CBSE > Class 12 > Biology | CBSE Board | Homework Help

Back cross is the cross of F1 generation hybrid with the one of its parents . Whereas test cross is a type of backcross in which the F1 generation dominant hybrid is crossed with homozygous recessive parent, in order to find that the dominant F1 individual is homozygous or heterozygous.

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Shivam Chaurasia 6 years, 7 months ago

Test cross is type of back cross in which offspring crossing with recessive parents.

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ANSWER

Amoeba reproduce both by binary fisson and muliple fission .how?

Posted by Priya Priya 6 years, 7 months ago

CBSE > Class 12 > Biology

1 answers

? Natasha Yadav? 6 years, 7 months ago

Under unsuitable climatic conditions , the amoeba cannot reproduce by binary fission, thus the multiple fission occurs. Is there need to explain what is multiple fission??

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ANSWER

Why we use these terms allelic genes , genes or alleles , gene and its alleles

Posted by Tannu Madaan 6 years, 7 months ago

CBSE > Class 12 > Biology

3 answers

? Natasha Yadav? 6 years, 7 months ago

Genes that code for characters( generally in pair) can be called alleles, but gene alone is anything that express information to next generation .

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Tannu Madaan 6 years, 7 months ago

How

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Shivam Chaurasia 6 years, 7 months ago

Gene is hereditary unit and in case of allels gene will contain two contrasting characters whichare not similar.

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ANSWER

Can we call gene "allele"

Posted by Tannu Madaan 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Shivam Chaurasia 6 years, 7 months ago

No, because gene with coding for contrasting characters are allels and gp. Of gene altogether is called genome.

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? Natasha Yadav? 6 years, 7 months ago

Gene and alleles are often used interchangeably , genes are units of inheritance . They contain information that is required to express a particular trait in an organism. Genes which code for a pair of contrasting traits are known as alleles. They are slightly different forms of the same gene.

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ANSWER

Why algae and fungi shift to sexual reproduction in adverse conditions

Posted by Tannu Madaan 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Tannu Madaan 6 years, 7 months ago

Can we add concept of variations here

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Shivam Chaurasia 6 years, 7 months ago

Because spore formtion take place at optimum condition.

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ANSWER

Hi kalraj test hai kya kal

Posted by Abhishek Pal 6 years, 7 months ago

CBSE > Class 12 > Biology

3 answers

Vinod Honda 6 years, 7 months ago

Bhai kaisa hai

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Abhishek Pal 6 years, 7 months ago

Good be practicing

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Vinod Honda 6 years, 7 months ago

Ha bhai physics ka hai kal

1Thank You

ANSWER

Different between inheritance and heredity

Posted by Amir Suhail 6 years, 7 months ago

CBSE > Class 12 > Biology

1 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

The study of heredity in biology is called genetics, which includes the field of epigenetics. Inheritance is the practice of passing on property, titles, debts, rights and obligations upon the death of an individual. ... The difference between inheritance and heredity is in interpreting the genetic traits or characters.

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ANSWER

waht is genetics

Posted by Lakshmane Gowda 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

the scientific study of the way that the development of living things is controlled by qualities that have been passed on from parents to children

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? Natasha Yadav? 6 years, 7 months ago

Genetics is the branch of biology which deals with the inheritance, variation of characters from parents to offspring.

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ANSWER

Out of active and passive smoking which is more dangerous and why

Posted by Devansh Gumber 6 years, 7 months ago

CBSE > Class 12 > Biology

0 answers

ANSWER

What is is sexual mode of reproduction

Posted by Kashish Aryan 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

Sexual reproduction is the process in which new organisms are created, by combining the genetic information from two individuals of different sexes. ... Sexual reproduction differs from asexual reproduction, which only requires one parent.

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Aastha Saxena 6 years, 7 months ago

The biological reproduction which involves two parents to produce a offspring identical or may be not identical to their parents..is called the sexual mode of reproduction

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ANSWER

What is IVF?

Posted by Parmar Manoj 6 years, 7 months ago

CBSE > Class 12 > Biology

3 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

In vitro fertilisation is a process of fertilisation where an egg is combined with sperm outside the body, in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from the woman's ovaries and letting sperm fertilise them in a liquid in a laboratory.

