Mass Transport In Water Flashcards
What is the function of Xylem?
Xylem function is the movement of water so plants carry out photosynthesis
What is the function of the Phloem?
Phloem function is responsible for transport of organic substances mass flow hypothesis
What is it called when Sugar moves around the body?
Translocation
How is water absorbed through the xylem?
Water enter the xylem by being ABSORBED via the root hair cells by osmosis.
Water reaches Xylem where its transported against gravity along its LONG-THICK-WALLED tube.
Transpiration occurs-Evaporation of water vapour through stomata.
What so special about root hair cells?
Roots hair cells specialised cells due to have Large:SA so more water absorbed.
What is Transpiration?
What factor effects Transpiration?
What effect does it have on the xylem?
Transpiration is evaporation of water vapour through the stomata.
Higher Temperature=Faster Evaporation
TRANSPIRATION PULL occurs when water column pulled up the Xylem puts tension on diameter of xylem.
How is water transported against Gravity?
Water is a (di)polar hydrogen bond formed between water molecules.
Results in CONTINUOUS water column being created in xylem.
So when water evaporates out of stomata TRANSPIRATION pull occurs-water columns pulled up xylem this puts tension of xylem decreases diameter.
Features of the xylem.
1.Xylem cells hollow because they are dead-have no organelles.
2.Xylem cells no end column can form.
Describe the Structure of Phloem.
Companion cell
Sieve tube Plate in the middle.
Sieve tube elements in the middle of sieve tube plate
How is sugar made and how is it transported into phloem?
1.Sugar/sucrose is created by Photosynthesis in the source cell and transported to companion cell by FACILITATED DIFFUSION.
2.Sugar/Sucroseis then Actively transported into phloem CO-TRANSPORTED with Hyrogen ions into Phloem.
What affects does Sucrose/Sugar Have when it enters phloem?
When Sucrose/sugar enter phloem it decrease water potential so water enters phloem from xylem by OSMOSIS.
How does Sucrose reach the Sink cell?
As water enters the Phloem the increase water increases the volume so increases the hydrostatic pressure CREATING a HYDROSTATIC PRESSURE GRADIENT.
Sucrose/sugar formed down to the bottom of phloem
Sucrose/Sugar used in sink cell increased water potential as sugar exists by OSMOSIS decreasing HYDROSTATIC PRESSURE
What are the experiments you need to know in Mass Flow Hypothesis?
Two experiment you need to know for for mass flow hypothesis is Ringing Experiment and Tracing Experiment
Give the experiment where it creates swelling?
[Mass Flow Hypothesis]
Ringing experiment.
1.Ring of bark along with phloem removed from tree trunk.
2.Trunk swells above removed ring- reason is contains liquid which is sugar and shows sugars can’t be transported due to removal of phloem.
Which test using Radioactively labelled CO2, give the full experiment?
Tracing Experiment.
1.Plants provided with radioactively labelled CO2 which is absorbed during photosynthesis to produce sugars.
2.Sugar produced radioactively labelled/
3.Plants then cut and sampled and placed on X-Ray Film which detects Radioactive material highlighting where phloem located.
