Vocab Unit 4 Flashcards
Organelle
A small structure within a cell that has a particular function.
Prokaryote
“First simple cells,” no nucleus, few organelles: membrane wall, ribosomes, flagella. Ex: Bacteria like E. coli.
Eukaryote
True nucleus, many organelles. Ex: Everything but bacteria.
Semi/selectively permeable membrane
Some materials can pass through membrane–CO2 and O2, but others can’t.
Fluid mosaic model
Describes the structure of the plasma/cell membrane. Fluid refers to the phospholipids, mosaic refers to the various proteins.
Diffusion
The movement of molecules from areas of high concentration to areas of low concentration to reach equilibrium.
Osmosis
The diffusion of water from high to low concentration.
Hypotonic solution
More solutes inside the cell than outside the cell. The cell gains water.
Hypertonic solution
More solutes outside the cell than inside the cell. The cell loses water.
Isotonic solution
Solutes and solvent are equal on both sides of the membrane. Water moves in and out equally.
Osmotic/turgor pressure
The water pressure that builds from osmosis. It causes plants to stand up.
Plasmolysis
The shrinkage of a cell and its organelles due to lack of water (hypertonic solution).
Facilitated diffusion
Diffusion with the help of carrier/transport proteins moving the molecules into the cell that are otherwise too big to come through. A form of passive transport.
Carrier protein
A protein that helps transport a molecule in facilitated diffusion.
Active transport
The transportation of molecules that requires energy because some molecules cannot get through otherwise.
Endocytosis
A form of active transport. Bringing a molecule into a cell by engulfing it in the cell membrane (surrounding it with a vesicle).
Exocytosis
A form of active transport. Forcing a molecule out of a cell by fusing the vesicle with the membrane to release the molecule.
Phagocytosis
A form of endocytosis involving large, solid particles, usually the organism’s food, by engulfing the prey in the membrane.
Tissue
A group of cells that are similar and working together to do a specific job.
Organ
A group of tissues working together to do a specific job.
Organ system
A group of organs working together to do a specific job.
Cell
The basic unit of life.
