Std. 12th Perfect Biology - 1 Notes, Science (MH Board)

CONTENT SAMPLE

Written as per the revised syllabus prescribed by the Maharashtra State Board of Secondary and Higher Secondary Education, Pune.

NT Perfect Biology ? I E STD.XII Sci. NT Salient Features O ? Exhaustive coverage of syllabus in Question Answer Format.

? Covers answers to all Textual Questions.

C ? Covers answers to all Board Questions till date.

? Includes solved Board Questions from 2013 to 2018. ? Covers relevant NCERT Questions.

E ? Includes Board Question Papers of 2017 and 2018.

? Quick Review, Exercise, Multiple Choice Questions and Topic test at the end of

L each chapter for effective preparation.

? Important inclusions: NCERT Corner, Apply Your Knowledge.

MP Printed at: Repro India Ltd., Mumbai A? Target Publications Pvt. Ltd.

No part of this book may be reproduced or transmitted in any form or by any means, C.D. ROM/Audio Video Cassettes or electronic, mechanical

Sincluding photocopying; recording or by any information storage and retrieval system without permission in writing from the Publisher. P.O. No. 141406

TEID: 12961_JUP

Preface

In the case of good books, the point is not how many of them you can get through, but rather how many can get through to you.

"Std. XII Sci. : PERFECT BIOLOGY - I" is a treasure house of knowledge that'd not only prepare you to face the conspicuous Std. XII final exam but also equip you up on parallel ground to face the prospective NEET exam.

T This book is specifically aimed at Maharashtra Board students. The content of the book is framed in accordance

with Maharashtra State board syllabus splattered with additional snippets of information from the NCERT syllabus. This lethal combination of apt material from both the syllabus makes it the ultimate reference material for Std. XII.

N This book has been developed on certain key features as detailed below:

Sub-topic wise classified Question and Answer format of the book provides students with appropriate

E answers for all textual questions. We've also included additional questions to ensure complete coverage of

every concept.

T Solutions to Board Questions along with marking scheme (wherever relevant) have been included.

NCERT Corner and Notes cover additional bits of relevant information on each topic.

Apply Your Knowledge covers brain-storming questions to stengthen the students' conceptual

N understanding.

Quick Review section facilitates instant revision at a glance.

O Exercise helps the students to gain insight on the various levels of theory questions.

Multiple Choice Questions and Topic Test assess the students on their range of preparation and the

C amount of knowledge of each topic.

The journey to create a complete book is strewn with triumphs, failures and near misses. If you think we've nearly missed something or want to applaud us for our triumphs, we'd love to hear from you.

Please write to us at : mail@

E A book affects eternity; one can never tell where its influence stops. PBesLt of luck to all the aspirants! Yours faithfully,

Publisher

M Edition: Second

Disclaimer

AThis reference book is transformative work based on textual contents published by Bureau of Textbook. We the publishers are making this reference book which constitutes as fair

use of textual contents which are transformed by adding and elaborating, with a view to simplify the same to enable the students to understand, memorize and reproduce the same

Sin examinations.

This work is purely inspired upon the course work as prescribed by the Maharashtra State Board of Secondary and Higher Secondary Education, Pune. Every care has been taken in the publication of this reference book by the Authors while creating the contents. The Authors and the Publishers shall not be responsible for any loss or damages caused to any person on account of errors or omissions which might have crept in or disagreement of any third party on the point of view expressed in the reference book.

? reserved with the Publisher for all the contents created by our Authors.

No copyright is claimed in the textual contents which are presented as part of fair dealing with a view to provide best supplementary study material for the benefit of students.

PAPER PATTERN

There will be one single paper of 70 Marks in Biology.

Duration of the paper will be 3 hours.

Section A:

(8 Marks)

This section will contain Multiple Choice Questions and Very Short Answer(VSA) type of questions.

T There will be 4 MCQs and 4 VSA type of questions, each carrying one mark.

Students will have to attempt all these questions.

N Section B:

(20 Marks)

This section will contain 10 Short Answer (SA-I) type of questions, each carrying 2 marks.

E Internal choice is provided for only one question.

Section C:

(27 Marks)

T This section will contain 9 Short Answer (SA-II) type of questions, each carrying 3 marks.

Internal choice is provided for only one question.

N Section D:

(15 Marks)

This section will contain 3 Long Answer (LA) type of questions, each carrying 5 marks.

Internal choice is provided for each question.

CO Distribution of Marks According to the Type of Questions

E MCQ

VSA

L SA - I

SA - II

SAMP LA

Type of Questions

1 Mark each 1 Mark each 2 Marks each 3 Marks each 5 Marks each

4 Marks 4 Marks 20 Marks 27 Marks 15 Marks

Contents

Sr. No.

Chapter

Marks

Page No.

1 2 3 4 5 6 7 8 9

Genetic Basis of Inheritance

Gene: Its Nature, Expression and Regulation

T Biotechnology: Process and Application

Enhancement in Food Production

N Microbes in Human Welfare

Photosynthesis

E Respiration T Reproduction in Plants

Organisms and Environment - I

N Board Question Paper - March 2017

Board Question Paper - July 2017

O Board Question Paper - March 2018 C Board Question Paper - July 2018

05

1

04

32

03

67

03

89

03

105

05

124

05

156

04

181

03

218

241

243

245

247

Note: All Textual questions are represented by * mark.

SAMPLE NCERT Questions are represented by # mark.

04 Enhancement in Food Production

Syllabus T 4.0 Introduction

4.1 Plant Breeding

4.2 Tissue Culture 4.3 Single Cell Protein

N 4.0 Introduction E Note T i. Plant breeding technology has helped in bringing about green revolution in India to fulfill the

national requirement of food production. ii. Plant breeding methods involve use of genetics, molecular biology and tissue culture techniques for

N developing plants with desired traits. O 4.1 Plant Breeding

*Q.1. What is plant breeding? Describe various steps involved in classical breeding of plants.

