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Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik.

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Presentation on theme: "Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik."— Presentation transcript:

1 Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – , India

2 SBT/SBI/SGS011-CP3-04 Introduction Programmes and Courses  SEP –SBT011 -U3-CP3  SEP – SGS011-U3-CP3

3 School of Science and Technology, Online Counseling Resource… Credits  Academic Inputs by Sonali Alkari Faculty YCMOU Nagpur Centre, Faculty LAD college P.G. D of Biotechnology Research officer Ankur Seeds Pvt Ltd 3© 2008, YCMOU. All Rights Reserved.

4 School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5 School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.5 Learning Objectives After studying this module, you should be able to: Describe asexual reproduction in plants Describe sexual reproduction in plants Describe photosynthesis Discuss light reaction Describe dark reaction

6 School of Science and Technology, Online Counseling Resource… Reproduction in Plants  Plant reproduction is the process by which plants generate new individuals, or offspring.  Reproduction is either sexual or asexual.  Sexual reproduction is the formation of offspring by the fusion of gametes.  Asexual reproduction is the formation of offspring without the fusion of gametes.  Sexual reproduction results in offspring genetically different from the parents.  Asexual offspring are genetically identical except for mutation. © 2008, YCMOU. All Rights Reserved.6

7 School of Science and Technology, Online Counseling Resource… Asexual Reproduction-1  Asexual reproduction is the formation of new individuals from the cell(s) of a single parent.  It is very common in plants; less so in animals.  Asexual reproduction in flowering plants is common.  Many different seed plants utilize one of a number of different methods of this form of reproduction.  There are several reasons why seed plants may find this form of reproduction advantageous.  If the environment has been stable for many generations, variability may not be as essential to the survival of the species. © 2008, YCMOU. All Rights Reserved.7

8 School of Science and Technology, Online Counseling Resource… Asexual Reproduction-2  Asexual reproduction which is not as complex and requires far less energy, would be preferable.  When colonizing a new area, finding a mate for sexual reproduction may be difficult or impossible.  If the environment is particularly harsh, the more delicate or susceptible organs or stages of sexual reproduction may not be able to survive.  Many plants which inhabit such areas as deserts or arctic tundra only reproduce asexually. © 2008, YCMOU. All Rights Reserved.8

9 School of Science and Technology, Online Counseling Resource… Asexual Reproduction-3  Asexual reproduction in plants is also called vegetative reproduction because it simply involves the growth of parts which eventually become detached to form new plants.  Since the new parts are produced by ordinary cell division, they are direct copies of the original, with no input from another individual as in sexual reproduction.  Consequently, asexual reproduction does not introduce variation, unlike sexual reproduction (flowers and seeds). However, it follows that asexual reproduction may be seen as a means of maintaining continuity.It is also a fairly quick method of increasing numbers. © 2008, YCMOU. All Rights Reserved.9

10 School of Science and Technology, Online Counseling Resource… Types of Asexual Reproduction-1  Rhizomes: Plants such as the grasses, cattails and sedges produce underground stems or rhizomes. As these stems grow through the soil, they will periodically produce adventitious roots and a new above ground shoot. If the rhizome subsequently dies, a new separate plant will have been formed.  Tubers: Tubers are actually modified rhizomes. They are formed in such plants as Irish potatoes. They develop when specialized stem branches grow down into the ground and swell up with starch containing cells. Buds on the tubers will grow into new plants. Examine the potato tuber and note the buds which are commonly termed "eyes". © 2008, YCMOU. All Rights Reserved.10

11 School of Science and Technology, Online Counseling Resource… Examples-1 © 2008, YCMOU. All Rights Reserved.11

12 School of Science and Technology, Online Counseling Resource… Examples-2 © 2008, YCMOU. All Rights Reserved.12

13 School of Science and Technology, Online Counseling Resource… Types of Asexual Reproduction-2  Runners (Stolons):These are horizontally growing stems that produce few, if any, leaves. At the spot where a leaf would normally develop a node, these plants will produce adventitious roots down into the soil, and new above ground shoots.  Plantlets: A few seed plants such as the duckweed and Kalanchoe sp. produce miniature plants on the margin of their leaves. These drop off and develop into mature plants. The duckweed, which is an aquatic plant, reproduces almost entirely by this method. © 2008, YCMOU. All Rights Reserved.13

14 School of Science and Technology, Online Counseling Resource… Types of Asexual Reproduction-3  Bulbs :Onions, chives and lilies over-winter in the form of a bulb. Each bulb has a very short stem which is surrounded by fleshy leaves. In the spring, the shoot apex begins to grow using the nutrients stored in the leaves.  Corms: This structure is similar to bulbs except that there are no storage leaves. The nutrients are, instead, stored in the swollen stem.  Asexual reproduction can be advantageous and/or disadvatageous.  One positive aspect is that it can create individuals rapidly and in large quantities. © 2008, YCMOU. All Rights Reserved.14

