Xylem and Phloem - AS Biology Revision - OCR (Unit 1.2.3)

Xylem and Phloem. AS Biology. OCR Exam Board. Unit 1.2.3. The "You need to know..." section has come from the OCR specification. By an AS Biology student. Music: Dog Days Are Over - Florence And The Machine (If you don't like the music, just mute it. There's no info through audio :)) thanks! :D

Category:

Education

Tags:

• xylem
• phloem
• water
• minerals
• sugars
• waste
• multicellular
• plants
• transport
• systems
• root
• stem
• lead
• vessel
• veins
• support
• long
• tube
• elements
• wall
• dead
• cytoplasm
• thickened
• lignin
• woody
• wood
• pits
• sieve
• fibres
• parenchyma
• companion
• cells
• transporting
• solutes
• no
• organelles
• tubes
• plate
• active

[jalalpurjattan]

0:40

Dont you mean plants have a large sa : vol ratio instead of small?????

[OCRBiologyAS]

@jalalpurjattan nope, plants have a small surface area to volume ratio!

[jalalpurjattan]

@jalalpurjattan Plants dont need a transport system for oxygen and co2 because their matabolism is lower, sa to vol ratio is large and diffusion thorugh air spaces and cells suffice!!

[OCRBiologyAS]

@jalalpurjattan From the OCR textbook: "there are many cells inside the plant that are not near the surface of the plant which need a transport system to provide it with water and nutrients to survive".

Also, "Once a multicellular organisms becomes larger, its surface-area-to-volume ratio becomes smaller and its cells needs more supplies".

[Kanabaro]

distributed*

[LynchMuK]

Lignin is also for waterproofing

[debby101]

@anon3339 Thank you. This video really helped aswell..please do some more

[anon3339]

@debby101 Florence and the machine- dog days are over

[debby101]

What is this song called?

[coolkat787]

Thanks, that was very useful,!

[tbcw1000]

thank you very much that was very useful! :)

[nirvanafreak5364]

its good except it goes to fast.. 

[safaanej]

thank you so much :)

[2pakaveli]

Will you sit my exam tomorrow?

Thank you kind sir x