The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

This discussion is now closed.

Check out other Related discussions

AQA BIOL2~3rd June 2013~AS Biology (Now Closed)

Scroll to see replies

Reply 2160
Avatar for rac1
rac1
18
On page 101 in the AQA textbook from Nelson Thornes (the one on kerbodle) there is a micrograph of a group of red blood cells, I was just wondering if anyone knows why one of the cells has a group of dot things on it?
Original post by madmadmax321
is the xylem living or dead tissue and why?

thanks


It is dead tissue, i.e it has no organelles or a cytoplasm

This allows;

Continuous collumn of water, so water can flow upwards.

Adhesion between xylem wall and water molecules

Cohesion of water molecules by H-bonds
(edited 10 years ago)
Original post by rac1
On page 101 in the AQA textbook from Nelson Thornes (the one on kerbodle) there is a micrograph of a group of red blood cells, I was just wondering if anyone knows why one of the cells has a group of dot things on it?


It's a daisy.
Original post by Jaydude
It is dead tissue, i.e it has no organelles or a cytoplasm

This allows;

Continuous collumn of water, so water can flow upwards.

Adhesion between xylem wall and water molecules

Cohesion of water molecules by H-bonds


thanks you!
Reply 2164
Avatar for zbert
zbert
air spaces throughout mesophyll

why is this good for rapid gas exchange in leaves? I forgot
Reply 2165
Avatar for Manni
Manni
This thread stresses me out at times lool
Reply 2166
Avatar for Liam2404
Liam2404
Could someone please write a 6 mark answer for water transport in plants from the root to the leaf? I thought i got it until the mark scheme started talking about the active transport of ions :s Would be much appreciated :smile:
Reply 2167
Avatar for eddyf
eddyf
has anyone got the Biol2 January 13 test and mark scheme??
Original post by saaaarn
Have you watched the khan academy video on it? :smile:
http://youtu.be/ijLc52LmFQg


Thank you so much!
If the stomata is constantly closed why does the plant die?


Posted from TSR Mobile
Reply 2170
Avatar for Nima123
Nima123
2
Can someone explain question 8ci to me image.jpg
Original post by eilish1903
U don't actually need to know the process!!
U just need to know about independent segregation and crossing over. Then u need to know how many cells and what type. And then be aware of the fact that the original cell divides once to produce two cells and these two cells divide to produce two cells each, giving u four genetically non identical daughter cells.

Posted from TSR Mobile


Ah okay! Thank youuu!
Original post by Jimmy20002012
If the stomata is constantly closed why does the plant die?


Posted from TSR Mobile

CO2 can't enter for photosynthesis
Reply 2173
Avatar for rac1
rac1
18
Original post by Amenbreak321
It's a daisy.


haha. I think its probably antigens.
Original post by Nima123
Can someone explain question 8ci to me image.jpg


All it is, is 82% of 24?


Posted from TSR Mobile
Original post by Liam2404
Could someone please write a 6 mark answer for water transport in plants from the root to the leaf? I thought i got it until the mark scheme started talking about the active transport of ions :s Would be much appreciated :smile:


I'll have a shot, but I can't say it will be perfect:
- Ions actively transported into xylem by endodermis
- This lowers the water potential of the xylem, causing water to move in by osmosis
- Continuous column of water up the xylem
- Hydrogen bonds between the water molecules give them cohesive properties
- This creates tension in the xylem
- Adhesion of water molecules and xylem wall also aids transpiration
Original post by Jimmy20002012
If the stomata is constantly closed why does the plant die?


Posted from TSR Mobile


Stomata allows gas exchange

If they are closed, no gas exchange of co2 and o2 can occur

Plant cannot respire, photosynthesis cannot occur

Plant cells die
Can someone write a 6 mark response to surface area and size. Noooo idea what I'd write
Reply 2178
Avatar for eddyf
eddyf
Original post by Nima123
Can someone explain question 8ci to me image.jpg

could you send me the link to this?
Original post by Nima123
Can someone explain question 8ci to me image.jpg


45% of 24 hours.

Related discussions

Latest

Trending

Trending

Articles for you