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Define asexual reproduction?

Posted by Mohd Sadeeq 7 years, 1 month ago

CBSE > Class 12 > Biology

0 answers

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Define air pollution

Posted by Mohd Sadeeq 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Yogita Ingle 7 years, 1 month ago

Air pollution is defined as the introduction of pollutants, organic molecules, or other unsafe materials into Earth’s atmosphere. This can be in the form of excessive gases like carbon dioxide and other vapours that cannot be effectively removed through natural cycles, such as the carbon cycle or the nitrogen cycle.

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DNA is always double standard

Posted by Yuvraj Singh 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Navya Singh 7 years, 1 month ago

Yups

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Statement of replication given by watson and crik (simple defination)

Posted by Mandeep Goswami 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Meghna Thapar 5 years, 8 months ago

A model of DNA structure in which the molecule is a cross-linked double-stranded helix, each strand is composed of alternating links of phosphate and deoxyribose, and the strands are cross-linked by pairs of purine and pyrimidine bases projecting inward from the deoxyribose sugars and joined by hydrogen bonds with adenine paired with thymine and with cytosine paired with guanine. Crick and Watson used their findings in their own research. In April 1953, they published the news of their discovery, a molecular structure of DNA based on all its known features - the double helix. Their model served to explain how DNA replicates and how hereditary information is coded on it.

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RNA has double stranded or not

Posted by Lakshay Bedi 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

Yuvraj Singh 7 years, 1 month ago

RNA Mag be Double standard

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Gaurav Seth 7 years, 1 month ago

DNA is double helix and RNA is single helix because of their functions inside the cell.

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where does cleavage occurs in uterus or fallopian tubes and morula stage in uterusor fallopian tubes piz tell me i am tottaly confused in this concept

Posted by ▪▪Amrit▪▪ ❤ 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

▪▪Amrit▪▪ ❤ 7 years ago

thanks but i am new in 12th so hadn't bought ncert . just listen to biomenter online lectures thank u vry mch

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Sinchana Malagond 7 years, 1 month ago

Cleavage occurs in fallopian tube but the formation of morula stage occurs in uterus kindly see ncert textbook diagram.

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What is tRNA and how it known as adapter

Posted by Shahnaz Seraj 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Bhanu Pratap Singh 7 years, 1 month ago

It is transfer RNA that brings uniqe base for each unique codon

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Mitochondriya

Posted by Ãshú Shãrmâ 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Rohit Sahani☺️ 7 years, 1 month ago

Known as power house of the cell

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Name the term used for metamorphosis of spermatids?

Posted by Ambuj Mishra?? 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

N Aaditya 7 years ago

Spermatogenesis.

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Moet

Posted by Mini Joshi 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

Kalas Sahu 7 years, 1 month ago

Multiple ovulation embryo transfer technology

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Hema Bisht 7 years, 1 month ago

MOET - Multiple Ovulated Embryo Transfer

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Siberian birds migrate reason for this

Posted by Som Dutt 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Shriya Gautam 7 years, 1 month ago

They migrate for survival and go to an hospitable condition where they can survive.

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Why is the length of food chain is an ecosystem generally limited to 3-4 trophic level explain with example

Posted by Som Dutt 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Sinchana Malagond 7 years, 1 month ago

Its limited since 10 percent of energy is transferred from one tropic level to the other as we have already learnt in class 10. Ex can be given that if more tropic levels are present then the energy transfer take in such a way that no further animal get enough energy to dissipation of heat and other vital activities. So, further it doesn't support more than 3 to 4 tropic level since energy produced by producers is small.

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Give reason siberian birds migrate

Posted by Som Dutt 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Sunil Yadav 7 years, 1 month ago

Because there is no suitable temperature and environment is present

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Definition of ammensalism

Posted by Som Dutt 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

Isha Ahuja 7 years, 1 month ago

For eg.....pencillium and other antibiotics

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Isha Ahuja 7 years, 1 month ago

It is a type of interaction in which one speices lose and the other one neither benfits nor lose

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Cut pieces of bryophyllum leaves when put into wet soil produce new plats, How ?

Posted by Rehan Khan 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Aakriti Choudhary 7 years, 1 month ago

Because in bryophyllum the new plant grows from the adventious root or reproduce from the vegetative part ie from leaves. Eg eyes of potatoes

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An simple trek for learning the lac operon concept.

Posted by Ashu Rathore 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

Barathi Babu 7 years, 1 month ago

Lac operon consists of one regulatory gene (i ) and three structural genes (y,z and a). Gene i code for the repressor of the lac operon. The z gene code for beta-galactosidase, that is responsible for hydrolysis of disaccharide, lactose into monomeric units, galactose and glucose. Gene y code for permease, which increases permeability of the cell. Gene a encode for transacetylase.

