TS Inter 2nd Year Botany Notes Unit 1 Plants Physiology

Here students can locate TS Inter 2nd Year Botany Notes Unit 1 Plants Physiology to prepare for their exam.

TS Inter 2nd Year Botany Notes Unit 1 Plants Physiology

→ Transport over longer distances through the vascular system is called translocation.

→ The movement of molecules from high concentration to lower concentration till it reaches equilibrium is called diffusion.

→ Membrane proteins help the movement of molecules across the membrane by diffusion is called facilitated diffusion.

→ Porins are proteins that form huge pores in the outer membrane of the plastids, mitochondria and some bacteria; allowing molecules upto the size of small proteins to pass through.

→ Water potential is a relative term, which refers to the chemical potential of pure water to that of chemical potential of a solution.

→ Water potential of pure water is zero.

→ Solute potential (Ψs) and pressure potential (Ψp) are the two main components that determine water potential

→ Osmosis is the term used to refer the diffusion of water across semi-permeable membrane.

→ The shrinkage of protoplast of cell due to loss of water and turgor is called plasmolysis.

→ The absorption of water by seeds and dry wood is done by imbibition.

→ Water, minerals and food cannot be moved within the body of a plant by diffusion alone therefore, they are transported by a mass flow system.

TS Inter 2nd Year Botany Notes Chapter 1 Plants Physiology

→ The movement of substance in bulk from one point to another as a result of pressure differences between the two points is called mass flow or pressure flow.

→ Water absorbed by root hairs moves deeper into the root by two distinct pathways. They are:

  • Apoplast
  • Symplast

→ Transpiration pull is the most acceptable factor to explain the transport of water or Ascent of sap.

→ Loss of water from the aerial pqrts of the plant body in the form of vapour is called transpiration.

→ Removal of excess, water through the tips of leaves of plant is done by guttation.

→ Phloem is responsible for transport of food (primary sucrose) from the source to the sink.

→ The translocation in phloem is bidirectional as source-sink relationship is variable due to seasonal changes. . .

→ The translocation in phloem is explained by the pressure-flow hypothesis.

→ Plants obtain their inorganic nutrients from air, water and soil

→ The technique of growing plants in a specified nutrient solution is known as hydroponics.

→ Not all the mineral elements that they absorb are required by plants.

→ Based upon the criteria for essentiality few elements have been found to be absolutely essential for plant growth and metabolism.

→ The elements required in large quantities are called macronutrients while the elements required in less quantities or in trace are termed as micronutrients.

→ Deficiency of essential elements may lead to symptoms called deficiency symptoms.

→ Plants absorb elements through roots by either passive or active processes.

→ Mineral salts are translocated through thexylem along with the ascending stream of water, which is pulled up through the plant by transpiration pull

→ Nitrogen is the essential mineral element required in the largest quantity by plants.

→ Plants cannot use atmospheric nitrogen directly.

→ Leguminous plants and some non-leguminous plants (alnus) can fix atmospheric nitrogen into the soil in the form of nitrates with the help of Rhizobium and Frankia bacteria.

→ The pink colour in the root nodules is due to the presence of leguminous haemoglobin or leg-haemoglobin.

→ The enzyme nitrogenase plays very important role in biological N2 fixation and it is very sensitive to oxygen.

→ Enzymes are biological catalysts. All enzymes are proteins.

TS Inter 2nd Year Botany Notes Chapter 1 Plants Physiology

→ Enzymes through their active site, catalyse reactions at a high rate.

→ Inorganic catalysts work efficiently at high temperature whereas enzymes get damaged at high temperatures.

→ Catalysed reactions proceeds at rates vastly higher than that of uncatalysed ones.

→ A multistep chemical reaction, when each of the steps is catalysed by the same enzyme complex or different enzymes it is called metabolic pathway.

