Biology Official 2023-2024 HSC Science (General) 12th Standard Board Exam Question Paper Solution

In monocot embryo the protective sheath of plumule is called ______.

perisperm 

scutellum 

coleorrhiza 

coleoptile

The synonymous term for centromere is ______.

primary constriction

telomere

secondary constriction

satellite

Protein digesting enzyme is ______.

polymerase 

protease 

pectinase

RNAase

Spermatids get transformed into a functional spermatozoa by the process of ______.

spermiogenesis 

spermatogenesis 

gamctogenesis 

oogenesis

Industrial melanism is one of the best example for ______.

speciation

natural selection

reproductive isolation

mutation

geographical isolation

adaptive radiation

Value of root pressure is +1 to +2 bars which is enough to pump water to a height of ______. 

50-60 meters

10-20 meters 

30-40 meters

20-30 meters

______ cellular fragments are formed from megakaryocytes.

Erythrocytes 

Leucocytes 

Thrombocytes 

Monocytes

Degeneration of dopamine producing neurons in the CNS causes ______ disease.

ADHD

Alzheimer’s

Parkinson’s

Fever

Addison's disease

Grave's disease

Choose the correct name of phases A, B and C in the given figure:

Stationary, Log, Lag 

Log, Lag, Stationary

Log, Stationary, Lag

Lag, Log, Stationary

Rivet Popper Hypothesis explains ______.

loss of biodiversity 

biomagnification

species arca relationship

significance of diversity

Write the ratio of methane, ammonia and hydrogen respectively in Urey and Miller's experiment.

What are the cells of Rauber?

Which gene is introduced in tobacco against pest like Zabrotes subfasciatus?

How many haploid nuclei are present in mature female gametophyte of Angiosperms?

Name the connection between pulmonary trunk and aortic arch representing remnant of embryonic ductus arteriosus.

Which endocrine gland plays an important, role in improving immunity?

Name the type of association:

Clownfish and sea anemone

Name the pioneer species in the aquatic habitat during primary succession.

Why DNA replication is called semi-conservative replication?

Name the scientist who experimentally proved the same.

Distinguish between Asexual and Sexual reproduction with reference to:

1. Cell division
2. Genetic makeup

Arrange the following stages of human evolution in the order of their increasing cranial capacity:

1. Homo sapiens
2. Neanderthal man
3. Australopithecus
4. Homo erectus

Identify chromosomal disorder caused due to non-disjunction of the 21^st number of chromosomes and enlist its symptoms.

What is radial translocation of food in plants?

What is tangential translocation of food in plants?

Give any ‘two’ factors responsible for genetic variation.

Identify A, B, C and D from the following table regarding respiratory system:

Give the function of the Nebenkern.

Give the function of the Zona pellucida.

Give location of corpus callosum of human brain.

Give location of arbor vitae of human brain.

Match cells of immune system in column-I and their functions in column-II and rewrite it.

Give any two examples of commercially exploited products of transgenic plants.

Write the scientific name of the causative agent of the following disease:

Typhoid

Give the symptoms of typhoid.

Write the mode of transmission of typhoid.

Suggest the specific term for the following:

Both male and female reproductive organs present in same organism.

Suggest the specific term for the following:

Y-linked gene

Suggest the specific term for the following:

Unfertilised egg develops into haploid male bee.

Explain the role of diazotrophs in nitrification.

Explain the following event of cardiac cycle with respect to type of valves and duration:

atrial systole

Explain the following event of cardiac cycle with respect to type of valves and duration:

ventricular systole

Explain the following event of cardiac cycle with respect to type of valves and duration:

Joint diastole

What is a reflex action?

Explain with one example each of the types of reflex actions based on previous experiences.

Select and fill in the blanks (a) to (f) from given list of options.

List of options -

Sickle cell anaemia, Widow's peak, Flower colour of Mirabilis, Human blood groups, Coat colour of cattle, Klinefelter's syndrome.

Give the role of the mycoherbicide Phytophthora.

Give the role of the mycoherbicide alternaria.

Explain the following term with respect to survival of an organism in a changed environment.

Regulate

Explain the following term with respect to survival of an organism in a changed environment.

Conform

Explain the following term with respect to survival of an organism in a changed environment.

Migrate

List any three major causes of loss of biodiversity.

Mention any two applications of cytokinin.

What is mycorrhiza?

Name its types of mycorrhiza.

State any three benefits of mycorrhiza.

What is leaching?

What is Humification?

Explain the mineralisation.

What is humus?

What is hematocrit?

Mention the term for Temporary increase in number of WBCs.

Mention the term for decrease in number of RBCs.

Describe mechanism of opening and closing of stomata with reference to Starch-sugar interconversion theory.

Describe mechanism of opening and closing of stomata with reference to Proton transport theory.

Define the following term:

Hormones

State properties of hormones.

Give diagrammatic representation of mode of hormone action through membrane bound receptors.

With respect to diagram, answer the following:    

1. Which type of ovule is given in the figure?   (1)
2. Name the first cell of embryo sac.   (1)
3. Identify and write the function of ‘A’ and ‘B’.   (2)

How transgenic pigs is commercially beneficial?

How transgenic cattle is commercially beneficial?

Explain the histological structure of testis.