Biology Model set 2 by shaalaa.com 2024-2025 HSC Science (General) 12th Standard Board Exam Question Paper Solution

Choose the correct alternative.

The muscular structure that separates the thoracic and abdominal cavity is _______.

Pleura

Diaphragm

Trachea

Epithelium

Which of the following requires maximum energy?

Secondary consumer

Decomposer

Primary consumer

Primary producer

The innermost layer of human eye is ______.

Choroid

Cornea

Sclero

Retina

Which of the following is the correct recognition sequence of restriction enzyme Eco RI?

S' _ _ _ A _ G ↓ _ C _ T _ _ _ 3'

3' _ _ _ T _ C _ ↑ _ G _ A _ _ _ S'

5' _ _ _ G _ _ G _ A _ T _ C _ C _ _ _ 3'

3' _ _ _ C _ C _ T _ A _ G _ _ G _ _ _ 5'

5' _ _ G _ T _ C _ ↓ _ G _  A _ C _ _ 3'

3' _ _ C _ A _ G _ ↑ _ C _ T _ G _ _ 5'

5' _ _ _ G _ ↓ _ A _  A _ T _ T _ C _ _ _ 3'

3' _ _ _ C _ T _ T _ A _ A _ ↑ _ G _ _ _ 5'

The earliest geological time period among the following is______.

Cambrian

Permian

Jurassic

Quaternary

Abscission means ______.

Yellowing of leaves

Death of tissues of leaves

Premature fall of flowers

Non-green patches on the leaves

Which statement is correct with respect to the food chain?

Every component of the food chain forms a trophic level.

Inter-relation between different food chains is known as a food web.

All the chains formed by nutritional relations are used to understand energy flow.

All of the above.

______ is the largest part of the brain.

Cerebrum

Cerebellum

Cranial nerve

Spinal nerve

medulla oblongata

The nucleic acid synthesis takes place in ______.

3' - 5' direction

5’-3’ direction

Both ways

Any direction

Genes involved in cancer are ______.

Tumour genes

Regulator genes

Oncogenes

Complementary genes

Which hormone is responsible for fruit ripening?

Give advantages of vernalization.

Name any two X-Linked recessive disorders.

Which vector is mostly used in rDNA technology in plants?

Name any two biodiversity hot spots in India.

Give statement of the law of dominance.

Define Alleles.

Name two better yielding varieties of rice developed in India.

Write short note on Gene pool.

Short answer question

Give a reason - Injury to medulla oblongata may prove fatal.

Give the economic importance of fishery.

Complete the chart:

Write two applications of Auxins.

Enlist the characteristics of genetic code.

What are X-linked genes?

Short answer question.

Write a note on IVF.

Give examples of X-linked traits.

Define ‘Ecological succession’.

Define Stratification.

Name two restriction enzymes used in PCR.

Give the main features of mutation theory.

What are transgenic animals?

Explain any four ways in which such animals can be beneficial for humans.

Write short note on Neanderthal man.

Short answer question

List the properties of the nerve fibres.

A normal visioned woman whose father is colourblind married a normal visioned man. What are the probabilities of her sons or daughters to be colourblind? Explain with the help of Punnett square.

State properties of hormones.

What is nitrification?

Name any two nitrifying bacteria in soil.

Sketch and label T. S. of Spinal cord.

Observe the given sequence of nitrogenous bases on a DNA fragments and answer the following questions:

5' - CAGAATTCTTA - 3'
3' - GTCTTAAGAAT - 5'

1. Name a restriction enzyme which can recognise this DNA sequence.
2. Write the sequence after digestion.
3. Why are the ends generated after digestion called sticky ends?

Explain the process of blood clotting.

How the resistance in crops can be developed?

What are long-day plants (LDP)? Give two examples.

Sketch and label Human Male Reproductive System.

Write briefly about the Testis.

Describe hormonal control in various phases of the menstrual cycle.

Describe structure of root hair.

Explain the formation of a typical spinal nerve with the help of a neat labelled diagram.

Draw the neat Labelled diagram of the internal structure of the human heart.

What is phosphorylation?

Describe the mechanism for absorption of water.