plant transport Flashcards
Define the term homeostasis
ability to maintain a constant stable internal environment
suggest one reason homeostasis is important to plants
for metabolism or for enzyme activity
explain the role of the cuticle in relation to homeostasis
prevent (reduce) water loss
in which of the labelled parts is the rate of photosynthesis highest
palisade (cells), highest concentration of chloroplasts (chlorophyll)
suggest two ways in which a leaf is well adapted for photosynthesis
large surface area / thin / presence of air spaces
with regard to the stomata ,name
1. the gas
2. the cells which control their opening
- C02 2. guard cells
like the stomata, the lenticels also function in gaseous exchange. on what part of the plant are they located?
stem
state one example of a plant which uses modified leads as a means of storing food
onion / daffodil / tulip / garlic
by what process does water enter the root hairs
osmosis
name two irish scientists who first described the upward movement of water in plants
Henry Dixon / John joly
describe in detail the upward movement of water in plants
root pressure pushes water / in xylem / cohesion or water molecules stick together / continuous column /adhesion or water molecules tick to xylem walls
give two structural differences between xylem and phloem
xylem has pits and phloem does not / xylem has lignin and phloem does not / phloem has companion cells and xylem does not / xylem has vessels or tracheids and phloem does not
biuret
to test for protein
Benedict’s solution
to test for reducing sugars
why would you use a coverslip in relation to plants
to prevent cells from drying out or to protect the objective lens from water or from stain
why do you apply methylene blue to the cells
to stain the cells or to make (the cells) easier to see
name the vascular tissue through which the products of photosynthesis are transported in plants
phloem
structural features of phloem
sieve tubes / companion cells / sieve plates
what do you understand by the term turgor in plant cells
pressure of cell contents against the cell wall
how do plant cells remain turgid for a considerable period of time
by taking in as water as they lose / by osmosis
what happens to a plant if many of its cells lose turgidity
wilt or lose righty or droop
explain how water enters root hairs and then passes to the vascular tissue
osmosis
in which of the vascular tissues will water now rise through the plant
xylem
give two features of xylem that facilates upward movement
narrow / continous tube (no end walls or open ended) / or pits / no cell contents /attraction of h20 to walls /thick walls
name and briefly explain any two processes involved in upward movement of water in plants
root pressure, h20 in pushes h20 up
suggest a way in which turgor is of value to plants
support
name hte tissue inplant stems through which water rises to the leaves
xylem
give one way in which xylem is adapted for the trasnport of water
narrow or continous lumen
give a precise location of xylem in the tissue
in vascular bundles / next to phloem
state another function for xylem
support or other transport function
describe the principle features of the cohesion-tension model
water molecules stick together / due to h-bonding / continous chain of water molecules / water tends to adhere to xylem walls / transpiration or water loss pulls the column of water up
the cohesion-tension model of transport attempts to explain water movement in plants against a particular force. Name this force
gravity
In order to allow photosynthesis and other metabolic reactions to occur plants need to be able to acquire and transport
Water, oxygen, carbon dioxide and minerals
What are the adaption of root hairs for absorption
Thin walls, not covered by cuticle and very numerous or large surface area
How does water enter the cytoplasm of root hairs
By osmosis
What does xylem transport
Water and materials
What are the two types of upwards water movements in plants
Root pressure and transpiration
Explain the term root pressure
As water is drawn into the roots by osmosis, the build up of water causes a pressure this root pressure pushes water up and through the xylem
Explain transpiration
Transpiration is the loss of water by evaporation from the leaves and other aerial parts of the plant
Where does transpiration take place
Most transpiration takes place through openings in the leaves called stomata
What happens when the leaf cells lose water
They become less turgid and will wilt
What helps the stomata reduce water lose
Guard cells
Does diffusion require energy
No
Does active transport require energy
Uses energy in form of atp
How are roots modified so plants can store food
Some dicots produce large roots that penetrate into the soil, and absorb water or in some plants eg carrots the tap roots become swollen and fleshy with stored food
How do modified stems allow plants to store food
Potato plants have underground stems that become swollen with stored starch
How do modified leaves allow plants to store food
Onions,garlic and tulips produce bulbs a bulb contains an underground stem that is reduced in size, swollen fleshy leaves are modified to store food and are attached to to this stem
What are lenticels
Lenticels are openings in the stems of plants that allow gas exchange
What is the cohesion tension model
The cohesion tension model in plants explains how water can be transported to great heights in some plants against the force of gravity
What is the main factor in the process of stomata opening and closing
The concentration of carbon dioxide in air spaces in leafs
name the tissue in plant stems through which water rises tot he leaves
xylem
give one way in which this tissue is adapted for the transport of water
narrow or continuous lumen
give a precise location of this tissue in the stem
in vascular bundles
state one function of xylem
support
the cohesion tension model of transport attempts to explain water movement in plants against a particular force
gravity
explain how water enters root hairs and then passes to the vascular tissue
cell to cell by osmosis, soil water more is more dilute
name and briefly explain any two processes involved in the upwards movement of water in plants
root pressure : water in root pushes water up
transpiration : water out pulls water up
conditions for highest transpiration rate
hottest temperature or sunniest
what is the advantage to plants having most of their stomata on the underside of the leaves
reduces water loss by transpiration
what is the disadvantage to plants having most of their stomata on the underside of the leaves
wilting
how do plants respond to wilting
close stomata / reduce stomata in size
