bio: #2

movement in & out of cells

diffusion

the net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient, as a result of their random movement

importance of diffusion in animals

to take in oxygen and remove carbon dioxide through lungs (alveoli), gills, and body surface

importance of diffusion in plants

to take in carbon dioxide, diffuse in and out oxygen, and diffuse out water vapour through stomata

mineral ions

nitrates and magnesium diffused across tissues of plant roots

water soluble vitamins

vitamin b and c absorbed into bloodstream through diffusion in the ileum

urea and salt

passed back into bloodstream by diffusion in the kidney

factors affecting diffusion rate

temperature, distance, surface area, concentration gradient

temperature

the higher the temperature, the higher the kinetic energy of molecules, the higher the diffusion rate

distance

the shorter the distance, the higher the diffusion rate

surface area (to volume ratio)

the larger the overall surface area, the higher the diffusion rate

concentration gradient

the bigger the concentration difference, the higher the diffusion rate

osmosis

the net movement of water particles from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable solution

water potential

the measure of whether a solution is likely to lose or gain water molecules from another solution

hypotonic

a solution that has lesser solutes than another solution, it is dilute & has higher water potential

effect of hypotonic solution on animal cells

the cell expands and may burst

effect of hypotonic solution on plant cells

the cell becomes very turgid (swollen)

isotonic

a solution that has the same amount of solutes with another solution

effect of isotonic solution on animal cells

water molecules move in & out of the cell at the same rate

effect of isotonic solution on plant cells

water molecules move in & out of the cell at the same rate, cell is turgid

hypertonic

a solution which has more solutes than another solution, it is concentrated & has lower water potential

effect of hypertonic solution on animal cells

the cell shrinks (crenation)

effect of hypertonic solution on plant cells

the cell becomes flaccid, or flabby (plasmolysis), cytoplasm shrinks away from rigid cell wall

active transport

the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration, using energy from respiration

carrier molecule

also known as a protein molecule, is responsible for transporting substances across the membrane during active transport

particles involved in diffusion

gas/dissolved solute

particles involved in osmosis

water molecules

particles involved in active transport

dissolved solute

direction of movement in diffusion

• high → low concentration

• down the concentration gradient

direction of movement in osmosis

high → low water potential

direction of movement in active transport

• low → high concentration

• up the concentration gradient

partially permeable membrane in diffusion

not necessarily required

partially permeable membrane in osmosis

required

partially permeable membrane in active transport

required

energy from respiration in diffusion

not required

energy from respiration in osmosis

not required

energy from respiration in active transport

required

protein pumps (carrier molecule) in diffusion

not required

protein pumps (carrier molecule) in osmosis

not required

protein pumps (carrier molecule) in active transport

required

what is the process by which human cells produce carbon dioxide?

aerobic respiration