15 School of Science and Technology, Online Counseling Resource… Asexual Reproduction: Importance  Secondly, bypassing the sexual process can help a plant in times of dryness since motile sperm require water to fertilize the egg.  Another advantage lies in the fact that plants with the desired characteristics can be cloned for economic reasons (agriculture).  However, if something goes wrong, such as as the occurance of a fatal mutation, the whole society of clones can be terminated.  For this reason, farmers are careful in determining how to propagate their vegetation. In conclusion, the asexual process of reproduction is an important one to plants. © 2008, YCMOU. All Rights Reserved.15

16 School of Science and Technology, Online Counseling Resource… Sexual Reproduction-1  Sexual reproduction in plants involves male and female plant organs.  The female structures invovled in sexual reproduction are the stigma, the style and the ovary.  The stigma is the sticky portion of the pistil that captures pollen.  The style is long and slender and supports the stigma.  The ovary is composed of one or more ovules and is responsible for housing the eggs.  The male structures involved in sexual reproduction are the filament and the anther. © 2008, YCMOU. All Rights Reserved.16

17 School of Science and Technology, Online Counseling Resource… Sexual Reproduction-2  The filament supports the anther which is responsible for storing and producing pollen.  Pollination is the transfer of pollen from an anther to a stigma.  Wind, water, insects, birds, and small mammals all aid in the pollination of plants.  After pollination, one nuclei of the pollen grain forms a tube down through the style to the micropyle of the ovary.  The second nuclei travels down the tube and splits into two sperm nuclei that fertilize the egg and combine with polar bodies to form the endosperm (stored fruit). © 2008, YCMOU. All Rights Reserved.17

18 School of Science and Technology, Online Counseling Resource… Sexual Reproduction-3  In higher plants, offspring are packaged in a protective seed, which can be long lived and candisperse the offspring some distance from the parents.  In flowering plants, the seed itself is contained inside a fruit, which may protect the developing seeds and aid in their dispersal. © 2008, YCMOU. All Rights Reserved.18

19 School of Science and Technology, Online Counseling Resource… Sexual Reproduction-4 © 2008, YCMOU. All Rights Reserved.19

20 School of Science and Technology, Online Counseling Resource… Photosynthesis-1  Photosynthesis is the process by which plants use the energy of light to produce carbohydrates and molecular oxygen (O 2 ) from carbon dioxide (CO 2 )and water: 6CO 2 + 6H 2 O * sunlight * C 6 H 12 O 6 + 6O 2  Virtually all ecosystems on Earth depend on photosynthesis as their source of energy, and all free oxygen on the planet, including that in the atmosphere, originates from photosynthesis.  The overall reaction is the reverse of respiration. which releases energy by oxidizing carbohydrates to produce CO 2 and water. © 2008, YCMOU. All Rights Reserved.20

21 School of Science and Technology, Online Counseling Resource… Photosynthesis-2  Photosynthesis and respiration are linked ecologically, being the cellular metabolic processes that drive the carbon and oxygen cycles.  Photosynthesis occurs in plants, photosynthetic protist (algae), and some bacteria.  In plants and algae, it takes place within chloroplasts, whereas in bacteria it occurs on the plasma membrane and in the cytosol. © 2008, YCMOU. All Rights Reserved.21

22 School of Science and Technology, Online Counseling Resource… Photosynthesis-3  Photosynthesis is divided into two sets of reactions: the light-dependent (light) reactions and the light-independent (dark) reactions.  As their names imply, the first set depends directly on light, whereas the second set does not.  Nevertheless, even the dark reactions will cease if the plants are deprived of light for too long because they rely on the products of the light reactions. © 2008, YCMOU. All Rights Reserved.22

23 School of Science and Technology, Online Counseling Resource… Light Reactions of Photosynthesis-1  The first reaction in photosynthesis which takes place in presence of light and involves two reactions, photophosphorylation and photolysis of water.  Chlorophyll absorb energy; this energy is transferred and then used in an electron transfer chain.  Photophosphorylation is a process by which light energy is transformed into chemical energy.  It is also called as hill reaction or photchemical reaction. © 2008, YCMOU. All Rights Reserved.23

24 School of Science and Technology, Online Counseling Resource… Light Reactions of Photosynthesis-2 © 2008, YCMOU. All Rights Reserved.24

