cells ✓ Flashcards
what is the acronym for the characteristics of living organisms ?
MRS GREN
what does MRS GREN stand for ?
Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition
what do living organisms do to their environment ?
they control it
put these words in order of smallest to largest
organisms organelle organs cell tissue organ systems
organelle cell tissue organs organ systems organism
what does tissue mean ?
a group of similar cells that work together to carry out a particular function
what does organ mean ?
is a group of different tissues that work together to perform a function
what are the similarities and differences between plant and animal cells ?
- animal cells have small vacuoles whereas the plant cells have large ones
- plants have chloroplasts but animal cells don’t
- plants have a cell wall but animal cells don’t
what is diffusion ?
movement of a substance from an area of high concentration to an area of low concentration
what is osmosis ?
is the diffusion of water molecules from a dilute solution to a more concentrated solution
what is a partially permeable membrane ?
allows some particles to pass through but not all particles
what is the affect of distance on the diffusion rate ?
the shorter the distance for diffusion the faster the rate
what is the affect of concentration gradient on the diffusion rate ?
the greater the difference between the concentration inside and outside the cells the faster the diffusion rate
what is the affect of surface area on the diffusion rate ?
the more surface area the faster the rate of movement into the cell
what is the affect of temperature on the diffusion rate ?
at a higher temperature diffusion is faster - molecules have more kinetic energy to move
what is the affect of volume ratio on the diffusion rate ?
as the surface area to volume ratio gets smaller it takes longer to diffuse
describe an experiment on osmosis
- get two Petri dishes
- get 2 thin slices of potato and 2 thin slices of cucumber
- put a slice of potato and a slice of cucumber in each dish
- pour pure water into one of the Petri dishes and a salt solution into the other one
what would the results of the osmosis experiment be ?
cucumber and potato in water would be harder and more sturdy, they were saturated because they took in water
cucumber and potato in the salt solution would be softer and more floppy because they lost water due to the salt solution
describe an experiment on diffusion
- get a piece of card
- draw a line near the bottom of the card
- draw coloured dots on the line
- put the card in some water below the line
- wait to see the colours have risen up the card
what is the process of active transport ?
is the process by which dissolved molecules move across a cell membrane from a lower to a higher concentration
what are the differences between active transport osmosis and diffusion ?
- active transport requires energy from a cell
- osmosis and diffusion have passive transport