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? Natasha Yadav? 6 years, 7 months ago

IVF is In vitro fertilization-- fertilization outside the body( in laboratory) in almost similar conditions as that in the body and if followed by embryo transfer . The fertilized zygote with 8 blastomeres is transferred in fallopion tube( ZIFT) . More than 8 blastomeres is transferred in uterus(IUT).

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Manish Tanwar 6 years, 7 months ago

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ANSWER

Name bisexual and unisexual animals

Posted by Kashish Aryan 6 years, 7 months ago

CBSE > Class 12 > Biology

1 answers

Shivalika Sharma 6 years, 7 months ago

Bisexual animals- earthworm,tapeworm..... Unisexual animals- cow, dogs,etc

2Thank You

ANSWER

Why all the experiments are performed on E.coli ?????????

Posted by Tanvi Toor 6 years, 7 months ago

CBSE > Class 12 > Biology

5 answers

Tanvi Toor 6 years, 7 months ago

Thnks @Niharika

2Thank You

? Natasha Yadav? 6 years, 7 months ago

You could have searched on Google.

1Thank You

? Natasha Yadav? 6 years, 7 months ago

E.coli is single celled organism so it has a rapid growth rate and is very easy to culture in laboratory . E.coli genetics are well studied and can be manipulated easily.

1Thank You

Tanvi Toor 6 years, 7 months ago

Clear nhi hua tbhi to yha pucha h!!! @Nilavazhagan ???

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Nilavazhagan Nilavazhagan 6 years, 7 months ago

Read your ncert book clearly...

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ANSWER

What are the symptoms of Haimophelia?

Posted by Tanvi Toor 6 years, 7 months ago

CBSE > Class 12 > Biology

6 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

Requires a medical diagnosis Symptoms include many large or deep bruises, joint pain and swelling, unexplained bleeding and blood in urine or stool. People may experience: Pain areas: in the joints Also common: bleeding, blood in stool, blood in urine, bruising, heavy or prolonged periods, internal bleeding, nosebleed, or swollen joint

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Tanvi Toor 6 years, 7 months ago

Thnks @Aastha ?

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Aastha Saxena 6 years, 7 months ago

The main symptom is if an affected individual got a simple cut , it starts non stop bleeding

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? Natasha Yadav? 6 years, 7 months ago

Most welcome.

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Tanvi Toor 6 years, 7 months ago

Thnks @Niharika

1Thank You

? Natasha Yadav? 6 years, 7 months ago

Haemophilia is a Mendelian disorder in which the clotting of blood is affected. An affected individual , if got a simple cut it will result in non stop bleeding .

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ANSWER

What is thalassemia

Posted by Naveen Singh 6 years, 7 months ago

CBSE > Class 12 > Biology

5 answers

Aastha Saxena 6 years, 7 months ago

Thalassemia is the mendelian autosome linked disorder in which the alteration in alpha and beta chains of haemoglobin occurs that results in abnormal haemoglobin molecules that further leads to anemia

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? Natasha Yadav? 6 years, 7 months ago

And in new books on page no. 91.

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Tanvi Toor 6 years, 7 months ago

Complete explanation is given in NCERT on page no. 289

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Yogita Ingle 6 years, 7 months ago

Thalassemia is an inherited blood disorder wherein the body produces an improper form of haemoglobin. Haemoglobin is a protein molecule that carries oxygen in the red blood cells. This disorder results in the extreme destruction of red blood cells that lead to anaemia. Anaemia is a condition in which the haemoglobin or red blood cells are less than the normal count.

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? Natasha Yadav? 6 years, 7 months ago

Thalassemia description is well explained in NCERT so please refer to it.

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ANSWER

How do i prepare chapter-6 molecular basis of inheritance? Not able to understand what should I prepare in this chapter nd what not ?? plzzz suggest!!!

Posted by Tanvi Toor 6 years, 7 months ago

CBSE > Class 12 > Biology

5 answers

Tanvi Toor 6 years, 7 months ago

@Shivam .... Nyc idea i will definitely try this.... Nd yes thnk u so much ☺

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Shivam Chaurasia 6 years, 7 months ago

First of all after reading ncert watch mechanisms animation which could give you better concept about that topics.

