Lab 2

Question 1

Brownian motion

Answer 1

Random movement of microscopic particles suspended in a gas or a liquid; caused by collision of small molecules in the surrounding medium

Question 2

What causes the molecules in Brownian motion to move or vibrate?

Answer 2

The kinetic energy of all molecules above absolute zero (approx. -459ºF)

Question 3

The rate of molecular movement or vibration depends on what 3 things?

Answer 3

1. 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)

Question 4

What is the magnification of oil immersion lenses?

Answer 4

1000x

Question 5

Diffusion

Answer 5

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

Question 6

What causes the movement in diffusion?

Answer 6

The intrinsic kinetic energy of the particles within the substance

Question 7

What are the factors that influence how fast particles move in diffusion?

Answer 7

1. 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)-

Question 8

Selective permeability

Answer 8

Must permit movement of particular materials back and forth across the cell membrane while keeping others from entering or leaving

Question 9

Molecules that are capable of diffusing across cell membrane

Answer 9

O₂, H₂O, CO₂

Question 10

Osmosis

Answer 10

Diffusion of water across a selectively permeable membrane; ONLY WATER

Question 11

What happens when cells swell or become turgid?

Answer 11

They exhibit lysis = they rupture

Question 12

What happens when cells dehydrate?

Answer 12

They shrink and exhibit crenation = becomes flaccid

Question 13

Tonicity

Answer 13

The ability of a solution to change the tone or shape of cells by alternating the internal water volume

Question 14

Isotonic

Answer 14

Water & solute = equal Zero water movement

Question 15

Hypertonic

Answer 15

Water = less Solute = more H2O leaves cell Cell shrinks

Question 16

Hypotonic

Answer 16

Water = more Solute = less H2O enters the cell Cell swells