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Describe how water and ion uptake occurs in plants?
. Introduction: In addition to anchoring the plant, roots perform two other vital functions. (i) Absorbs water and salts from the soil. (ii) Secondly, they provide conducting tissues for distributing these substances to the tissues of the stem. 2. Internal Structure of Root (i) Conducting Tissues Conducting tissues (xylem and phloem) of root are grouped in the center to form a rod shaped core, which extends throughout the length of the root. (ii) Pericycle Outside the conducting tissues, there is a narrow layer of thin walled cells, the pericycle. (iii) Endothermic and Cortex A single layer of cells, endothermic surrounds the pericycle layer. External to this, there is a broad zone of cortex which consists of large and thin walled cells. (iv) Epidermis The cortex is bounded on the outside by a single layer of epidermal cells. (v) Root Hairs Roots also have cluster of tiny root hairs, which are actually the extensions of epidermal cells. Functions of Root Hair: (i) Large Surface Area for Absorption Root hairs provide large surface area for absorption. They grow out into the spaces between soil particles where they are in direct contact with the water. (ii) Absorption and Transport of Water The cytoplasm of the root hairs has higher concentration of salts than the soil water, so water moves by osmosis into the root hairs. Salts also enter root hairs by diffusion or active transport. After their entry into the root hairs, water and salts travel through inter cellular spaces or through cells (via channels, called piasmodesrnata and reach xylem tissues. Once in xylem, water and salts are carried to all the aerial parts of plant.
What is transpiration. Describe transpiration and factors affecting rate of transpiration.
How transport of food in plants takes place?
Transport of Food. Phloem is responsible for transporting food substance throughout the plant. Phloem is a two way street for food. In most plants, the food is transported in the form of sucrose. Importance of Food The glucose formed during photosynthesis in mesophyll cells is used in respiration and excess of it is converted into sucrose. Pressure-Flow mechanism In pressure-flow mechanism, the food is moved from sources to sinks. Sources: The sources include the exporting organs typically a mature leaf or storage organ. A storage organ is capable of storing food and exporting the stored materials. Sinks: Sinks are the areas of active metabolism or storage e.g., roots, tubers, developing fruits and leaves, and the growing regions.. Similarly, root of beet is a sink in first growing season, but becomes source in the next growing season, when sugars are utilized in the growth of new shoots. Explanation of Pressure-Flow mechanism At the source, the food (sugar) is moved by active transport into the sieve tubes of phloem. Due to the presence of sugar in sieve tubes, their solute concentration increases and water enters from xylem via osmosis. This results in higher pressure in these tubes, which drives the solution towards sink. At the sink end, the food is unloaded by active transport. Water also exits from the sieve tubes. This decreases the pressure in sieve tubes, which causes a mass flow from the higher pressure at the source to the now lowered pressure at the sink.
Explain different disorders of blood.
Blood Disorder: There are many types of blood disorders including. (I) bleeding disorders. (Hemophilia) (ii) Leukemia (blood cancer) (iii) Thalassemia (Cooley's Anemia) i. Leukaemia (Blood Cancer) Leukaemia is the production of great number of immature and abnormal white blood cells. Cause of leukaemia: It is caused by a cancerous mutation in bone marrow or lymph tissue cells- and result in uncontrolled production of WBCs. Treatment: (i) During this serious disorder, patients need to change the blood regularly with the normal blood, got from donar. (ii) The second method is bone marrow transplant, which is in most cases effective, but very expensive treatment. ii. Thalassaemia (Cooley's anemia) It is also called Cooley's anaemia on the name of Thomas B. Cooley, an American Physician. It is a genetic problem due to mutation in the gene of haemoglobin. Patient cannot transport oxygen properly. Cause of Thalassemia: The mutation results in the production of defective haemoglobin. Treatment: (i) Blood of patients is to be replaced regularly with normal blood. (ii) It can be cured by bone marrow transplantation but it does not give 100% cure rate.
What are factor affecting the rate of transpiration.
Wind carries away the evaporated water from leaves and it causes an increase in the rate of evaporation from the surfaces of mesphyll
The rate of transpiration is directly controlled by the opening and closing of stomataand it is under the influence of light
Higher temperature reduces the humidity of surrounding air and also increases the kinetic energy of water molecules. In this way it increases
rate of transpiration.
Leaf surface area
The rate of transpiration also depends upon the surface area of
leaf. More surface area provides more stomataand there is more transpiration.
Write a shortnote Blood plasma.?
Plasma is primarily water in which proteins, salts,
metabolitiesand wasters are dissolved. Water constitutes about 90-92% of plasma, 9-10% are dissolved substance salts make up 0.9% of plasma by wheightproteins make 7-9 % by weight of plasma. Plsmaalso contains digested food, nitrogenuos wastes and hormones,
gases i.e CO2 and O2 are present in the plasma
How transport of water in plantstakes place
The process by which water is raised to considerable heights in plants has been studied for years in botany, The result of this research is "Cohesion Tension" theory. When a leaf transpires, the water concentration of its
mesophyllcells drops . This drop cause water to move by osmosis from the xylem of leaf into mesophylldiameter. Water molecules adhere to the walls of xylem tube .It cohere to each other.
Write a note A.B.O blood system.
It is the most important blood systems in human. It was discovered by
Austrain karlLandsteiner, In this system, there are four blood groups
Blood Group A
In persons which blood group A, is present and antigen B is absent. So their blood serum will contain anti-B antibodies.
Blood Group B
In persons which blood group B
,antigen B is present and antigen A is absent.
Blood Group AB
are present i.e. neither is absent.
Blood Group O
Antigens A nor antigen B is
present i.e both are absent
Where red blood cells are formed in human? Describe their structure and function.?
In 1930 the R-h blood group system. In this system, there are two blood group r
,e Rh+ and RH-, These blood groups are distinct from each other on the basis of antigens called Rh factors present on the surface of RBC. A person having Rh factors has blood group Rh-positive while a person not having Rh factors has blood group Rh- negative - Unlike the naturally occurringanti A and anti - B antibodies of the Also- system, an Rh- veperson does not produce anti-Rh antibodies unless Rh-factors enters in his/her blood.
What four chambers make the human heart and how blood flows through these chambers.
The heart is
muscularorgan responsible for pumping blood through the blood vessels by repeated contractions. Heart is enclosed in a sac known as pericardium . Pericardial Fluid: Artia:
There is a fluid, known as
pericardial fluid, between pericardium and heart walls. It reduces friction between pericardium and heart, during heart contractions
Human heart consist of four
chamber like the heart of mammals and birds
The upper thin-walled chambers are called left and right atria (singular Catrium)
The lower thick walled chambers are called left and right ventricles
.Left ventricles is the largest and strongest chamber in heart