Life Process- NUTRITION 2


                                                TOPIC - LIFE PROCESSES
                                                           CLASS 10


Welcome back students!
LESSON 2

At the end of this lesson you will be able to:
1.     Define Photosynthesis.
2.     Write chemical equation for photosynthesis.
3.     Outline the steps of photosynthesis
4.     Draw a neat labelled diagram of cross- section of a leaf.
5.     Study the structure of stomata and draw its neat labelled diagram.

Before we begin our lesson today, let us check our yesterday’s assignment.

A1) Autotrophs are organisms that can prepare their own food with the help of inorganic sources such as carbon dioxide and water in the presence of sunlight and chlorophyll.
Examples- green plants and some bacteria.

A2) Enzymes are bio catalysts which help to speed up a reaction or process in our bodies.

A3) The food (carbohydrates) prepared are stored in the form of starch in plants and in the form of glycogen in animals.

PLEASE COPY EVERYTHING IN YOUR BIOLOGY NOTEBOOK EXCEPT THAT WHICH IS WRITTEN IN RED. KEEP YOUR NCERT WITH YOU FOR ANY REFERENCE.


DRAW THE ABOVE TABLE
WE WILL BEGIN WITH AUTOTROPHIC NUTRITION









AUTOTROPHIC NUTRITION
PHOTOSYNTHESIS
Process in which green plants trap solar energy and manufacture their food in the form of simple sugar from inorganic compounds like CO2 and water in the presence of chlorophyll.
EQUATION – COPY FROM BOOK PAGE 96

    











( DO NOT DRAW THE FIGURE)
STEPS OF PHOTOSYNTHESIS
1.       Absorption of light energy by chlorophyll.
2.        Conversion of light energy to chemical energy and splitting of water molecule.
3.        Reduction of carbon dioxide to carbohydrates.

IMP. NOTE –  the steps listed above may not take place in order.
The light energy is used to split water molecules into oxygen gas and hydrogen gas. This hydrogen is added to carbon dioxide and carbohydrate is prepared.  Read page 96. Do not read activity now. Will be discussed later.

DRAW NEAT LABELLED DIAGRAM TO SHOW CROSS SECTION OF A LEAF. ( PAGE= 96, FIG 6.1))

In the diagram, observe that the upper epidermis (outermost tissue of plants) is covered by a waxy cuticle for protection. The lower epidermis has more number of stomata. The green dots visible are chloroplasts which help in photosynthesis.

 STOMATA – tiny pores present on the surface of leaves.

Functions of stomata - 
       1)      Exchange of gases take place.
       2)      Excess of water is removed from these pores and this process is called Transpiration.
Transpiration also occurs through surface of stems and roots.

GUARD CELLS - kidney shaped cells that control the opening and closing of Stomata.
      Q)     How do the guard cells control the opening and closing of stomata?

      A)     The guard cells swell up when water flows into them, causing stomatal pore to open.
The guard cells shrink when water flows out of them, causing stomatal pore to close

DRAW FIGURE 6.3 a) and b) page 97

ASSIGNMENT-
Q1) Choose the event that does not occur in photosynthesis:  (copy all options in MCQ type questions)
     a)      Absorption of light energy by chlorophyll.
     b)      Reduction of carbon dioxide to carbohydrates.
     c)       Oxidation of carbon to carbon dioxide.
     d)       Conversion of light energy to chemical energy.

Q2) The opening and closing of stomatal pore depends upon:
        a)      Oxygen
        b)      Temperature
        c)       Water in guard cells
       d)      Concentration of carbon dioxide in stomata.

Q3) A gas is released during photosynthesis. Name the gas and also state the way by which the gas is evolved.

Q4) How do the desert plants perform photosynthesis?

THAT IS ALL FOR TODAY,  STUDENTS. WILL MEET YOU TOMORROW.
TAKE CARE!



Location: New Delhi, Delhi, India

Comments

  1. Anmol SinghMarch 24, 2020 at 9:15 AM

    ANMOL THIS SIDE .....Thank you sir I have completed the assignment

    ReplyDelete
  2. AnonymousMarch 24, 2020 at 3:35 PM

    Vidit goel
    Sir how does temperature affect the opening and closing of stomatal pore

    ReplyDelete
    Replies
    1. SCS SCIENCE ASHISHMarch 25, 2020 at 8:18 AM

      Increase in the temperature causes stomata to open. Temperature has significant effect on the permeability of the wall of the guard cells and therefore greatly affect the osmotic phenomenon which is responsible for the movement of these cells.

      Delete
    2. AnonymousMarch 25, 2020 at 6:45 PM

      Thank you sir

      Delete
  3. AnonymousMarch 24, 2020 at 4:29 PM

    Sir completed the above assignment

    ReplyDelete
  4. SCS SCIENCE ASHISHMarch 25, 2020 at 8:23 AM

    Dear All Learner,

    As you are aware of fact, we all are facing lock down situation all over the country. But our learning should stop. We all need to thrive and fight against this odd situations. You would like to answer all your queries. I am available on phone also. Just feel free to connect.

    Further, I want you all to excel in this board class. You should all complete you home task (assignments) and notes in your respective note books.

    Read each and every line of your science text book, this is very important. As by CBSE notification, any text can be framed into a questions. Go through it properly.

    Ashish

    ReplyDelete

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