25 School of Science and Technology, Online Counseling Resource… Chloroplasts convert light energy into chemical energy  High-energy electrons in chloroplasts are transported through two photosystems.  During this transit, which culminates in the generation of reducing power, ATP is synthesized in a manner analogous to mitochondrial ATP synthesis.  Electrons in chloroplasts are energized by light. © 2008, YCMOU. All Rights Reserved.25

26 School of Science and Technology, Online Counseling Resource… Photosynthesis-4  The light reactions, which convert the energy in light into chemical energy, take place within the thylakoid membranes of the chloroplasts,  Whereas the dark reactions, which use that chemical energy to fix CO2 into organic molecules, take place in the stroma of the chloroplast.  In the light reactions, the energy of light is used to “split water,” stripping a pair of electrons from it (and causing the two hydrogens to be lost), thus generating molecular oxygen. © 2008, YCMOU. All Rights Reserved.26

27 School of Science and Technology, Online Counseling Resource… Photosynthesis-5  The energy in light is transferred to these electrons, and is then used to generate adenosine triphosphate (ATP) and the electron carrier NADPH.  These two products carry the energy and electrons generated in the light reactions to the stroma, where they are used by the dark reactions to synthesize sugars from CO2.  These electrons are used to produce NADPH as well as ATP in a series of reactions called the light reactions because they require light. NADPH and ATP formed by the action of light then reduce carbon dioxide and convert it into phosphoglycerate by a series of reactions called the Calvin cycle or the dark reactions. © 2008, YCMOU. All Rights Reserved.27

28 School of Science and Technology, Online Counseling Resource… Photosynthetic Phosphorylation  Two separate and alternate pathways of electron transfer away from cholrophyll molecule exist.  These are cyclic and non-cyclic photophosphorylation.  In non cyclic photophosphorylation the electron released by the cholorophyll molecule does not return to it, water splits into hydrogen ions, oxygen and ATP and NADPH are produced.  Cyclic photophosphorylation comprises the return of the electron finally to the cholrophyll molecule,only ATP is produced, no spliiting of water and no evolution of oxygen occurs. © 2008, YCMOU. All Rights Reserved.28

29 School of Science and Technology, Online Counseling Resource… Calvin Cycle-1  Melvin Calvin worked out the reactions by which CO 2 and hydrogen produced carbohydrates.  Calvin received the Nobal Prize for this work.  The dark reaction of carbohydrate synthesis occurs in a cyclic sequence of carboxylation, reduction, hexoses formation and regeneration.  The three major products of photosynthesis are starch, sucrose and amino acids. Starch is synthesized in cholroplast whereas sucrose are formed in cytoplasm and amino acid synthesis can takes place in most of the cell compartments. © 2008, YCMOU. All Rights Reserved.29

30 School of Science and Technology, Online Counseling Resource… Calvin Cycle-2 © 2008, YCMOU. All Rights Reserved.30

31 School of Science and Technology, Online Counseling Resource… What You Learn… You have learnt that… Plants reproduce by sexual as well asexual reproduction. Sexual reproduction is the formation of offspring by the fusion of gametes. Asexual reproduction is the formation of offspring without the fusion of gametes. Photosynthesis is the process by which plants use the energy of light to produce carbohydrates and molecular oxygen (O 2 ) from carbon dioxide (CO 2 )and water. Photosynthesis is divided into two sets of reactions: the light-dependent (light) reactions and the light- independent (dark) reactions. 31© 2008, YCMOU. All Rights Reserved.

32 School of Science and Technology, Online Counseling Resource… Critical Thinking Questions 1.Describe in details asexual reproduction in plants. 2.Describe in details sexual reproduction in plants. 3.Describe light reaction of photosynthesis. 4.Write short note on dark reaction of photosynthesis. © 2008, YCMOU. All Rights Reserved.32

33 School of Science and Technology, Online Counseling Resource… Hints For Critical Thinking Question 1.Describe different modes of asexual reproduction and significance. 2.Describe different modes of sexual reproduction and significance. 3.Chemical reaction and outcome of light reaction. 4.Chemical reaction and outcome of dark reaction. © 2008, YCMOU. All Rights Reserved.33

34 School of Science and Technology, Online Counseling Resource… Study Tips  Book1 Title:The Living World Author: George Johnson  Book2 Title: ABC Of Biology Publisher: Holy Faith  Book3 Title: Biological Science Author: Taylor, Green & Stout 34© 2008, YCMOU. All Rights Reserved.

35 School of Science and Technology, Online Counseling Resource… Study Tips Microsoft Encarta Encyclopedia Wikipedia the free encyclopedia 35© 2008, YCMOU. All Rights Reserved.

36 School of Science and Technology, Online Counseling Resource… End of the Presentation Thank You 36© 2008, YCMOU. All Rights Reserved.


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