Topic J -Transport in cells and animals Flashcards
definition of diffusion
net movement of particles from high concentration to a lower concentration down a concentration gradient till reaches equilibrium
example of diffusion
gasses and liquids O2 and CO2 diffuse in and out of blood
definition of osmosis
movement of water from an area of high water potential to low water potential down a gradient across a semi permeable membrane
example of osmosis
water enters into root hair cells by osmosis
definition of active transport
net movement of particles from low to high against concentration gradient across semi permeable membrane.
Requires energy
example of active transport
mineral ions are actively transported into root hair cells
what factors effect the rate of movement of substances in and out of cells
surface area to volume ratio
distance
temperature
concentration gradient
why can simple unicellular organisms rely on diffusion for movement of substances in out of cells
all the life processes in a unicellular organism take place in that one cell
why do multicellular organisms need transport systems
Multicellular organisms need organ systems to carry out functions such as:
1. Communication between cells, eg the nervous system and circulatory system
- Supplying the cells with nutrients, eg the digestive system
- Controlling exchanges with the environment, eg the respiratory system and excretory system
how is the heart structured
has 4 chambers, right atrium, right ventricle, left atrium and left ventricle
how does adrenaline effect heart rate
increase heart rate
how does exercise effect heart rate and why
- body’s cells need more glucose and oxygen during exercise, and the blood supplies this
- muscles need more energy = respire more - heart rate increases as activity increases in = blood flow faster=more oxygen into cells + co2 removed
- detected as a faster pulse rate. .
what factors increase the rate of coronary heart disease
smoking
high blood pressure
high levels of salt in the diet
high levels of saturated fat in the diet
describe structure of arteries
thick muscual wall + narrow lumen
contain no valves
blood pressure high due to thin lumen + muscular walls
function of arteries
carries oxygenated blood from heart to organs ( movement out)
structure of veins
thin muscular wall + wide lumen
contains valves
blood pressure = low
function of veins
carries deoxygenated blood from organs to heart ( movement in )
structure of capillaries
1 cell thick + no wall
contains no valves
blood pressure low cos tubes let substances out