→ In our skeletal muscle, under anaerobic condition lactic acid is formed Under normal aerobic conditions, pyruvic acid is formed

→ Enzymes i.e., proteins with three dimensional structures including an active site, convert a substrate (S) into a product (P).

→ The difference between average energy content of S and transition state is called activation energy.

→ The activity of enzyme is affected by different factors.

→ Ribozymes are nucleic acids with catalytic power.

→ Enzymes exhibit substrate specificity, require optimum temperature and pH for maximum activity.

→ Enzymes are divided into six classes.

→ Each enzyme can be identified by 4 numbers that denote – major class, sub-class, sub – subclass and its serial number.

→ Green plants are autotrophs. They form their food by means of a process Photosynthesis.

→ Photosynthesis is a Physico-chemical process by which they use light energy to drive the synthesis of carbohydrates.

→ Photosynthesis takes place in the green leaves of the plant due to presence ofchloroplast

→ Chlorophyll pigments are chlorophyll a, chlorophyll b, xanthophylls and carotenoids.

→ Graph showing light absorption by photosynthetic pigment as a function ofwavelength of light is Absorption spectrum.

→ Graph showing rate of photosynthesis as a function of wavelength is Action spectrum.

→ Photosynthesis includes two phases viz., light reaction and dark reaction.

→ Light phase occurs in grana ofchloroplast. In light phase NADPH and ATP are generated.

→ There are two types of photosystems PS I & PS II.

→ PS I has a 700 nm absorbing chlorophyll a P 700 molecule at its reaction centre.

→ PS II has a P 680 reaction centre that absorbs red light at 680 nm.

→ After absorbing light electron get exited and transferred through PS II and PS I and finally to NAD forming NADH.

→ The break down of proton gradient due to movement through the part of the ATPase enzyme releases enough energy for synthesis of ATP.

TS Inter 2nd Year Botany Notes Chapter 1 Plants Physiology

→ Splitting of water molecules is associated with PS II resulting in the release of O2 protons and transfer of electrons to PS II.

→ Dark phase occurs in the stroma of chloroplast During dark phase, CO2 is reduced to carbohydrates by utilising ATP and NADPH produced in light phase.

→ Based on the first stable compound produced during CO2 reduction, two pathways are identified They are Calvin cycle and Hatch – Slack pathway.

→ Calvin cycle includes 3 phases viz carboxylation, reduction and regeneration. The first stable compound is PGA which is 3 carbon compound Hence Calvin cycle is also called C3 cycle.

→ Hatch-Slack pathway operates in two photosynthetic cells – Mesophyll and bundle sheath cells. In this the first stable compound is OAA which is 4 carbon compound Hence this pathway is also called C4 cycle.

→ In C3 plants, RuBisCO also catalysed a wasteful oxygenation reaction called photorespiration.

→ The breaking of the C-C bonds of the complex compounds through oxidation within the cells leading to release of considerable amount of energy is called respiration.

→ The compounds that are oxidised during respiration are known as respiratory substrates.

→ A cellular process in which glucose is broken down into two molecules of pyruvic acid is termed as glycolysis. It occurs in cytoplasm.

→ The fate of the pyruvate depends on the availability of oxygen and the organism.

→ Under anaerobic condition, either lactic acid fermentation or alcohol fermentation occurs.

→ Fermentation occurs in many prokaryotes, unicellular eukaryotes and in germinating seeds.

→ Aerobic respiration occurs in the presence of oxygen.

→ In aerobic respiration, pyruvic acid is transported into the mitochondria where it is converted into acetyl CoA with the release of CO2

→ Acetyl CoA then enters the tricarboxylic acid pathway or Krebs cycle in the matrix of mitochondria.

→ In Krebs cycle NADH + H+ and FADH3 are formed

→ After Krebs cycle, Electron transport system occurs in on the inner membrane of mitochondria.

→ As the electrons are moved through the electron transport system, energy released that are trapped to synthesis ATP.

→ This synthesis of ATP is called oxidative phosphorylation as O2 is the ultimate electron acceptor in this process and it gets reduced to water.

