Maharashtra Board Class 12 Biology Question Paper 2023 with Answer Key

Histones are rich in ...........

• (1) Lysine and Arginine
• (2) Serine and Leucine
• (3) Leucine and Methionine
• (4) Phenylalanine and Lysine

How many mitotic divisions take place during the formation of a female gametophyte from a functional megaspore?

• (1) One
• (2) Two
• (3) Three
• (4) Four

Which of the following is the only gaseous plant growth regulator?

• (1) ABA
• (2) Cytokinin
• (3) Ethylene
• (4) Gibberellin

The pH of nutrient medium for plant tissue culture is in the range of .............

• (1) 2 to 4.2
• (2) 5 to 5.8
• (3) 7 to 7.5
• (4) 8 to 9.5

Rivet Popper Hypothesis is an analogy to explain the significance of ..........

• (1) Biodiversity
• (2) sex-ratio
• (3) natality
• (4) age distribution ratio

Which of the following group shows ZW-ZZ type of sex determination?

• (1) Pigeon, Parrot, Sparrow
• (2) Parrot, Bat, Fowl
• (3) Bat, Fowl, Crow
• (4) Sparrow, Fowl, Cat

In Hamburger’s phenomenon,.........

• (1) Cl⁻ diffuse into WBCs
• (2) Cl⁻ diffuse into RBCs
• (3) Na⁺ diffuse into RBCs
• (4) Na⁺ diffuse into WBCs

Calcium and Phosphate ions are balanced between blood and other tissues by ............

• (1) Thymosin and Parathormone
• (2) Calcitonin and Somatostatin
• (3) Collip’s hormone and Calcitonin
• (4) Calcitonin and Thymosin

Identify the INCORRECT statement.

• (1) In a flaccid cell, T.P. is zero
• (2) In a turgid cell, DPD is zero
• (3) In a fully turgid cell, TP = OP
• (4) Water potential of pure water is negative

Which of the following is a hormone releasing contraceptive?

• (1) Cu-T
• (2) Cu-7
• (3) Multiload-375
• (4) LNG-20

Which disease is caused by HPV?

Which device is used to clean both dust and gases from polluted air?

Mention the name of sterile animal produced by intergeneric hybridisation.

Give the name of the first transgenic plant.

A child has low BMR, delayed puberty and mental retardation. Identify the disease.

Identify 'A' in the given graph of population growth:

Complete the following box with reference to symptoms of mineral deficiency:



\begin{tabular{|c|c|
\hline
Symptom & Mineral Deficiency

\hline
Pre-mature fall of flowers, fruits and leaves & Abscission

\hline
Appearance of green and non-green patches on leaves & Chlorosis

\hline
\end{tabular

Give an example of a plant having both kidney and dumb-bell shaped guard cells in stomata.

Define the terms:


a. Gross Primary Productivity

Draw a neat diagram of the thyroid gland and label thyroid follicle, follicular cells, and blood capillaries.

i. Give reason - ABA is also known as an antitranspirant.

Complete the chart showing human proteins produced by rDNA technology to treat human diseases and re-write.



\begin{tabular{|c|c|
\hline
Disorders/Diseases & Recombinant Proteins

\hline
Anemia & Erythropoietin

\hline
Asthma & Monoclonal antibodies

\hline
Emphysema & Alpha-1-antitrypsin

\hline
\end{tabular

i. Define – Imbibition

Draw a neat diagram of the conducting system of human heart and label AV node, Bundle of His, and Purkinje fibres.

Distinguish between heterochromatin and euchromatin with reference to staining property and activity.

Complete the following chart regarding energy flow in an Ecosystem and re-write:



\begin{tabular{|c|c|
\hline
? & Herbivores

\hline
Primary Producer & Grass

\hline
? & Man, Lion

\hline
Secondary Consumer & Tiger

\hline
\end{tabular

i. What is biofortification?

Differentiate between X-chromosome and Y-chromosome with reference to –


i. Length of non-homologous regions

Define the terms:


i. Genetic drift

i. What is ex-situ conservation?

i. Define – Incomplete Dominance.

i. Differentiate between sympathetic and parasympathetic nervous system with reference to the following:


a. Pre and post ganglionic nerve fibres.

i. Draw a suitable diagram of replication of eukaryotic DNA and label any three parts.

Describe the steps in breathing.

i. What is spermatogenesis?

i. What is a connecting link?

Complete the following chart regarding population interaction and re-write:



\begin{tabular{|c|c|
\hline
Sr. No. & Name of Interaction & Interaction Between

\hline
1 & Plasmodium and Man & Parasitism

2 & Leopard and Lion & Competition

3 & Clown fish and Sea-anemone & Mutualism

\hline
\end{tabular

i. What is composition of bio-gas?

i. Give reason – Water acts as thermal buffer.

Explain three main functions of free antibodies produced by B-lymphocytes.

i. Following are the diagrams of entry of pollen tube into ovule. Identify the type A and B.

i. Name the hormone which is responsible for apical dominance.

i. What is blood pressure?

i. Describe any three adaptations in anemophilous flowers.

i. What is polymerase chain reaction (PCR)?

i. Give any four significances of fertilization in human.

i. Give any two functions of cerebellum.