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Divya Deep Srivastava 6 years, 7 months ago

Wlcm

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Tanvi Toor 6 years, 7 months ago

Thnk u so much ☺

1Thank You

Divya Deep Srivastava 6 years, 7 months ago

Main topics are- First of all learn all the characteristics of dna,its length. Then,the main expts organised to prove dna as genetic material,mainly transformation priciple. Then,requirqd characteristics of genetic material. Trancription process and the enzyme that catalyses it,then,tRNA which is important to understand translation and genetic code. Then,translation and enzymes catalysing it. Lac operon and objectives of HGP. Then main points of DNA fingerprinting. If you do not remember in one time then leave it for some time and after some time read it.Do not take stress on not understanding this ch.

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ANSWER

Structure of deoxyribonucleoside triphoshate

Posted by Riyanshi Trivedi 6 years, 7 months ago

CBSE > Class 12 > Biology

1 answers

? Natasha Yadav? 6 years, 7 months ago

Sorry can't able to give.

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ANSWER

What is the difference between biennial plant and annual plant

Posted by Zahid Mas 6 years, 7 months ago

CBSE > Class 12 > Biology

1 answers

Sia ? 6 years, 7 months ago

<th scope="col">Annual Plants</th> <th scope="col">Biennial Plants</th>

These plants complete their life cycle over one year.	These plants complete their life cycle in two years.
The vegetative and reproductive phases get completed within a year.	Flowering occurs during the second year, after a year of vegetative growth.
They are usually of low maintenance as they are grown over less period of time.	These plants are usually of comparatively high maintenance type as they grow over a longer time period.
E.g. Cereals, Legumes, marigold, etc.	E.g. Shrubs, poppy, foxglove, etc.

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ANSWER

Difference Between gene and allele .

Posted by ꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 7 months ago

CBSE > Class 12 > Biology

7 answers

K@Łp@N@ $Øđh!?? 6 years, 7 months ago

Alleles are also genetic sequences, and they too code for the transmission of traits. ... The short answer is that an allele is a variant form of a gene. Explained in greater detail, each gene resides at a specific locus (location on a chromosome) in two copies, one copy of the gene inherited from each parent.

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Aastha Saxena 6 years, 7 months ago

A gene is the unit of inheritance..and alleles are the contrasting pair of genes

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 7 months ago

Online nahi aa rahi thi , isliye puccha.

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Srishti Choudhary ✍⏳ 6 years, 7 months ago

What happened ??

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 7 months ago

Kaha ho tum...??

1Thank You

Amol Gùpta 6 years, 7 months ago

Alleles are also genetic sequences, and they too code for the transmission of traits. ... The short answer is that an allele is a variant form of a gene

1Thank You

Srishti Choudhary ✍⏳ 6 years, 7 months ago

Gene - part of DNA that determine a specific trait...a pair of alleles is called gene or factor... Allele- various forms of gene having same position on chromosomes....also called alleleomorphs...

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ANSWER

What is ZIFT.?

Posted by Mohd. Bilal 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Tanvi Toor 6 years, 7 months ago

Zygote intra fallopian transfer

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Aastha Saxena 6 years, 7 months ago

It is zygote intra fallopian transfer.A method in which the zygote or early embryos with upto 8 blastomeres are transferred into the fallopian tube

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ANSWER

Every organism that takes birth and dies after completing of its life spem.this phenomenon cannot be seen in the organism belonging to

Posted by Munesh Singh 6 years, 7 months ago

CBSE > Class 12 > Biology

3 answers

Munesh Singh 6 years, 7 months ago

Amoeiba is the answer

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Gurmanjeet Khera 6 years, 7 months ago

Unicellular organisms produced by Asexual repdroduction does not show this phenomenon.as they didnt die their one parent splits into 2 or more daughter ones so nothing is left behind for dying.so they are immortal

1Thank You

Sugandha Tiwari 6 years, 7 months ago

May be the answer is life span

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ANSWER

Function of tapetum

Posted by Jaat Sahil 6 years, 7 months ago

CBSE > Class 12 > Biology

4 answers

Krupa Kannan 6 years, 7 months ago

Tapetum is the innermost layer that surrounds the pollen sac. Functions : It hepls in formation of callase enzyme. Helps in degenration of callose wall. Plays a role in formation of exine layer. It nourishes the pollen mother cell and pollen grains. Helps in pollen kitt formation that is made of lipids and carotenoids.

