Biology (9-1) - 0970 CIE

Diffusion

Gbogbo ọrọ náà

Open a bottle of perfume in one corner of a room and soon you can smell it everywhere. The scent particles have spread out by diffusion, moving from where they were crowded to where they were sparse, with no pump or effort. Your cells use this same free process every second to take in oxygen and get rid of carbon dioxide.

In this lesson you will learn exactly what diffusion is, where its energy comes from, why it is vital to living organisms, and how surface area, temperature, concentration gradient and distance change its rate.

Ebumnobi

Describe diffusion as the net movement of particles from a region of their higher concentration to a region of their lower concentration (i.e. down a concentration gradient), as a result of their random movement
State that the energy for diffusion comes from the kinetic energy of random movement of molecules and ions
State that some substances move into and out of cells by diffusion through the cell membrane
Describe the importance of diffusion of gases and solutes in living organisms
Investigate the factors that influence diffusion, limited to: surface area, temperature, concentration gradient and distance

Akọmọ Ojú-ẹkọ

Diffusion moves gases and dissolved substances into and out of every cell without using any of the cell's energy. Gas exchange in lungs, leaves and gills, and the absorption of digested food, all depend on it. Examiners want the precise definition and a clear explanation of how each factor changes the rate, so this is a high-value topic.

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Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Diffusion. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

Diffusion is the net movement of particles: A. from low to high concentration B. from high to low concentration C. only of water D. using energy from respiration Answer: B
The energy for diffusion comes from: A. respiration in the cell B. active transport C. the kinetic energy of the particles D. sunlight Answer: C
Which change would speed up diffusion? A. lower temperature B. smaller surface area C. steeper concentration gradient D. greater distance Answer: C
A larger surface area increases the rate of diffusion because: A. particles move slower B. more particles can cross at once C. the gradient disappears D. energy is added Answer: B
Which substance does NOT normally cross the cell membrane by diffusion? A. oxygen B. carbon dioxide C. large protein molecules D. water Answer: C