Movement of Substances (osmosis, direct transport, diffusion) Flashcards
how does oxygen get into the body
oxygen is breathed in, in air - travels down trachea - bronchus - lung - bronchioles - alveoli - diffuses into blood
what happens to oxygen inside a capillary
moves into red blood cells - combines with haemoglobin
why does oxygen need to move around the body
body cells require oxygen for aerobic respiration in mitochondria to create energy - energy used to move, generate heat (enzymes), growth (creating new cells), chemical reactions (digestion) etc
concentration
how many particles are in a fixed area/volume
movement of particles in diffusion
move from high to low concentration until even distribution (equilibrium)
how is it possible for oxygen to move from alveolus to capillary
alveolus & capillary wall are 1 cell thick - easier for diffusion to occur (high to low concentration - alveolus has high, capillary has low)
how is it possible for carbon dioxide to move from capillary into alveolus
co2 created as waste product of respiration in bloodstream in plasma - diffuses out down concentration gradient
why is it important for co2 to be removed from body
it’s toxic/poisonous - cannot be allowed to build up - can make body too acidic - affect enzymes
how is it possible for co2 to move from air into palisade cells in leaf
higher concentration outside of leaf -lower inside. diffuses into leaf through stoma, through air spaces between spongy mesophyll. even lower concentration inside palisade cells as constantly used in photosynthesis
why does co2 diffusion not occur in plants at night, and what does the plant do because of this
there is no concentration gradient as the plant is not photosynthesising due to lack of light. stomata closes so the plant does not lose excess water
what is urea and why is it found in liver
toxic chemical - dissolved in urine - extra protein cannot be stored - liver breaks it down into urea
how does urea move out of liver cells into blood plasma
diffusion - higher concentration in liver - lower in blood plasma (blood flows constantly and takes it away)
what happens to urea in kidneys
higher concentration in blood plasma -lower in kidneys - diffusion. filtered - moves to bladder - excretion
factors affecting rate of diffusion
temperature, sa, concentration gradient
how does a high temperature affect rate of diffusion
higher temp - particles have more kinetic energy - increased motion - move and diffuse quicker. vice versa for low temperature
how does large sa affect rate of diffusion
larger sa - more space for particles to diffuse across - quicker. vice versa for smaller sa
how does a steep concentration gradient affect diffusion rate
greater difference - steeper gradient - faster diffusion as trying to move from a place of high to low. vice versa for shallow concentration gradient
how is amoeba specialised for diffusion
not regular shape - lots of psedopods etc. increases sa - higher rate of diffusion
how are humans adapted to low sa:v ratio
transport systems i.e circulatory system (tubes/vessels). specialised exchange surfaces i.e. lungs (thin, moist, large area)
sa
outer layer of something
v
amount of space something occupies
sa:v ratio
amount of sa per unit v of an object
ventilation
movement of air in and out of an animal
how are lungs adapted for exchange of gases, and which gases are these
gases: co2, o2, nitrogen, argon, water vapour. adaptations: large sa - lots of rounded alveoli. short diffusion distance - lots of capillaries nearby - wall 1 cell thick. steep concentration gradient - much co2 in body, not in air - much o2 in air, not body - constantly breathing
how is the small intestine adapted for diffusion, and what substances are exchanged
substances: nutrients, fats, carbs, proteins. adaptations: large sa - millions of villi - very long - highly folded. short diffusion distance - wall 1 cell thick - nearby capillaries & blood vessels. steep concentration gradient - lymph vessel runs through centre to transport fatty acids and glycerol - blood constantly moves - body regularly eats and egests.
how are fish gills adapted for diffusion, and what substances are exchanged
substances: o2, co2, h2o. adaptations: large sa - lamellae - protrusions - filaments. short diffusion distance - rich blood supply - thin walls. steep concentration gradient - counter-current flow principle - ventilation.
how are plant roots adapted for diffusion, and what substances are exchanged
substances: water, minerals. adaptations: large sa - long root hair. short diffusion distance - thin cell walls. steep concentration gradient - lots of water outside, not in - xylem and phloem - transpiration