C Ans: Plant breeding: Plant breeding is an applied branch of Botany which involves collective use of art and

science for changing and improving the heredity of plants in order to create desired types. The main steps in breeding a new genetic variety of a crop are: i. Collection of variability.

ii. Evaluation and selection of parents.

E iii. Cross hybridisation among the selected parents.

iv. Selection and selfing of superior recombinants.

L v. Testing, release and commercialization of new cultivars. i. Collection of variability: Variations are the differences seen among individuals of a species or population, for a P particular character. They are inheritable and useful in selection. Collection and preservation of all the different wild varieties, species and relatives of cultivated species is done for the exploitation of natural genes available in the population. All such collected genes are effectively exploited for the plant breeding programmes. MThe germplasm collection is the entire collection of plants and seeds having all the diverse alleles for all genes in a particular crop. ii. Evaluation and selection of parents: A The germplasm is evaluated for identifying plants with desirable combination of characters. Such identified plants are selected and then used in the process of hybridization. Purelines are created whenever desirable and possible.

S iii. Cross hybridization among the selected parents:

Hybridization is the crossing of two plants differing from each other genotypically in one or

more characters or traits.

Useful characters are usually scattered in different races, varieties, etc. It is possible to combine

all the characters in a single variety, through hybridization.

89

Std. XII Sci.: Perfect Biology - I

Its main objectives are:

a. To produce a single variety having a combination of good characters.

b. To exploit and utilize the hybrid vigour.

c. To increase and generate genetic variations through recombination.

iv. Selection and selfing of superior recombinants:

This step involves selection of only those plants from the progeny of hybrids, that have the desired combinations of characters.

The plants which are superior to both the parents and exhibit hybrid vigour are collected.

T These plants are self-pollinated for a number of generations till they become homozygous for

the trait.

Due to this, plants attain a state of uniformity and characters do not segregate in the progeny.

N Such plants are called pure lines.

v. Testing, release and commercialization of new cultivars:

The newly developed variety undergoes critical evaluation for yield, quality, resistance to

E diseases and insect pests, etc. before it is released for cultivation.

In India, such evaluations are carried out by the Indian Council of Agricultural Research (ICAR), New Delhi.

T The varieties developed by different breeders are evaluated together at several locations in

different agroclimatic zones of the country.

The performance of the new varieties is compared with that of the existing varieties and also

N with one another.

The variety that is superior is chosen for release under a new name with the permission of the Government.

O *Q.2. Give the objectives of plant breeding.

Ans: Objectives/Need of plant breeding:

C i. To develop desired plants that are better suited for cultivation, give better yield and are disease resistant.

ii. To develop plants with improved quality.

iii. To produce plants that have increased tolerance limits to environmental stresses like drought, salinity and extreme temperatures

iv. To develop plants which are resistant to pathogens and pests.

E Q.3. What is domestication?

Ans: Domestication is the process of bringing a species under human management. All our major food crops

L represent domesticated varieties.

Q.4. Explain the steps involved in hybridization.

Ans: Hybridization involves the following steps:

P i. Selection and isolation of parents:

Here, two healthy plants with desirable characters are selected.

The parent plants are grown separately on isolated plots to avoid cross pollination. Self pollination is

Mcarried out in both the parents to produce purelines.

Self pollination is done for 6-8 generations till the majority of plants become homozygous and true

breeding.

AThe last generation of both the parents are used for further steps of hybridization.

ii. Emasculation: It is the removal of stamens from one of the parents (if bisexual) before they release

their pollen grains. It is done by the following methods:

S a. Forceps method

b. Hot water or alcohol method

Importance of emasculation: It prevents self-pollination.

iii. Bagging: Soon after emasculation, the flowers are covered by butter paper or polythene bags to

prevent cross-pollination by undesired pollen grains. The bags are tied at the base of the flower or

inflorescence.

90

Chapter 04: Enhancement in Food Production

iv. Collection of pollen grains: At maturity, pollens from other non-emasculated selected parent plants

are collected in dry bags.

v. Crossing: Fresh pollens are used for crossing. In wheat and oats, the pollen viability is only of few

minutes. When the stigma of emasculated flower matures, the polythene bag is removed and stigma is

dusted with pollen grains. It is advisable to perform crossing early in the morning as in most of the

crops, stigma becomes receptive at different times in the morning.

vi. Tagging: A tag with relevant information is attached to the plants. The tag carries information like:

a. date of emasculation

b. field record number

T c. date of pollination and crossing

d. details of male and female parents

Q.5. With the help of suitable diagram, define `bagging' and `tagging' of flower.

[Oct 13]

Ans: i. Bagging:

N During hybridization, emasculated flowers are covered with butter paper or polythene bag of suitable

size to prevent pollination by pollen grains of unwanted source. This is known as bagging. [? mark]

ii. Tagging:

E After dusting the pollen grains on the stigma of the emasculated flower, it is rebagged and a tag with

relevant information such as date of emasculation, date of pollination, details of male and female

T parents, etc. is attached with plants. This is known as tagging.

[? mark]

Polythene bag

CON Tag

Bagging and Tagging

E[Correct diagram and labels (Tag, polythene bag) 1 mark]

Q.6. Draw neat labelled diagrams of emasculation of flowers by: (i) Hot water method (ii) Forceps method.

L Ans: P Forcep

SAM Stamen

(i) Hot Water Method

Flower bud

Bud opened

Emasculation

(ii) Forceps Method

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