Lab 2 Flashcards
Brownian motion
Random movement of microscopic particles suspended in a gas or a liquid; caused by collision of small molecules in the surrounding medium
What causes the molecules in Brownian motion to move or vibrate?
The kinetic energy of all molecules above absolute zero (approx. -459ºF)
The rate of molecular movement or vibration depends on what 3 things?
- The amount of energy in the form of heat (more energy, more movement) 2. The size of the particle (smaller the particle the more rapid movement) 3. The state of matter (determined by amount of heat; molecules in gases move faster than those in solids or liq. are intermediate)
What is the magnification of oil immersion lenses?
1000x
Diffusion
Random movement of substances from an area of greater concentration to one of lesser concentration until equally distributed or reaches equilibrium; primary way that substances move in cells
What causes the movement in diffusion?
The intrinsic kinetic energy of the particles within the substance
What are the factors that influence how fast particles move in diffusion?
- The steepness of the concentration (the greater the difference in concentration the steeper the gradient and the more rapid diffusion)+ 2. Temperature (the higher the more rapid)+ 3. Particle size (the smaller the more rapid)-
Selective permeability
Must permit movement of particular materials back and forth across the cell membrane while keeping others from entering or leaving
Molecules that are capable of diffusing across cell membrane
O2, H2O, CO2
Osmosis
Diffusion of water across a selectively permeable membrane; ONLY WATER
What happens when cells swell or become turgid?
They exhibit lysis = they rupture
What happens when cells dehydrate?
They shrink and exhibit crenation = becomes flaccid
Tonicity
The ability of a solution to change the tone or shape of cells by alternating the internal water volume
Isotonic
Water & solute = equal Zero water movement
Hypertonic
Water = less Solute = more H2O leaves cell Cell shrinks
