cell processes Flashcards
what is homeostasis?
maintaining a constant internal environment
what’s one important factor for homeostasis?
movement of materials into and out of the cell
what’s involved in homeostasis?
delicate balance between cellular activities and the conditions of the cell’s activities
what is passive transport?
method of transport that doesn’t involve use of cellular energy to move substances into or out of the cell
what does passive transport rely on?
natural constant motion of the particles which causes molecules to collide and scatter
if possible will occur until an equilibrium is reached
what are the forms of passive transport?
diffusion, osmosis, and facilitated diffusion
what is diffusion?
movement of substance from an area of high concentration to an area of low concentration
what is said of the substances during diffusion?
diffuse down a concentration gradient
what is concentration gradient?
difference in concentration between two areas
what will diffuse across the cell membrane?
small lipids, and other nonpolar moelcules such as O and CO2
what’s an important factor in diffusion?
solubility
what is osmosis?
diffusion of water across selectively permeable membrane
what is a facilitated diffusion?
diffusion of substances by use of carrier molecules (aka channel proteins) that are in cell membrane
what enters by facilitated diffusion?
ions and large polar molecules
how to determine direction of movement of objects by diffusion?
compare the concentration of the two solutions involved
where is the comparison in living organisms?
between concentration of solution inside cell vs concentration of solution outside the cell
solution in cell- 1% solute 99% solvent, solution in beaker 9% solute 91% solvent
the solution in the cell is hypotonic so the water moves out of the cell, the solution in the beaker is hypertonic so the water moves into the cell as a result the mass decreases, equilibrium concentration 5% solute 95% solvent
what is an equilibrium?
Equilibrium means balance. Equilibrium can also be defined as a stable situation in which forces affecting an object cancel one another
what’s plasmolysis?
occurs when cell has lost water and shrinks in size
what happens during plasmolysis in plants?
results when water leaves the vacuole and turgor pressure within cell decreases so plant wilts
what is cytolysis?
rupturing or bursting of cell b/c of inward movement of water beyond the capacity of cell
can plants undergo cytolysis?
no b/c they have a cell wall
depending on what will plasmolysis or cytolysis occur?
direction and amount of water involved
what are the descriptive terms used to describe solutions?
hypotonic solution, hypertonic solution, and isotonic solution
what is a hypotonic solution?
has lower concentration of dissolved particles so has higher concentration of water molecules than other solution (solvent)
- water molec. move from hypotonic solution they’re in
what is a hypertonic solution?
has higher concentration of dissolved particles than other solution, solution contains less water molec., water molec. move to hypertonic solution
what is an isotonic solution?
both solutions have same concentration of dissolved particles
how is the movement of water in an isotonic solution?
between two isotonic solutions if equal in both directions
how to predict water movement?
moves by form of passive transport known as osmosis which means water will move from area of high water concentration to area of low water concentration
what is an active transport?
method of transport that does involve use of cellular energy to move substances into or out of cell
what is needed for substances to be moved in active transport?
energy is needed b/c substances are being moved up concentration gradient aka going from an area of low concentration to an area of high concentration (often involves use of carrier proteins)
what does endocytosis literally mean?
into the cell
what is endocytosis?
process of taking in liquids or fairly large molecules into cell by engulfing them in membrane
what does the cell do during endocytosis?
uses energy to make pocket around substance
what are the two types of endocytosis?
phagocytosis and pinocytosis
what is phagocytosis?
literally means cell eating, cell membrane engulfs large particles
what does phagocytosis play a key role in?
immune system since some white blood cells take in foreign invaders and destroy them
what is pinocytosis?
literally means cell drinking, cell membrane engulfs large quantities of liquid
what does exocytosis literally mean?
exit the cell
what is exocytosis?
release of substance out of cell by fusion of vesicle with cell membrane
what does exocytosis involve?
golgi apparatus that places liquid bilayer around substance so that is may pass through lipid bilayer of cell membrane when it comes in contact with it thus releasing substance from cellq
