just water usage? - I also wondered this but obtained the investigation
elsewhere so don’ t know. I thought perhaps the plant does not put onthat much mass compared to the mass of the water so it becomes insignificant
Dicotyledonous stem
Leaves develop from the nodes.
The sections of stem between the nodes are called internodes.
An axillary bud is often found at the node. These forms lateral branches.
A terminal bud is found at the tip of the stem and allows the stem to increase
in length.
Internal structure of the dicotyledonous stem
This diagram of a cross section shows the internal structure of a young dicot
stem
A waterproof cuticle is found on the outside of the epidermis to prevent water
loss.
The epidermis consists of a single layer of cells to protect the underlying
tissue.
The cortex is made up of parenchyma cells that stores water and food.
The vascular bundles are arranged in a ring in the medulla and are surrounded by
non-living sclerenchyma cells for strengthening and support.
Each vascular bundle contains the following:
Cambium (contains meristematic cells that divide to widen the stem)
Phloem (transports food from leaves to the roots)
Xylem (transports water from the roots to the stem)
This is a link to an online tutorial about phloem, xylem and pressure flow.
Movement of water up the stem
Water moves up the xylem from the roots to the leaves.
Adaptations of xylem for transporting water:
Long, elongated tubes joined end-to-end without any cross-walls, forming good
conducting tubes.
The cell walls are thickened with lignin for support (annual or spiral
thickening) so that they do not collapse due to the upward pull of water
Pitted vessels and tracheids allow for lateral movement of water into
neighbouring xylem vessels.
Cells are dead, so there is no obstruction to water transport
Diagram of xylem
Three forces are responsible for the movement of water up the xylem –
capillarity, root pressure and transpiration suction force.
Capillarity involves forces of cohesion (forces of attraction between water
molecules) and adhesion (forces of attraction between water molecules and thesides of the xylem vessels). Because the xylem’s lumen (opening) is so
tiny, water will move up by capillary. However, this force is weak and its rolein moving water up the stem is small.
Root pressure is a force that pushes water up the xylem. As water enters the
root by osmosis, it pushes the water that is already in the xylem of the stemupwards.
Transpiration suction force is a very important force that pulls water up the
xylem of the stem. As water evaporates from the stomata of the leaves duringtranspiration, it creates a sucking force that will pull the water up the
xylem.
Investigation: plant tissue anatomy (root and stem)
Aim: To examine the structure of the root and stem
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Microbiology is the scientific study of microorganisms
Ibra
the microorganisms in a particular environment (including the body or a part of the body).
Ibra
describe the bacterial cell
Akello
The biggest populations of microbes reside in the gut.other popular habitats include the skin genitals.The microbial cells and their genetic material ,the microbiome ,live with human from birth .
Zahreen
can agriculture be integrated into biology
David
Got questions? Join the online conversation and get instant answers!