Transport, Storage and Gas Exchange in Flowering Plants Flashcards
Ch 24
What does autotrophic mean?
make own food
What is metabolism?
all chemical reactions in an organism
Plant metabolism refers to reactions like?
photosynthesis or respiration
The materials which are transported include?
water, carbon dioxide, minerals, (carbohydrates)
Root hairs are adapted for water absorption, why?
thin walls,
occur in large numbers giving a large surface area
Water enters the roots by?
osmosis
Definition of osmosis?
the movement of water across a semi-permeable membrane from a region of high water concentration to a region of low water concentration
Cytoplasm is more concentrated than what in the soil?
the water
Water _____ from the root hairs into the ground tissue and eventually?
diffuses,
reaches the xylem
Definition of transpiration?
is the evaporation of liquid water into water vapour through the stomata on the underside of leaves. This results in upward movement of water through a plant.
What are the 2 mechanisms that combine to cause the movement of water from the roots to the upper parts of a plant?
root pressure,
transpiration
How does root pressure work (upward movement of water)?
water moves into roots through osmosis and builds pressure on the roots,
this pushes water into the stems
(Controlling water loss/transpiration), give 3 ways its prevented.
- waxy cuticle covers some leaves which stops water from passing through
- some leaves have thin spiny needles, eg: cactus
- stomata are on the under surface of the leaf, avoiding direct sunlight
Stomata open/closes when (night/day)?
close at night
open during the day
What things might change stomata’s opening and closing?
high temp, carbon dioxide concentration, high winds
Does stomata open or close under high carbon dioxide concentration? Why?
closes, rate of photosynthesis decreases at night causing carbon dioxide levels to build up
Does stomata open or close under low carbon dioxide concentration? Why?
opens, when photosynthesis begins in the morning carbon dioxide is absorbed by ground tissue
What open and closes the stomata?
guard cells
MODIFIED ROOT - FOOD STORAGE
- __ plants produce __ main tap root.
- the tap root becomes?
- dicot plants produce one main tap root
- becomes fleshy and swollen with starch/food
MODIFIED STEM - FOOD STORAGE
- ___ have an ___ system.
- the tips of their roots are called? What happens them?
- potatoes have an underground system
- tubers, become swollen with starch
MODIFIED LEAF - FOOD STORAGE
- what is a bulb? Give eg.
- an underground stem that has leaves which become fleshy and stolen with starch, eg: onion.
What are lenticels?
openings in the stems of plants that allow gas exchange
What two scientists are associated with the cohesion-tension model?
Dixon and Joly
What does cohesion mean?
similar molecules are attracted to each other (water)
What does adhesion mean?
attraction between different substances (water and xylem)
2 points on water in relation to the cohesion-tension model?
water has a high cohesion
water adheres to the walls of xylem
Outline the cohesion-tension model in 3 points.
1) water evaporates from the xylem through the stomata by transpiration
2) due to cohesion, next water molecule is pulled up by the molecule in front of it
3) xylem are narrow and when water column is streched it is under tension (adhesion occurs between xylem walls and water)
