the nucleus to communicate with the rest of the cell.
Lysosomes
A vesicle derived from the Golgi apparatus that contains hydrolytic enzymes that break down macromolecules such as proteins, nucleic acids, lipids, and complex carbohydrates. Play a key role in intracellular digestion and the recycling of organic compounds.
Mitochondria
Organelles that harness energy from chemical compounds such as sugars and convert it into ATP which serves as the universal energy currency of the cell.
Amphipathic
Having both hydrophilic and hydrophobic regions.
Integral Membrane Protein
A protein that is permanently associated with the cell membrane and cannot be separated form the membrane experimentally without destroying the membrane itself. Mostly transmembrane proteins.
Peripheral Membrane Protein
A protein that is temporarily associated with the lipid bilayer or with integral membrane proteins through weak non-covalent interactions. Can be associated with either the internal or external side of the membrane.
Transmembrane Protein
A protein that spans the entire lipid bilayer.
Channel Protein
A membrane transporter with a passage that allows the movement of molecules through it.
Carrier Protein
A transporter that facilitates movement of molecules across a cell membrane.
Symporter
Protein transporters that move two molecules in the same direction.
Antiporter
Protein transporters that move two different molecules in opposite directions.
Electrochemical Gradient
A gradient that has a difference in charge and concentration.
Cell Wall
A structural layer external to the cell membrane that helps maintain the shape and internal composition of the cell. Present in plants, fungi, many protists, archaea, and bacteria.
Vacuole
Absorbs water and contributes to turgor pressure.
Cytoskeleton
An internal protein scaffold that helps cells to maintain their shape and serves as a network of tracks for the movement of substances within cells.
Endoplasmic Reticulum (ER)
An organelle composed of a network of membranes that is involved in the synthesis of proteins and lipids.
Golgi Apparatus
The organelle that modifies proteins and lipids produced by the endoplasmic reticulum and acts as a sorting station as they move to their final destinations.
Chloroplasts
Organelles that capture the energy of sunlight to synthesize simple sugars.