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Rishabh Gupta 7 years, 1 month ago

Read ncert ch 6

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Explain in detail about chicken gunia disease?

Posted by Pranjul Malik 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Papa . 7 years, 1 month ago

Chickungunya Causative Agent: Chikungunya Virus Vector: Aedes aegypti (Mosquito) Medication and Prevention: Protection from infectiouos Mosquito. No specific traetment known but symptoms can be controlled by medications. Symptoms: Fever upto 104 F Severe Joint pain Muscle pain Headache Nausea Fatigue Rash If it is written u would get full marks.. All the best

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What is the difference between thalassemla and sickled cell diseases

Posted by Sneha Bhosale 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Aakriti Choudhary 7 years, 1 month ago

In sickle cell anemia the RBC get sickle shaped in which hemoglobin does not able to transport the oxygen to the tissue of the body Whereas, In thalassemia the faulty protein synthesis occur due to which the oxygen is not carried out

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Explain process of embryogenesis

Posted by Sakshika Roy 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Aakriti Choudhary 7 years, 1 month ago

It is the process of development of embryo

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What is meiotic and mitotic cell devision ?

Posted by Shivani Yadav 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Amaan Khan 7 years, 1 month ago

From one diploid(2n) cell to 4 haploid(n) cells is called meiotic division or reduction division. Form one diploid(2n) cell to two diploid(2n) cells called mitotic division.

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Explain biomagnification?

Posted by Ritu Barman 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Yogita Ingle 7 years, 1 month ago

Biomagnification is the increase in concentration of the persistant toxicant at successive trophic levels. It happens because a toxic substance accumulated by an organism cannot be metabolised or excreted and is thus passed onto the next higher trophic level.

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How to get marks above 90% in 30 day's in biology?How to study?

Posted by Rajveer Ranawat 7 years, 1 month ago

CBSE > Class 12 > Biology

2 answers

Silent Punk 7 years, 1 month ago

If you want to score more!!!! Start from today!!! Plan your time table, stick on it All the best !!!

2Thank You

Vishali Raina 7 years, 1 month ago

Focus on ncert and cbse previous years question ppr

3Thank You

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What is Ti plasmid?

Posted by Anjali Sharma 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Aakriti Choudhary 7 years, 1 month ago

Ti plasmid is a tumor causing plasmid. But is widely used for transfer of genetic material in plants like golden wheat

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Biomagnification and it's effect

Posted by Ashish Kumar 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Sunil Yadav 7 years, 1 month ago

Increase in toxic substance from one organism to next

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Process of spermatogenesis

Posted by Aniket Gaonkar 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Aakriti Choudhary 7 years, 1 month ago

The process of development of spermatozoa

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What are the important topics

Posted by Jitendraaseri Aseri 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Rohit Sahani☺️ 7 years, 1 month ago

Alll

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Why the distance between two polynucleotide chains in DNA remains almost constant ?

Posted by Hassanain Akram 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Meghna Thapar 5 years, 8 months ago

The bases in two strands of DNA are paired through hydrogen bond (H-bonds) forming base pairs (bp). Adenine forms two hydrogen bonds with Thymine from opposite strand and vice-versa. Similarly, Guanine is bonded with Cytosine with three H-bonds. As a result of these bonds, the distance between two polynucleotide chains in DNA remains almost constant.

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If E. Coli was allowed to grow for 80 minutes then what would be the proportions of light and hybrid densities DNA molecule

Posted by Ritik Rai 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Gaurav Seth 7 years, 1 month ago

E coli bacteria divides in every 20 min so in 80 min it will be four generations.
N15 isotope is present in the environment than shifted in N14 environment, so it will result in the presence of N15 and N14 strands in DNA.
In the second generation, half will have the previous hybrid bacteria and half will have the light bacteria.
In the third generation, hybrid generation will again cut half, this time 25% hybrid and 75% light
In fourth generation, 16 copies will be hybrid and 14 will be light

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Can you recall what centrifugal force is anything why a molecule with higher mass/ density would sediment faster ?

Posted by Ritik Rai 7 years, 1 month ago

CBSE > Class 12 > Biology

1 answers

Gaurav Seth 7 years, 1 month ago

Centrifugal force or fictitious force is the force that appears to act on the object as seen in a rotating reference frame and directed away from the axis of rotation. It does not exists when measurements are made in an inertial frame of reference.

Higher mass means that there will be higher gravitational force acting on it. The momentum is the product of mass and velocity of the particles so this means mass and velocity are inversely proportional to each other as the momentum distribution is constant. This means in higher mass, velocity will be less in centrifuge process. so higher mass particles comes to rest soon than lighter particles.

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Examples of seasonal breeders and continuous breeders?

Posted by Silent Punk 7 years, 1 month ago

CBSE > Class 12 > Biology