Chapter 24 - Transport, Storage And Gas Exchange In Flowering Plants Flashcards
What is a heterotrophic
An organism that take in their own food for example humans
What is an autotrophic
An organism that make their own food example plants
How is water transported
Water is transported by osmosis
Water defuses from root hairs into ground tissue and then the xylem
What are root hairs and what do they do
are extensions of a route epiderm are cells
Increase surface area for absorption
what is root pressure
Water drawn in to root by osmosis
it is aided by root hairs
the buildup of water results in a pressure that can push water up
this pressure is not strong enough to push water up to the top of tall trees
What is transpiration
Transpiration is the loss of water vapour by evaporation from the leaves of the plant
Describe transpiration
Water vapour escape through the underside of the leaf through openings called stomata
What three things control transpiration
Waxy cuticle
stomata
guard cells
How does the waxy cuticle control transpiration
Water cannot pass on upper surface
How does stomata control transpiration
On lower surface has more change of operation on upper surface
How do you guard cells control transpiration
Two on each stoma, opening during the day, close at night
What is the chemical equation for photosynthesis
Sun
Co2 + H2o ——————— C6 H12 O6 + 6O2
Chlorophyll
Where does the plan to get CO2 from
The atmosphere
Where does the plant get H2O from
So oil
What happens when the stoma is open
Water loss increases
What happens when the stoma is close
Water loss decreases
What is three conditions are there for the stoma to be closed during the day
No water available - drought
high-temperature
high wind
How are minerals transported to plants
They enter the plant dissolves in water through the roots they can either be active or passive transport
Once inside the plants it is transported by the xylem
How is carbon dioxide transported to plants
The atmosphere carbon dioxide defuses in from the atmosphere through the stomata and lenticel
respiration produced by the leaf cell
How are the products of photosynthesis transported
Oxygen - diffuses out of the plant through the stomata and lenticels
some of this is used for respiration by the plants
Glucose - Transported by the phloem
all around the plant
use for respiration
stored as starch
converted to sucrose called sap
Describe gas exchange during the day
Carbon dioxide enters through the stomata
Oxygen and water are released
Called diffusion
In the stem where does gas exchange take place
Lenticels
Describe gas exchange at night
Oxygen enters through the stomata
Carbon dioxide and water are released
What is the controlling factor for the opening and closing of the stomata
Carbon dioxide
High concentration - closed (no photosynthesis)
Low concentration - open (photosynthesis)
3 types of food storage
Modified root
Modified stem
Modified leaf
Describe modified roots
Tap root becomes swollen and fleshy
E.g carrots, turnips, sugar beet
Describe modified stem
Potato plants have an underground stem system
Stems become swollen (tubers)
Describe modified leaves
Bulbs are fleshy swollen leaves that surround an apical bud
E.g onion
What is cohesion
When similar molecules stick together
E.g water sticking to water
What is adhesion
Different molecules sticking to each other, not as strong as cohesion
E.g water sticking to wall of xylem
What is the cohesion tension model
Explains how water is transported in plants to extremem heights against the force of gravity
Name the two Irish scientists who put the idea of the cohesion tension model forward in 1894
Henry Dixon
John joly
Describe the 5 steps of the cohesion tension model
- Water evaporates from xylem into air spaces in the leaf - each water molecule pulls the next one behind it (cohesion)
- Water in the xylem is under tension
- This tension on xylem can pull water up to 150 meters
- Xylem narrows under tension - stem becomes narrow during daytime - lignin prevents the xylem from collapsing
- When transpiration stops no tension - xylem returns to original shape - xylem walls are elastic for this