2Thank You

Yogita Ingle 6 years, 7 months ago

Tapetum is the innermost layer of Microsporangium which has dense Cytoplasm.
Functions

i) It release Ubisch bodies.
ii) It provides nutrition to developing Pollen grain.
iii) It release callase enzyme.

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Aastha Saxena 6 years, 7 months ago

The inner wall layer of microsporangium is called tapetum.it nourishes the developing pollen grains.

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Ďãřşháñăã Yadav ? ? ? 6 years, 7 months ago

tepetum nourishes developing pollen grain.

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ANSWER

What is emasculation ?

Posted by Ramvir Singh 6 years, 7 months ago

CBSE > Class 12 > Biology

5 answers

? Natasha Yadav? 6 years, 7 months ago

Removal anthers before pollination

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Krupa Kannan 6 years, 7 months ago

The process of removal of stamen from a bisexual flower before the maturation of pollen grains in order to avoid self pollination in these flowers.

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Gaurav Anand 6 years, 7 months ago

The removal of anther in bisexual flowers is called emasculation.

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K@Łp@N@ $Øđh!?? 6 years, 7 months ago

Anther are removed from the bisexual flowers using forceps. This is emasculation and is done before the anther dehisces.

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Tanvi Toor 6 years, 7 months ago

Anther of bisexual flowering plants are cutted so that they cannot pollinate itself

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ANSWER

Important diagram kon se chapter me se aayege

Posted by Subhanjali Verma 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Tanvi Toor 6 years, 7 months ago

Sbhi chapters k diagrams imp. H

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Shivam Chaurasia 6 years, 7 months ago

2 ,3,5,6

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ANSWER

Major differences between inheritance and heredity.

Posted by Shivam Chaurasia 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Avinash Singh 6 years, 7 months ago

Aur inheritance ko hi heridity bhi khate hin.....also known as biological inheritance

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Avinash Singh 6 years, 7 months ago

The character which transfer from one generation to next generation known as inheritance

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ANSWER

Why does dna shows negative change

Posted by Gursharn Kaur 6 years, 7 months ago

CBSE > Class 12 > Biology

4 answers

Aastha Saxena 6 years, 7 months ago

Because it has phosphate charge

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K@Łp@N@ $Øđh!?? 6 years, 7 months ago

DNA has an overall negative charge. Phosphate groups in the DNA backbone carry negatively-charged oxygen molecules giving the phosphate-sugar backbone of DNA an overall negative charge. 5. ... The negatively charged DNA can be pulled toward the positive field of the gel.

1Thank You

Shivam Chaurasia 6 years, 7 months ago

Because protein shows high positive charge. In order to packaging high order of electrostatic force will be needed in order to package higly lengrh dna within nucleus of order 10^-10 m.

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Gursharn Kaur 6 years, 7 months ago

Charge

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ANSWER

What is the importance of apomixes

Posted by Rajesh Singh Rathore 6 years, 7 months ago

CBSE > Class 12 > Biology

2 answers

Yogita Ingle 6 years, 7 months ago

Apomixis is the mechanism of seed production without involving the process of meiosis and syngamy. It plays an important role in hybrid seed production. The method of producing hybrid seeds by cultivation is very expensive for farmers. Also, by sowing hybrid seeds, it is difficult to maintain hybrid characters as characters segregate during meiosis. Apomixis prevents the loss of specific characters in the hybrid. Also, it is a cost-effective method for producing seeds.

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Divya Deep Srivastava 6 years, 7 months ago

It helps in faster production of seeds & is easily available to farmers at low cost.

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ANSWER

Imp diagram in human reproduction

Posted by Md Zubair Khan 6 years, 7 months ago

CBSE > Class 12 > Biology