Transport Flashcards
name parts of dicot root?
from outermost to innermost?
- root hair
- epidermis
- cortex
- endodermis
- pericycle
- parenchyma cells
- pith
- vascular bundles
Outside the conducting tissues, there
is a narrow layer of _______ cells, the _________.
cortex consists of ______ cells which are ________.
root hairs are extension of ________.
water vapors escape out of ______ through stomata.
how water enters root hair cells?
why water should go to xylem? how?
pericycle
thin-walled
parenchyma
large & thin-walled cells
epidermal cells
mesophyll cell walls
The cytoplasm of root hairs has higher concentration of salts than soil water, so water moves by osmosis into root hairs.
to be transported
water travels through intercellular spaces or through cells (via channels, called plasmodesmata) by osmosis & reach xylem
tissue. Once in xylem, water is carried to all the aerial parts of plant.
how mineral salts are transported to xylem?
what would happen if there aren’t minerals in soil?
Xylem is a ______from ____to____. Phloem is _______for _________.
most mineral salts pass through by simple diffusion into the root hair & then through the cortex Into the xylem vessels.
the absorption of mineral salts by the root hair is carried out by active transport.
one way
roots to leaves for water and salts
a two way street for food.
what is transpiration?
where does water come from in transpiration? explain the process?
the process in which water is lost as water vapor from the aerial parts of the plants through stomata or lenticles.
Water is drawn from xylem into mesophyll cells, from where it comes out and makes a water-film on the cell walls of mesophyll.
special openings called lenticels present in the stems of some plants.
link transpiration to surface area?
how & where does water become water vapor in transpiration?
the S.A of mesophyll cells of leaf provide large surface area for the evaporation of water.
* Once water molecules reach the surface of the leaf, they have enough energy to break free from the liquid phase & enter the gas phase, becoming water vapor. This process is called evaporation.
* Water vapours then diffuse from air spaces towards stomata & then pass to outside air.
Transpiration is water evaporation through leaves.
what is stomata?
explain the structure?
where is it present?
what is guard cell?
the inner wall of each guard cell is ________
the outer wall is _______.
the guard cell is surrounded by ___________
tiny pores on the leaf surface
each stoma is surrounded by 2 guard cells
thick & elastic
much thinner
epidermal cells
explain starch sugar hypothesis?
pg 132
explain the influx of K hypothesis?
what causes the water to stay in cell?
why does water flow back?
light causes the movement of K ions from epidermal cells into guard cells. Water follows these ions & enters guard cells. Thus their turgidity increases and stoma opens.
As the day progresses,**guard cells make glucose i.e. become hypertonic. So water stays in them. **
At the end of the day, K ions flow back from guard cells to epidermal cells & the concentration of glucose also falls. Due to it, water moves to epidermal cells & guard cells loose turgor. It causes the closure of stoma.
why is transpiration called necessary evil?
significance of transpiration?
leads to excessive loss of water sometimes causing the wilting of leaves. drying up or death.
1. transport of water & minerals to the aerial parts of the plant.
2. helps in the conduction of water & minerals to different parts of the plants.
3. evaporation of water has cooling effect on plant.
how transpiration results in wilting?
- during hot sunny days transpiration speeds up & causes cells to lose their water content & become flaccid.
- The flaccid cells give no support to the plant & wilting occurs so that the leaves flowers & other non-woody tissues droop.
- The gurad cells become flaccid due to wilting, stomata close & the rate of transpiration is reduced.
- The rate of photosynthesis also reduces because entry CO2 in leaf stops due to closing of stomata
The rate of transpiration
________ with every rise of 10 °C.
40-45 °C causes ________.
doubles
closure of stomata
what affects the rate of transpiration?
In _______ air, the rate of the _______ of water vapours is reduced & the rate of transpiration is _______.
More S.A of leaf provides more stomata and there is _____ transpiration .
- Higher temperature reduces the humidity of surrounding air & also increases the kinetic energy of water molecules.
- When air is dry, water vapours diffuse more quickly from the surface of mesophyll cells into leaf air spaces & then from air spaces to outside. This increases the rate of transpiration.
- Wind carries away the evaporated water from leaves as soon as it diffuses out & it causes an increase in rate of evaporation.
humid diffusion low
more
Wind (air in motion)
4
what object, what is the force called, how & what does water get transported?
xylem vessel
transpiration pull
As transpiration occurs, evaporation of water lowersthe concentration of water, creating tension. The tension created by transpiration “pulls” water in the xylem. by TACT mechanism
water & DISSOLVED MINERAL SALTS
define transpiration pull?
how is it formed in first place?
When a leaf transpires (loses water), the water concentration of its mesophyll cells drops. This drop causes water to move by osmosis from the xylem of leaf into mesophyll cells. When one water molecule moves up in the xylem of the leaf, it creates a pulling force that continues all the way to root.
This pulling force created by the transpiration of water is called transpirational pull. It also causes water to move transversely.
reasons for creation of transpirational pull.
1. Water is held in a tube (xylem) that has small diameter.
2. Water molecules adhere to the walls of xylem tube (adhesion).
3. Water molecules cohere to each other
(cohesion)
(from root epidermis to cortex and pericycle)
how does food get transported in plants?
sugar source & sink consists of? examples?
translocation & that is done by pressure flow mechanism which is a widely accepeted hypothesis.
source part of the plant where sugars are produced how is it produced?
sink part of the plant where sugars are used or stored, area of active metabolism. tubers, seeds, roots, developing fruits & leaves.
by photo. or breakdown of stored starch
explain transport of food in plant?
At source, food (sugars) is moved by active transport into the sieve tubes of phloem. Due to which their solute concentration increases & water enters them from xylem (via osmosis). This results in higher pressure of water in these tubes, which drives the solution of food towards sink.
At the sink end, food is unloaded by active transport. Water also exits from the sieve tubes. The exit of water decreases pressure in sieve tubes, which causes a mass flow from the higher pressure at the source to the now lowered pressure at the sink.
what is the actual force behind the movement of food in phloem?
The average
adult body has about ______ of blood.
what is the percentage composition of blood?
how does blood transport when it is just a fluid?
Drop in the pressure at the sink end.
5 litres
plasma = 55% by volume of blood
cells or cell-like bodies = 45% by volume of the blood. RBC = 44% WBC platelets = 1%
almost all the substances to be transported are present either dissolved or suspended in blood.
define plasma? components?
Plasma is primarily water in which proteins, salts, metabolites and wastes are dissolved. Water constitutes about 90-92% of plasma & 8-10% are dissolved substances.
Proteins make 7-9 % by weight of plasma.
pg 135
dissolved substances include proteins, mineral ions/salts, metabolites, waste, hormones & dissolved gases
in 10 % of dissolved substances proteins take up 7 to 9% of it.
what are RBCs also called function
define the structure of a single RBC?
how are RBCs formed in fetus & adults?
what is the average lifespan of RBC?
where does it break down? how?
erythrocytes
circular flattened biconcave disk & has no nucleus it has iron containing pigment hemoglobin in cytoplasm which gives red colour to the blood
RBCs are formed in bone marrow after birth
In embryonic & foetal life, they are formed in liver & spleen
Average life span of RBC is about 4 months (120 days) after which it breaks down in liver & spleen by phagocytosis.
foetal life= begins around the ninth week & lasts until birth