Biology 12 past paper 2023

A snail was moving on a table. When the table was tapped, the snail stopped moving. When tapping was done repeatedly, the snail stopped responding to it. Identify the type of behav…

MCQ1 marksannual

Compare the mechanism of osmoregulation in marine and freshwater animals.

Part B3 marksannual

Describe stages of the Menstrual Cycle in Human Female. Also draw the diagram outline.

Part C7 marksannual

Due to lightning, a forest was set on fire and destroyed. The type of succession which will occur then is termed as:

MCQ1 marksannual

How are 'Counter Current Multiplier' mechanism and 'hormones' involved in concentrating urine?

Part B3 marksannual

Explain **Latent Learning** with example.

Part C6 marksannual

Which one is a steroid hormone?

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Write the names and functions of hormones produced by **Thyroid Gland**. Write about the problems related with abnormal secretion of hormones in different stages.

Part C7 marksannual

Enlist the cells associated with bones. Also write their respective functions.

Part B3 marksannual

Explain events of Gastrulation in Human. Also draw the diagram.

Part C6 marksannual

Differentiate between two types of Neurotransmitters. Also give one example of each.

Part B3 marksannual

Describe the mechanism of DNA Analysis using Restriction Fragment Length Polymorphism (RFLP).

Part C7 marksannual

The workers in a honey bee hive exhibit:

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Limbic system lies under cerebrum. Write down its parts and their functions.

Part B3 marksannual

How is **Carbon Dioxide** transported through blood as **Bicarbonate ions**? Explain in detail.

Part C6 marksannual

A man and a woman with blood groups A and B respectively have four children all with different blood groups of the ABO system. By a cross show genotypes of both parents and offspri…

Part B3 marksannual

Which one of the following is **NOT** a Sexually Transmitted Disease?

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$XO-XX$ is a pattern of sex determination. Explain with example.

Part B3 marksannual

The extra embryonic membrane which provides a fluid filled environment for developing fetus is:

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Write about the causes and symptoms of Phenylketonuria.

Part B3 marksannual

In pea plant, round and wrinkled seed shape is controlled by $R$ and $r$ alleles respectively. The cross which will give rise to a 1:1 ratio of both phenotypes can be:

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Baldness is more common in males than in females because it is a:

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Briefly explain any three characteristics of **Genetic Code**.

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In DNA replication, the primer:

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What is **Speciation**? Briefly explain **Sympatric Speciation**?

Part B3 marksannual

After successful implantation of blastocyst into endometrium of uterus, level of which hormone increases?

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What is **Divergent Evolution**? Explain with a suitable example.

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Normally vaccination can be done at any age for:

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How does the **Endosymbiont hypothesis** explain the evolution of Eukaryotes from Prokaryotes?

Part B3 marksannual

According to Hardy Weinberg Theorem, which one of the following factor cannot change allelic frequency?

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Populations have many characteristics. Write about any three characteristics.

Part B3 marksannual

Restriction endonucleases can be used in Genetic Engineering to:

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Enlist the sources of Chlorofluorocarbons (CFCs). How do they cause Ozone Depletion?

Part B3 marksannual

In Nitrogen cycle, conversion of Nitrates into nitrogen is termed as:

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a. What is the role of **CFTR gene** in a normal person? b. Write down symptoms of **Cystic Fibrosis**. c. Write mechanism of **Gene Therapy** used to cure Cystic Fibrosis.

Part B3 marksannual

Elaborate the role of **Microbes** in **Food Processing** by giving any three examples.

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Write about two major techniques of animal cell culture.

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What are **Acclimatization** and **Selection**? How do they help to improve crops?

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