→ The respiratory pathway is involved both anabolism and catabolism. So it is termed as amphibolic pathway.

→ In aerobic respiration 2 ATP molecules are formed Respiratory quotient is defined as the ratio of CO2 evolved to O2 taken during respiration.

→ RQ indicates the kind of substate undergoing oxidation in the respiration

→ Growth is regarded as one of the most fundamental and conspicuous characteristics of a living being.

→ Growth is an irreversible permanent increase in size of an organ on its parts or even of an individual cells.

→ Growth conspicuously involves increase protoplasmic material

→ In plants, meristems are the sites of growth.

→ Root and Shoot meristems sometimes along with intercalary meristem, contribute to the growth of plant axes.

TS Inter 2nd Year Botany Notes Chapter 1 Plants Physiology

→ Growth is indeterminate in higher plants.

→ The growth could be arithmetic or geometrical

→ There are three phases of growth – the lag, the log and the senescent phase.

→ When a cell loses the capacity to divide, it leads to differentiation.

→ Differentiation results in development of structure that is commensurate with the function of the cells finally have to perform.

→ General principles of differentiation for cells, tissues and organs are similar.

→ A differentiated cell may be dedifferentiate and then redifferentiate.

→ Since differentiation in plants is open, the development could also be flexible i.e., the development is the sum of growth and differentiation.

→ Plant exhibit plasticity in development

→ Plant growth and development are under the control of both intrinsic and extrinsic factors.

→ Intrinsic factors are the chemical substances called plant growth regulators (PGR) whereas the extrinsic factors are light, temperature, nutrition, gravity, oxygen etc.

→ PGRbelong to five groups. They are auxins, gibberellins, cytokinins, abscisicacid, andethylene.

→ The influence of the relative duration of day and night on the flowering response of plants is called photoperiodism.

→ According to critical day length, plants are grouped into three

  • Short day plants
  • Long day plants
  • Day – neutral plants.

→ The method ofinducing early flowering in plants by pretreatment at low temperature is called vernalization.

TS Inter 2nd Year Botany Notes Chapter 1 Plants Physiology

→ JAGADISH CHANDRA BOSE: Jagadish Chandra Bose in Royal Institution, London

  • Born: 30 November 1858 Bikrampur, Bengal Presidency, British India
  • Died: 23 November 1937 (age 79) Giridih, Bengal Presidency, British India
  • Residence: Kolkata, Bengal Presidency, British India
  • Nationality: British Indian
  • Field: Physics, Biophysics, Biology, Botany, Archaeology, Bengali Literature, Bengali Science Fiction
  • Institution:
    • University of Calcutta
    • University of Cambridge
    • University of London
  • Alma mater: St. Xavier’s College, Calcutta University of Cambridge
  • Academic advisors John Strutt (Rayleigh)
  • Notable students: Satyendra Nath Bose, Meghnad Saha
  • Known for:
    • Millimetre waves Radio
    • Crescograph Plant soence
  • Notable awards:
    • Companion of the Order of the Indian
    • Empire (CIE) (1903)
    • Companion of the Order of the Star of India (CSI) (1911)
    • Knight Bachelor (1917)

→ Acharya Sir Jagadish Chandra Bose:
He pioneered the investigation of radio and microwave optics, made very significant contributions to plant science, and laid the foundations of experimental science in the Indian subcontinent. IEEE named him one of the fathers of radio science. He is also considered as the father of Bengali science fiction. He also invented the crescograph. He used his own invention, the crescograph, to measure plant response to various stimuli, and thereby scientifically proved parallelism between animal and plant tissues. Bose’s demonstration of an apparent power of feeling in plants, exemplified by the quivering of injured plants. His books include Response in the Living and Non-Living (1902) and The Nervous Mechanism. He explained various bio-electrical responses shown by plants through his pulsating theory. He was the first Indian to become a fellow of Royal Society.

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