Cell transport 1B Flashcards
what is a sub-cellular structure?
small structures inside the cell e.g nucleus
what does differentiation mean?
when a cell becomes a specialised cell.
What is mitosis?
cell division where one set of chromosomes are pulled to each end of the cell and the nucleus divide
How to work out magnification
= size of image / size of real object
What is diffusion?
diffusion is the spreading out of particles ( in a solution or gas ) resulting in net movement from an area of higher concentration to an area of lower concentration
What is the concentration gradient?
the difference in concentration between 2 areas
Which way do particles move in diffusion
particles move down the concentration gradient
what does it mean when the concentration gradient is steeper?
the steeper it is the more likely particles are going to diffuse down the concentration gradient, so diffusion is faster.
What happens to diffusion at a higher temperature?
all particles have more kinetic energy
more likely to spread out from a high to low concentration
diffusion is faster
What happens to diffusion with surface area?
the larger the surface area of the membrane the quicker particles will diffuse at once
diffusion is faster
what does distance have to do with diffusion?
if particles have further to diffuse the longer it’ll take
diffusion will be slower
How to work out the surface area
mm squared x number of sides
how to work out the volume
mm side length cubed ( x3 )
How to work out surface area : volume ratio
SA / Volume
how to work out the rate of diffusion?
min-1
How are the alveoli adapted for efficient gas exchange
large surface area
- many aveoli
- spherical shape
maintain concentration gradient
- breathing and ventilation
- good blood supply
Short distance
- one flattened cell thick
How are villi adapted?
Short Distance
- one cell thick
many villi
- large surface area
Maintain concentration gradient
- peristalsis ( muscle contraction )
- rich bloody supply
How are Fish gills adapted?
thin - short diffusion distance
many gill filaments - large SA
Rich bloody supply - maintain concentration gradient
How are leaves in plants adapted?
Large SA - large flat leaves
Thin leaves - short diffusion distance
spongy cells with air space - large SA - diffusion in gas is faster
how are roots in plants adapted?
thin cell walls - short diffusion distance
root hairs - large surface area
many mitochondria - active transport of mineral ions - maintains concentration gradient for water uptake
Osmosis definition
diffusion of water from a dilute solution to a concentrated solution across a partially permeable membrane
how to work out a percentage change
% change = final mass - start mass
start mass x100
What is active transport?
substances move from an area of low concentration to an area of higher concentration against a concentration gradient
Requires energy from respiration
Key facts about active transport
- low -> high concentration
against the gradient - needs energy - respiration
- Many mitochondria needed
- aerobic respiration needs
oxygen - carrier proteins are needed
